From ae06e04cd225d2c2147ca355e2dd39b4f6cf6775 Mon Sep 17 00:00:00 2001 From: Scott Rifenbark Date: Mon, 29 Jan 2018 15:18:03 -0800 Subject: documentation: Created new "Getting Started" manual. Creation involved removing the overview-manual and replacing it with the getting-started manual. All links to the string "&YOCTO_DOCS_OVERVIEW_URL" had to be replaced with "&YOCTO_DOCS_GS_URL" across the entire YP manual set. I renamed files used to create the manual with prefixes suited for the new manual name, which is "Getting Started With Yocto Project". The style sheet for the new manual needed updating to display the new .PNG image for the title page. The mega-manual file had to be updated to include the files. The mega-manual.sed file had to be updated to include the new manual and not use the overview manual. (From yocto-docs rev: 6c7abf9192390121000f577d6c98f259d290d15d) Signed-off-by: Scott Rifenbark Signed-off-by: Richard Purdie --- documentation/Makefile | 10 +- documentation/bsp-guide/bsp.xml | 6 +- .../dev-manual/dev-manual-common-tasks.xml | 30 +- documentation/dev-manual/dev-manual-newbie.xml | 10 +- documentation/dev-manual/dev-manual-start.xml | 12 +- .../eclipse/getting-started-toc.xml | 86 + .../automatically-added-runtime-dependencies.html | 164 + .../html/getting-started/basic-commands.html | 176 + .../getting-started/bitbake-dev-environment.html | 31 + .../eclipse/html/getting-started/bsp-layer.html | 54 + ...figuration-and-compilation-dev-environment.html | 93 + .../cross-development-toolchain-generation.html | 241 ++ .../html/getting-started/development-concepts.html | 66 + .../eclipse/html/getting-started/distro-layer.html | 60 + .../html/getting-started/enable-building.html | 37 + .../enable-installation-in-an-image.html | 27 + 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+ .../html/getting-started/running-weston.html | 53 + .../eclipse/html/getting-started/scms.html | 42 + .../html/getting-started/sdk-dev-environment.html | 150 + .../sdk-generation-dev-environment.html | 72 + .../setscene-tasks-and-shared-state.html | 122 + .../html/getting-started/shared-state-cache.html | 93 + .../eclipse/html/getting-started/shared-state.html | 268 ++ .../html/getting-started/software-layer.html | 27 + .../source-fetching-dev-environment.html | 93 + .../html/getting-started/source-mirrors.html | 37 + .../getting-started/sources-dev-environment.html | 80 + .../stamp-files-and-the-rerunning-of-tasks.html | 83 + .../html/getting-started/tips-and-tricks.html | 22 + .../getting-started/upstream-project-releases.html | 25 + .../html/getting-started/user-configuration.html | 232 ++ ...oky-LIC_FILES_CHKSUM-explanation-of-syntax.html | 76 + .../usingpoky-components-bitbake.html | 82 + .../usingpoky-components-classes.html | 30 + .../usingpoky-components-configuration.html | 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documentation/ref-manual/ref-structure.xml | 6 +- .../ref-manual/ref-system-requirements.xml | 2 +- documentation/ref-manual/ref-tasks.xml | 34 +- documentation/ref-manual/ref-terms.xml | 4 +- documentation/ref-manual/ref-variables.xml | 50 +- documentation/ref-manual/resources.xml | 2 +- documentation/sdk-manual/sdk-appendix-obtain.xml | 2 +- documentation/sdk-manual/sdk-extensible.xml | 2 +- documentation/tools/mega-manual.sed | 4 +- documentation/yocto-project-qs/qs.xml | 8 +- 174 files changed, 16204 insertions(+), 6182 deletions(-) create mode 100644 documentation/getting-started/eclipse/getting-started-toc.xml create mode 100644 documentation/getting-started/eclipse/html/getting-started/automatically-added-runtime-dependencies.html create mode 100644 documentation/getting-started/eclipse/html/getting-started/basic-commands.html create mode 100644 documentation/getting-started/eclipse/html/getting-started/bitbake-dev-environment.html create mode 100644 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documentation/overview-manual/overview-style.css (limited to 'documentation') diff --git a/documentation/Makefile b/documentation/Makefile index 5e166a2ba0..6f8e0d491b 100644 --- a/documentation/Makefile +++ b/documentation/Makefile @@ -84,10 +84,10 @@ # for the 'denzil' branch. # -ifeq ($(DOC),overview-manual) +ifeq ($(DOC),getting-started) XSLTOPTS = --xinclude ALLPREQ = html eclipse tarball -TARFILES = overview-style.css overview-manual.html figures/overview-title.png \ +TARFILES = getting-started-style.css getting-started.html figures/getting-started-title.png \ figures/git-workflow.png figures/source-repos.png figures/index-downloads.png \ figures/yp-download.png figures/yocto-environment-ref.png figures/user-configuration.png \ figures/layer-input.png figures/source-input.png figures/package-feeds.png \ @@ -268,7 +268,7 @@ TARFILES = mega-manual.html mega-style.css \ figures/sdk-devtool-add-flow.png figures/sdk-installed-extensible-sdk-directory.png \ figures/sdk-devtool-modify-flow.png figures/sdk-eclipse-dev-flow.png \ figures/sdk-devtool-upgrade-flow.png figures/bitbake-build-flow.png figures/ypqs-title.png \ - figures/overview-title.png + figures/getting-started-title.png endif MANUALS = $(DOC)/$(DOC).html @@ -417,11 +417,11 @@ eclipse: eclipse-generate eclipse-resolve-links .PHONY : eclipse-generate eclipse-resolve-links eclipse-generate: -ifeq ($(filter $(DOC), overview-manual sdk-manual bsp-guide dev-manual kernel-dev profile-manual ref-manual yocto-project-qs),) +ifeq ($(filter $(DOC), getting-started sdk-manual bsp-guide dev-manual kernel-dev profile-manual ref-manual yocto-project-qs),) @echo " " @echo "ERROR: You can only create eclipse documentation" @echo " of the following documentation parts:" - @echo " - overview-manual" + @echo " - getting-started" @echo " - sdk-manual" @echo " - bsp-guide" @echo " - dev-manual" diff --git a/documentation/bsp-guide/bsp.xml b/documentation/bsp-guide/bsp.xml index 7d3345e06a..b52366adf4 100644 --- a/documentation/bsp-guide/bsp.xml +++ b/documentation/bsp-guide/bsp.xml @@ -55,7 +55,7 @@ To help understand the BSP layer concept, consider the BSPs that the Yocto Project supports and provides with each release. You can see the layers in the - Yocto Project Source Repositories + Yocto Project Source Repositories through a web interface at . If you go to that interface, you will find near the bottom of the list @@ -1415,7 +1415,7 @@ Thus, the build system can build the corresponding recipe and include the component in the image. See the - "Enabling Commercially Licensed Recipes" + "Enabling Commercially Licensed Recipes" section in the Yocto Project Overview Manual for details on how to use these variables. If you build as you normally would, without @@ -1486,7 +1486,7 @@ Designed to have a command interface somewhat like - Git, each + Git, each tool is structured as a set of sub-commands under a top-level command. The top-level command (yocto-bsp diff --git a/documentation/dev-manual/dev-manual-common-tasks.xml b/documentation/dev-manual/dev-manual-common-tasks.xml index 0c2101fde9..8b97c715d7 100644 --- a/documentation/dev-manual/dev-manual-common-tasks.xml +++ b/documentation/dev-manual/dev-manual-common-tasks.xml @@ -1507,7 +1507,7 @@ For information on recipe syntax, see the - "Recipe Syntax" + "Recipe Syntax" section in the Yocto Project Overview Manual. @@ -1798,7 +1798,7 @@ You can find more information about the build process in - "The Yocto Project Development Environment" + "The Yocto Project Development Environment" chapter of the Yocto Project Overview Manual. @@ -1815,7 +1815,7 @@ Your recipe must have a SRC_URI variable that points to where the source is located. For a graphical representation of source locations, see the - "Sources" + "Sources" section in the Yocto Project Overview Manual. @@ -2128,7 +2128,7 @@ containing the current checksum. For more explanation and examples of how to set the LIC_FILES_CHKSUM variable, see the - "Tracking License Changes" + "Tracking License Changes" section in the Yocto Project Overview Manual. To determine the correct checksum string, you can list the appropriate files in the @@ -2275,7 +2275,7 @@ automatically add a runtime dependency to "mypackage" on "example"). See the - "Automatically Added Runtime Dependencies" + "Automatically Added Runtime Dependencies" in the Yocto Project Overview Manual for further details. @@ -3211,7 +3211,7 @@ The variable LIC_FILES_CHKSUM is used to track source license changes as described in the - "Tracking License Changes" + "Tracking License Changes" section in the Yocto Project Overview Manual. You can quickly create Autotool-based recipes in a manner similar to the previous example. @@ -3418,7 +3418,7 @@ allows runtime dependencies between packages to be added automatically. See the - "Automatically Added Runtime Dependencies" + "Automatically Added Runtime Dependencies" section in the Yocto Project Overview Manual for more information. @@ -4543,7 +4543,7 @@ architectures. For more information on x32 psABI, see the - "x32 psABI" + "x32 psABI" section in the Yocto Project Overview Manual. To use the x32 psABI, you need to edit your @@ -5217,7 +5217,7 @@ can use an existing file provided by the Wic installation. As shipped, kickstart files can be found in the Yocto Project - Source Repositories + Source Repositories in the following two locations: poky/meta-yocto-bsp/wic @@ -7347,7 +7347,7 @@ Some notes from Cal: Because the OpenEmbedded build system uses - "signatures", + "signatures", which are unique to a given build, the build system knows when to rebuild packages. All the inputs into a given task are represented by a @@ -7451,7 +7451,7 @@ Some notes from Cal: For more information on shared state, see the - "Shared State Cache" + "Shared State Cache" section in the Yocto Project Overview Manual. @@ -7696,7 +7696,7 @@ Some notes from Cal: connman.inc file in the meta/recipes-connectivity/connman/ directory of the poky - source repository. + source repository. You can also find examples in meta/classes/kernel.bbclass. @@ -9162,7 +9162,7 @@ Some notes from Cal: Enabling build history as previously described causes the OpenEmbedded build system to collect build output information and commit it as a single commit to a local - Git + Git repository. Enabling build history increases your build times slightly, @@ -11024,7 +11024,7 @@ Some notes from Cal: ${BUILDDIR}/tmp/stamps/i586-poky-linux/db/6.0.30-r1.do_fetch.sigdata.7c048c18222b16ff0bcee2000ef648b1 For tasks that are accelerated through the shared state - (sstate) + (sstate) cache, an additional siginfo file is written into SSTATE_DIR @@ -11133,7 +11133,7 @@ Some notes from Cal: -c, BitBake will only run the task if it considers it "out of date". See the - "Stamp Files and the Rerunning of Tasks" + "Stamp Files and the Rerunning of Tasks" section in the Yocto Project Overview Manual for how BitBake determines whether a task is "out of date". diff --git a/documentation/dev-manual/dev-manual-newbie.xml b/documentation/dev-manual/dev-manual-newbie.xml index 638d9112c7..acbdc280a4 100644 --- a/documentation/dev-manual/dev-manual-newbie.xml +++ b/documentation/dev-manual/dev-manual-newbie.xml @@ -99,7 +99,7 @@ with the OpenEmbedded build system is advisable. Of the SCMs BitBake supports, the Yocto Project team strongly recommends using - Git. + Git. Git is a distributed system that is easy to backup, allows you to work remotely, and then connects back to the infrastructure. @@ -311,7 +311,7 @@ Use - Git + Git as the source control system. @@ -325,7 +325,7 @@ Separate the project's Metadata and code by using separate Git repositories. See the - "Yocto Project Source Repositories" + "Yocto Project Source Repositories" section for information on these repositories. See the "Working With Yocto Project Source Files" @@ -549,7 +549,7 @@ pull the change into the component's upstream repository. You do this by pushing to a contribution repository that is upstream. See the - "Workflows" + "Workflows" section in the Yocto Project Overview Manual for additional concepts on working in the Yocto Project development environment. @@ -749,7 +749,7 @@ Search by File: - Using Git, + Using Git, you can enter the following command to bring up a short list of all commits against a specific file: diff --git a/documentation/dev-manual/dev-manual-start.xml b/documentation/dev-manual/dev-manual-start.xml index 27237c0d20..356abdf0a8 100644 --- a/documentation/dev-manual/dev-manual-start.xml +++ b/documentation/dev-manual/dev-manual-start.xml @@ -260,12 +260,12 @@ For concepts and introductory information about Git as it is used in the Yocto Project, see the - "Git" + "Git" section in the Yocto Project Overview Manual. For concepts on Yocto Project source repositories, see the - "Yocto Project Source Repositories" + "Yocto Project Source Repositories" section in the Yocto Project Overview Manual." @@ -277,7 +277,7 @@ Working from a copy of the upstream Yocto Project - Source Repositories + Source Repositories is the preferred method for obtaining and using a Yocto Project release. You can view the Yocto Project Source Repositories at @@ -306,7 +306,7 @@ Find the URL Used to Clone the Repository: At the bottom of the page, note the URL used to - clone + clone that repository (e.g. &YOCTO_GIT_URL;/poky). @@ -466,7 +466,7 @@ You create your Source Directory by using - Git to clone a local + Git to clone a local copy of the upstream poky repository. Tip The preferred method of getting the Yocto Project Source @@ -741,7 +741,7 @@ Build Directory under tmp/deploy/images. For detailed information on the build process using BitBake, see the - "Images" + "Images" section in the Yocto Project Overview Manual. diff --git a/documentation/getting-started/eclipse/getting-started-toc.xml b/documentation/getting-started/eclipse/getting-started-toc.xml new file mode 100644 index 0000000000..6f1c29af30 --- /dev/null +++ b/documentation/getting-started/eclipse/getting-started-toc.xml @@ -0,0 +1,86 @@ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + diff --git a/documentation/getting-started/eclipse/html/getting-started/automatically-added-runtime-dependencies.html b/documentation/getting-started/eclipse/html/getting-started/automatically-added-runtime-dependencies.html new file mode 100644 index 0000000000..885ee089e1 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/automatically-added-runtime-dependencies.html @@ -0,0 +1,164 @@ + + + +3.4. Automatically Added Runtime Dependencies + + + + + + + +
+

+3.4. Automatically Added Runtime Dependencies

+

+ The OpenEmbedded build system automatically adds common types of + runtime dependencies between packages, which means that you do not + need to explicitly declare the packages using + RDEPENDS. + Three automatic mechanisms exist (shlibdeps, + pcdeps, and depchains) + that handle shared libraries, package configuration (pkg-config) + modules, and -dev and + -dbg packages, respectively. + For other types of runtime dependencies, you must manually declare + the dependencies. +

+
    +
  • +

    + shlibdeps: + During the + do_package + task of each recipe, all shared libraries installed by the + recipe are located. + For each shared library, the package that contains the + shared library is registered as providing the shared + library. + More specifically, the package is registered as providing + the + soname + of the library. + The resulting shared-library-to-package mapping + is saved globally in + PKGDATA_DIR + by the + do_packagedata + task.

    +

    Simultaneously, all executables and shared libraries + installed by the recipe are inspected to see what shared + libraries they link against. + For each shared library dependency that is found, + PKGDATA_DIR is queried to + see if some package (likely from a different recipe) + contains the shared library. + If such a package is found, a runtime dependency is added + from the package that depends on the shared library to the + package that contains the library.

    +

    The automatically added runtime dependency also + includes a version restriction. + This version restriction specifies that at least the + current version of the package that provides the shared + library must be used, as if + "package (>= version)" + had been added to + RDEPENDS. + This forces an upgrade of the package containing the shared + library when installing the package that depends on the + library, if needed.

    +

    If you want to avoid a package being registered as + providing a particular shared library (e.g. because the library + is for internal use only), then add the library to + PRIVATE_LIBS + inside the package's recipe. +

    +
    • +
  • +

    + pcdeps: + During the + do_package + task of each recipe, all pkg-config modules + (*.pc files) installed by the recipe + are located. + For each module, the package that contains the module is + registered as providing the module. + The resulting module-to-package mapping is saved globally in + PKGDATA_DIR + by the + do_packagedata + task.

    +

    Simultaneously, all pkg-config modules installed by + the recipe are inspected to see what other pkg-config + modules they depend on. + A module is seen as depending on another module if it + contains a "Requires:" line that specifies the other module. + For each module dependency, + PKGDATA_DIR is queried to see if some + package contains the module. + If such a package is found, a runtime dependency is added + from the package that depends on the module to the package + that contains the module. +

    +
    +

    Note

    + The pcdeps mechanism most often + infers dependencies between -dev + packages. +
    +

    +

    +
    • +
  • +

    + depchains: + If a package foo depends on a package + bar, then foo-dev + and foo-dbg are also made to depend on + bar-dev and + bar-dbg, respectively. + Taking the -dev packages as an + example, the bar-dev package might + provide headers and shared library symlinks needed by + foo-dev, which shows the need + for a dependency between the packages.

    +

    The dependencies added by + depchains are in the form of + RRECOMMENDS. +

    +
    +

    Note

    + By default, foo-dev also has an + RDEPENDS-style dependency on + foo, because the default value of + RDEPENDS_${PN}-dev (set in + bitbake.conf) includes + "${PN}". +
    +

    To ensure that the dependency chain is never broken, + -dev and -dbg + packages are always generated by default, even if the + packages turn out to be empty. + See the + ALLOW_EMPTY + variable for more information. +

    +
    • +
+

+

+

+ The do_package task depends on the + do_packagedata + task of each recipe in + DEPENDS + through use of a + [deptask] + declaration, which guarantees that the required + shared-library/module-to-package mapping information will be available + when needed as long as DEPENDS has been + correctly set. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/basic-commands.html b/documentation/getting-started/eclipse/html/getting-started/basic-commands.html new file mode 100644 index 0000000000..b145086974 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/basic-commands.html @@ -0,0 +1,176 @@ + + + +2.4.2. Basic Commands + + + + + + + +
+

+2.4.2. Basic Commands

+

+ Git has an extensive set of commands that lets you manage changes + and perform collaboration over the life of a project. + Conveniently though, you can manage with a small set of basic + operations and workflows once you understand the basic + philosophy behind Git. + You do not have to be an expert in Git to be functional. + A good place to look for instruction on a minimal set of Git + commands is + here. +

+

+ If you do not know much about Git, you should educate + yourself by visiting the links previously mentioned. +

+

+ The following list of Git commands briefly describes some basic + Git operations as a way to get started. + As with any set of commands, this list (in most cases) simply shows + the base command and omits the many arguments they support. + See the Git documentation for complete descriptions and strategies + on how to use these commands: +

+
    +

  • + git init: + Initializes an empty Git repository. + You cannot use Git commands unless you have a + .git repository. +

    • +

  • + git clone: + Creates a local clone of a Git repository that is on + equal footing with a fellow developer’s Git repository + or an upstream repository. +

    • +

  • + git add: + Locally stages updated file contents to the index that + Git uses to track changes. + You must stage all files that have changed before you + can commit them. +

    • +

  • + git commit: + Creates a local "commit" that documents the changes you + made. + Only changes that have been staged can be committed. + Commits are used for historical purposes, for determining + if a maintainer of a project will allow the change, + and for ultimately pushing the change from your local + Git repository into the project’s upstream repository. +

    • +

  • + git status: + Reports any modified files that possibly need to be + staged and gives you a status of where you stand regarding + local commits as compared to the upstream repository. +

    • +

  • + git checkout branch-name: + Changes your working branch. + This command is analogous to "cd". +

    • +

  • git checkout –b working-branch: + Creates and checks out a working branch on your local + machine that you can use to isolate your work. + It is a good idea to use local branches when adding + specific features or changes. + Using isolated branches facilitates easy removal of + changes if they do not work out. +

    • +

  • git branch: + Displays the existing local branches associated with your + local repository. + The branch that you have currently checked out is noted + with an asterisk character. +

    • +

  • + git branch -D branch-name: + Deletes an existing local branch. + You need to be in a local branch other than the one you + are deleting in order to delete + branch-name. +

    • +

  • + git pull: + Retrieves information from an upstream Git repository + and places it in your local Git repository. + You use this command to make sure you are synchronized with + the repository from which you are basing changes + (.e.g. the "master" branch). +

    • +

  • + git push: + Sends all your committed local changes to the upstream Git + repository that your local repository is tracking + (e.g. a contribution repository). + The maintainer of the project draws from these repositories + to merge changes (commits) into the appropriate branch + of project's upstream repository. +

    • +

  • + git merge: + Combines or adds changes from one + local branch of your repository with another branch. + When you create a local Git repository, the default branch + is named "master". + A typical workflow is to create a temporary branch that is + based off "master" that you would use for isolated work. + You would make your changes in that isolated branch, + stage and commit them locally, switch to the "master" + branch, and then use the git merge + command to apply the changes from your isolated branch + into the currently checked out branch (e.g. "master"). + After the merge is complete and if you are done with + working in that isolated branch, you can safely delete + the isolated branch. +

    • +

  • + git cherry-pick: + Choose and apply specific commits from one branch + into another branch. + There are times when you might not be able to merge + all the changes in one branch with + another but need to pick out certain ones. +

    • +
  • +

    + gitk: + Provides a GUI view of the branches and changes in your + local Git repository. + This command is a good way to graphically see where things + have diverged in your local repository. +

    +
    +

    Note

    + You need to install the gitk + package on your development system to use this + command. +
    +

    +

    +
    • +

  • + git log: + Reports a history of your commits to the repository. + This report lists all commits regardless of whether you + have pushed them upstream or not. +

    • +

  • + git diff: + Displays line-by-line differences between a local + working file and the same file as understood by Git. + This command is useful to see what you have changed + in any given file. +

    • +
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/bitbake-dev-environment.html b/documentation/getting-started/eclipse/html/getting-started/bitbake-dev-environment.html new file mode 100644 index 0000000000..eda2c3370f --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/bitbake-dev-environment.html @@ -0,0 +1,31 @@ + + + +2.8.5. BitBake + + + + + + + +
+

+2.8.5. BitBake

+

+ The OpenEmbedded build system uses + BitBake + to produce images. + You can see from the + general Yocto Project Development Environment figure, + the BitBake area consists of several functional areas. + This section takes a closer look at each of those areas. +

+

+ Separate documentation exists for the BitBake tool. + See the + BitBake User Manual + for reference material on BitBake. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/bsp-layer.html b/documentation/getting-started/eclipse/html/getting-started/bsp-layer.html new file mode 100644 index 0000000000..2d009d5720 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/bsp-layer.html @@ -0,0 +1,54 @@ + + + +2.8.2.2. BSP Layer + + + + + + + +
+

+2.8.2.2. BSP Layer

+

+ The BSP Layer provides machine configurations. + Everything in this layer is specific to the machine for which + you are building the image or the SDK. + A common structure or form is defined for BSP layers. + You can learn more about this structure in the + Yocto Project Board Support Package (BSP) Developer's Guide. +

+
+

Note

+ In order for a BSP layer to be considered compliant with the + Yocto Project, it must meet some structural requirements. +
+

+

+

+ The BSP Layer's configuration directory contains + configuration files for the machine + (conf/machine/machine.conf) and, + of course, the layer (conf/layer.conf). +

+

+ The remainder of the layer is dedicated to specific recipes + by function: recipes-bsp, + recipes-core, + recipes-graphics, and + recipes-kernel. + Metadata can exist for multiple formfactors, graphics + support systems, and so forth. +

+
+

Note

+ While the figure shows several recipes-* + directories, not all these directories appear in all + BSP layers. +
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/configuration-and-compilation-dev-environment.html b/documentation/getting-started/eclipse/html/getting-started/configuration-and-compilation-dev-environment.html new file mode 100644 index 0000000000..9a94cc47da --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/configuration-and-compilation-dev-environment.html @@ -0,0 +1,93 @@ + + + +2.8.5.3. Configuration and Compilation + + + + + + + +
+

+2.8.5.3. Configuration and Compilation

+

+ After source code is patched, BitBake executes tasks that + configure and compile the source code: +

+
+

+

+

+ This step in the build process consists of three tasks: +

+
    +

  • + do_prepare_recipe_sysroot: + This task sets up the two sysroots in + ${WORKDIR} + (i.e. recipe-sysroot and + recipe-sysroot-native) so that + the sysroots contain the contents of the + do_populate_sysroot + tasks of the recipes on which the recipe + containing the tasks depends. + A sysroot exists for both the target and for the native + binaries, which run on the host system. +

    • +
  • +

    do_configure: + This task configures the source by enabling and + disabling any build-time and configuration options for + the software being built. + Configurations can come from the recipe itself as well + as from an inherited class. + Additionally, the software itself might configure itself + depending on the target for which it is being built. +

    +

    The configurations handled by the + do_configure + task are specific + to source code configuration for the source code + being built by the recipe.

    +

    If you are using the + autotools + class, + you can add additional configuration options by using + the + EXTRA_OECONF + or + PACKAGECONFIG_CONFARGS + variables. + For information on how this variable works within + that class, see the + meta/classes/autotools.bbclass file. +

    +
    • +

  • do_compile: + Once a configuration task has been satisfied, BitBake + compiles the source using the + do_compile + task. + Compilation occurs in the directory pointed to by the + B + variable. + Realize that the B directory is, by + default, the same as the + S + directory.

    • +

  • do_install: + Once compilation is done, BitBake executes the + do_install + task. + This task copies files from the B + directory and places them in a holding area pointed to + by the + D + variable.

    • +
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/cross-development-toolchain-generation.html b/documentation/getting-started/eclipse/html/getting-started/cross-development-toolchain-generation.html new file mode 100644 index 0000000000..a1aef9119d --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/cross-development-toolchain-generation.html @@ -0,0 +1,241 @@ + + + +3.2. Cross-Development Toolchain Generation + + + + + + + +
+

+3.2. Cross-Development Toolchain Generation

+

+ The Yocto Project does most of the work for you when it comes to + creating + cross-development toolchains. + This section provides some technical background on how + cross-development toolchains are created and used. + For more information on toolchains, you can also see the + Yocto Project Application Development and the Extensible Software Development Kit (eSDK) + manual. +

+

+ In the Yocto Project development environment, cross-development + toolchains are used to build the image and applications that run + on the target hardware. + With just a few commands, the OpenEmbedded build system creates + these necessary toolchains for you. +

+

+ The following figure shows a high-level build environment regarding + toolchain construction and use. +

+

+

+
+

+

+

+ Most of the work occurs on the Build Host. + This is the machine used to build images and generally work within the + the Yocto Project environment. + When you run BitBake to create an image, the OpenEmbedded build system + uses the host gcc compiler to bootstrap a + cross-compiler named gcc-cross. + The gcc-cross compiler is what BitBake uses to + compile source files when creating the target image. + You can think of gcc-cross simply as an + automatically generated cross-compiler that is used internally within + BitBake only. +

+
+

Note

+ The extensible SDK does not use + gcc-cross-canadian since this SDK + ships a copy of the OpenEmbedded build system and the sysroot + within it contains gcc-cross. +
+

+

+

+ The chain of events that occurs when gcc-cross is + bootstrapped is as follows: +

+
+     gcc -> binutils-cross -> gcc-cross-initial -> linux-libc-headers -> glibc-initial -> glibc -> gcc-cross -> gcc-runtime
+
+

+

+
    +

  • + gcc: + The build host's GNU Compiler Collection (GCC). +

    • +

  • + binutils-cross: + The bare minimum binary utilities needed in order to run + the gcc-cross-initial phase of the + bootstrap operation. +

    • +

  • + gcc-cross-initial: + An early stage of the bootstrap process for creating + the cross-compiler. + This stage builds enough of the gcc-cross, + the C library, and other pieces needed to finish building the + final cross-compiler in later stages. + This tool is a "native" package (i.e. it is designed to run on + the build host). +

    • +

  • + linux-libc-headers: + Headers needed for the cross-compiler. +

    • +

  • + glibc-initial: + An initial version of the Embedded GLIBC needed to bootstrap + glibc. +

    • +
  • +

    + gcc-cross: + The final stage of the bootstrap process for the + cross-compiler. + This stage results in the actual cross-compiler that + BitBake uses when it builds an image for a targeted + device. +

    +
    +

    Note

    + If you are replacing this cross compiler toolchain + with a custom version, you must replace + gcc-cross. +
    +

    + This tool is also a "native" package (i.e. it is + designed to run on the build host). +

    +
    • +

  • + gcc-runtime: + Runtime libraries resulting from the toolchain bootstrapping + process. + This tool produces a binary that consists of the + runtime libraries need for the targeted device. +

    • +
+

+

+

+ You can use the OpenEmbedded build system to build an installer for + the relocatable SDK used to develop applications. + When you run the installer, it installs the toolchain, which contains + the development tools (e.g., the + gcc-cross-canadian), + binutils-cross-canadian, and other + nativesdk-* tools, + which are tools native to the SDK (i.e. native to + SDK_ARCH), + you need to cross-compile and test your software. + The figure shows the commands you use to easily build out this + toolchain. + This cross-development toolchain is built to execute on the + SDKMACHINE, + which might or might not be the same + machine as the Build Host. +

+
+

Note

+ If your target architecture is supported by the Yocto Project, + you can take advantage of pre-built images that ship with the + Yocto Project and already contain cross-development toolchain + installers. +
+

+

+

+ Here is the bootstrap process for the relocatable toolchain: +

+
+     gcc -> binutils-crosssdk -> gcc-crosssdk-initial -> linux-libc-headers ->
+        glibc-initial -> nativesdk-glibc -> gcc-crosssdk -> gcc-cross-canadian
+
+

+

+
    +

  • + gcc: + The build host's GNU Compiler Collection (GCC). +

    • +

  • + binutils-crosssdk: + The bare minimum binary utilities needed in order to run + the gcc-crosssdk-initial phase of the + bootstrap operation. +

    • +

  • + gcc-crosssdk-initial: + An early stage of the bootstrap process for creating + the cross-compiler. + This stage builds enough of the + gcc-crosssdk and supporting pieces so that + the final stage of the bootstrap process can produce the + finished cross-compiler. + This tool is a "native" binary that runs on the build host. +

    • +

  • + linux-libc-headers: + Headers needed for the cross-compiler. +

    • +

  • + glibc-initial: + An initial version of the Embedded GLIBC needed to bootstrap + nativesdk-glibc. +

    • +

  • + nativesdk-glibc: + The Embedded GLIBC needed to bootstrap the + gcc-crosssdk. +

    • +

  • + gcc-crosssdk: + The final stage of the bootstrap process for the + relocatable cross-compiler. + The gcc-crosssdk is a transitory compiler + and never leaves the build host. + Its purpose is to help in the bootstrap process to create the + eventual relocatable gcc-cross-canadian + compiler, which is relocatable. + This tool is also a "native" package (i.e. it is + designed to run on the build host). +

    • +

  • + gcc-cross-canadian: + The final relocatable cross-compiler. + When run on the + SDKMACHINE, + this tool + produces executable code that runs on the target device. + Only one cross-canadian compiler is produced per architecture + since they can be targeted at different processor optimizations + using configurations passed to the compiler through the + compile commands. + This circumvents the need for multiple compilers and thus + reduces the size of the toolchains. +

    • +
+

+

+
+

Note

+ For information on advantages gained when building a + cross-development toolchain installer, see the + "Building an SDK Installer" + section in the Yocto Project Application Development and the + Extensible Software Development Kit (eSDK) manual. +
+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/development-concepts.html b/documentation/getting-started/eclipse/html/getting-started/development-concepts.html new file mode 100644 index 0000000000..ccfb73189a --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/development-concepts.html @@ -0,0 +1,66 @@ + + + +2.8. Development Concepts + + + + + + + +
+

+2.8. Development Concepts

+

+ This section takes a more detailed look inside the development + process. + The following diagram represents development at a high level. + The remainder of this chapter expands on the fundamental input, output, + process, and + Metadata) blocks + that make up development in the Yocto Project environment. +

+

+

+
+

+

+

+ In general, development consists of several functional areas: +

+
    +

  • User Configuration: + Metadata you can use to control the build process. +

    • +

  • Metadata Layers: + Various layers that provide software, machine, and + distro Metadata.

    • +

  • Source Files: + Upstream releases, local projects, and SCMs.

    • +

  • Build System: + Processes under the control of + BitBake. + This block expands on how BitBake fetches source, applies + patches, completes compilation, analyzes output for package + generation, creates and tests packages, generates images, and + generates cross-development tools.

    • +

  • Package Feeds: + Directories containing output packages (RPM, DEB or IPK), + which are subsequently used in the construction of an image or + SDK, produced by the build system. + These feeds can also be copied and shared using a web server or + other means to facilitate extending or updating existing + images on devices at runtime if runtime package management is + enabled.

    • +

  • Images: + Images produced by the development process. +

    • +

  • Application Development SDK: + Cross-development tools that are produced along with an image + or separately with BitBake.

    • +
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/distro-layer.html b/documentation/getting-started/eclipse/html/getting-started/distro-layer.html new file mode 100644 index 0000000000..da6da55986 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/distro-layer.html @@ -0,0 +1,60 @@ + + + +2.8.2.1. Distro Layer + + + + + + + +
+

+2.8.2.1. Distro Layer

+

+ The distribution layer provides policy configurations for your + distribution. + Best practices dictate that you isolate these types of + configurations into their own layer. + Settings you provide in + conf/distro/distro.conf override + similar + settings that BitBake finds in your + conf/local.conf file in the Build + Directory. +

+

+ The following list provides some explanation and references + for what you typically find in the distribution layer: +

+
    +

  • classes: + Class files (.bbclass) hold + common functionality that can be shared among + recipes in the distribution. + When your recipes inherit a class, they take on the + settings and functions for that class. + You can read more about class files in the + "Classes" + section of the Yocto Reference Manual. +

    • +

  • conf: + This area holds configuration files for the + layer (conf/layer.conf), + the distribution + (conf/distro/distro.conf), + and any distribution-wide include files. +

    • +

  • recipes-*: + Recipes and append files that affect common + functionality across the distribution. + This area could include recipes and append files + to add distribution-specific configuration, + initialization scripts, custom image recipes, + and so forth.

    • +
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/enable-building.html b/documentation/getting-started/eclipse/html/getting-started/enable-building.html new file mode 100644 index 0000000000..af70491f97 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/enable-building.html @@ -0,0 +1,37 @@ + + + +3.6.2.1. Building + + + + + + + +
+

+3.6.2.1. Building

+

+ To cause Mesa to build the wayland-egl + platform and Weston to build Wayland with Kernel Mode + Setting + (KMS) + support, include the "wayland" flag in the + DISTRO_FEATURES + statement in your local.conf file: +

+
+     DISTRO_FEATURES_append = " wayland"
+
+

+

+
+

Note

+ If X11 has been enabled elsewhere, Weston will build + Wayland with X11 support +
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/enable-installation-in-an-image.html b/documentation/getting-started/eclipse/html/getting-started/enable-installation-in-an-image.html new file mode 100644 index 0000000000..490f1d1036 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/enable-installation-in-an-image.html @@ -0,0 +1,27 @@ + + + +3.6.2.2. Installing + + + + + + + +
+

+3.6.2.2. Installing

+

+ To install the Wayland feature into an image, you must + include the following + CORE_IMAGE_EXTRA_INSTALL + statement in your local.conf file: +

+
+     CORE_IMAGE_EXTRA_INSTALL += "wayland weston"
+
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/enabling-commercially-licensed-recipes.html b/documentation/getting-started/eclipse/html/getting-started/enabling-commercially-licensed-recipes.html new file mode 100644 index 0000000000..1a31d0e6b1 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/enabling-commercially-licensed-recipes.html @@ -0,0 +1,91 @@ + + + +3.7.2. Enabling Commercially Licensed Recipes + + + + + + + +
+

+3.7.2. Enabling Commercially Licensed Recipes

+

+ By default, the OpenEmbedded build system disables + components that have commercial or other special licensing + requirements. + Such requirements are defined on a + recipe-by-recipe basis through the + LICENSE_FLAGS + variable definition in the affected recipe. + For instance, the + poky/meta/recipes-multimedia/gstreamer/gst-plugins-ugly + recipe contains the following statement: +

+
+     LICENSE_FLAGS = "commercial"
+
+

+ Here is a slightly more complicated example that contains both + an explicit recipe name and version (after variable expansion): +

+
+     LICENSE_FLAGS = "license_${PN}_${PV}"
+
+

+ In order for a component restricted by a + LICENSE_FLAGS definition to be enabled and + included in an image, it needs to have a matching entry in the + global + LICENSE_FLAGS_WHITELIST + variable, which is a variable typically defined in your + local.conf file. + For example, to enable the + poky/meta/recipes-multimedia/gstreamer/gst-plugins-ugly + package, you could add either the string + "commercial_gst-plugins-ugly" or the more general string + "commercial" to LICENSE_FLAGS_WHITELIST. + See the + "License Flag Matching" + section for a full + explanation of how LICENSE_FLAGS matching + works. + Here is the example: +

+
+     LICENSE_FLAGS_WHITELIST = "commercial_gst-plugins-ugly"
+
+

+ Likewise, to additionally enable the package built from the + recipe containing + LICENSE_FLAGS = "license_${PN}_${PV}", + and assuming that the actual recipe name was + emgd_1.10.bb, the following string would + enable that package as well as the original + gst-plugins-ugly package: +

+
+     LICENSE_FLAGS_WHITELIST = "commercial_gst-plugins-ugly license_emgd_1.10"
+
+

+ As a convenience, you do not need to specify the complete + license string in the whitelist for every package. + You can use an abbreviated form, which consists + of just the first portion or portions of the license + string before the initial underscore character or characters. + A partial string will match any license that contains the + given string as the first portion of its license. + For example, the following whitelist string will also match + both of the packages previously mentioned as well as any other + packages that have licenses starting with "commercial" or + "license". +

+
+     LICENSE_FLAGS_WHITELIST = "commercial license"
+
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/enabling-wayland-in-an-image.html b/documentation/getting-started/eclipse/html/getting-started/enabling-wayland-in-an-image.html new file mode 100644 index 0000000000..6a325dbfd2 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/enabling-wayland-in-an-image.html @@ -0,0 +1,20 @@ + + + +3.6.2. Enabling Wayland in an Image + + + + + + + +
+

+3.6.2. Enabling Wayland in an Image

+

+ To enable Wayland, you need to enable it to be built and enable + it to be included in the image. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/fakeroot-and-pseudo.html b/documentation/getting-started/eclipse/html/getting-started/fakeroot-and-pseudo.html new file mode 100644 index 0000000000..8354ad6730 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/fakeroot-and-pseudo.html @@ -0,0 +1,91 @@ + + + +3.5. Fakeroot and Pseudo + + + + + + + +
+

+3.5. Fakeroot and Pseudo

+

+ Some tasks are easier to implement when allowed to perform certain + operations that are normally reserved for the root user (e.g. + do_install, + do_package_write*, + do_rootfs, + and + do_image*). + For example, the do_install task benefits + from being able to set the UID and GID of installed files to + arbitrary values. +

+

+ One approach to allowing tasks to perform root-only operations + would be to require BitBake to run as root. + However, this method is cumbersome and has security issues. + The approach that is actually used is to run tasks that benefit + from root privileges in a "fake" root environment. + Within this environment, the task and its child processes believe + that they are running as the root user, and see an internally + consistent view of the filesystem. + As long as generating the final output (e.g. a package or an image) + does not require root privileges, the fact that some earlier + steps ran in a fake root environment does not cause problems. +

+

+ The capability to run tasks in a fake root environment is known as + "fakeroot", + which is derived from the BitBake keyword/variable + flag that requests a fake root environment for a task. +

+

+ In the OpenEmbedded build system, the program that implements + fakeroot is known as Pseudo. + Pseudo overrides system calls by using the environment variable + LD_PRELOAD, which results in the illusion + of running as root. + To keep track of "fake" file ownership and permissions resulting + from operations that require root permissions, Pseudo uses + an SQLite 3 database. + This database is stored in + ${WORKDIR}/pseudo/files.db + for individual recipes. + Storing the database in a file as opposed to in memory + gives persistence between tasks and builds, which is not + accomplished using fakeroot. +

+
+

Caution

+ If you add your own task that manipulates the same files or + directories as a fakeroot task, then that task also needs to + run under fakeroot. + Otherwise, the task cannot run root-only operations, and + cannot see the fake file ownership and permissions set by the + other task. + You need to also add a dependency on + virtual/fakeroot-native:do_populate_sysroot, + giving the following: + 
+       fakeroot do_mytask () {
+           ...
+       }
+       do_mytask[depends] += "virtual/fakeroot-native:do_populate_sysroot"
+
+
+

+ For more information, see the + FAKEROOT* + variables in the BitBake User Manual. + You can also reference the + "Pseudo" + and + "Why Not Fakeroot?" + articles for background information on Pseudo. +

+
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+

+2.4. Git

+

+ The Yocto Project makes extensive use of Git, which is a + free, open source distributed version control system. + Git supports distributed development, non-linear development, + and can handle large projects. + It is best that you have some fundamental understanding + of how Git tracks projects and how to work with Git if + you are going to use the Yocto Project for development. + This section provides a quick overview of how Git works and + provides you with a summary of some essential Git commands. +

+
+

Notes

+
    +

  • + For more information on Git, see + http://git-scm.com/documentation. +

    • +

  • + If you need to download Git, it is recommended that you add + Git to your system through your distribution's "software + store" (e.g. for Ubuntu, use the Ubuntu Software feature). + For the Git download page, see + http://git-scm.com/download. +

    • +

  • + For examples beyond the limited few in this section on how + to use Git with the Yocto Project, see the + "Working With Yocto Project Source Files" + section in the Yocto Project Development Tasks Manual. +

    • +
+
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/image-generation-dev-environment.html b/documentation/getting-started/eclipse/html/getting-started/image-generation-dev-environment.html new file mode 100644 index 0000000000..9f682d082c --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/image-generation-dev-environment.html @@ -0,0 +1,178 @@ + + + +2.8.5.5. Image Generation + + + + + + + +
+

+2.8.5.5. Image Generation

+

+ Once packages are split and stored in the Package Feeds area, + the OpenEmbedded build system uses BitBake to generate the + root filesystem image: +

+
+

+

+

+ The image generation process consists of several stages and + depends on several tasks and variables. + The + do_rootfs + task creates the root filesystem (file and directory structure) + for an image. + This task uses several key variables to help create the list + of packages to actually install: +

+
    +

  • IMAGE_INSTALL: + Lists out the base set of packages to install from + the Package Feeds area.

    • +

  • PACKAGE_EXCLUDE: + Specifies packages that should not be installed. +

    • +

  • IMAGE_FEATURES: + Specifies features to include in the image. + Most of these features map to additional packages for + installation.

    • +

  • PACKAGE_CLASSES: + Specifies the package backend to use and consequently + helps determine where to locate packages within the + Package Feeds area.

    • +

  • IMAGE_LINGUAS: + Determines the language(s) for which additional + language support packages are installed. +

    • +

  • PACKAGE_INSTALL: + The final list of packages passed to the package manager + for installation into the image. +

    • +
+

+

+

+ With + IMAGE_ROOTFS + pointing to the location of the filesystem under construction and + the PACKAGE_INSTALL variable providing the + final list of packages to install, the root file system is + created. +

+

+ Package installation is under control of the package manager + (e.g. dnf/rpm, opkg, or apt/dpkg) regardless of whether or + not package management is enabled for the target. + At the end of the process, if package management is not + enabled for the target, the package manager's data files + are deleted from the root filesystem. + As part of the final stage of package installation, postinstall + scripts that are part of the packages are run. + Any scripts that fail to run + on the build host are run on the target when the target system + is first booted. + If you are using a + read-only root filesystem, + all the post installation scripts must succeed during the + package installation phase since the root filesystem is + read-only. +

+

+ The final stages of the do_rootfs task + handle post processing. + Post processing includes creation of a manifest file and + optimizations. +

+

+ The manifest file (.manifest) resides + in the same directory as the root filesystem image. + This file lists out, line-by-line, the installed packages. + The manifest file is useful for the + testimage + class, for example, to determine whether or not to run + specific tests. + See the + IMAGE_MANIFEST + variable for additional information. +

+

+ Optimizing processes run across the image include + mklibs, prelink, + and any other post-processing commands as defined by the + ROOTFS_POSTPROCESS_COMMAND + variable. + The mklibs process optimizes the size + of the libraries, while the + prelink process optimizes the dynamic + linking of shared libraries to reduce start up time of + executables. +

+

+ After the root filesystem is built, processing begins on + the image through the + do_image + task. + The build system runs any pre-processing commands as defined + by the + IMAGE_PREPROCESS_COMMAND + variable. + This variable specifies a list of functions to call before + the OpenEmbedded build system creates the final image output + files. +

+

+ The OpenEmbedded build system dynamically creates + do_image_* tasks as needed, based + on the image types specified in the + IMAGE_FSTYPES + variable. + The process turns everything into an image file or a set of + image files and compresses the root filesystem image to reduce + the overall size of the image. + The formats used for the root filesystem depend on the + IMAGE_FSTYPES variable. +

+

+ As an example, a dynamically created task when creating a + particular image type would take the + following form: +

+
+     do_image_type[depends]
+
+

+ So, if the type as specified by the + IMAGE_FSTYPES were + ext4, the dynamically generated task + would be as follows: +

+
+     do_image_ext4[depends]
+
+

+

+

+ The final task involved in image creation is the + do_image_complete + task. + This task completes the image by applying any image + post processing as defined through the + IMAGE_POSTPROCESS_COMMAND + variable. + The variable specifies a list of functions to call once the + OpenEmbedded build system has created the final image output + files. +

+
+

Note

+ The entire image generation process is run under Pseudo. + Running under Pseudo ensures that the files in the root + filesystem have correct ownership. +
+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/images-dev-environment.html b/documentation/getting-started/eclipse/html/getting-started/images-dev-environment.html new file mode 100644 index 0000000000..2561f1f4a6 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/images-dev-environment.html @@ -0,0 +1,99 @@ + + + +2.8.6. Images + + + + + + + +
+

+2.8.6. Images

+

+ The images produced by the OpenEmbedded build system + are compressed forms of the + root filesystem that are ready to boot on a target device. + You can see from the + general Yocto Project Development Environment figure + that BitBake output, in part, consists of images. + This section is going to look more closely at this output: +

+
+

+

+

+ For a list of example images that the Yocto Project provides, + see the + "Images" + chapter in the Yocto Project Reference Manual. +

+

+ Images are written out to the + Build Directory + inside the + tmp/deploy/images/machine/ + folder as shown in the figure. + This folder contains any files expected to be loaded on the + target device. + The + DEPLOY_DIR + variable points to the deploy directory, + while the + DEPLOY_DIR_IMAGE + variable points to the appropriate directory containing images for + the current configuration. +

+
    +

  • kernel-image: + A kernel binary file. + The + KERNEL_IMAGETYPE + variable setting determines the naming scheme for the + kernel image file. + Depending on that variable, the file could begin with + a variety of naming strings. + The deploy/images/machine + directory can contain multiple image files for the + machine.

    • +

  • root-filesystem-image: + Root filesystems for the target device (e.g. + *.ext3 or *.bz2 + files). + The + IMAGE_FSTYPES + variable setting determines the root filesystem image + type. + The deploy/images/machine + directory can contain multiple root filesystems for the + machine.

    • +

  • kernel-modules: + Tarballs that contain all the modules built for the kernel. + Kernel module tarballs exist for legacy purposes and + can be suppressed by setting the + MODULE_TARBALL_DEPLOY + variable to "0". + The deploy/images/machine + directory can contain multiple kernel module tarballs + for the machine.

    • +

  • bootloaders: + Bootloaders supporting the image, if applicable to the + target machine. + The deploy/images/machine + directory can contain multiple bootloaders for the + machine.

    • +

  • symlinks: + The deploy/images/machine + folder contains + a symbolic link that points to the most recently built file + for each machine. + These links might be useful for external scripts that + need to obtain the latest version of each file. +

    • +
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/index.html b/documentation/getting-started/eclipse/html/getting-started/index.html new file mode 100644 index 0000000000..94826ce0c6 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/index.html @@ -0,0 +1,154 @@ + + + +Getting Started With Yocto Project + + + + + +
+
+
+

+ + Getting Started With Yocto Project +

+
+
+

+Scott Rifenbark +

+
+ Scotty's Documentation Services, INC
 +
+ +
+
+

Copyright © 2010-2018 Linux Foundation

+
+ +

+ Permission is granted to copy, distribute and/or modify this document under + the terms of the + Creative Commons Attribution-Share Alike 2.0 UK: England & Wales as published by + Creative Commons. +

+
+

Manual Notes

+
    +

  • + This version of the + Yocto Project Overview Manual + is for the 2.5 release of the + Yocto Project. + To be sure you have the latest version of the manual + for this release, use the manual from the + Yocto Project documentation page. +

    • +

  • + For manuals associated with other releases of the Yocto + Project, go to the + Yocto Project documentation page + and use the drop-down "Active Releases" button + and choose the manual associated with the desired + Yocto Project. +

    • +

  • + To report any inaccuracies or problems with this + manual, send an email to the Yocto Project + discussion group at + yocto@yoctoproject.com or log into + the freenode #yocto channel. +

    • +
+
+
+
+ + + + + + +
Revision History
Revision 2.5April 2018
The initial document released with the Yocto Project 2.5 Release.
+
+
+
+
+

Table of Contents

+
+
1. The Yocto Project Overview Manual
+
+
1.1. Welcome
+
1.2. Other Information
+
+
2. The Yocto Project Development Environment
+
+
2.1. Introduction
+
2.2. Open Source Philosophy
+
2.3. Workflows
+
2.4. Git
+
+
2.4.1. Repositories, Tags, and Branches
+
2.4.2. Basic Commands
+
+
2.5. Yocto Project Source Repositories
+
2.6. Licensing
+
2.7. Recipe Syntax
+
2.8. Development Concepts
+
+
2.8.1. User Configuration
+
2.8.2. Metadata, Machine Configuration, and Policy Configuration
+
2.8.3. Sources
+
2.8.4. Package Feeds
+
2.8.5. BitBake
+
2.8.6. Images
+
2.8.7. Application Development SDK
+
+
+
3. Yocto Project Concepts
+
+
3.1. Yocto Project Components
+
+
3.1.1. BitBake
+
3.1.2. Metadata (Recipes)
+
3.1.3. Metadata (Virtual Providers)
+
3.1.4. Classes
+
3.1.5. Configuration
+
+
3.2. Cross-Development Toolchain Generation
+
3.3. Shared State Cache
+
+
3.3.1. Overall Architecture
+
3.3.2. Checksums (Signatures)
+
3.3.3. Shared State
+
3.3.4. Tips and Tricks
+
+
3.4. Automatically Added Runtime Dependencies
+
3.5. Fakeroot and Pseudo
+
3.6. Wayland
+
+
3.6.1. Support
+
3.6.2. Enabling Wayland in an Image
+
3.6.3. Running Weston
+
+
3.7. Licenses
+
+
3.7.1. Tracking License Changes
+
3.7.2. Enabling Commercially Licensed Recipes
+
+
3.8. x32 psABI
+
+
+
+ + + + + + + + +
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/index.xml b/documentation/getting-started/eclipse/html/getting-started/index.xml new file mode 100644 index 0000000000..9edb4b92ac --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/index.xml @@ -0,0 +1,2 @@ + + diff --git a/documentation/getting-started/eclipse/html/getting-started/invalidating-shared-state.html b/documentation/getting-started/eclipse/html/getting-started/invalidating-shared-state.html new file mode 100644 index 0000000000..ef4a2aac5e --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/invalidating-shared-state.html @@ -0,0 +1,77 @@ + + + +3.3.4.2. Invalidating Shared State + + + + + + + +
+

+3.3.4.2. Invalidating Shared State

+

+ The OpenEmbedded build system uses checksums and shared + state cache to avoid unnecessarily rebuilding tasks. + Collectively, this scheme is known as "shared state code." +

+

+ As with all schemes, this one has some drawbacks. + It is possible that you could make implicit changes to your + code that the checksum calculations do not take into + account. + These implicit changes affect a task's output but do not + trigger the shared state code into rebuilding a recipe. + Consider an example during which a tool changes its output. + Assume that the output of rpmdeps + changes. + The result of the change should be that all the + package and + package_write_rpm shared state cache + items become invalid. + However, because the change to the output is + external to the code and therefore implicit, + the associated shared state cache items do not become + invalidated. + In this case, the build process uses the cached items + rather than running the task again. + Obviously, these types of implicit changes can cause + problems. +

+

+ To avoid these problems during the build, you need to + understand the effects of any changes you make. + Realize that changes you make directly to a function + are automatically factored into the checksum calculation. + Thus, these explicit changes invalidate the associated + area of shared state cache. + However, you need to be aware of any implicit changes that + are not obvious changes to the code and could affect + the output of a given task. +

+

+ When you identify an implicit change, you can easily + take steps to invalidate the cache and force the tasks + to run. + The steps you can take are as simple as changing a + function's comments in the source code. + For example, to invalidate package shared state files, + change the comment statements of + do_package + or the comments of one of the functions it calls. + Even though the change is purely cosmetic, it causes the + checksum to be recalculated and forces the OpenEmbedded + build system to run the task again. +

+
+

Note

+ For an example of a commit that makes a cosmetic + change to invalidate shared state, see this + commit. +
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/license-flag-matching.html b/documentation/getting-started/eclipse/html/getting-started/license-flag-matching.html new file mode 100644 index 0000000000..1e08bafad1 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/license-flag-matching.html @@ -0,0 +1,126 @@ + + + +3.7.2.1. License Flag Matching + + + + + + + +
+

+3.7.2.1. License Flag Matching

+

+ License flag matching allows you to control what recipes + the OpenEmbedded build system includes in the build. + Fundamentally, the build system attempts to match + LICENSE_FLAGS + strings found in recipes against + LICENSE_FLAGS_WHITELIST + strings found in the whitelist. + A match causes the build system to include a recipe in the + build, while failure to find a match causes the build + system to exclude a recipe. +

+

+ In general, license flag matching is simple. + However, understanding some concepts will help you + correctly and effectively use matching. +

+

+ Before a flag + defined by a particular recipe is tested against the + contents of the whitelist, the expanded string + _${PN} is appended to the flag. + This expansion makes each + LICENSE_FLAGS value recipe-specific. + After expansion, the string is then matched against the + whitelist. + Thus, specifying + LICENSE_FLAGS = "commercial" + in recipe "foo", for example, results in the string + "commercial_foo". + And, to create a match, that string must appear in the + whitelist. +

+

+ Judicious use of the LICENSE_FLAGS + strings and the contents of the + LICENSE_FLAGS_WHITELIST variable + allows you a lot of flexibility for including or excluding + recipes based on licensing. + For example, you can broaden the matching capabilities by + using license flags string subsets in the whitelist. +

+
+

Note

+ When using a string subset, be sure to use the part of + the expanded string that precedes the appended + underscore character (e.g. + usethispart_1.3, + usethispart_1.4, and so forth). +
+

+ For example, simply specifying the string "commercial" in + the whitelist matches any expanded + LICENSE_FLAGS definition that starts + with the string "commercial" such as "commercial_foo" and + "commercial_bar", which are the strings the build system + automatically generates for hypothetical recipes named + "foo" and "bar" assuming those recipes simply specify the + following: +

+
+     LICENSE_FLAGS = "commercial"
+
+

+ Thus, you can choose to exhaustively + enumerate each license flag in the whitelist and + allow only specific recipes into the image, or + you can use a string subset that causes a broader range of + matches to allow a range of recipes into the image. +

+

+ This scheme works even if the + LICENSE_FLAGS string already + has _${PN} appended. + For example, the build system turns the license flag + "commercial_1.2_foo" into "commercial_1.2_foo_foo" and + would match both the general "commercial" and the specific + "commercial_1.2_foo" strings found in the whitelist, as + expected. +

+

+ Here are some other scenarios: +

+
    +

  • + You can specify a versioned string in the recipe + such as "commercial_foo_1.2" in a "foo" recipe. + The build system expands this string to + "commercial_foo_1.2_foo". + Combine this license flag with a whitelist that has + the string "commercial" and you match the flag + along with any other flag that starts with the + string "commercial". +

    • +

  • + Under the same circumstances, you can use + "commercial_foo" in the whitelist and the build + system not only matches "commercial_foo_1.2" but + also matches any license flag with the string + "commercial_foo", regardless of the version. +

    • +

  • + You can be very specific and use both the + package and version parts in the whitelist (e.g. + "commercial_foo_1.2") to specifically match a + versioned recipe. +

    • +
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/licensing.html b/documentation/getting-started/eclipse/html/getting-started/licensing.html new file mode 100644 index 0000000000..ade868705c --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/licensing.html @@ -0,0 +1,91 @@ + + + +2.6. Licensing + + + + + + + +
+

+2.6. Licensing

+

+ Because open source projects are open to the public, they have + different licensing structures in place. + License evolution for both Open Source and Free Software has an + interesting history. + If you are interested in this history, you can find basic information + here: +

+
+

+

+

+ In general, the Yocto Project is broadly licensed under the + Massachusetts Institute of Technology (MIT) License. + MIT licensing permits the reuse of software within proprietary + software as long as the license is distributed with that software. + MIT is also compatible with the GNU General Public License (GPL). + Patches to the Yocto Project follow the upstream licensing scheme. + You can find information on the MIT license + here. + You can find information on the GNU GPL + here. +

+

+ When you build an image using the Yocto Project, the build process + uses a known list of licenses to ensure compliance. + You can find this list in the + Source Directory + at meta/files/common-licenses. + Once the build completes, the list of all licenses found and used + during that build are kept in the + Build Directory + at tmp/deploy/licenses. +

+

+ If a module requires a license that is not in the base list, the + build process generates a warning during the build. + These tools make it easier for a developer to be certain of the + licenses with which their shipped products must comply. + However, even with these tools it is still up to the developer to + resolve potential licensing issues. +

+

+ The base list of licenses used by the build process is a combination + of the Software Package Data Exchange (SPDX) list and the Open + Source Initiative (OSI) projects. + SPDX Group is a working group of + the Linux Foundation that maintains a specification for a standard + format for communicating the components, licenses, and copyrights + associated with a software package. + OSI is a corporation + dedicated to the Open Source Definition and the effort for reviewing + and approving licenses that conform to the Open Source Definition + (OSD). +

+

+ You can find a list of the combined SPDX and OSI licenses that the + Yocto Project uses in the + meta/files/common-licenses directory in your + Source Directory. +

+

+ For information that can help you maintain compliance with various + open source licensing during the lifecycle of a product created using + the Yocto Project, see the + "Maintaining Open Source License Compliance During Your Product's Lifecycle" + section in the Yocto Project Development Tasks Manual. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/local-projects.html b/documentation/getting-started/eclipse/html/getting-started/local-projects.html new file mode 100644 index 0000000000..9ed618701c --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/local-projects.html @@ -0,0 +1,39 @@ + + + +2.8.3.2. Local Projects + + + + + + + +
+

+2.8.3.2. Local Projects

+

+ Local projects are custom bits of software the user provides. + These bits reside somewhere local to a project - perhaps + a directory into which the user checks in items (e.g. + a local directory containing a development source tree + used by the group). +

+

+ The canonical method through which to include a local project + is to use the + externalsrc + class to include that local project. + You use either the local.conf or a + recipe's append file to override or set the + recipe to point to the local directory on your disk to pull + in the whole source tree. +

+

+ For information on how to use the + externalsrc class, see the + "externalsrc.bbclass" + section. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/metadata-machine-configuration-and-policy-configuration.html b/documentation/getting-started/eclipse/html/getting-started/metadata-machine-configuration-and-policy-configuration.html new file mode 100644 index 0000000000..24f32f394f --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/metadata-machine-configuration-and-policy-configuration.html @@ -0,0 +1,93 @@ + + + +2.8.2. Metadata, Machine Configuration, and Policy Configuration + + + + + + + +
+

+2.8.2. Metadata, Machine Configuration, and Policy Configuration

+

+ The previous section described the user configurations that + define BitBake's global behavior. + This section takes a closer look at the layers the build system + uses to further control the build. + These layers provide Metadata for the software, machine, and + policy. +

+

+ In general, three types of layer input exist: +

+
    +

  • Policy Configuration: + Distribution Layers provide top-level or general + policies for the image or SDK being built. + For example, this layer would dictate whether BitBake + produces RPM or IPK packages.

    • +

  • Machine Configuration: + Board Support Package (BSP) layers provide machine + configurations. + This type of information is specific to a particular + target architecture.

    • +

  • Metadata: + Software layers contain user-supplied recipe files, + patches, and append files. +

    • +
+

+

+

+ The following figure shows an expanded representation of the + Metadata, Machine Configuration, and Policy Configuration input + (layers) boxes of the + general Yocto Project Development Environment figure: +

+

+

+
+

+

+

+ In general, all layers have a similar structure. + They all contain a licensing file + (e.g. COPYING) if the layer is to be + distributed, a README file as good practice + and especially if the layer is to be distributed, a + configuration directory, and recipe directories. +

+

+ The Yocto Project has many layers that can be used. + You can see a web-interface listing of them on the + Source Repositories + page. + The layers are shown at the bottom categorized under + "Yocto Metadata Layers." + These layers are fundamentally a subset of the + OpenEmbedded Metadata Index, + which lists all layers provided by the OpenEmbedded community. +

+
+

Note

+ Layers exist in the Yocto Project Source Repositories that + cannot be found in the OpenEmbedded Metadata Index. + These layers are either deprecated or experimental in nature. +
+

+

+

+ BitBake uses the conf/bblayers.conf file, + which is part of the user configuration, to find what layers it + should be using as part of the build. +

+

+ For more information on layers, see the + "Understanding and Creating Layers" + section in the Yocto Project Development Tasks Manual. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/metadata-virtual-providers.html b/documentation/getting-started/eclipse/html/getting-started/metadata-virtual-providers.html new file mode 100644 index 0000000000..ebbae37990 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/metadata-virtual-providers.html @@ -0,0 +1,74 @@ + + + +3.1.3. Metadata (Virtual Providers) + + + + + + + +
+

+3.1.3. Metadata (Virtual Providers)

+

+ Prior to the build, if you know that several different recipes + provide the same functionality, you can use a virtual provider + (i.e. virtual/*) as a placeholder for the + actual provider. + The actual provider would be determined at build time. + In this case, you should add virtual/* + to + DEPENDS, + rather than listing the specified provider. + You would select the actual provider by setting the + PREFERRED_PROVIDER + variable (i.e. + PREFERRED_PROVIDER_virtual/*) + in the build's configuration file (e.g. + poky/build/conf/local.conf). +

+
+

Note

+ Any recipe that PROVIDES a virtual/* + item that is ultimately not selected through + PREFERRED_PROVIDER does not get built. + Preventing these recipes from building is usually the + desired behavior since this mechanism's purpose is to + select between mutually exclusive alternative providers. +
+

+

+

+ The following lists specific examples of virtual providers: +

+
    +

  • + virtual/mesa: + Provides gbm.pc. +

    • +

  • + virtual/egl: + Provides egl.pc and possibly + wayland-egl.pc. +

    • +

  • + virtual/libgl: + Provides gl.pc (i.e. libGL). +

    • +

  • + virtual/libgles1: + Provides glesv1_cm.pc + (i.e. libGLESv1_CM). +

    • +

  • + virtual/libgles2: + Provides glesv2.pc + (i.e. libGLESv2). +

    • +
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/open-source-philosophy.html b/documentation/getting-started/eclipse/html/getting-started/open-source-philosophy.html new file mode 100644 index 0000000000..bd9467e001 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/open-source-philosophy.html @@ -0,0 +1,54 @@ + + + +2.2. Open Source Philosophy + + + + + + + +
+

+2.2. Open Source Philosophy

+

+ Open source philosophy is characterized by software development + directed by peer production and collaboration through an active + community of developers. + Contrast this to the more standard centralized development models + used by commercial software companies where a finite set of developers + produces a product for sale using a defined set of procedures that + ultimately result in an end product whose architecture and source + material are closed to the public. +

+

+ Open source projects conceptually have differing concurrent agendas, + approaches, and production. + These facets of the development process can come from anyone in the + public (community) that has a stake in the software project. + The open source environment contains new copyright, licensing, domain, + and consumer issues that differ from the more traditional development + environment. + In an open source environment, the end product, source material, + and documentation are all available to the public at no cost. +

+

+ A benchmark example of an open source project is the Linux kernel, + which was initially conceived and created by Finnish computer science + student Linus Torvalds in 1991. + Conversely, a good example of a non-open source project is the + Windows® family of operating + systems developed by + Microsoft® Corporation. +

+

+ Wikipedia has a good historical description of the Open Source + Philosophy + here. + You can also find helpful information on how to participate in the + Linux Community + here. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/other-variables-related-to-commercial-licenses.html b/documentation/getting-started/eclipse/html/getting-started/other-variables-related-to-commercial-licenses.html new file mode 100644 index 0000000000..73d152bb40 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/other-variables-related-to-commercial-licenses.html @@ -0,0 +1,59 @@ + + + +3.7.2.2. Other Variables Related to Commercial Licenses + + + + + + + +
+

+3.7.2.2. Other Variables Related to Commercial Licenses

+

+ Other helpful variables related to commercial + license handling exist and are defined in the + poky/meta/conf/distro/include/default-distrovars.inc file: +

+
+     COMMERCIAL_AUDIO_PLUGINS ?= ""
+     COMMERCIAL_VIDEO_PLUGINS ?= ""
+
+

+ If you want to enable these components, you can do so by + making sure you have statements similar to the following + in your local.conf configuration file: +

+
+     COMMERCIAL_AUDIO_PLUGINS = "gst-plugins-ugly-mad \
+        gst-plugins-ugly-mpegaudioparse"
+     COMMERCIAL_VIDEO_PLUGINS = "gst-plugins-ugly-mpeg2dec \
+        gst-plugins-ugly-mpegstream gst-plugins-bad-mpegvideoparse"
+     LICENSE_FLAGS_WHITELIST = "commercial_gst-plugins-ugly commercial_gst-plugins-bad commercial_qmmp"
+
+

+ Of course, you could also create a matching whitelist + for those components using the more general "commercial" + in the whitelist, but that would also enable all the + other packages with + LICENSE_FLAGS + containing "commercial", which you may or may not want: +

+
+     LICENSE_FLAGS_WHITELIST = "commercial"
+
+

+

+

+ Specifying audio and video plug-ins as part of the + COMMERCIAL_AUDIO_PLUGINS and + COMMERCIAL_VIDEO_PLUGINS statements + (along with the enabling + LICENSE_FLAGS_WHITELIST) includes the + plug-ins or components into built images, thus adding + support for media formats or components. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/overall-architecture.html b/documentation/getting-started/eclipse/html/getting-started/overall-architecture.html new file mode 100644 index 0000000000..974b05792a --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/overall-architecture.html @@ -0,0 +1,40 @@ + + + +3.3.1. Overall Architecture + + + + + + + +
+

+3.3.1. Overall Architecture

+

+ When determining what parts of the system need to be built, + BitBake works on a per-task basis rather than a per-recipe + basis. + You might wonder why using a per-task basis is preferred over + a per-recipe basis. + To help explain, consider having the IPK packaging backend + enabled and then switching to DEB. + In this case, the + do_install + and + do_package + task outputs are still valid. + However, with a per-recipe approach, the build would not + include the .deb files. + Consequently, you would have to invalidate the whole build and + rerun it. + Rerunning everything is not the best solution. + Also, in this case, the core must be "taught" much about + specific tasks. + This methodology does not scale well and does not allow users + to easily add new tasks in layers or as external recipes + without touching the packaged-staging core. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/overview-checksums.html b/documentation/getting-started/eclipse/html/getting-started/overview-checksums.html new file mode 100644 index 0000000000..09ad110f71 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/overview-checksums.html @@ -0,0 +1,209 @@ + + + +3.3.2. Checksums (Signatures) + + + + + + + +
+

+3.3.2. Checksums (Signatures)

+

+ The shared state code uses a checksum, which is a unique + signature of a task's inputs, to determine if a task needs to + be run again. + Because it is a change in a task's inputs that triggers a + rerun, the process needs to detect all the inputs to a given + task. + For shell tasks, this turns out to be fairly easy because + the build process generates a "run" shell script for each task + and it is possible to create a checksum that gives you a good + idea of when the task's data changes. +

+

+ To complicate the problem, there are things that should not be + included in the checksum. + First, there is the actual specific build path of a given + task - the + WORKDIR. + It does not matter if the work directory changes because it + should not affect the output for target packages. + Also, the build process has the objective of making native + or cross packages relocatable. +

+
+

Note

+ Both native and cross packages run on the build host. + However, cross packages generate output for the target + architecture. +
+

+ The checksum therefore needs to exclude + WORKDIR. + The simplistic approach for excluding the work directory is to + set WORKDIR to some fixed value and + create the checksum for the "run" script. +

+

+ Another problem results from the "run" scripts containing + functions that might or might not get called. + The incremental build solution contains code that figures out + dependencies between shell functions. + This code is used to prune the "run" scripts down to the + minimum set, thereby alleviating this problem and making the + "run" scripts much more readable as a bonus. +

+

+ So far we have solutions for shell scripts. + What about Python tasks? + The same approach applies even though these tasks are more + difficult. + The process needs to figure out what variables a Python + function accesses and what functions it calls. + Again, the incremental build solution contains code that first + figures out the variable and function dependencies, and then + creates a checksum for the data used as the input to the task. +

+

+ Like the WORKDIR case, situations exist + where dependencies should be ignored. + For these cases, you can instruct the build process to + ignore a dependency by using a line like the following: +

+
+     PACKAGE_ARCHS[vardepsexclude] = "MACHINE"
+
+

+ This example ensures that the + PACKAGE_ARCHS + variable does not depend on the value of + MACHINE, + even if it does reference it. +

+

+ Equally, there are cases where we need to add dependencies + BitBake is not able to find. + You can accomplish this by using a line like the following: +

+
+      PACKAGE_ARCHS[vardeps] = "MACHINE"
+
+

+ This example explicitly adds the MACHINE + variable as a dependency for + PACKAGE_ARCHS. +

+

+ Consider a case with in-line Python, for example, where + BitBake is not able to figure out dependencies. + When running in debug mode (i.e. using + -DDD), BitBake produces output when it + discovers something for which it cannot figure out dependencies. + The Yocto Project team has currently not managed to cover + those dependencies in detail and is aware of the need to fix + this situation. +

+

+ Thus far, this section has limited discussion to the direct + inputs into a task. + Information based on direct inputs is referred to as the + "basehash" in the code. + However, there is still the question of a task's indirect + inputs - the things that were already built and present in the + Build Directory. + The checksum (or signature) for a particular task needs to add + the hashes of all the tasks on which the particular task + depends. + Choosing which dependencies to add is a policy decision. + However, the effect is to generate a master checksum that + combines the basehash and the hashes of the task's + dependencies. +

+

+ At the code level, there are a variety of ways both the + basehash and the dependent task hashes can be influenced. + Within the BitBake configuration file, we can give BitBake + some extra information to help it construct the basehash. + The following statement effectively results in a list of + global variable dependency excludes - variables never + included in any checksum: +

+
+     BB_HASHBASE_WHITELIST ?= "TMPDIR FILE PATH PWD BB_TASKHASH BBPATH DL_DIR \
+         SSTATE_DIR THISDIR FILESEXTRAPATHS FILE_DIRNAME HOME LOGNAME SHELL TERM \
+         USER FILESPATH STAGING_DIR_HOST STAGING_DIR_TARGET COREBASE PRSERV_HOST \
+         PRSERV_DUMPDIR PRSERV_DUMPFILE PRSERV_LOCKDOWN PARALLEL_MAKE \
+         CCACHE_DIR EXTERNAL_TOOLCHAIN CCACHE CCACHE_DISABLE LICENSE_PATH SDKPKGSUFFIX"
+
+

+ The previous example excludes + WORKDIR + since that variable is actually constructed as a path within + TMPDIR, + which is on the whitelist. +

+

+ The rules for deciding which hashes of dependent tasks to + include through dependency chains are more complex and are + generally accomplished with a Python function. + The code in meta/lib/oe/sstatesig.py shows + two examples of this and also illustrates how you can insert + your own policy into the system if so desired. + This file defines the two basic signature generators + OE-Core + uses: "OEBasic" and "OEBasicHash". + By default, there is a dummy "noop" signature handler enabled + in BitBake. + This means that behavior is unchanged from previous versions. + OE-Core uses the "OEBasicHash" signature handler by default + through this setting in the bitbake.conf + file: +

+
+     BB_SIGNATURE_HANDLER ?= "OEBasicHash"
+
+

+ The "OEBasicHash" BB_SIGNATURE_HANDLER + is the same as the "OEBasic" version but adds the task hash to + the stamp files. + This results in any + Metadata + change that changes the task hash, automatically + causing the task to be run again. + This removes the need to bump + PR + values, and changes to Metadata automatically ripple across + the build. +

+

+ It is also worth noting that the end result of these + signature generators is to make some dependency and hash + information available to the build. + This information includes: +

+
    +

  • + BB_BASEHASH_task-taskname: + The base hashes for each task in the recipe. +

    • +

  • + BB_BASEHASH_filename:taskname: + The base hashes for each dependent task. +

    • +

  • + BBHASHDEPS_filename:taskname: + The task dependencies for each task. +

    • +

  • + BB_TASKHASH: + The hash of the currently running task. +

    • +
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/overview-concepts.html b/documentation/getting-started/eclipse/html/getting-started/overview-concepts.html new file mode 100644 index 0000000000..855d22e109 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/overview-concepts.html @@ -0,0 +1,57 @@ + + + +Chapter 3. Yocto Project Concepts + + + + + + + +
+

+Chapter 3. Yocto Project Concepts

+
+

Table of Contents

+
+
3.1. Yocto Project Components
+
+
3.1.1. BitBake
+
3.1.2. Metadata (Recipes)
+
3.1.3. Metadata (Virtual Providers)
+
3.1.4. Classes
+
3.1.5. Configuration
+
+
3.2. Cross-Development Toolchain Generation
+
3.3. Shared State Cache
+
+
3.3.1. Overall Architecture
+
3.3.2. Checksums (Signatures)
+
3.3.3. Shared State
+
3.3.4. Tips and Tricks
+
+
3.4. Automatically Added Runtime Dependencies
+
3.5. Fakeroot and Pseudo
+
3.6. Wayland
+
+
3.6.1. Support
+
3.6.2. Enabling Wayland in an Image
+
3.6.3. Running Weston
+
+
3.7. Licenses
+
+
3.7.1. Tracking License Changes
+
3.7.2. Enabling Commercially Licensed Recipes
+
+
3.8. x32 psABI
+
+
+

+ This chapter describes concepts for various areas of the Yocto Project. + Currently, topics include Yocto Project components, cross-development + generation, shared state (sstate) cache, runtime dependencies, + Pseudo and Fakeroot, x32 psABI, Wayland support, and Licenses. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/overview-debugging.html b/documentation/getting-started/eclipse/html/getting-started/overview-debugging.html new file mode 100644 index 0000000000..b8b4c880e7 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/overview-debugging.html @@ -0,0 +1,28 @@ + + + +3.3.4.1. Debugging + + + + + + + +
+

+3.3.4.1. Debugging

+

+ Seeing what metadata went into creating the input signature + of a shared state (sstate) task can be a useful debugging + aid. + This information is available in signature information + (siginfo) files in + SSTATE_DIR. + For information on how to view and interpret information in + siginfo files, see the + "Viewing Task Variable Dependencies" + section in the Yocto Project Development Tasks Manual. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/overview-development-environment.html b/documentation/getting-started/eclipse/html/getting-started/overview-development-environment.html new file mode 100644 index 0000000000..c8030fee19 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/overview-development-environment.html @@ -0,0 +1,56 @@ + + + +Chapter 2. The Yocto Project Development Environment + + + + + + + +
+

+Chapter 2. The Yocto Project Development Environment

+
+

Table of Contents

+
+
2.1. Introduction
+
2.2. Open Source Philosophy
+
2.3. Workflows
+
2.4. Git
+
+
2.4.1. Repositories, Tags, and Branches
+
2.4.2. Basic Commands
+
+
2.5. Yocto Project Source Repositories
+
2.6. Licensing
+
2.7. Recipe Syntax
+
2.8. Development Concepts
+
+
2.8.1. User Configuration
+
2.8.2. Metadata, Machine Configuration, and Policy Configuration
+
2.8.3. Sources
+
2.8.4. Package Feeds
+
2.8.5. BitBake
+
2.8.6. Images
+
2.8.7. Application Development SDK
+
+
+
+

+ This chapter takes a look at the Yocto Project development + environment and also provides a detailed look at what goes on during + development in that environment. + The chapter provides Yocto Project Development environment concepts that + help you understand how work is accomplished in an open source environment, + which is very different as compared to work accomplished in a closed, + proprietary environment. +

+

+ Specifically, this chapter addresses open source philosophy, workflows, + Git, source repositories, licensing, recipe syntax, and development + syntax. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/overview-licenses.html b/documentation/getting-started/eclipse/html/getting-started/overview-licenses.html new file mode 100644 index 0000000000..eca1f71d2d --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/overview-licenses.html @@ -0,0 +1,29 @@ + + + +3.7. Licenses + + + + + + + +
+

+3.7. Licenses

+

+ This section describes the mechanism by which the OpenEmbedded + build system tracks changes to licensing text. + The section also describes how to enable commercially licensed + recipes, which by default are disabled. +

+

+ For information that can help you maintain compliance with + various open source licensing during the lifecycle of the product, + see the + "Maintaining Open Source License Compliance During Your Project's Lifecycle" + section in the Yocto Project Development Tasks Manual. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/overview-manual-intro.html b/documentation/getting-started/eclipse/html/getting-started/overview-manual-intro.html new file mode 100644 index 0000000000..ab4e1f338f --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/overview-manual-intro.html @@ -0,0 +1,23 @@ + + + +Chapter 1. The Yocto Project Overview Manual + + + + + + + +
+

+Chapter 1. The Yocto Project Overview Manual

+
+

Table of Contents

+
+
1.1. Welcome
+
1.2. Other Information
+
+
+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/overview-other-information.html b/documentation/getting-started/eclipse/html/getting-started/overview-other-information.html new file mode 100644 index 0000000000..03210c6ebf --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/overview-other-information.html @@ -0,0 +1,31 @@ + + + +1.2. Other Information + + + + + + + +
+

+1.2. Other Information

+

+ Because this manual presents information for many different + topics, supplemental information is recommended for full + comprehension. + For additional introductory information on the Yocto Project, see + the Yocto Project Website. + You can find an introductory to using the Yocto Project by working + through the + Yocto Project Quick Start. +

+

+ For a comprehensive list of links and other documentation, see the + "Links and Related Documentation" + section in the Yocto Project Reference Manual. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/overview-welcome.html b/documentation/getting-started/eclipse/html/getting-started/overview-welcome.html new file mode 100644 index 0000000000..1bc34e081c --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/overview-welcome.html @@ -0,0 +1,85 @@ + + + +1.1. Welcome + + + + + + + +
+

+1.1. Welcome

+

+ Welcome to the Yocto Project Overview Manual! + This manual introduces the Yocto Project by providing concepts, + software overviews, best-known-methods (BKMs), and any other + high-level introductory information suitable for a new Yocto + Project user. +

+

+ The following list describes what you can get from this manual: +

+
    +

  • + Major Topic: + Provide a high-level description of this major topic. +

    • +

  • + Major Topic: + Provide a high-level description of this major topic. +

    • +

  • + Major Topic: + Provide a high-level description of this major topic. +

    • +

  • + Major Topic: + Provide a high-level description of this major topic. +

    • +
+

+

+

+ This manual does not give you the following: +

+
    +

  • + Step-by-step Instructions for Development Tasks: + Instructional procedures reside in other manuals within + the Yocto Project documentation set. + For example, the + Yocto Project Development Tasks Manual + provides examples on how to perform various development + tasks. + As another example, the + Yocto Project Application Development and the Extensible Software Development Kit (eSDK) + manual contains detailed instructions on how to install an + SDK, which is used to develop applications for target + hardware. +

    • +

  • + Reference Material: + This type of material resides in an appropriate reference + manual. + For example, system variables are documented in the + Yocto Project Reference Manual. + As another example, the + Yocto Project Board Support Package (BSP) Developer's Guide + contains reference information on BSPs. +

    • +

  • + Detailed Public Information Not Specific to the + Yocto Project: + For example, exhaustive information on how to use the + Source Control Manager Git is better covered with Internet + searches and official Git Documentation than through the + Yocto Project documentation. +

    • +
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/package-feeds-dev-environment.html b/documentation/getting-started/eclipse/html/getting-started/package-feeds-dev-environment.html new file mode 100644 index 0000000000..ad3d67f660 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/package-feeds-dev-environment.html @@ -0,0 +1,98 @@ + + + +2.8.4. Package Feeds + + + + + + + +
+

+2.8.4. Package Feeds

+

+ When the OpenEmbedded build system generates an image or an SDK, + it gets the packages from a package feed area located in the + Build Directory. + The + general Yocto Project Development Environment figure + shows this package feeds area in the upper-right corner. +

+

+ This section looks a little closer into the package feeds area used + by the build system. + Here is a more detailed look at the area: +

+
+

+

+

+ Package feeds are an intermediary step in the build process. + The OpenEmbedded build system provides classes to generate + different package types, and you specify which classes to enable + through the + PACKAGE_CLASSES + variable. + Before placing the packages into package feeds, + the build process validates them with generated output quality + assurance checks through the + insane + class. +

+

+ The package feed area resides in the Build Directory. + The directory the build system uses to temporarily store packages + is determined by a combination of variables and the particular + package manager in use. + See the "Package Feeds" box in the illustration and note the + information to the right of that area. + In particular, the following defines where package files are + kept: +

+
    +

  • DEPLOY_DIR: + Defined as tmp/deploy in the Build + Directory. +

    • +

  • DEPLOY_DIR_*: + Depending on the package manager used, the package type + sub-folder. + Given RPM, IPK, or DEB packaging and tarball creation, the + DEPLOY_DIR_RPM, + DEPLOY_DIR_IPK, + DEPLOY_DIR_DEB, + or + DEPLOY_DIR_TAR, + variables are used, respectively. +

    • +

  • PACKAGE_ARCH: + Defines architecture-specific sub-folders. + For example, packages could exist for the i586 or qemux86 + architectures. +

    • +
+

+

+

+ BitBake uses the do_package_write_* tasks to + generate packages and place them into the package holding area (e.g. + do_package_write_ipk for IPK packages). + See the + "do_package_write_deb", + "do_package_write_ipk", + "do_package_write_rpm", + and + "do_package_write_tar" + sections for additional information. + As an example, consider a scenario where an IPK packaging manager + is being used and package architecture support for both i586 + and qemux86 exist. + Packages for the i586 architecture are placed in + build/tmp/deploy/ipk/i586, while packages for + the qemux86 architecture are placed in + build/tmp/deploy/ipk/qemux86. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/package-splitting-dev-environment.html b/documentation/getting-started/eclipse/html/getting-started/package-splitting-dev-environment.html new file mode 100644 index 0000000000..882d66c31c --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/package-splitting-dev-environment.html @@ -0,0 +1,94 @@ + + + +2.8.5.4. Package Splitting + + + + + + + +
+

+2.8.5.4. Package Splitting

+

+ After source code is configured and compiled, the + OpenEmbedded build system analyzes + the results and splits the output into packages: +

+
+

+

+

+ The + do_package + and + do_packagedata + tasks combine to analyze + the files found in the + D directory + and split them into subsets based on available packages and + files. + The analyzing process involves the following as well as other + items: splitting out debugging symbols, + looking at shared library dependencies between packages, + and looking at package relationships. + The do_packagedata task creates package + metadata based on the analysis such that the + OpenEmbedded build system can generate the final packages. + Working, staged, and intermediate results of the analysis + and package splitting process use these areas: +

+
    +

  • PKGD - + The destination directory for packages before they are + split. +

    • +

  • PKGDATA_DIR - + A shared, global-state directory that holds data + generated during the packaging process. +

    • +

  • PKGDESTWORK - + A temporary work area used by the + do_package task. +

    • +

  • PKGDEST - + The parent directory for packages after they have + been split. +

    • +
+

+ The FILES + variable defines the files that go into each package in + PACKAGES. + If you want details on how this is accomplished, you can + look at the + package + class. +

+

+ Depending on the type of packages being created (RPM, DEB, or + IPK), the do_package_write_* task + creates the actual packages and places them in the + Package Feed area, which is + ${TMPDIR}/deploy. + You can see the + "Package Feeds" + section for more detail on that part of the build process. +

+
+

Note

+ Support for creating feeds directly from the + deploy/* directories does not exist. + Creating such feeds usually requires some kind of feed + maintenance mechanism that would upload the new packages + into an official package feed (e.g. the + Ångström distribution). + This functionality is highly distribution-specific + and thus is not provided out of the box. +
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/patching-dev-environment.html b/documentation/getting-started/eclipse/html/getting-started/patching-dev-environment.html new file mode 100644 index 0000000000..60ae6b020b --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/patching-dev-environment.html @@ -0,0 +1,48 @@ + + + +2.8.5.2. Patching + + + + + + + +
+

+2.8.5.2. Patching

+

+ Once source code is fetched and unpacked, BitBake locates + patch files and applies them to the source files: +

+
+

+

+

+ The + do_patch + task processes recipes by + using the + SRC_URI + variable to locate applicable patch files, which by default + are *.patch or + *.diff files, or any file if + "apply=yes" is specified for the file in + SRC_URI. +

+

+ BitBake finds and applies multiple patches for a single recipe + in the order in which it finds the patches. + Patches are applied to the recipe's source files located in the + S + directory. +

+

+ For more information on how the source directories are + created, see the + "Source Fetching" + section. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/recipe-syntax.html b/documentation/getting-started/eclipse/html/getting-started/recipe-syntax.html new file mode 100644 index 0000000000..fcf46d9d35 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/recipe-syntax.html @@ -0,0 +1,383 @@ + + + +2.7. Recipe Syntax + + + + + + + +
+

+2.7. Recipe Syntax

+

+ Understanding recipe file syntax is important for + writing recipes. + The following list overviews the basic items that make up a + BitBake recipe file. + For more complete BitBake syntax descriptions, see the + "Syntax and Operators" + chapter of the BitBake User Manual. +

+
    +
  • +

    Variable Assignments and Manipulations: + Variable assignments allow a value to be assigned to a + variable. + The assignment can be static text or might include + the contents of other variables. + In addition to the assignment, appending and prepending + operations are also supported.

    +

    The following example shows some of the ways + you can use variables in recipes: +

    +
    +     S = "${WORKDIR}/postfix-${PV}"
+     CFLAGS += "-DNO_ASM"
+     SRC_URI_append = " file://fixup.patch"
+
    +

    +

    +
    • +
  • +

    Functions: + Functions provide a series of actions to be performed. + You usually use functions to override the default + implementation of a task function or to complement + a default function (i.e. append or prepend to an + existing function). + Standard functions use sh shell + syntax, although access to OpenEmbedded variables and + internal methods are also available.

    +

    The following is an example function from the + sed recipe: +

    +
    +     do_install () {
+         autotools_do_install
+         install -d ${D}${base_bindir}
+         mv ${D}${bindir}/sed ${D}${base_bindir}/sed
+         rmdir ${D}${bindir}/
+     }
+
    +

    + It is also possible to implement new functions that + are called between existing tasks as long as the + new functions are not replacing or complementing the + default functions. + You can implement functions in Python + instead of shell. + Both of these options are not seen in the majority of + recipes.

    +
    • +
  • +

    Keywords: + BitBake recipes use only a few keywords. + You use keywords to include common + functions (inherit), load parts + of a recipe from other files + (include and + require) and export variables + to the environment (export).

    +

    The following example shows the use of some of + these keywords: +

    +
    +     export POSTCONF = "${STAGING_BINDIR}/postconf"
+     inherit autoconf
+     require otherfile.inc
+
    +

    +

    +
    • +
  • +

    Comments: + Any lines that begin with the hash character + (#) are treated as comment lines + and are ignored: +

    +
    +     # This is a comment
+
    +

    +

    +
    • +
+

+

+

+ This next list summarizes the most important and most commonly + used parts of the recipe syntax. + For more information on these parts of the syntax, you can + reference the + Syntax and Operators + chapter in the BitBake User Manual. +

+
    +
  • +

    Line Continuation: \ - + Use the backward slash (\) + character to split a statement over multiple lines. + Place the slash character at the end of the line that + is to be continued on the next line: +

    +
    +     VAR = "A really long \
+            line"
+
    +

    +

    +
    +

    Note

    + You cannot have any characters including spaces + or tabs after the slash character. +
    +

    +

    +
    • +
  • +

    + Using Variables: ${...} - + Use the ${VARNAME} syntax to + access the contents of a variable: +

    +
    +     SRC_URI = "${SOURCEFORGE_MIRROR}/libpng/zlib-${PV}.tar.gz"
+
    +

    +

    +
    +

    Note

    + It is important to understand that the value of a + variable expressed in this form does not get + substituted automatically. + The expansion of these expressions happens + on-demand later (e.g. usually when a function that + makes reference to the variable executes). + This behavior ensures that the values are most + appropriate for the context in which they are + finally used. + On the rare occasion that you do need the variable + expression to be expanded immediately, you can use + the := operator instead of + = when you make the + assignment, but this is not generally needed. +
    +

    +

    +
    • +
  • +

    Quote All Assignments: "value" - + Use double quotes around the value in all variable + assignments. +

    +
    +     VAR1 = "${OTHERVAR}"
+     VAR2 = "The version is ${PV}"
+
    +

    +

    +
    • +
  • +

    Conditional Assignment: ?= - + Conditional assignment is used to assign a value to + a variable, but only when the variable is currently + unset. + Use the question mark followed by the equal sign + (?=) to make a "soft" assignment + used for conditional assignment. + Typically, "soft" assignments are used in the + local.conf file for variables + that are allowed to come through from the external + environment. +

    +

    Here is an example where + VAR1 is set to "New value" if + it is currently empty. + However, if VAR1 has already been + set, it remains unchanged: +

    +
    +     VAR1 ?= "New value"
+
    +

    + In this next example, VAR1 + is left with the value "Original value": +

    +
    +     VAR1 = "Original value"
+     VAR1 ?= "New value"
+
    +

    +

    +
    • +
  • +

    Appending: += - + Use the plus character followed by the equals sign + (+=) to append values to existing + variables. +

    +
    +

    Note

    + This operator adds a space between the existing + content of the variable and the new content. +
    +

    Here is an example: +

    +
    +     SRC_URI += "file://fix-makefile.patch"
+
    +

    +

    +
    • +
  • +

    Prepending: =+ - + Use the equals sign followed by the plus character + (=+) to prepend values to existing + variables. +

    +
    +

    Note

    + This operator adds a space between the new content + and the existing content of the variable. +
    +

    Here is an example: +

    +
    +     VAR =+ "Starts"
+
    +

    +

    +
    • +
  • +

    Appending: _append - + Use the _append operator to + append values to existing variables. + This operator does not add any additional space. + Also, the operator is applied after all the + +=, and + =+ operators have been applied and + after all = assignments have + occurred. +

    +

    The following example shows the space being + explicitly added to the start to ensure the appended + value is not merged with the existing value: +

    +
    +     SRC_URI_append = " file://fix-makefile.patch"
+
    +

    + You can also use the _append + operator with overrides, which results in the actions + only being performed for the specified target or + machine: +

    +
    +     SRC_URI_append_sh4 = " file://fix-makefile.patch"
+
    +

    +

    +
    • +
  • +

    Prepending: _prepend - + Use the _prepend operator to + prepend values to existing variables. + This operator does not add any additional space. + Also, the operator is applied after all the + +=, and + =+ operators have been applied and + after all = assignments have + occurred. +

    +

    The following example shows the space being + explicitly added to the end to ensure the prepended + value is not merged with the existing value: +

    +
    +     CFLAGS_prepend = "-I${S}/myincludes "
+
    +

    + You can also use the _prepend + operator with overrides, which results in the actions + only being performed for the specified target or + machine: +

    +
    +     CFLAGS_prepend_sh4 = "-I${S}/myincludes "
+
    +

    +

    +
    • +
  • +

    Overrides: - + You can use overrides to set a value conditionally, + typically based on how the recipe is being built. + For example, to set the + KBRANCH + variable's value to "standard/base" for any target + MACHINE, + except for qemuarm where it should be set to + "standard/arm-versatile-926ejs", you would do the + following: +

    +
    +     KBRANCH = "standard/base"
+     KBRANCH_qemuarm  = "standard/arm-versatile-926ejs"
+
    +

    + Overrides are also used to separate alternate values + of a variable in other situations. + For example, when setting variables such as + FILES + and + RDEPENDS + that are specific to individual packages produced by + a recipe, you should always use an override that + specifies the name of the package. +

    +
    • +

  • Indentation: + Use spaces for indentation rather than than tabs. + For shell functions, both currently work. + However, it is a policy decision of the Yocto Project + to use tabs in shell functions. + Realize that some layers have a policy to use spaces + for all indentation. +

    • +
  • +

    Using Python for Complex Operations: ${@python_code} - + For more advanced processing, it is possible to use + Python code during variable assignments (e.g. + search and replacement on a variable).

    +

    You indicate Python code using the + ${@python_code} + syntax for the variable assignment: +

    +
    +     SRC_URI = "ftp://ftp.info-zip.org/pub/infozip/src/zip${@d.getVar('PV',1).replace('.', '')}.tgz
+
    +

    +

    +
    • +

  • Shell Function Syntax: + Write shell functions as if you were writing a shell + script when you describe a list of actions to take. + You should ensure that your script works with a generic + sh and that it does not require + any bash or other shell-specific + functionality. + The same considerations apply to various system + utilities (e.g. sed, + grep, awk, + and so forth) that you might wish to use. + If in doubt, you should check with multiple + implementations - including those from BusyBox. +

    • +
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/repositories-tags-and-branches.html b/documentation/getting-started/eclipse/html/getting-started/repositories-tags-and-branches.html new file mode 100644 index 0000000000..d813948375 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/repositories-tags-and-branches.html @@ -0,0 +1,173 @@ + + + +2.4.1. Repositories, Tags, and Branches + + + + + + + +
+

+2.4.1. Repositories, Tags, and Branches

+

+ As mentioned briefly in the previous section and also in the + "Workflows" section, + the Yocto Project maintains source repositories at + http://git.yoctoproject.org/cgit.cgi. + If you look at this web-interface of the repositories, each item + is a separate Git repository. +

+

+ Git repositories use branching techniques that track content + change (not files) within a project (e.g. a new feature or updated + documentation). + Creating a tree-like structure based on project divergence allows + for excellent historical information over the life of a project. + This methodology also allows for an environment from which you can + do lots of local experimentation on projects as you develop + changes or new features. +

+

+ A Git repository represents all development efforts for a given + project. + For example, the Git repository poky contains + all changes and developments for Poky over the course of its + entire life. + That means that all changes that make up all releases are captured. + The repository maintains a complete history of changes. +

+

+ You can create a local copy of any repository by "cloning" it + with the git clone command. + When you clone a Git repository, you end up with an identical + copy of the repository on your development system. + Once you have a local copy of a repository, you can take steps to + develop locally. + For examples on how to clone Git repositories, see the + "Working With Yocto Project Source Files" + section in the Yocto Project Development Tasks Manual. +

+

+ It is important to understand that Git tracks content change and + not files. + Git uses "branches" to organize different development efforts. + For example, the poky repository has + several branches that include the current "sumo" + branch, the "master" branch, and many branches for past + Yocto Project releases. + You can see all the branches by going to + http://git.yoctoproject.org/cgit.cgi/poky/ and + clicking on the + [...] + link beneath the "Branch" heading. +

+

+ Each of these branches represents a specific area of development. + The "master" branch represents the current or most recent + development. + All other branches represent offshoots of the "master" branch. +

+

+ When you create a local copy of a Git repository, the copy has + the same set of branches as the original. + This means you can use Git to create a local working area + (also called a branch) that tracks a specific development branch + from the upstream source Git repository. + in other words, you can define your local Git environment to + work on any development branch in the repository. + To help illustrate, consider the following example Git commands: +

+
+     $ cd ~
+     $ git clone git://git.yoctoproject.org/poky
+     $ cd poky
+     $ git checkout -b sumo origin/sumo
+
+

+ In the previous example after moving to the home directory, the + git clone command creates a + local copy of the upstream poky Git repository. + By default, Git checks out the "master" branch for your work. + After changing the working directory to the new local repository + (i.e. poky), the + git checkout command creates + and checks out a local branch named "sumo", which + tracks the upstream "origin/sumo" branch. + Changes you make while in this branch would ultimately affect + the upstream "sumo" branch of the + poky repository. +

+

+ It is important to understand that when you create and checkout a + local working branch based on a branch name, + your local environment matches the "tip" of that particular + development branch at the time you created your local branch, + which could be different from the files in the "master" branch + of the upstream repository. + In other words, creating and checking out a local branch based on + the "sumo" branch name is not the same as + cloning and checking out the "master" branch if the repository. + Keep reading to see how you create a local snapshot of a Yocto + Project Release. +

+

+ Git uses "tags" to mark specific changes in a repository. + Typically, a tag is used to mark a special point such as the final + change before a project is released. + You can see the tags used with the poky Git + repository by going to + http://git.yoctoproject.org/cgit.cgi/poky/ and + clicking on the + [...] + link beneath the "Tag" heading. +

+

+ Some key tags for the poky are + jethro-14.0.3, + morty-16.0.1, + pyro-17.0.0, and + sumo-20.0.0. + These tags represent Yocto Project releases. +

+

+ When you create a local copy of the Git repository, you also + have access to all the tags in the upstream repository. + Similar to branches, you can create and checkout a local working + Git branch based on a tag name. + When you do this, you get a snapshot of the Git repository that + reflects the state of the files when the change was made associated + with that tag. + The most common use is to checkout a working branch that matches + a specific Yocto Project release. + Here is an example: +

+
+     $ cd ~
+     $ git clone git://git.yoctoproject.org/poky
+     $ cd poky
+     $ git fetch --all --tags --prune
+     $ git checkout tags/pyro-17.0.0 -b my-pyro-17.0.0
+
+

+ In this example, the name of the top-level directory of your + local Yocto Project repository is poky. + After moving to the poky directory, the + git fetch command makes all the upstream + tags available locally in your repository. + Finally, the git checkout command + creates and checks out a branch named "my-pyro-17.0.0" that is + based on the specific change upstream in the repository + associated with the "pyro-17.0.0" tag. + The files in your repository now exactly match that particular + Yocto Project release as it is tagged in the upstream Git + repository. + It is important to understand that when you create and + checkout a local working branch based on a tag, your environment + matches a specific point in time and not the entire development + branch (i.e. the "tip" of the branch). +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/running-weston.html b/documentation/getting-started/eclipse/html/getting-started/running-weston.html new file mode 100644 index 0000000000..b68f574134 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/running-weston.html @@ -0,0 +1,53 @@ + + + +3.6.3. Running Weston + + + + + + + +
+

+3.6.3. Running Weston

+

+ To run Weston inside X11, enabling it as described earlier and + building a Sato image is sufficient. + If you are running your image under Sato, a Weston Launcher + appears in the "Utility" category. +

+

+ Alternatively, you can run Weston through the command-line + interpretor (CLI), which is better suited for development work. + To run Weston under the CLI, you need to do the following after + your image is built: +

+
    +
  1. +

    + Run these commands to export + XDG_RUNTIME_DIR: +

    +
    +     mkdir -p /tmp/$USER-weston
+     chmod 0700 /tmp/$USER-weston
+     export XDG_RUNTIME_DIR=/tmp/$USER-weston
+
    +

    +

    +
    2. +
  2. +

    + Launch Weston in the shell: +

    +
    +     weston
+
    +
    3. +
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/scms.html b/documentation/getting-started/eclipse/html/getting-started/scms.html new file mode 100644 index 0000000000..f2ec54340c --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/scms.html @@ -0,0 +1,42 @@ + + + +2.8.3.3. Source Control Managers (Optional) + + + + + + + +
+

+2.8.3.3. Source Control Managers (Optional)

+

+ Another place the build system can get source files from is + through an SCM such as Git or Subversion. + In this case, a repository is cloned or checked out. + The + do_fetch + task inside BitBake uses + the SRC_URI + variable and the argument's prefix to determine the correct + fetcher module. +

+
+

Note

+ For information on how to have the OpenEmbedded build system + generate tarballs for Git repositories and place them in the + DL_DIR + directory, see the + BB_GENERATE_MIRROR_TARBALLS + variable. +
+

+ When fetching a repository, BitBake uses the + SRCREV + variable to determine the specific revision from which to + build. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/sdk-dev-environment.html b/documentation/getting-started/eclipse/html/getting-started/sdk-dev-environment.html new file mode 100644 index 0000000000..d2cd6a480e --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/sdk-dev-environment.html @@ -0,0 +1,150 @@ + + + +2.8.7. Application Development SDK + + + + + + + +
+

+2.8.7. Application Development SDK

+

+ In the + general Yocto Project Development Environment figure, + the output labeled "Application Development SDK" represents an + SDK. + The SDK generation process differs depending on whether you build + a standard SDK + (e.g. bitbake -c populate_sdk imagename) + or an extensible SDK + (e.g. bitbake -c populate_sdk_ext imagename). + This section is going to take a closer look at this output: +

+
+

+

+

+ The specific form of this output is a self-extracting + SDK installer (*.sh) that, when run, + installs the SDK, which consists of a cross-development + toolchain, a set of libraries and headers, and an SDK + environment setup script. + Running this installer essentially sets up your + cross-development environment. + You can think of the cross-toolchain as the "host" + part because it runs on the SDK machine. + You can think of the libraries and headers as the "target" + part because they are built for the target hardware. + The environment setup script is added so that you can initialize + the environment before using the tools. +

+
+

Notes

+
+
+

+ Once built, the SDK installers are written out to the + deploy/sdk folder inside the + Build Directory + as shown in the figure at the beginning of this section. + Depending on the type of SDK, several variables exist that help + configure these files. + The following list shows the variables associated with a standard + SDK: +

+
    +

  • DEPLOY_DIR: + Points to the deploy + directory.

    • +

  • SDKMACHINE: + Specifies the architecture of the machine + on which the cross-development tools are run to + create packages for the target hardware. +

    • +

  • SDKIMAGE_FEATURES: + Lists the features to include in the "target" part + of the SDK. +

    • +

  • TOOLCHAIN_HOST_TASK: + Lists packages that make up the host + part of the SDK (i.e. the part that runs on + the SDKMACHINE). + When you use + bitbake -c populate_sdk imagename + to create the SDK, a set of default packages + apply. + This variable allows you to add more packages. +

    • +

  • TOOLCHAIN_TARGET_TASK: + Lists packages that make up the target part + of the SDK (i.e. the part built for the + target hardware). +

    • +

  • SDKPATH: + Defines the default SDK installation path offered by the + installation script. +

    • +
+

+ This next list, shows the variables associated with an extensible + SDK: +

+
    +

  • DEPLOY_DIR: + Points to the deploy directory. +

    • +

  • SDK_EXT_TYPE: + Controls whether or not shared state artifacts are copied + into the extensible SDK. + By default, all required shared state artifacts are copied + into the SDK. +

    • +

  • SDK_INCLUDE_PKGDATA: + Specifies whether or not packagedata will be included in + the extensible SDK for all recipes in the "world" target. +

    • +

  • SDK_INCLUDE_TOOLCHAIN: + Specifies whether or not the toolchain will be included + when building the extensible SDK. +

    • +

  • SDK_LOCAL_CONF_WHITELIST: + A list of variables allowed through from the build system + configuration into the extensible SDK configuration. +

    • +

  • SDK_LOCAL_CONF_BLACKLIST: + A list of variables not allowed through from the build + system configuration into the extensible SDK configuration. +

    • +

  • SDK_INHERIT_BLACKLIST: + A list of classes to remove from the + INHERIT + value globally within the extensible SDK configuration. +

    • +
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/sdk-generation-dev-environment.html b/documentation/getting-started/eclipse/html/getting-started/sdk-generation-dev-environment.html new file mode 100644 index 0000000000..1dfda5fab5 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/sdk-generation-dev-environment.html @@ -0,0 +1,72 @@ + + + +2.8.5.6. SDK Generation + + + + + + + +
+

+2.8.5.6. SDK Generation

+

+ The OpenEmbedded build system uses BitBake to generate the + Software Development Kit (SDK) installer script for both the + standard and extensible SDKs: + +

+
+

Note

+ For more information on the cross-development toolchain + generation, see the + "Cross-Development Toolchain Generation" + section. + For information on advantages gained when building a + cross-development toolchain using the + do_populate_sdk + task, see the + "Building an SDK Installer" + section in the Yocto Project Application Development and the + Extensible Software Development Kit (SDK) manual. +
+

+ Like image generation, the SDK script process consists of + several stages and depends on many variables. + The do_populate_sdk and + do_populate_sdk_ext tasks use these + key variables to help create the list of packages to actually + install. + For information on the variables listed in the figure, see the + "Application Development SDK" + section. +

+

+ The do_populate_sdk task helps create + the standard SDK and handles two parts: a target part and a + host part. + The target part is the part built for the target hardware and + includes libraries and headers. + The host part is the part of the SDK that runs on the + SDKMACHINE. +

+

+ The do_populate_sdk_ext task helps create + the extensible SDK and handles host and target parts + differently than its counter part does for the standard SDK. + For the extensible SDK, the task encapsulates the build system, + which includes everything needed (host and target) for the SDK. +

+

+ Regardless of the type of SDK being constructed, the + tasks perform some cleanup after which a cross-development + environment setup script and any needed configuration files + are created. + The final output is the Cross-development + toolchain installation script (.sh file), + which includes the environment setup script. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/setscene-tasks-and-shared-state.html b/documentation/getting-started/eclipse/html/getting-started/setscene-tasks-and-shared-state.html new file mode 100644 index 0000000000..644e404b66 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/setscene-tasks-and-shared-state.html @@ -0,0 +1,122 @@ + + + +2.8.5.8. Setscene Tasks and Shared State + + + + + + + +
+

+2.8.5.8. Setscene Tasks and Shared State

+

+ The description of tasks so far assumes that BitBake needs to + build everything and there are no prebuilt objects available. + BitBake does support skipping tasks if prebuilt objects are + available. + These objects are usually made available in the form of a + shared state (sstate) cache. +

+
+

Note

+ For information on variables affecting sstate, see the + SSTATE_DIR + and + SSTATE_MIRRORS + variables. +
+

+

+

+ The idea of a setscene task (i.e + do_taskname_setscene) + is a version of the task where + instead of building something, BitBake can skip to the end + result and simply place a set of files into specific locations + as needed. + In some cases, it makes sense to have a setscene task variant + (e.g. generating package files in the + do_package_write_* task). + In other cases, it does not make sense, (e.g. a + do_patch + task or + do_unpack + task) since the work involved would be equal to or greater than + the underlying task. +

+

+ In the OpenEmbedded build system, the common tasks that have + setscene variants are + do_package, + do_package_write_*, + do_deploy, + do_packagedata, + and + do_populate_sysroot. + Notice that these are most of the tasks whose output is an + end result. +

+

+ The OpenEmbedded build system has knowledge of the relationship + between these tasks and other tasks that precede them. + For example, if BitBake runs + do_populate_sysroot_setscene for + something, there is little point in running any of the + do_fetch, do_unpack, + do_patch, + do_configure, + do_compile, and + do_install tasks. + However, if do_package needs to be run, + BitBake would need to run those other tasks. +

+

+ It becomes more complicated if everything can come from an + sstate cache because some objects are simply not required at + all. + For example, you do not need a compiler or native tools, such + as quilt, if there is nothing to compile or patch. + If the do_package_write_* packages are + available from sstate, BitBake does not need the + do_package task data. +

+

+ To handle all these complexities, BitBake runs in two phases. + The first is the "setscene" stage. + During this stage, BitBake first checks the sstate cache for + any targets it is planning to build. + BitBake does a fast check to see if the object exists rather + than a complete download. + If nothing exists, the second phase, which is the setscene + stage, completes and the main build proceeds. +

+

+ If objects are found in the sstate cache, the OpenEmbedded + build system works backwards from the end targets specified + by the user. + For example, if an image is being built, the OpenEmbedded build + system first looks for the packages needed for that image and + the tools needed to construct an image. + If those are available, the compiler is not needed. + Thus, the compiler is not even downloaded. + If something was found to be unavailable, or the download or + setscene task fails, the OpenEmbedded build system then tries + to install dependencies, such as the compiler, from the cache. +

+

+ The availability of objects in the sstate cache is handled by + the function specified by the + BB_HASHCHECK_FUNCTION + variable and returns a list of the objects that are available. + The function specified by the + BB_SETSCENE_DEPVALID + variable is the function that determines whether a given + dependency needs to be followed, and whether for any given + relationship the function needs to be passed. + The function returns a True or False value. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/shared-state-cache.html b/documentation/getting-started/eclipse/html/getting-started/shared-state-cache.html new file mode 100644 index 0000000000..c5c6be04a3 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/shared-state-cache.html @@ -0,0 +1,93 @@ + + + +3.3. Shared State Cache + + + + + + + +
+

+3.3. Shared State Cache

+

+ By design, the OpenEmbedded build system builds everything from + scratch unless BitBake can determine that parts do not need to be + rebuilt. + Fundamentally, building from scratch is attractive as it means all + parts are built fresh and there is no possibility of stale data + causing problems. + When developers hit problems, they typically default back to + building from scratch so they know the state of things from the + start. +

+

+ Building an image from scratch is both an advantage and a + disadvantage to the process. + As mentioned in the previous paragraph, building from scratch + ensures that everything is current and starts from a known state. + However, building from scratch also takes much longer as it + generally means rebuilding things that do not necessarily need + to be rebuilt. +

+

+ The Yocto Project implements shared state code that supports + incremental builds. + The implementation of the shared state code answers the following + questions that were fundamental roadblocks within the OpenEmbedded + incremental build support system: +

+
    +

  • + What pieces of the system have changed and what pieces have + not changed? +

    • +

  • + How are changed pieces of software removed and replaced? +

    • +

  • + How are pre-built components that do not need to be rebuilt + from scratch used when they are available? +

    • +
+

+

+

+ For the first question, the build system detects changes in the + "inputs" to a given task by creating a checksum (or signature) of + the task's inputs. + If the checksum changes, the system assumes the inputs have changed + and the task needs to be rerun. + For the second question, the shared state (sstate) code tracks + which tasks add which output to the build process. + This means the output from a given task can be removed, upgraded + or otherwise manipulated. + The third question is partly addressed by the solution for the + second question assuming the build system can fetch the sstate + objects from remote locations and install them if they are deemed + to be valid. +

+
+

Note

+ The OpenEmbedded build system does not maintain + PR + information as part of the shared state packages. + Consequently, considerations exist that affect maintaining + shared state feeds. + For information on how the OpenEmbedded build system + works with packages and can track incrementing + PR information, see the + "Automatically Incrementing a Binary Package Revision Number" + section in the Yocto Project Development Tasks Manual. +
+

+

+

+ The rest of this section goes into detail about the overall + incremental build architecture, the checksums (signatures), shared + state, and some tips and tricks. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/shared-state.html b/documentation/getting-started/eclipse/html/getting-started/shared-state.html new file mode 100644 index 0000000000..4389684f3b --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/shared-state.html @@ -0,0 +1,268 @@ + + + +3.3.3. Shared State + + + + + + + +
+

+3.3.3. Shared State

+

+ Checksums and dependencies, as discussed in the previous + section, solve half the problem of supporting a shared state. + The other part of the problem is being able to use checksum + information during the build and being able to reuse or rebuild + specific components. +

+

+ The + sstate + class is a relatively generic implementation of how to + "capture" a snapshot of a given task. + The idea is that the build process does not care about the + source of a task's output. + Output could be freshly built or it could be downloaded and + unpacked from somewhere - the build process does not need to + worry about its origin. +

+

+ There are two types of output, one is just about creating a + directory in + WORKDIR. + A good example is the output of either + do_install + or + do_package. + The other type of output occurs when a set of data is merged + into a shared directory tree such as the sysroot. +

+

+ The Yocto Project team has tried to keep the details of the + implementation hidden in sstate class. + From a user's perspective, adding shared state wrapping to a task + is as simple as this + do_deploy + example taken from the + deploy + class: +

+
+     DEPLOYDIR = "${WORKDIR}/deploy-${PN}"
+     SSTATETASKS += "do_deploy"
+     do_deploy[sstate-inputdirs] = "${DEPLOYDIR}"
+     do_deploy[sstate-outputdirs] = "${DEPLOY_DIR_IMAGE}"
+
+     python do_deploy_setscene () {
+         sstate_setscene(d)
+     }
+     addtask do_deploy_setscene
+     do_deploy[dirs] = "${DEPLOYDIR} ${B}"
+
+

+ The following list explains the previous example: +

+
    +

  • + Adding "do_deploy" to SSTATETASKS + adds some required sstate-related processing, which is + implemented in the + sstate + class, to before and after the + do_deploy + task. +

    • +

  • + The + do_deploy[sstate-inputdirs] = "${DEPLOYDIR}" + declares that do_deploy places its + output in ${DEPLOYDIR} when run + normally (i.e. when not using the sstate cache). + This output becomes the input to the shared state cache. +

    • +
  • +

    + The + do_deploy[sstate-outputdirs] = "${DEPLOY_DIR_IMAGE}" + line causes the contents of the shared state cache to be + copied to ${DEPLOY_DIR_IMAGE}. +

    +
    +

    Note

    + If do_deploy is not already in + the shared state cache or if its input checksum + (signature) has changed from when the output was + cached, the task will be run to populate the shared + state cache, after which the contents of the shared + state cache is copied to + ${DEPLOY_DIR_IMAGE}. + If do_deploy is in the shared + state cache and its signature indicates that the + cached output is still valid (i.e. if no + relevant task inputs have changed), then the + contents of the shared state cache will be copied + directly to + ${DEPLOY_DIR_IMAGE} by the + do_deploy_setscene task + instead, skipping the + do_deploy task. +
    +

    +

    +
    • +
  • +

    + The following task definition is glue logic needed to + make the previous settings effective: +

    +
    +     python do_deploy_setscene () {
+         sstate_setscene(d)
+     }
+     addtask do_deploy_setscene
+
    +

    + sstate_setscene() takes the flags + above as input and accelerates the + do_deploy task through the + shared state cache if possible. + If the task was accelerated, + sstate_setscene() returns True. + Otherwise, it returns False, and the normal + do_deploy task runs. + For more information, see the + "setscene" + section in the BitBake User Manual. +

    +
    • +
  • +

    + The do_deploy[dirs] = "${DEPLOYDIR} ${B}" + line creates ${DEPLOYDIR} and + ${B} before the + do_deploy task runs, and also sets + the current working directory of + do_deploy to + ${B}. + For more information, see the + "Variable Flags" + section in the BitBake User Manual. +

    +
    +

    Note

    + In cases where + sstate-inputdirs and + sstate-outputdirs would be the + same, you can use + sstate-plaindirs. + For example, to preserve the + ${PKGD} and + ${PKGDEST} output from the + do_package + task, use the following: + 
    +     do_package[sstate-plaindirs] = "${PKGD} ${PKGDEST}"
+
    +
    +

    +

    +
    • +
  • +

    + sstate-inputdirs and + sstate-outputdirs can also be used + with multiple directories. + For example, the following declares + PKGDESTWORK and + SHLIBWORK as shared state + input directories, which populates the shared state + cache, and PKGDATA_DIR and + SHLIBSDIR as the corresponding + shared state output directories: +

    +
    +     do_package[sstate-inputdirs] = "${PKGDESTWORK} ${SHLIBSWORKDIR}"
+     do_package[sstate-outputdirs] = "${PKGDATA_DIR} ${SHLIBSDIR}"
+
    +

    +

    +
    • +
  • +

    + These methods also include the ability to take a + lockfile when manipulating shared state directory + structures, for cases where file additions or removals + are sensitive: +

    +
    +     do_package[sstate-lockfile] = "${PACKAGELOCK}"
+
    +

    +

    +
    • +
+

+

+

+ Behind the scenes, the shared state code works by looking in + SSTATE_DIR + and + SSTATE_MIRRORS + for shared state files. + Here is an example: +

+
+     SSTATE_MIRRORS ?= "\
+     file://.* http://someserver.tld/share/sstate/PATH;downloadfilename=PATH \n \
+     file://.* file:///some/local/dir/sstate/PATH"
+
+

+

+
+

Note

+ The shared state directory + (SSTATE_DIR) is organized into + two-character subdirectories, where the subdirectory + names are based on the first two characters of the hash. + If the shared state directory structure for a mirror has the + same structure as SSTATE_DIR, you must + specify "PATH" as part of the URI to enable the build system + to map to the appropriate subdirectory. +
+

+

+

+ The shared state package validity can be detected just by + looking at the filename since the filename contains the task + checksum (or signature) as described earlier in this section. + If a valid shared state package is found, the build process + downloads it and uses it to accelerate the task. +

+

+ The build processes use the *_setscene + tasks for the task acceleration phase. + BitBake goes through this phase before the main execution + code and tries to accelerate any tasks for which it can find + shared state packages. + If a shared state package for a task is available, the + shared state package is used. + This means the task and any tasks on which it is dependent + are not executed. +

+

+ As a real world example, the aim is when building an IPK-based + image, only the + do_package_write_ipk + tasks would have their shared state packages fetched and + extracted. + Since the sysroot is not used, it would never get extracted. + This is another reason why a task-based approach is preferred + over a recipe-based approach, which would have to install the + output from every task. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/software-layer.html b/documentation/getting-started/eclipse/html/getting-started/software-layer.html new file mode 100644 index 0000000000..26e169a281 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/software-layer.html @@ -0,0 +1,27 @@ + + + +2.8.2.3. Software Layer + + + + + + + +
+

+2.8.2.3. Software Layer

+

+ The software layer provides the Metadata for additional + software packages used during the build. + This layer does not include Metadata that is specific to the + distribution or the machine, which are found in their + respective layers. +

+

+ This layer contains any new recipes that your project needs + in the form of recipe files. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/source-fetching-dev-environment.html b/documentation/getting-started/eclipse/html/getting-started/source-fetching-dev-environment.html new file mode 100644 index 0000000000..afcdafdc76 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/source-fetching-dev-environment.html @@ -0,0 +1,93 @@ + + + +2.8.5.1. Source Fetching + + + + + + + +
+

+2.8.5.1. Source Fetching

+

+ The first stages of building a recipe are to fetch and unpack + the source code: +

+
+

+

+

+ The + do_fetch + and + do_unpack + tasks fetch the source files and unpack them into the work + directory. +

+
+

Note

+ For every local file (e.g. file://) + that is part of a recipe's + SRC_URI + statement, the OpenEmbedded build system takes a checksum + of the file for the recipe and inserts the checksum into + the signature for the do_fetch. + If any local file has been modified, the + do_fetch task and all tasks that + depend on it are re-executed. +
+

+ By default, everything is accomplished in the + Build Directory, + which has a defined structure. + For additional general information on the Build Directory, + see the + "build/" + section in the Yocto Project Reference Manual. +

+

+ Unpacked source files are pointed to by the + S + variable. + Each recipe has an area in the Build Directory where the + unpacked source code resides. + The name of that directory for any given recipe is defined from + several different variables. + You can see the variables that define these directories + by looking at the figure: +

+
    +

  • TMPDIR - + The base directory where the OpenEmbedded build system + performs all its work during the build. +

    • +

  • PACKAGE_ARCH - + The architecture of the built package or packages. +

    • +

  • TARGET_OS - + The operating system of the target device. +

    • +

  • PN - + The name of the built package. +

    • +

  • PV - + The version of the recipe used to build the package. +

    • +

  • PR - + The revision of the recipe used to build the package. +

    • +

  • WORKDIR - + The location within TMPDIR where + a specific package is built. +

    • +

  • S - + Contains the unpacked source files for a given recipe. +

    • +
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/source-mirrors.html b/documentation/getting-started/eclipse/html/getting-started/source-mirrors.html new file mode 100644 index 0000000000..178903c96e --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/source-mirrors.html @@ -0,0 +1,37 @@ + + + +2.8.3.4. Source Mirror(s) + + + + + + + +
+

+2.8.3.4. Source Mirror(s)

+

+ Two kinds of mirrors exist: pre-mirrors and regular mirrors. + The + PREMIRRORS + and + MIRRORS + variables point to these, respectively. + BitBake checks pre-mirrors before looking upstream for any + source files. + Pre-mirrors are appropriate when you have a shared directory + that is not a directory defined by the + DL_DIR + variable. + A Pre-mirror typically points to a shared directory that is + local to your organization. +

+

+ Regular mirrors can be any site across the Internet that is + used as an alternative location for source code should the + primary site not be functioning for some reason or another. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/sources-dev-environment.html b/documentation/getting-started/eclipse/html/getting-started/sources-dev-environment.html new file mode 100644 index 0000000000..ab7718074f --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/sources-dev-environment.html @@ -0,0 +1,80 @@ + + + +2.8.3. Sources + + + + + + + +
+

+2.8.3. Sources

+

+ In order for the OpenEmbedded build system to create an image or + any target, it must be able to access source files. + The + general Yocto Project Development Environment figure + represents source files using the "Upstream Project Releases", + "Local Projects", and "SCMs (optional)" boxes. + The figure represents mirrors, which also play a role in locating + source files, with the "Source Mirror(s)" box. +

+

+ The method by which source files are ultimately organized is + a function of the project. + For example, for released software, projects tend to use tarballs + or other archived files that can capture the state of a release + guaranteeing that it is statically represented. + On the other hand, for a project that is more dynamic or + experimental in nature, a project might keep source files in a + repository controlled by a Source Control Manager (SCM) such as + Git. + Pulling source from a repository allows you to control + the point in the repository (the revision) from which you want to + build software. + Finally, a combination of the two might exist, which would give the + consumer a choice when deciding where to get source files. +

+

+ BitBake uses the + SRC_URI + variable to point to source files regardless of their location. + Each recipe must have a SRC_URI variable + that points to the source. +

+

+ Another area that plays a significant role in where source files + come from is pointed to by the + DL_DIR + variable. + This area is a cache that can hold previously downloaded source. + You can also instruct the OpenEmbedded build system to create + tarballs from Git repositories, which is not the default behavior, + and store them in the DL_DIR by using the + BB_GENERATE_MIRROR_TARBALLS + variable. +

+

+ Judicious use of a DL_DIR directory can + save the build system a trip across the Internet when looking + for files. + A good method for using a download directory is to have + DL_DIR point to an area outside of your + Build Directory. + Doing so allows you to safely delete the Build Directory + if needed without fear of removing any downloaded source file. +

+

+ The remainder of this section provides a deeper look into the + source files and the mirrors. + Here is a more detailed look at the source file area of the + base figure: +

+
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/stamp-files-and-the-rerunning-of-tasks.html b/documentation/getting-started/eclipse/html/getting-started/stamp-files-and-the-rerunning-of-tasks.html new file mode 100644 index 0000000000..b649c69b2b --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/stamp-files-and-the-rerunning-of-tasks.html @@ -0,0 +1,83 @@ + + + +2.8.5.7. Stamp Files and the Rerunning of Tasks + + + + + + + +
+

+2.8.5.7. Stamp Files and the Rerunning of Tasks

+

+ For each task that completes successfully, BitBake writes a + stamp file into the + STAMPS_DIR + directory. + The beginning of the stamp file's filename is determined by the + STAMP + variable, and the end of the name consists of the task's name + and current + input checksum. +

+
+

Note

+ This naming scheme assumes that + BB_SIGNATURE_HANDLER + is "OEBasicHash", which is almost always the case in + current OpenEmbedded. +
+

+ To determine if a task needs to be rerun, BitBake checks if a + stamp file with a matching input checksum exists for the task. + If such a stamp file exists, the task's output is assumed to + exist and still be valid. + If the file does not exist, the task is rerun. +

+
+

Note

+

The stamp mechanism is more general than the shared + state (sstate) cache mechanism described in the + "Setscene Tasks and Shared State" + section. + BitBake avoids rerunning any task that has a valid + stamp file, not just tasks that can be accelerated through + the sstate cache.

+

However, you should realize that stamp files only + serve as a marker that some work has been done and that + these files do not record task output. + The actual task output would usually be somewhere in + TMPDIR + (e.g. in some recipe's + WORKDIR.) + What the sstate cache mechanism adds is a way to cache task + output that can then be shared between build machines. +

+
+

+ Since STAMPS_DIR is usually a subdirectory + of TMPDIR, removing + TMPDIR will also remove + STAMPS_DIR, which means tasks will + properly be rerun to repopulate TMPDIR. +

+

+ If you want some task to always be considered "out of date", + you can mark it with the + nostamp + varflag. + If some other task depends on such a task, then that task will + also always be considered out of date, which might not be what + you want. +

+

+ For details on how to view information about a task's + signature, see the + "Viewing Task Variable Dependencies" + section in the Yocto Project Development Tasks Manual. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/tips-and-tricks.html b/documentation/getting-started/eclipse/html/getting-started/tips-and-tricks.html new file mode 100644 index 0000000000..d0c8522d95 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/tips-and-tricks.html @@ -0,0 +1,22 @@ + + + +3.3.4. Tips and Tricks + + + + + + + +
+

+3.3.4. Tips and Tricks

+

+ The code in the build system that supports incremental builds + is not simple code. + This section presents some tips and tricks that help you work + around issues related to shared state code. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/upstream-project-releases.html b/documentation/getting-started/eclipse/html/getting-started/upstream-project-releases.html new file mode 100644 index 0000000000..ef9bc18dde --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/upstream-project-releases.html @@ -0,0 +1,25 @@ + + + +2.8.3.1. Upstream Project Releases + + + + + + + +
+

+2.8.3.1. Upstream Project Releases

+

+ Upstream project releases exist anywhere in the form of an + archived file (e.g. tarball or zip file). + These files correspond to individual recipes. + For example, the figure uses specific releases each for + BusyBox, Qt, and Dbus. + An archive file can be for any released product that can be + built using a recipe. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/user-configuration.html b/documentation/getting-started/eclipse/html/getting-started/user-configuration.html new file mode 100644 index 0000000000..6f10791e7a --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/user-configuration.html @@ -0,0 +1,232 @@ + + + +2.8.1. User Configuration + + + + + + + +
+

+2.8.1. User Configuration

+

+ User configuration helps define the build. + Through user configuration, you can tell BitBake the + target architecture for which you are building the image, + where to store downloaded source, and other build properties. +

+

+ The following figure shows an expanded representation of the + "User Configuration" box of the + general Yocto Project Development Environment figure: +

+

+

+
+

+

+

+ BitBake needs some basic configuration files in order to complete + a build. + These files are *.conf files. + The minimally necessary ones reside as example files in the + Source Directory. + For simplicity, this section refers to the Source Directory as + the "Poky Directory." +

+

+ When you clone the poky Git repository or you + download and unpack a Yocto Project release, you can set up the + Source Directory to be named anything you want. + For this discussion, the cloned repository uses the default + name poky. +

+
+

Note

+ The Poky repository is primarily an aggregation of existing + repositories. + It is not a canonical upstream source. +
+

+

+

+ The meta-poky layer inside Poky contains + a conf directory that has example + configuration files. + These example files are used as a basis for creating actual + configuration files when you source the build environment + script + (i.e. + oe-init-build-env). +

+

+ Sourcing the build environment script creates a + Build Directory + if one does not already exist. + BitBake uses the Build Directory for all its work during builds. + The Build Directory has a conf directory that + contains default versions of your local.conf + and bblayers.conf configuration files. + These default configuration files are created only if versions + do not already exist in the Build Directory at the time you + source the build environment setup script. +

+

+ Because the Poky repository is fundamentally an aggregation of + existing repositories, some users might be familiar with running + the oe-init-build-env script in the context + of separate OpenEmbedded-Core and BitBake repositories rather than a + single Poky repository. + This discussion assumes the script is executed from within a cloned + or unpacked version of Poky. +

+

+ Depending on where the script is sourced, different sub-scripts + are called to set up the Build Directory (Yocto or OpenEmbedded). + Specifically, the script + scripts/oe-setup-builddir inside the + poky directory sets up the Build Directory and seeds the directory + (if necessary) with configuration files appropriate for the + Yocto Project development environment. +

+
+

Note

+ The scripts/oe-setup-builddir script + uses the $TEMPLATECONF variable to + determine which sample configuration files to locate. +
+

+

+

+ The local.conf file provides many + basic variables that define a build environment. + Here is a list of a few. + To see the default configurations in a local.conf + file created by the build environment script, see the + local.conf.sample in the + meta-poky layer: +

+
+

+

+
+

Note

+ Configurations set in the conf/local.conf + file can also be set in the + conf/site.conf and + conf/auto.conf configuration files. +
+

+

+

+ The bblayers.conf file tells BitBake what + layers you want considered during the build. + By default, the layers listed in this file include layers + minimally needed by the build system. + However, you must manually add any custom layers you have created. + You can find more information on working with the + bblayers.conf file in the + "Enabling Your Layer" + section in the Yocto Project Development Tasks Manual. +

+

+ The files site.conf and + auto.conf are not created by the environment + initialization script. + If you want the site.conf file, you need to + create that yourself. + The auto.conf file is typically created by + an autobuilder: +

+
    +
  • +

    site.conf: + You can use the conf/site.conf + configuration file to configure multiple build directories. + For example, suppose you had several build environments and + they shared some common features. + You can set these default build properties here. + A good example is perhaps the packaging format to use + through the + PACKAGE_CLASSES + variable.

    +

    One useful scenario for using the + conf/site.conf file is to extend your + BBPATH + variable to include the path to a + conf/site.conf. + Then, when BitBake looks for Metadata using + BBPATH, it finds the + conf/site.conf file and applies your + common configurations found in the file. + To override configurations in a particular build directory, + alter the similar configurations within that build + directory's conf/local.conf file. +

    +
    • +

  • auto.conf: + The file is usually created and written to by + an autobuilder. + The settings put into the file are typically the same as + you would find in the conf/local.conf + or the conf/site.conf files. +

    • +
+

+

+

+ You can edit all configuration files to further define + any particular build environment. + This process is represented by the "User Configuration Edits" + box in the figure. +

+

+ When you launch your build with the + bitbake target + command, BitBake sorts out the configurations to ultimately + define your build environment. + It is important to understand that the OpenEmbedded build system + reads the configuration files in a specific order: + site.conf, auto.conf, + and local.conf. + And, the build system applies the normal assignment statement + rules. + Because the files are parsed in a specific order, variable + assignments for the same variable could be affected. + For example, if the auto.conf file and + the local.conf set + variable1 to different values, because + the build system parses local.conf after + auto.conf, + variable1 is assigned the value from + the local.conf file. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/usingpoky-LIC_FILES_CHKSUM-explanation-of-syntax.html b/documentation/getting-started/eclipse/html/getting-started/usingpoky-LIC_FILES_CHKSUM-explanation-of-syntax.html new file mode 100644 index 0000000000..7e43ebd923 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/usingpoky-LIC_FILES_CHKSUM-explanation-of-syntax.html @@ -0,0 +1,76 @@ + + + +3.7.1.2. Explanation of Syntax + + + + + + + +
+

+3.7.1.2. Explanation of Syntax

+

+ As mentioned in the previous section, the + LIC_FILES_CHKSUM variable lists all + the important files that contain the license text for the + source code. + It is possible to specify a checksum for an entire file, + or a specific section of a file (specified by beginning and + ending line numbers with the "beginline" and "endline" + parameters, respectively). + The latter is useful for source files with a license + notice header, README documents, and so forth. + If you do not use the "beginline" parameter, then it is + assumed that the text begins on the first line of the file. + Similarly, if you do not use the "endline" parameter, + it is assumed that the license text ends with the last + line of the file. +

+

+ The "md5" parameter stores the md5 checksum of the license + text. + If the license text changes in any way as compared to + this parameter then a mismatch occurs. + This mismatch triggers a build failure and notifies + the developer. + Notification allows the developer to review and address + the license text changes. + Also note that if a mismatch occurs during the build, + the correct md5 checksum is placed in the build log and + can be easily copied to the recipe. +

+

+ There is no limit to how many files you can specify using + the LIC_FILES_CHKSUM variable. + Generally, however, every project requires a few + specifications for license tracking. + Many projects have a "COPYING" file that stores the + license information for all the source code files. + This practice allows you to just track the "COPYING" + file as long as it is kept up to date. +

+
+

Tips

+
    +

  • + If you specify an empty or invalid "md5" + parameter, BitBake returns an md5 mis-match + error and displays the correct "md5" parameter + value during the build. + The correct parameter is also captured in + the build log. +

    • +

  • + If the whole file contains only license text, + you do not need to use the "beginline" and + "endline" parameters. +

    • +
+
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/usingpoky-components-bitbake.html b/documentation/getting-started/eclipse/html/getting-started/usingpoky-components-bitbake.html new file mode 100644 index 0000000000..39fa32b154 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/usingpoky-components-bitbake.html @@ -0,0 +1,82 @@ + + + +3.1.1. BitBake + + + + + + + +
+

+3.1.1. BitBake

+

+ BitBake is the tool at the heart of the OpenEmbedded build + system and is responsible for parsing the + Metadata, + generating a list of tasks from it, and then executing those + tasks. +

+

+ This section briefly introduces BitBake. + If you want more information on BitBake, see the + BitBake User Manual. +

+

+ To see a list of the options BitBake supports, use either of + the following commands: +

+
+     $ bitbake -h
+     $ bitbake --help
+
+

+

+

+ The most common usage for BitBake is + bitbake packagename, + where packagename is the name of the + package you want to build (referred to as the "target" in this + manual). + The target often equates to the first part of a recipe's + filename (e.g. "foo" for a recipe named + foo_1.3.0-r0.bb). + So, to process the + matchbox-desktop_1.2.3.bb recipe file, you + might type the following: +

+
+     $ bitbake matchbox-desktop
+
+

+ Several different versions of + matchbox-desktop might exist. + BitBake chooses the one selected by the distribution + configuration. + You can get more details about how BitBake chooses between + different target versions and providers in the + "Preferences" + section of the BitBake User Manual. +

+

+ BitBake also tries to execute any dependent tasks first. + So for example, before building + matchbox-desktop, BitBake would build a + cross compiler and glibc if they had not + already been built. +

+

+ A useful BitBake option to consider is the + -k or --continue + option. + This option instructs BitBake to try and continue processing + the job as long as possible even after encountering an error. + When an error occurs, the target that failed and those that + depend on it cannot be remade. + However, when you use this option other dependencies can + still be processed. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/usingpoky-components-classes.html b/documentation/getting-started/eclipse/html/getting-started/usingpoky-components-classes.html new file mode 100644 index 0000000000..809906c999 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/usingpoky-components-classes.html @@ -0,0 +1,30 @@ + + + +3.1.4. Classes + + + + + + + +
+

+3.1.4. Classes

+

+ Class files (.bbclass) contain information + that is useful to share between + Metadata + files. + An example is the + autotools + class, which contains common settings for any application that + Autotools uses. + The + "Classes" + chapter in the Yocto Project Reference Manual provides + details about classes and how to use them. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/usingpoky-components-configuration.html b/documentation/getting-started/eclipse/html/getting-started/usingpoky-components-configuration.html new file mode 100644 index 0000000000..a1ca039c9b --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/usingpoky-components-configuration.html @@ -0,0 +1,27 @@ + + + +3.1.5. Configuration + + + + + + + +
+

+3.1.5. Configuration

+

+ The configuration files (.conf) define + various configuration variables that govern the OpenEmbedded + build process. + These files fall into several areas that define machine + configuration options, distribution configuration options, + compiler tuning options, general common configuration options, + and user configuration options in + local.conf, which is found in the + Build Directory. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/usingpoky-components-metadata.html b/documentation/getting-started/eclipse/html/getting-started/usingpoky-components-metadata.html new file mode 100644 index 0000000000..b25324502e --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/usingpoky-components-metadata.html @@ -0,0 +1,35 @@ + + + +3.1.2. Metadata (Recipes) + + + + + + + +
+

+3.1.2. Metadata (Recipes)

+

+ Files that have the .bb suffix are + "recipes" files. + In general, a recipe contains information about a single piece + of software. + This information includes the location from which to download + the unaltered source, any source patches to be applied to that + source (if needed), which special configuration options to + apply, how to compile the source files, and how to package the + compiled output. +

+

+ The term "package" is sometimes used to refer to recipes. + However, since the word "package" is used for the packaged + output from the OpenEmbedded build system (i.e. + .ipk or .deb files), + this document avoids using the term "package" when referring + to recipes. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/usingpoky-configuring-LIC_FILES_CHKSUM.html b/documentation/getting-started/eclipse/html/getting-started/usingpoky-configuring-LIC_FILES_CHKSUM.html new file mode 100644 index 0000000000..ee59e3bc10 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/usingpoky-configuring-LIC_FILES_CHKSUM.html @@ -0,0 +1,24 @@ + + + +3.7.1. Tracking License Changes + + + + + + + +
+

+3.7.1. Tracking License Changes

+

+ The license of an upstream project might change in the future. + In order to prevent these changes going unnoticed, the + LIC_FILES_CHKSUM + variable tracks changes to the license text. The checksums are + validated at the end of the configure step, and if the + checksums do not match, the build will fail. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/usingpoky-specifying-LIC_FILES_CHKSUM.html b/documentation/getting-started/eclipse/html/getting-started/usingpoky-specifying-LIC_FILES_CHKSUM.html new file mode 100644 index 0000000000..ed9a3cc501 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/usingpoky-specifying-LIC_FILES_CHKSUM.html @@ -0,0 +1,82 @@ + + + +3.7.1.1. Specifying the LIC_FILES_CHKSUM Variable + + + + + + + +
+

+3.7.1.1. Specifying the LIC_FILES_CHKSUM Variable

+

+ The LIC_FILES_CHKSUM + variable contains checksums of the license text in the + source code for the recipe. + Following is an example of how to specify + LIC_FILES_CHKSUM: +

+
+     LIC_FILES_CHKSUM = "file://COPYING;md5=xxxx \
+                         file://licfile1.txt;beginline=5;endline=29;md5=yyyy \
+                         file://licfile2.txt;endline=50;md5=zzzz \
+                         ..."
+
+

+

+
+

Notes

+
    +

  • + When using "beginline" and "endline", realize + that line numbering begins with one and not + zero. + Also, the included lines are inclusive (i.e. + lines five through and including 29 in the + previous example for + licfile1.txt). +

    • +

  • + When a license check fails, the selected license + text is included as part of the QA message. + Using this output, you can determine the exact + start and finish for the needed license text. +

    • +
+
+

+

+

+ The build system uses the + S + variable as the default directory when searching files + listed in LIC_FILES_CHKSUM. + The previous example employs the default directory. +

+

+ Consider this next example: +

+
+     LIC_FILES_CHKSUM = "file://src/ls.c;beginline=5;endline=16;\
+                                         md5=bb14ed3c4cda583abc85401304b5cd4e"
+     LIC_FILES_CHKSUM = "file://${WORKDIR}/license.html;md5=5c94767cedb5d6987c902ac850ded2c6"
+
+

+

+

+ The first line locates a file in + ${S}/src/ls.c and isolates lines five + through 16 as license text. + The second line refers to a file in + WORKDIR. +

+

+ Note that LIC_FILES_CHKSUM variable is + mandatory for all recipes, unless the + LICENSE variable is set to "CLOSED". +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/wayland-support.html b/documentation/getting-started/eclipse/html/getting-started/wayland-support.html new file mode 100644 index 0000000000..da810a4439 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/wayland-support.html @@ -0,0 +1,46 @@ + + + +3.6.1. Support + + + + + + + +
+

+3.6.1. Support

+

+ The Wayland protocol libraries and the reference Weston + compositor ship as integrated packages in the + meta layer of the + Source Directory. + Specifically, you can find the recipes that build both Wayland + and Weston at + meta/recipes-graphics/wayland. +

+

+ You can build both the Wayland and Weston packages for use only + with targets that accept the + Mesa 3D and Direct Rendering Infrastructure, + which is also known as Mesa DRI. + This implies that you cannot build and use the packages if your + target uses, for example, the + Intel® Embedded Media + and Graphics Driver + (Intel® EMGD) that + overrides Mesa DRI. +

+
+

Note

+ Due to lack of EGL support, Weston 1.0.3 will not run + directly on the emulated QEMU hardware. + However, this version of Weston will run under X emulation + without issues. +
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/wayland.html b/documentation/getting-started/eclipse/html/getting-started/wayland.html new file mode 100644 index 0000000000..0747c9238c --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/wayland.html @@ -0,0 +1,34 @@ + + + +3.6. Wayland + + + + + + + +
+

+3.6. Wayland

+

+ Wayland + is a computer display server protocol that + provides a method for compositing window managers to communicate + directly with applications and video hardware and expects them to + communicate with input hardware using other libraries. + Using Wayland with supporting targets can result in better control + over graphics frame rendering than an application might otherwise + achieve. +

+

+ The Yocto Project provides the Wayland protocol libraries and the + reference + Weston + compositor as part of its release. + This section describes what you need to do to implement Wayland and + use the compositor when building an image for a supporting target. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/workflows.html b/documentation/getting-started/eclipse/html/getting-started/workflows.html new file mode 100644 index 0000000000..9d53975678 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/workflows.html @@ -0,0 +1,207 @@ + + + +2.3. Workflows + + + + + + + +
+

+2.3. Workflows

+

+ This section provides workflow concepts using the Yocto Project and + Git. + In particular, the information covers basic practices that describe + roles and actions in a collaborative development environment. +

+
+

Note

+ If you are familiar with this type of development environment, you + might not want to read this section. +
+

+

+

+ The Yocto Project files are maintained using Git in "master" + branches whose Git histories track every change and whose structures + provides branches for all diverging functionality. + Although there is no need to use Git, many open source projects do so. +

+

+ +

+

+ For the Yocto Project, a key individual called the "maintainer" is + responsible for the "master" branch of a given Git repository. + The "master" branch is the “upstream” repository from which final or + most recent builds of the project occur. + The maintainer is responsible for accepting changes from other + developers and for organizing the underlying branch structure to + reflect release strategies and so forth. +

+
+

Note

For information on finding out who is responsible for (maintains) + a particular area of code, see the + "Submitting a Change to the Yocto Project" + section of the Yocto Project Development Tasks Manual. +
+

+

+

+ The Yocto Project poky Git repository also has an + upstream contribution Git repository named + poky-contrib. + You can see all the branches in this repository using the web interface + of the + Source Repositories organized + within the "Poky Support" area. + These branches temporarily hold changes to the project that have been + submitted or committed by the Yocto Project development team and by + community members who contribute to the project. + The maintainer determines if the changes are qualified to be moved + from the "contrib" branches into the "master" branch of the Git + repository. +

+

+ Developers (including contributing community members) create and + maintain cloned repositories of the upstream "master" branch. + The cloned repositories are local to their development platforms and + are used to develop changes. + When a developer is satisfied with a particular feature or change, + they "push" the changes to the appropriate "contrib" repository. +

+

+ Developers are responsible for keeping their local repository + up-to-date with "master". + They are also responsible for straightening out any conflicts that + might arise within files that are being worked on simultaneously by + more than one person. + All this work is done locally on the developer’s machine before + anything is pushed to a "contrib" area and examined at the maintainer’s + level. +

+

+ A somewhat formal method exists by which developers commit changes + and push them into the "contrib" area and subsequently request that + the maintainer include them into "master". + This process is called “submitting a patch” or "submitting a change." + For information on submitting patches and changes, see the + "Submitting a Change to the Yocto Project" + section in the Yocto Project Development Tasks Manual. +

+

+ To summarize the development workflow: a single point of entry + exists for changes into the project’s "master" branch of the + Git repository, which is controlled by the project’s maintainer. + And, a set of developers exist who independently develop, test, and + submit changes to "contrib" areas for the maintainer to examine. + The maintainer then chooses which changes are going to become a + permanent part of the project. +

+

+

+
+

+

+

+ While each development environment is unique, there are some best + practices or methods that help development run smoothly. + The following list describes some of these practices. + For more information about Git workflows, see the workflow topics in + the + Git Community Book. +

+
    +
  • +

    + Make Small Changes: + It is best to keep the changes you commit small as compared to + bundling many disparate changes into a single commit. + This practice not only keeps things manageable but also allows + the maintainer to more easily include or refuse changes.

    +

    It is also good practice to leave the repository in a + state that allows you to still successfully build your project. + In other words, do not commit half of a feature, + then add the other half as a separate, later commit. + Each commit should take you from one buildable project state + to another buildable state. +

    +
    • +

  • + Use Branches Liberally: + It is very easy to create, use, and delete local branches in + your working Git repository. + You can name these branches anything you like. + It is helpful to give them names associated with the particular + feature or change on which you are working. + Once you are done with a feature or change and have merged it + into your local master branch, simply discard the temporary + branch. +

    • +

  • + Merge Changes: + The git merge command allows you to take + the changes from one branch and fold them into another branch. + This process is especially helpful when more than a single + developer might be working on different parts of the same + feature. + Merging changes also automatically identifies any collisions + or "conflicts" that might happen as a result of the same lines + of code being altered by two different developers. +

    • +

  • + Manage Branches: + Because branches are easy to use, you should use a system + where branches indicate varying levels of code readiness. + For example, you can have a "work" branch to develop in, a + "test" branch where the code or change is tested, a "stage" + branch where changes are ready to be committed, and so forth. + As your project develops, you can merge code across the + branches to reflect ever-increasing stable states of the + development. +

    • +

  • + Use Push and Pull: + The push-pull workflow is based on the concept of developers + "pushing" local commits to a remote repository, which is + usually a contribution repository. + This workflow is also based on developers "pulling" known + states of the project down into their local development + repositories. + The workflow easily allows you to pull changes submitted by + other developers from the upstream repository into your + work area ensuring that you have the most recent software + on which to develop. + The Yocto Project has two scripts named + create-pull-request and + send-pull-request that ship with the + release to facilitate this workflow. + You can find these scripts in the scripts + folder of the + Source Directory. + For information on how to use these scripts, see the + "Using Scripts to Push a Change Upstream and Request a Pull" + section in the Yocto Project Development Tasks Manual. +

    • +

  • + Patch Workflow: + This workflow allows you to notify the maintainer through an + email that you have a change (or patch) you would like + considered for the "master" branch of the Git repository. + To send this type of change, you format the patch and then + send the email using the Git commands + git format-patch and + git send-email. + For information on how to use these scripts, see the + "Submitting a Change to the Yocto Project" + section in the Yocto Project Development Tasks Manual. +

    • +
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/x32.html b/documentation/getting-started/eclipse/html/getting-started/x32.html new file mode 100644 index 0000000000..daffedbeea --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/x32.html @@ -0,0 +1,75 @@ + + + +3.8. x32 psABI + + + + + + +
+

+3.8. x32 psABI

+

+ x32 processor-specific Application Binary Interface + (x32 psABI) + is a native 32-bit processor-specific ABI for + Intel® 64 (x86-64) + architectures. + An ABI defines the calling conventions between functions in a + processing environment. + The interface determines what registers are used and what the sizes are + for various C data types. +

+

+ Some processing environments prefer using 32-bit applications even + when running on Intel 64-bit platforms. + Consider the i386 psABI, which is a very old 32-bit ABI for Intel + 64-bit platforms. + The i386 psABI does not provide efficient use and access of the + Intel 64-bit processor resources, leaving the system underutilized. + Now consider the x86_64 psABI. + This ABI is newer and uses 64-bits for data sizes and program + pointers. + The extra bits increase the footprint size of the programs, + libraries, and also increases the memory and file system size + requirements. + Executing under the x32 psABI enables user programs to utilize CPU + and system resources more efficiently while keeping the memory + footprint of the applications low. + Extra bits are used for registers but not for addressing mechanisms. +

+

+ The Yocto Project supports the final specifications of x32 psABI + as follows: +

+
    +

  • + You can create packages and images in x32 psABI format on + x86_64 architecture targets. +

    • +

  • + You can successfully build recipes with the x32 toolchain. +

    • +

  • + You can create and boot + core-image-minimal and + core-image-sato images. +

    • +

  • + RPM Package Manager (RPM) support exists for x32 binaries. +

    • +

  • + Support for large images exists. +

    • +
+

+

+

+ For steps on how to use x32 psABI, see the + "Using x32 psABI" + section in the Yocto Project Development Tasks Manual. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/yocto-project-components.html b/documentation/getting-started/eclipse/html/getting-started/yocto-project-components.html new file mode 100644 index 0000000000..0ad63b2402 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/yocto-project-components.html @@ -0,0 +1,62 @@ + + + +3.1. Yocto Project Components + + + + + + + +
+

+3.1. Yocto Project Components

+

+ The + BitBake + task executor together with various types of configuration files + form the OpenEmbedded Core. + This section overviews these components by describing their use and + how they interact. +

+

+ BitBake handles the parsing and execution of the data files. + The data itself is of various types: +

+
    +

  • + Recipes: + Provides details about particular pieces of software. +

    • +

  • + Class Data: + Abstracts common build information (e.g. how to build a + Linux kernel). +

    • +

  • + Configuration Data: + Defines machine-specific settings, policy decisions, and + so forth. + Configuration data acts as the glue to bind everything + together. +

    • +
+

+

+

+ BitBake knows how to combine multiple data sources together and + refers to each data source as a layer. + For information on layers, see the + "Understanding and Creating Layers" + section of the Yocto Project Development Tasks Manual. +

+

+ Following are some brief details on these core components. + For additional information on how these components interact during + a build, see the + "Development Concepts" + section. +

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/yocto-project-repositories.html b/documentation/getting-started/eclipse/html/getting-started/yocto-project-repositories.html new file mode 100644 index 0000000000..3dcc2af5eb --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/yocto-project-repositories.html @@ -0,0 +1,135 @@ + + + +2.5. Yocto Project Source Repositories + + + + + + + +
+

+2.5. Yocto Project Source Repositories

+

+ The Yocto Project team maintains complete source repositories for all + Yocto Project files at + http://git.yoctoproject.org/cgit/cgit.cgi. + This web-based source code browser is organized into categories by + function such as IDE Plugins, Matchbox, Poky, Yocto Linux Kernel, and + so forth. + From the interface, you can click on any particular item in the "Name" + column and see the URL at the bottom of the page that you need to clone + a Git repository for that particular item. + Having a local Git repository of the + Source Directory, + which is usually named "poky", allows + you to make changes, contribute to the history, and ultimately enhance + the Yocto Project's tools, Board Support Packages, and so forth. +

+

+ For any supported release of Yocto Project, you can also go to the + Yocto Project Website and + select the "Downloads" tab and get a released tarball of the + poky repository or any supported BSP tarballs. + Unpacking these tarballs gives you a snapshot of the released + files. +

+
+

Notes

+
    +

  • + The recommended method for setting up the Yocto Project + Source Directory + and the files for supported BSPs + (e.g., meta-intel) is to use + Git to create a local copy of + the upstream repositories. +

    • +

  • + Be sure to always work in matching branches for both + the selected BSP repository and the + Source Directory + (i.e. poky) repository. + For example, if you have checked out the "master" branch + of poky and you are going to use + meta-intel, be sure to checkout the + "master" branch of meta-intel. +

    • +
+
+

+

+

+ In summary, here is where you can get the project files needed for + development: +

+
    +
  • +

    + + Source Repositories: + + This area contains IDE Plugins, Matchbox, Poky, Poky Support, + Tools, Yocto Linux Kernel, and Yocto Metadata Layers. + You can create local copies of Git repositories for each of + these areas.

    +

    +

    +
    +

    + For steps on how to view and access these upstream Git + repositories, see the + "Accessing Source Repositories" + Section in the Yocto Project Development Tasks Manual. +

    +
    • +
  • +

    + + Index of /releases: + + This is an index of releases such as + the Eclipse™ + Yocto Plug-in, miscellaneous support, Poky, Pseudo, installers + for cross-development toolchains, and all released versions of + Yocto Project in the form of images or tarballs. + Downloading and extracting these files does not produce a local + copy of the Git repository but rather a snapshot of a + particular release or image.

    +

    +

    +
    +

    + For steps on how to view and access these files, see the + "Accessing Index of Releases" + section in the Yocto Project Development Tasks Manual. +

    +
    • +
  • +

    + "Downloads" page for the + Yocto Project Website: +

    +

    This section will change due to + reworking of the YP Website.

    +

    The Yocto Project website includes a "Downloads" tab + that allows you to download any Yocto Project + release and Board Support Package (BSP) in tarball form. + The tarballs are similar to those found in the + Index of /releases: area.

    +

    +

    +
    +

    + For steps on how to use the "Downloads" page, see the + "Using the Downloads Page" + section in the Yocto Project Development Tasks Manual. +

    +
    • +
+

+

+
+ diff --git a/documentation/getting-started/eclipse/html/getting-started/yp-intro.html b/documentation/getting-started/eclipse/html/getting-started/yp-intro.html new file mode 100644 index 0000000000..42ad0d3088 --- /dev/null +++ b/documentation/getting-started/eclipse/html/getting-started/yp-intro.html @@ -0,0 +1,119 @@ + + + +2.1. Introduction + + + + + + + +
+

+2.1. Introduction

+

+ The Yocto Project is an open-source collaboration project whose + focus is for developers of embedded Linux systems. + Among other things, the Yocto Project uses an + OpenEmbedded build system. + The build system, which is based on the OpenEmbedded (OE) project and + uses the + BitBake tool, + constructs complete Linux images for architectures based on ARM, MIPS, + PowerPC, x86 and x86-64. +

+
+

Note

+ Historically, the OpenEmbedded build system, which is the + combination of BitBake and OE components, formed a reference + build host that was known as + "Poky" + (Pah-kee). + The term "Poky", as used throughout the Yocto Project Documentation + set, can have different meanings. +
+

+ The Yocto Project provides various ancillary tools for the embedded + developer and also features the Sato reference User Interface, which + is optimized for stylus-driven, low-resolution screens. +

+
+

+ Here are some highlights for the Yocto Project: +

+
    +

  • + Provides a recent Linux kernel along with a set of system + commands and libraries suitable for the embedded + environment. +

    • +

  • + Makes available system components such as X11, GTK+, Qt, + Clutter, and SDL (among others) so you can create a rich user + experience on devices that have display hardware. + For devices that do not have a display or where you wish to + use alternative UI frameworks, these components need not be + installed. +

    • +

  • + Creates a focused and stable core compatible with the + OpenEmbedded project with which you can easily and reliably + build and develop. +

    • +

  • + Fully supports a wide range of hardware and device emulation + through the Quick EMUlator (QEMU). +

    • +

  • + Provides a layer mechanism that allows you to easily extend + the system, make customizations, and keep them organized. +

    • +
+

+ You can use the Yocto Project to generate images for many kinds + of devices. + As mentioned earlier, the Yocto Project supports creation of + reference images that you can boot within and emulate using QEMU. + The standard example machines target QEMU full-system + emulation for 32-bit and 64-bit variants of x86, ARM, MIPS, and + PowerPC architectures. + Beyond emulation, you can use the layer mechanism to extend + support to just about any platform that Linux can run on and that + a toolchain can target. +

+

+ Another Yocto Project feature is the Sato reference User + Interface. + This optional UI that is based on GTK+ is intended for devices with + restricted screen sizes and is included as part of the + OpenEmbedded Core layer so that developers can test parts of the + software stack. +

+

+ While the Yocto Project does not provide a strict testing framework, + it does provide or generate for you artifacts that let you perform + target-level and emulated testing and debugging. + Additionally, if you are an + Eclipse™ IDE user, you can + install an Eclipse Yocto Plug-in to allow you to develop within that + familiar environment. +

+

+ By default, using the Yocto Project to build an image creates a Poky + distribution. + However, you can create your own distribution by providing key + Metadata. + A good example is Angstrom, which has had a distribution + based on the Yocto Project since its inception. + Other examples include commercial distributions like + Wind River Linux, + Mentor Embedded Linux, + ENEA Linux + and others. + See the "Creating Your Own Distribution" + section in the Yocto Project Development Tasks Manual for more + information. +

+
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for various areas of the Yocto Project. + Currently, topics include Yocto Project components, cross-development + generation, shared state (sstate) cache, runtime dependencies, + Pseudo and Fakeroot, x32 psABI, Wayland support, and Licenses. + + +
+ Yocto Project Components + + + The + BitBake + task executor together with various types of configuration files + form the OpenEmbedded Core. + This section overviews these components by describing their use and + how they interact. + + + + BitBake handles the parsing and execution of the data files. + The data itself is of various types: + + + Recipes: + Provides details about particular pieces of software. + + + Class Data: + Abstracts common build information (e.g. how to build a + Linux kernel). + + + Configuration Data: + Defines machine-specific settings, policy decisions, and + so forth. + Configuration data acts as the glue to bind everything + together. + + + + + + BitBake knows how to combine multiple data sources together and + refers to each data source as a layer. + For information on layers, see the + "Understanding and Creating Layers" + section of the Yocto Project Development Tasks Manual. + + + + Following are some brief details on these core components. + For additional information on how these components interact during + a build, see the + "Development Concepts" + section. + + +
+ BitBake + + + BitBake is the tool at the heart of the OpenEmbedded build + system and is responsible for parsing the + Metadata, + generating a list of tasks from it, and then executing those + tasks. + + + + This section briefly introduces BitBake. + If you want more information on BitBake, see the + BitBake User Manual. + + + + To see a list of the options BitBake supports, use either of + the following commands: + + $ bitbake -h + $ bitbake --help + + + + + The most common usage for BitBake is + bitbake packagename, + where packagename is the name of the + package you want to build (referred to as the "target" in this + manual). + The target often equates to the first part of a recipe's + filename (e.g. "foo" for a recipe named + foo_1.3.0-r0.bb). + So, to process the + matchbox-desktop_1.2.3.bb recipe file, you + might type the following: + + $ bitbake matchbox-desktop + + Several different versions of + matchbox-desktop might exist. + BitBake chooses the one selected by the distribution + configuration. + You can get more details about how BitBake chooses between + different target versions and providers in the + "Preferences" + section of the BitBake User Manual. + + + + BitBake also tries to execute any dependent tasks first. + So for example, before building + matchbox-desktop, BitBake would build a + cross compiler and glibc if they had not + already been built. + + + + A useful BitBake option to consider is the + -k or --continue + option. + This option instructs BitBake to try and continue processing + the job as long as possible even after encountering an error. + When an error occurs, the target that failed and those that + depend on it cannot be remade. + However, when you use this option other dependencies can + still be processed. + +
+ +
+ Metadata (Recipes) + + + Files that have the .bb suffix are + "recipes" files. + In general, a recipe contains information about a single piece + of software. + This information includes the location from which to download + the unaltered source, any source patches to be applied to that + source (if needed), which special configuration options to + apply, how to compile the source files, and how to package the + compiled output. + + + + The term "package" is sometimes used to refer to recipes. + However, since the word "package" is used for the packaged + output from the OpenEmbedded build system (i.e. + .ipk or .deb files), + this document avoids using the term "package" when referring + to recipes. + +
+ +
+ Metadata (Virtual Providers) + + + Prior to the build, if you know that several different recipes + provide the same functionality, you can use a virtual provider + (i.e. virtual/*) as a placeholder for the + actual provider. + The actual provider would be determined at build time. + In this case, you should add virtual/* + to + DEPENDS, + rather than listing the specified provider. + You would select the actual provider by setting the + PREFERRED_PROVIDER + variable (i.e. + PREFERRED_PROVIDER_virtual/*) + in the build's configuration file (e.g. + poky/build/conf/local.conf). + + Any recipe that PROVIDES a virtual/* + item that is ultimately not selected through + PREFERRED_PROVIDER does not get built. + Preventing these recipes from building is usually the + desired behavior since this mechanism's purpose is to + select between mutually exclusive alternative providers. + + + + + The following lists specific examples of virtual providers: + + + virtual/mesa: + Provides gbm.pc. + + + virtual/egl: + Provides egl.pc and possibly + wayland-egl.pc. + + + virtual/libgl: + Provides gl.pc (i.e. libGL). + + + virtual/libgles1: + Provides glesv1_cm.pc + (i.e. libGLESv1_CM). + + + virtual/libgles2: + Provides glesv2.pc + (i.e. libGLESv2). + + + +
+ +
+ Classes + + + Class files (.bbclass) contain information + that is useful to share between + Metadata + files. + An example is the + autotools + class, which contains common settings for any application that + Autotools uses. + The + "Classes" + chapter in the Yocto Project Reference Manual provides + details about classes and how to use them. + +
+ +
+ Configuration + + + The configuration files (.conf) define + various configuration variables that govern the OpenEmbedded + build process. + These files fall into several areas that define machine + configuration options, distribution configuration options, + compiler tuning options, general common configuration options, + and user configuration options in + local.conf, which is found in the + Build Directory. + +
+
+ +
+ Cross-Development Toolchain Generation + + + The Yocto Project does most of the work for you when it comes to + creating + cross-development toolchains. + This section provides some technical background on how + cross-development toolchains are created and used. + For more information on toolchains, you can also see the + Yocto Project Application Development and the Extensible Software Development Kit (eSDK) + manual. + + + + In the Yocto Project development environment, cross-development + toolchains are used to build the image and applications that run + on the target hardware. + With just a few commands, the OpenEmbedded build system creates + these necessary toolchains for you. + + + + The following figure shows a high-level build environment regarding + toolchain construction and use. + + + + + + + + Most of the work occurs on the Build Host. + This is the machine used to build images and generally work within the + the Yocto Project environment. + When you run BitBake to create an image, the OpenEmbedded build system + uses the host gcc compiler to bootstrap a + cross-compiler named gcc-cross. + The gcc-cross compiler is what BitBake uses to + compile source files when creating the target image. + You can think of gcc-cross simply as an + automatically generated cross-compiler that is used internally within + BitBake only. + + The extensible SDK does not use + gcc-cross-canadian since this SDK + ships a copy of the OpenEmbedded build system and the sysroot + within it contains gcc-cross. + + + + + The chain of events that occurs when gcc-cross is + bootstrapped is as follows: + + gcc -> binutils-cross -> gcc-cross-initial -> linux-libc-headers -> glibc-initial -> glibc -> gcc-cross -> gcc-runtime + + + + gcc: + The build host's GNU Compiler Collection (GCC). + + + binutils-cross: + The bare minimum binary utilities needed in order to run + the gcc-cross-initial phase of the + bootstrap operation. + + + gcc-cross-initial: + An early stage of the bootstrap process for creating + the cross-compiler. + This stage builds enough of the gcc-cross, + the C library, and other pieces needed to finish building the + final cross-compiler in later stages. + This tool is a "native" package (i.e. it is designed to run on + the build host). + + + linux-libc-headers: + Headers needed for the cross-compiler. + + + glibc-initial: + An initial version of the Embedded GLIBC needed to bootstrap + glibc. + + + gcc-cross: + The final stage of the bootstrap process for the + cross-compiler. + This stage results in the actual cross-compiler that + BitBake uses when it builds an image for a targeted + device. + + If you are replacing this cross compiler toolchain + with a custom version, you must replace + gcc-cross. + + This tool is also a "native" package (i.e. it is + designed to run on the build host). + + + gcc-runtime: + Runtime libraries resulting from the toolchain bootstrapping + process. + This tool produces a binary that consists of the + runtime libraries need for the targeted device. + + + + + + You can use the OpenEmbedded build system to build an installer for + the relocatable SDK used to develop applications. + When you run the installer, it installs the toolchain, which contains + the development tools (e.g., the + gcc-cross-canadian), + binutils-cross-canadian, and other + nativesdk-* tools, + which are tools native to the SDK (i.e. native to + SDK_ARCH), + you need to cross-compile and test your software. + The figure shows the commands you use to easily build out this + toolchain. + This cross-development toolchain is built to execute on the + SDKMACHINE, + which might or might not be the same + machine as the Build Host. + + If your target architecture is supported by the Yocto Project, + you can take advantage of pre-built images that ship with the + Yocto Project and already contain cross-development toolchain + installers. + + + + + Here is the bootstrap process for the relocatable toolchain: + + gcc -> binutils-crosssdk -> gcc-crosssdk-initial -> linux-libc-headers -> + glibc-initial -> nativesdk-glibc -> gcc-crosssdk -> gcc-cross-canadian + + + + gcc: + The build host's GNU Compiler Collection (GCC). + + + binutils-crosssdk: + The bare minimum binary utilities needed in order to run + the gcc-crosssdk-initial phase of the + bootstrap operation. + + + gcc-crosssdk-initial: + An early stage of the bootstrap process for creating + the cross-compiler. + This stage builds enough of the + gcc-crosssdk and supporting pieces so that + the final stage of the bootstrap process can produce the + finished cross-compiler. + This tool is a "native" binary that runs on the build host. + + + linux-libc-headers: + Headers needed for the cross-compiler. + + + glibc-initial: + An initial version of the Embedded GLIBC needed to bootstrap + nativesdk-glibc. + + + nativesdk-glibc: + The Embedded GLIBC needed to bootstrap the + gcc-crosssdk. + + + gcc-crosssdk: + The final stage of the bootstrap process for the + relocatable cross-compiler. + The gcc-crosssdk is a transitory compiler + and never leaves the build host. + Its purpose is to help in the bootstrap process to create the + eventual relocatable gcc-cross-canadian + compiler, which is relocatable. + This tool is also a "native" package (i.e. it is + designed to run on the build host). + + + gcc-cross-canadian: + The final relocatable cross-compiler. + When run on the + SDKMACHINE, + this tool + produces executable code that runs on the target device. + Only one cross-canadian compiler is produced per architecture + since they can be targeted at different processor optimizations + using configurations passed to the compiler through the + compile commands. + This circumvents the need for multiple compilers and thus + reduces the size of the toolchains. + + + + + + For information on advantages gained when building a + cross-development toolchain installer, see the + "Building an SDK Installer" + section in the Yocto Project Application Development and the + Extensible Software Development Kit (eSDK) manual. + +
+ + + + +
+ Shared State Cache + + + By design, the OpenEmbedded build system builds everything from + scratch unless BitBake can determine that parts do not need to be + rebuilt. + Fundamentally, building from scratch is attractive as it means all + parts are built fresh and there is no possibility of stale data + causing problems. + When developers hit problems, they typically default back to + building from scratch so they know the state of things from the + start. + + + + Building an image from scratch is both an advantage and a + disadvantage to the process. + As mentioned in the previous paragraph, building from scratch + ensures that everything is current and starts from a known state. + However, building from scratch also takes much longer as it + generally means rebuilding things that do not necessarily need + to be rebuilt. + + + + The Yocto Project implements shared state code that supports + incremental builds. + The implementation of the shared state code answers the following + questions that were fundamental roadblocks within the OpenEmbedded + incremental build support system: + + + What pieces of the system have changed and what pieces have + not changed? + + + How are changed pieces of software removed and replaced? + + + How are pre-built components that do not need to be rebuilt + from scratch used when they are available? + + + + + + For the first question, the build system detects changes in the + "inputs" to a given task by creating a checksum (or signature) of + the task's inputs. + If the checksum changes, the system assumes the inputs have changed + and the task needs to be rerun. + For the second question, the shared state (sstate) code tracks + which tasks add which output to the build process. + This means the output from a given task can be removed, upgraded + or otherwise manipulated. + The third question is partly addressed by the solution for the + second question assuming the build system can fetch the sstate + objects from remote locations and install them if they are deemed + to be valid. + + The OpenEmbedded build system does not maintain + PR + information as part of the shared state packages. + Consequently, considerations exist that affect maintaining + shared state feeds. + For information on how the OpenEmbedded build system + works with packages and can track incrementing + PR information, see the + "Automatically Incrementing a Binary Package Revision Number" + section in the Yocto Project Development Tasks Manual. + + + + + The rest of this section goes into detail about the overall + incremental build architecture, the checksums (signatures), shared + state, and some tips and tricks. + + +
+ Overall Architecture + + + When determining what parts of the system need to be built, + BitBake works on a per-task basis rather than a per-recipe + basis. + You might wonder why using a per-task basis is preferred over + a per-recipe basis. + To help explain, consider having the IPK packaging backend + enabled and then switching to DEB. + In this case, the + do_install + and + do_package + task outputs are still valid. + However, with a per-recipe approach, the build would not + include the .deb files. + Consequently, you would have to invalidate the whole build and + rerun it. + Rerunning everything is not the best solution. + Also, in this case, the core must be "taught" much about + specific tasks. + This methodology does not scale well and does not allow users + to easily add new tasks in layers or as external recipes + without touching the packaged-staging core. + +
+ +
+ Checksums (Signatures) + + + The shared state code uses a checksum, which is a unique + signature of a task's inputs, to determine if a task needs to + be run again. + Because it is a change in a task's inputs that triggers a + rerun, the process needs to detect all the inputs to a given + task. + For shell tasks, this turns out to be fairly easy because + the build process generates a "run" shell script for each task + and it is possible to create a checksum that gives you a good + idea of when the task's data changes. + + + + To complicate the problem, there are things that should not be + included in the checksum. + First, there is the actual specific build path of a given + task - the + WORKDIR. + It does not matter if the work directory changes because it + should not affect the output for target packages. + Also, the build process has the objective of making native + or cross packages relocatable. + + Both native and cross packages run on the build host. + However, cross packages generate output for the target + architecture. + + The checksum therefore needs to exclude + WORKDIR. + The simplistic approach for excluding the work directory is to + set WORKDIR to some fixed value and + create the checksum for the "run" script. + + + + Another problem results from the "run" scripts containing + functions that might or might not get called. + The incremental build solution contains code that figures out + dependencies between shell functions. + This code is used to prune the "run" scripts down to the + minimum set, thereby alleviating this problem and making the + "run" scripts much more readable as a bonus. + + + + So far we have solutions for shell scripts. + What about Python tasks? + The same approach applies even though these tasks are more + difficult. + The process needs to figure out what variables a Python + function accesses and what functions it calls. + Again, the incremental build solution contains code that first + figures out the variable and function dependencies, and then + creates a checksum for the data used as the input to the task. + + + + Like the WORKDIR case, situations exist + where dependencies should be ignored. + For these cases, you can instruct the build process to + ignore a dependency by using a line like the following: + + PACKAGE_ARCHS[vardepsexclude] = "MACHINE" + + This example ensures that the + PACKAGE_ARCHS + variable does not depend on the value of + MACHINE, + even if it does reference it. + + + + Equally, there are cases where we need to add dependencies + BitBake is not able to find. + You can accomplish this by using a line like the following: + + PACKAGE_ARCHS[vardeps] = "MACHINE" + + This example explicitly adds the MACHINE + variable as a dependency for + PACKAGE_ARCHS. + + + + Consider a case with in-line Python, for example, where + BitBake is not able to figure out dependencies. + When running in debug mode (i.e. using + -DDD), BitBake produces output when it + discovers something for which it cannot figure out dependencies. + The Yocto Project team has currently not managed to cover + those dependencies in detail and is aware of the need to fix + this situation. + + + + Thus far, this section has limited discussion to the direct + inputs into a task. + Information based on direct inputs is referred to as the + "basehash" in the code. + However, there is still the question of a task's indirect + inputs - the things that were already built and present in the + Build Directory. + The checksum (or signature) for a particular task needs to add + the hashes of all the tasks on which the particular task + depends. + Choosing which dependencies to add is a policy decision. + However, the effect is to generate a master checksum that + combines the basehash and the hashes of the task's + dependencies. + + + + At the code level, there are a variety of ways both the + basehash and the dependent task hashes can be influenced. + Within the BitBake configuration file, we can give BitBake + some extra information to help it construct the basehash. + The following statement effectively results in a list of + global variable dependency excludes - variables never + included in any checksum: + + BB_HASHBASE_WHITELIST ?= "TMPDIR FILE PATH PWD BB_TASKHASH BBPATH DL_DIR \ + SSTATE_DIR THISDIR FILESEXTRAPATHS FILE_DIRNAME HOME LOGNAME SHELL TERM \ + USER FILESPATH STAGING_DIR_HOST STAGING_DIR_TARGET COREBASE PRSERV_HOST \ + PRSERV_DUMPDIR PRSERV_DUMPFILE PRSERV_LOCKDOWN PARALLEL_MAKE \ + CCACHE_DIR EXTERNAL_TOOLCHAIN CCACHE CCACHE_DISABLE LICENSE_PATH SDKPKGSUFFIX" + + The previous example excludes + WORKDIR + since that variable is actually constructed as a path within + TMPDIR, + which is on the whitelist. + + + + The rules for deciding which hashes of dependent tasks to + include through dependency chains are more complex and are + generally accomplished with a Python function. + The code in meta/lib/oe/sstatesig.py shows + two examples of this and also illustrates how you can insert + your own policy into the system if so desired. + This file defines the two basic signature generators + OE-Core + uses: "OEBasic" and "OEBasicHash". + By default, there is a dummy "noop" signature handler enabled + in BitBake. + This means that behavior is unchanged from previous versions. + OE-Core uses the "OEBasicHash" signature handler by default + through this setting in the bitbake.conf + file: + + BB_SIGNATURE_HANDLER ?= "OEBasicHash" + + The "OEBasicHash" BB_SIGNATURE_HANDLER + is the same as the "OEBasic" version but adds the task hash to + the stamp files. + This results in any + Metadata + change that changes the task hash, automatically + causing the task to be run again. + This removes the need to bump + PR + values, and changes to Metadata automatically ripple across + the build. + + + + It is also worth noting that the end result of these + signature generators is to make some dependency and hash + information available to the build. + This information includes: + + + BB_BASEHASH_task-taskname: + The base hashes for each task in the recipe. + + + BB_BASEHASH_filename:taskname: + The base hashes for each dependent task. + + + BBHASHDEPS_filename:taskname: + The task dependencies for each task. + + + BB_TASKHASH: + The hash of the currently running task. + + + +
+ +
+ Shared State + + + Checksums and dependencies, as discussed in the previous + section, solve half the problem of supporting a shared state. + The other part of the problem is being able to use checksum + information during the build and being able to reuse or rebuild + specific components. + + + + The + sstate + class is a relatively generic implementation of how to + "capture" a snapshot of a given task. + The idea is that the build process does not care about the + source of a task's output. + Output could be freshly built or it could be downloaded and + unpacked from somewhere - the build process does not need to + worry about its origin. + + + + There are two types of output, one is just about creating a + directory in + WORKDIR. + A good example is the output of either + do_install + or + do_package. + The other type of output occurs when a set of data is merged + into a shared directory tree such as the sysroot. + + + + The Yocto Project team has tried to keep the details of the + implementation hidden in sstate class. + From a user's perspective, adding shared state wrapping to a task + is as simple as this + do_deploy + example taken from the + deploy + class: + + DEPLOYDIR = "${WORKDIR}/deploy-${PN}" + SSTATETASKS += "do_deploy" + do_deploy[sstate-inputdirs] = "${DEPLOYDIR}" + do_deploy[sstate-outputdirs] = "${DEPLOY_DIR_IMAGE}" + + python do_deploy_setscene () { + sstate_setscene(d) + } + addtask do_deploy_setscene + do_deploy[dirs] = "${DEPLOYDIR} ${B}" + + The following list explains the previous example: + + + Adding "do_deploy" to SSTATETASKS + adds some required sstate-related processing, which is + implemented in the + sstate + class, to before and after the + do_deploy + task. + + + The + do_deploy[sstate-inputdirs] = "${DEPLOYDIR}" + declares that do_deploy places its + output in ${DEPLOYDIR} when run + normally (i.e. when not using the sstate cache). + This output becomes the input to the shared state cache. + + + The + do_deploy[sstate-outputdirs] = "${DEPLOY_DIR_IMAGE}" + line causes the contents of the shared state cache to be + copied to ${DEPLOY_DIR_IMAGE}. + + If do_deploy is not already in + the shared state cache or if its input checksum + (signature) has changed from when the output was + cached, the task will be run to populate the shared + state cache, after which the contents of the shared + state cache is copied to + ${DEPLOY_DIR_IMAGE}. + If do_deploy is in the shared + state cache and its signature indicates that the + cached output is still valid (i.e. if no + relevant task inputs have changed), then the + contents of the shared state cache will be copied + directly to + ${DEPLOY_DIR_IMAGE} by the + do_deploy_setscene task + instead, skipping the + do_deploy task. + + + + The following task definition is glue logic needed to + make the previous settings effective: + + python do_deploy_setscene () { + sstate_setscene(d) + } + addtask do_deploy_setscene + + sstate_setscene() takes the flags + above as input and accelerates the + do_deploy task through the + shared state cache if possible. + If the task was accelerated, + sstate_setscene() returns True. + Otherwise, it returns False, and the normal + do_deploy task runs. + For more information, see the + "setscene" + section in the BitBake User Manual. + + + The do_deploy[dirs] = "${DEPLOYDIR} ${B}" + line creates ${DEPLOYDIR} and + ${B} before the + do_deploy task runs, and also sets + the current working directory of + do_deploy to + ${B}. + For more information, see the + "Variable Flags" + section in the BitBake User Manual. + + In cases where + sstate-inputdirs and + sstate-outputdirs would be the + same, you can use + sstate-plaindirs. + For example, to preserve the + ${PKGD} and + ${PKGDEST} output from the + do_package + task, use the following: + + do_package[sstate-plaindirs] = "${PKGD} ${PKGDEST}" + + + + + sstate-inputdirs and + sstate-outputdirs can also be used + with multiple directories. + For example, the following declares + PKGDESTWORK and + SHLIBWORK as shared state + input directories, which populates the shared state + cache, and PKGDATA_DIR and + SHLIBSDIR as the corresponding + shared state output directories: + + do_package[sstate-inputdirs] = "${PKGDESTWORK} ${SHLIBSWORKDIR}" + do_package[sstate-outputdirs] = "${PKGDATA_DIR} ${SHLIBSDIR}" + + + + These methods also include the ability to take a + lockfile when manipulating shared state directory + structures, for cases where file additions or removals + are sensitive: + + do_package[sstate-lockfile] = "${PACKAGELOCK}" + + + + + + + Behind the scenes, the shared state code works by looking in + SSTATE_DIR + and + SSTATE_MIRRORS + for shared state files. + Here is an example: + + SSTATE_MIRRORS ?= "\ + file://.* http://someserver.tld/share/sstate/PATH;downloadfilename=PATH \n \ + file://.* file:///some/local/dir/sstate/PATH" + + + The shared state directory + (SSTATE_DIR) is organized into + two-character subdirectories, where the subdirectory + names are based on the first two characters of the hash. + If the shared state directory structure for a mirror has the + same structure as SSTATE_DIR, you must + specify "PATH" as part of the URI to enable the build system + to map to the appropriate subdirectory. + + + + + The shared state package validity can be detected just by + looking at the filename since the filename contains the task + checksum (or signature) as described earlier in this section. + If a valid shared state package is found, the build process + downloads it and uses it to accelerate the task. + + + + The build processes use the *_setscene + tasks for the task acceleration phase. + BitBake goes through this phase before the main execution + code and tries to accelerate any tasks for which it can find + shared state packages. + If a shared state package for a task is available, the + shared state package is used. + This means the task and any tasks on which it is dependent + are not executed. + + + + As a real world example, the aim is when building an IPK-based + image, only the + do_package_write_ipk + tasks would have their shared state packages fetched and + extracted. + Since the sysroot is not used, it would never get extracted. + This is another reason why a task-based approach is preferred + over a recipe-based approach, which would have to install the + output from every task. + +
+ +
+ Tips and Tricks + + + The code in the build system that supports incremental builds + is not simple code. + This section presents some tips and tricks that help you work + around issues related to shared state code. + + +
+ Debugging + + + Seeing what metadata went into creating the input signature + of a shared state (sstate) task can be a useful debugging + aid. + This information is available in signature information + (siginfo) files in + SSTATE_DIR. + For information on how to view and interpret information in + siginfo files, see the + "Viewing Task Variable Dependencies" + section in the Yocto Project Development Tasks Manual. + +
+ +
+ Invalidating Shared State + + + The OpenEmbedded build system uses checksums and shared + state cache to avoid unnecessarily rebuilding tasks. + Collectively, this scheme is known as "shared state code." + + + + As with all schemes, this one has some drawbacks. + It is possible that you could make implicit changes to your + code that the checksum calculations do not take into + account. + These implicit changes affect a task's output but do not + trigger the shared state code into rebuilding a recipe. + Consider an example during which a tool changes its output. + Assume that the output of rpmdeps + changes. + The result of the change should be that all the + package and + package_write_rpm shared state cache + items become invalid. + However, because the change to the output is + external to the code and therefore implicit, + the associated shared state cache items do not become + invalidated. + In this case, the build process uses the cached items + rather than running the task again. + Obviously, these types of implicit changes can cause + problems. + + + + To avoid these problems during the build, you need to + understand the effects of any changes you make. + Realize that changes you make directly to a function + are automatically factored into the checksum calculation. + Thus, these explicit changes invalidate the associated + area of shared state cache. + However, you need to be aware of any implicit changes that + are not obvious changes to the code and could affect + the output of a given task. + + + + When you identify an implicit change, you can easily + take steps to invalidate the cache and force the tasks + to run. + The steps you can take are as simple as changing a + function's comments in the source code. + For example, to invalidate package shared state files, + change the comment statements of + do_package + or the comments of one of the functions it calls. + Even though the change is purely cosmetic, it causes the + checksum to be recalculated and forces the OpenEmbedded + build system to run the task again. + + For an example of a commit that makes a cosmetic + change to invalidate shared state, see this + commit. + + +
+
+
+ +
+ Automatically Added Runtime Dependencies + + + The OpenEmbedded build system automatically adds common types of + runtime dependencies between packages, which means that you do not + need to explicitly declare the packages using + RDEPENDS. + Three automatic mechanisms exist (shlibdeps, + pcdeps, and depchains) + that handle shared libraries, package configuration (pkg-config) + modules, and -dev and + -dbg packages, respectively. + For other types of runtime dependencies, you must manually declare + the dependencies. + + + shlibdeps: + During the + do_package + task of each recipe, all shared libraries installed by the + recipe are located. + For each shared library, the package that contains the + shared library is registered as providing the shared + library. + More specifically, the package is registered as providing + the + soname + of the library. + The resulting shared-library-to-package mapping + is saved globally in + PKGDATA_DIR + by the + do_packagedata + task. + + Simultaneously, all executables and shared libraries + installed by the recipe are inspected to see what shared + libraries they link against. + For each shared library dependency that is found, + PKGDATA_DIR is queried to + see if some package (likely from a different recipe) + contains the shared library. + If such a package is found, a runtime dependency is added + from the package that depends on the shared library to the + package that contains the library. + + The automatically added runtime dependency also + includes a version restriction. + This version restriction specifies that at least the + current version of the package that provides the shared + library must be used, as if + "package (>= version)" + had been added to + RDEPENDS. + This forces an upgrade of the package containing the shared + library when installing the package that depends on the + library, if needed. + + If you want to avoid a package being registered as + providing a particular shared library (e.g. because the library + is for internal use only), then add the library to + PRIVATE_LIBS + inside the package's recipe. + + + pcdeps: + During the + do_package + task of each recipe, all pkg-config modules + (*.pc files) installed by the recipe + are located. + For each module, the package that contains the module is + registered as providing the module. + The resulting module-to-package mapping is saved globally in + PKGDATA_DIR + by the + do_packagedata + task. + + Simultaneously, all pkg-config modules installed by + the recipe are inspected to see what other pkg-config + modules they depend on. + A module is seen as depending on another module if it + contains a "Requires:" line that specifies the other module. + For each module dependency, + PKGDATA_DIR is queried to see if some + package contains the module. + If such a package is found, a runtime dependency is added + from the package that depends on the module to the package + that contains the module. + + The pcdeps mechanism most often + infers dependencies between -dev + packages. + + + + depchains: + If a package foo depends on a package + bar, then foo-dev + and foo-dbg are also made to depend on + bar-dev and + bar-dbg, respectively. + Taking the -dev packages as an + example, the bar-dev package might + provide headers and shared library symlinks needed by + foo-dev, which shows the need + for a dependency between the packages. + + The dependencies added by + depchains are in the form of + RRECOMMENDS. + + By default, foo-dev also has an + RDEPENDS-style dependency on + foo, because the default value of + RDEPENDS_${PN}-dev (set in + bitbake.conf) includes + "${PN}". + + + To ensure that the dependency chain is never broken, + -dev and -dbg + packages are always generated by default, even if the + packages turn out to be empty. + See the + ALLOW_EMPTY + variable for more information. + + + + + + The do_package task depends on the + do_packagedata + task of each recipe in + DEPENDS + through use of a + [deptask] + declaration, which guarantees that the required + shared-library/module-to-package mapping information will be available + when needed as long as DEPENDS has been + correctly set. + +
+ +
+ Fakeroot and Pseudo + + + Some tasks are easier to implement when allowed to perform certain + operations that are normally reserved for the root user (e.g. + do_install, + do_package_write*, + do_rootfs, + and + do_image*). + For example, the do_install task benefits + from being able to set the UID and GID of installed files to + arbitrary values. + + + + One approach to allowing tasks to perform root-only operations + would be to require BitBake to run as root. + However, this method is cumbersome and has security issues. + The approach that is actually used is to run tasks that benefit + from root privileges in a "fake" root environment. + Within this environment, the task and its child processes believe + that they are running as the root user, and see an internally + consistent view of the filesystem. + As long as generating the final output (e.g. a package or an image) + does not require root privileges, the fact that some earlier + steps ran in a fake root environment does not cause problems. + + + + The capability to run tasks in a fake root environment is known as + "fakeroot", + which is derived from the BitBake keyword/variable + flag that requests a fake root environment for a task. + + + + In the OpenEmbedded build system, the program that implements + fakeroot is known as Pseudo. + Pseudo overrides system calls by using the environment variable + LD_PRELOAD, which results in the illusion + of running as root. + To keep track of "fake" file ownership and permissions resulting + from operations that require root permissions, Pseudo uses + an SQLite 3 database. + This database is stored in + ${WORKDIR}/pseudo/files.db + for individual recipes. + Storing the database in a file as opposed to in memory + gives persistence between tasks and builds, which is not + accomplished using fakeroot. + Caution + If you add your own task that manipulates the same files or + directories as a fakeroot task, then that task also needs to + run under fakeroot. + Otherwise, the task cannot run root-only operations, and + cannot see the fake file ownership and permissions set by the + other task. + You need to also add a dependency on + virtual/fakeroot-native:do_populate_sysroot, + giving the following: + + fakeroot do_mytask () { + ... + } + do_mytask[depends] += "virtual/fakeroot-native:do_populate_sysroot" + + + For more information, see the + FAKEROOT* + variables in the BitBake User Manual. + You can also reference the + "Pseudo" + and + "Why Not Fakeroot?" + articles for background information on Pseudo. + +
+ +
+ Wayland + + + Wayland + is a computer display server protocol that + provides a method for compositing window managers to communicate + directly with applications and video hardware and expects them to + communicate with input hardware using other libraries. + Using Wayland with supporting targets can result in better control + over graphics frame rendering than an application might otherwise + achieve. + + + + The Yocto Project provides the Wayland protocol libraries and the + reference + Weston + compositor as part of its release. + This section describes what you need to do to implement Wayland and + use the compositor when building an image for a supporting target. + + +
+ Support + + + The Wayland protocol libraries and the reference Weston + compositor ship as integrated packages in the + meta layer of the + Source Directory. + Specifically, you can find the recipes that build both Wayland + and Weston at + meta/recipes-graphics/wayland. + + + + You can build both the Wayland and Weston packages for use only + with targets that accept the + Mesa 3D and Direct Rendering Infrastructure, + which is also known as Mesa DRI. + This implies that you cannot build and use the packages if your + target uses, for example, the + Intel Embedded Media + and Graphics Driver + (Intel EMGD) that + overrides Mesa DRI. + + Due to lack of EGL support, Weston 1.0.3 will not run + directly on the emulated QEMU hardware. + However, this version of Weston will run under X emulation + without issues. + + +
+ +
+ Enabling Wayland in an Image + + + To enable Wayland, you need to enable it to be built and enable + it to be included in the image. + + +
+ Building + + + To cause Mesa to build the wayland-egl + platform and Weston to build Wayland with Kernel Mode + Setting + (KMS) + support, include the "wayland" flag in the + DISTRO_FEATURES + statement in your local.conf file: + + DISTRO_FEATURES_append = " wayland" + + + If X11 has been enabled elsewhere, Weston will build + Wayland with X11 support + + +
+ +
+ Installing + + + To install the Wayland feature into an image, you must + include the following + CORE_IMAGE_EXTRA_INSTALL + statement in your local.conf file: + + CORE_IMAGE_EXTRA_INSTALL += "wayland weston" + + +
+
+ +
+ Running Weston + + + To run Weston inside X11, enabling it as described earlier and + building a Sato image is sufficient. + If you are running your image under Sato, a Weston Launcher + appears in the "Utility" category. + + + + Alternatively, you can run Weston through the command-line + interpretor (CLI), which is better suited for development work. + To run Weston under the CLI, you need to do the following after + your image is built: + + + Run these commands to export + XDG_RUNTIME_DIR: + + mkdir -p /tmp/$USER-weston + chmod 0700 /tmp/$USER-weston + export XDG_RUNTIME_DIR=/tmp/$USER-weston + + + + Launch Weston in the shell: + + weston + + + +
+
+ +
+ Licenses + + + This section describes the mechanism by which the OpenEmbedded + build system tracks changes to licensing text. + The section also describes how to enable commercially licensed + recipes, which by default are disabled. + + + + For information that can help you maintain compliance with + various open source licensing during the lifecycle of the product, + see the + "Maintaining Open Source License Compliance During Your Project's Lifecycle" + section in the Yocto Project Development Tasks Manual. + + +
+ Tracking License Changes + + + The license of an upstream project might change in the future. + In order to prevent these changes going unnoticed, the + LIC_FILES_CHKSUM + variable tracks changes to the license text. The checksums are + validated at the end of the configure step, and if the + checksums do not match, the build will fail. + + +
+ Specifying the <filename>LIC_FILES_CHKSUM</filename> Variable + + + The LIC_FILES_CHKSUM + variable contains checksums of the license text in the + source code for the recipe. + Following is an example of how to specify + LIC_FILES_CHKSUM: + + LIC_FILES_CHKSUM = "file://COPYING;md5=xxxx \ + file://licfile1.txt;beginline=5;endline=29;md5=yyyy \ + file://licfile2.txt;endline=50;md5=zzzz \ + ..." + + Notes + + + When using "beginline" and "endline", realize + that line numbering begins with one and not + zero. + Also, the included lines are inclusive (i.e. + lines five through and including 29 in the + previous example for + licfile1.txt). + + + When a license check fails, the selected license + text is included as part of the QA message. + Using this output, you can determine the exact + start and finish for the needed license text. + + + + + + + The build system uses the + S + variable as the default directory when searching files + listed in LIC_FILES_CHKSUM. + The previous example employs the default directory. + + + + Consider this next example: + + LIC_FILES_CHKSUM = "file://src/ls.c;beginline=5;endline=16;\ + md5=bb14ed3c4cda583abc85401304b5cd4e" + LIC_FILES_CHKSUM = "file://${WORKDIR}/license.html;md5=5c94767cedb5d6987c902ac850ded2c6" + + + + + The first line locates a file in + ${S}/src/ls.c and isolates lines five + through 16 as license text. + The second line refers to a file in + WORKDIR. + + + + Note that LIC_FILES_CHKSUM variable is + mandatory for all recipes, unless the + LICENSE variable is set to "CLOSED". + +
+ +
+ Explanation of Syntax + + + As mentioned in the previous section, the + LIC_FILES_CHKSUM variable lists all + the important files that contain the license text for the + source code. + It is possible to specify a checksum for an entire file, + or a specific section of a file (specified by beginning and + ending line numbers with the "beginline" and "endline" + parameters, respectively). + The latter is useful for source files with a license + notice header, README documents, and so forth. + If you do not use the "beginline" parameter, then it is + assumed that the text begins on the first line of the file. + Similarly, if you do not use the "endline" parameter, + it is assumed that the license text ends with the last + line of the file. + + + + The "md5" parameter stores the md5 checksum of the license + text. + If the license text changes in any way as compared to + this parameter then a mismatch occurs. + This mismatch triggers a build failure and notifies + the developer. + Notification allows the developer to review and address + the license text changes. + Also note that if a mismatch occurs during the build, + the correct md5 checksum is placed in the build log and + can be easily copied to the recipe. + + + + There is no limit to how many files you can specify using + the LIC_FILES_CHKSUM variable. + Generally, however, every project requires a few + specifications for license tracking. + Many projects have a "COPYING" file that stores the + license information for all the source code files. + This practice allows you to just track the "COPYING" + file as long as it is kept up to date. + Tips + + + If you specify an empty or invalid "md5" + parameter, BitBake returns an md5 mis-match + error and displays the correct "md5" parameter + value during the build. + The correct parameter is also captured in + the build log. + + + If the whole file contains only license text, + you do not need to use the "beginline" and + "endline" parameters. + + + + +
+
+ +
+ Enabling Commercially Licensed Recipes + + + By default, the OpenEmbedded build system disables + components that have commercial or other special licensing + requirements. + Such requirements are defined on a + recipe-by-recipe basis through the + LICENSE_FLAGS + variable definition in the affected recipe. + For instance, the + poky/meta/recipes-multimedia/gstreamer/gst-plugins-ugly + recipe contains the following statement: + + LICENSE_FLAGS = "commercial" + + Here is a slightly more complicated example that contains both + an explicit recipe name and version (after variable expansion): + + LICENSE_FLAGS = "license_${PN}_${PV}" + + In order for a component restricted by a + LICENSE_FLAGS definition to be enabled and + included in an image, it needs to have a matching entry in the + global + LICENSE_FLAGS_WHITELIST + variable, which is a variable typically defined in your + local.conf file. + For example, to enable the + poky/meta/recipes-multimedia/gstreamer/gst-plugins-ugly + package, you could add either the string + "commercial_gst-plugins-ugly" or the more general string + "commercial" to LICENSE_FLAGS_WHITELIST. + See the + "License Flag Matching" + section for a full + explanation of how LICENSE_FLAGS matching + works. + Here is the example: + + LICENSE_FLAGS_WHITELIST = "commercial_gst-plugins-ugly" + + Likewise, to additionally enable the package built from the + recipe containing + LICENSE_FLAGS = "license_${PN}_${PV}", + and assuming that the actual recipe name was + emgd_1.10.bb, the following string would + enable that package as well as the original + gst-plugins-ugly package: + + LICENSE_FLAGS_WHITELIST = "commercial_gst-plugins-ugly license_emgd_1.10" + + As a convenience, you do not need to specify the complete + license string in the whitelist for every package. + You can use an abbreviated form, which consists + of just the first portion or portions of the license + string before the initial underscore character or characters. + A partial string will match any license that contains the + given string as the first portion of its license. + For example, the following whitelist string will also match + both of the packages previously mentioned as well as any other + packages that have licenses starting with "commercial" or + "license". + + LICENSE_FLAGS_WHITELIST = "commercial license" + + + +
+ License Flag Matching + + + License flag matching allows you to control what recipes + the OpenEmbedded build system includes in the build. + Fundamentally, the build system attempts to match + LICENSE_FLAGS + strings found in recipes against + LICENSE_FLAGS_WHITELIST + strings found in the whitelist. + A match causes the build system to include a recipe in the + build, while failure to find a match causes the build + system to exclude a recipe. + + + + In general, license flag matching is simple. + However, understanding some concepts will help you + correctly and effectively use matching. + + + + Before a flag + defined by a particular recipe is tested against the + contents of the whitelist, the expanded string + _${PN} is appended to the flag. + This expansion makes each + LICENSE_FLAGS value recipe-specific. + After expansion, the string is then matched against the + whitelist. + Thus, specifying + LICENSE_FLAGS = "commercial" + in recipe "foo", for example, results in the string + "commercial_foo". + And, to create a match, that string must appear in the + whitelist. + + + + Judicious use of the LICENSE_FLAGS + strings and the contents of the + LICENSE_FLAGS_WHITELIST variable + allows you a lot of flexibility for including or excluding + recipes based on licensing. + For example, you can broaden the matching capabilities by + using license flags string subsets in the whitelist. + + When using a string subset, be sure to use the part of + the expanded string that precedes the appended + underscore character (e.g. + usethispart_1.3, + usethispart_1.4, and so forth). + + For example, simply specifying the string "commercial" in + the whitelist matches any expanded + LICENSE_FLAGS definition that starts + with the string "commercial" such as "commercial_foo" and + "commercial_bar", which are the strings the build system + automatically generates for hypothetical recipes named + "foo" and "bar" assuming those recipes simply specify the + following: + + LICENSE_FLAGS = "commercial" + + Thus, you can choose to exhaustively + enumerate each license flag in the whitelist and + allow only specific recipes into the image, or + you can use a string subset that causes a broader range of + matches to allow a range of recipes into the image. + + + + This scheme works even if the + LICENSE_FLAGS string already + has _${PN} appended. + For example, the build system turns the license flag + "commercial_1.2_foo" into "commercial_1.2_foo_foo" and + would match both the general "commercial" and the specific + "commercial_1.2_foo" strings found in the whitelist, as + expected. + + + + Here are some other scenarios: + + + You can specify a versioned string in the recipe + such as "commercial_foo_1.2" in a "foo" recipe. + The build system expands this string to + "commercial_foo_1.2_foo". + Combine this license flag with a whitelist that has + the string "commercial" and you match the flag + along with any other flag that starts with the + string "commercial". + + + Under the same circumstances, you can use + "commercial_foo" in the whitelist and the build + system not only matches "commercial_foo_1.2" but + also matches any license flag with the string + "commercial_foo", regardless of the version. + + + You can be very specific and use both the + package and version parts in the whitelist (e.g. + "commercial_foo_1.2") to specifically match a + versioned recipe. + + + +
+ + +
+
+ +
+ x32 psABI + + + x32 processor-specific Application Binary Interface + (x32 psABI) + is a native 32-bit processor-specific ABI for + Intel 64 (x86-64) + architectures. + An ABI defines the calling conventions between functions in a + processing environment. + The interface determines what registers are used and what the sizes are + for various C data types. + + + + Some processing environments prefer using 32-bit applications even + when running on Intel 64-bit platforms. + Consider the i386 psABI, which is a very old 32-bit ABI for Intel + 64-bit platforms. + The i386 psABI does not provide efficient use and access of the + Intel 64-bit processor resources, leaving the system underutilized. + Now consider the x86_64 psABI. + This ABI is newer and uses 64-bits for data sizes and program + pointers. + The extra bits increase the footprint size of the programs, + libraries, and also increases the memory and file system size + requirements. + Executing under the x32 psABI enables user programs to utilize CPU + and system resources more efficiently while keeping the memory + footprint of the applications low. + Extra bits are used for registers but not for addressing mechanisms. + + + + The Yocto Project supports the final specifications of x32 psABI + as follows: + + + You can create packages and images in x32 psABI format on + x86_64 architecture targets. + + + You can successfully build recipes with the x32 toolchain. + + + You can create and boot + core-image-minimal and + core-image-sato images. + + + RPM Package Manager (RPM) support exists for x32 binaries. + + + Support for large images exists. + + + + + + For steps on how to use x32 psABI, see the + "Using x32 psABI" + section in the Yocto Project Development Tasks Manual. + +
+ + diff --git a/documentation/getting-started/getting-started-customization.xsl b/documentation/getting-started/getting-started-customization.xsl new file mode 100644 index 0000000000..9733bf87b2 --- /dev/null +++ b/documentation/getting-started/getting-started-customization.xsl @@ -0,0 +1,27 @@ + + + + + + + + + + + + + + + + + + + + + diff --git a/documentation/getting-started/getting-started-development-environment.xml b/documentation/getting-started/getting-started-development-environment.xml new file mode 100644 index 0000000000..7d177cecca --- /dev/null +++ b/documentation/getting-started/getting-started-development-environment.xml @@ -0,0 +1,2890 @@ + %poky; ] > + + +The Yocto Project Development Environment + + + This chapter takes a look at the Yocto Project development + environment and also provides a detailed look at what goes on during + development in that environment. + The chapter provides Yocto Project Development environment concepts that + help you understand how work is accomplished in an open source environment, + which is very different as compared to work accomplished in a closed, + proprietary environment. + + + + Specifically, this chapter addresses open source philosophy, workflows, + Git, source repositories, licensing, recipe syntax, and development + syntax. + + +
+ Introduction + + + The Yocto Project is an open-source collaboration project whose + focus is for developers of embedded Linux systems. + Among other things, the Yocto Project uses an + OpenEmbedded build system. + The build system, which is based on the OpenEmbedded (OE) project and + uses the + BitBake tool, + constructs complete Linux images for architectures based on ARM, MIPS, + PowerPC, x86 and x86-64. + + Historically, the OpenEmbedded build system, which is the + combination of BitBake and OE components, formed a reference + build host that was known as + "Poky" + (Pah-kee). + The term "Poky", as used throughout the Yocto Project Documentation + set, can have different meanings. + + The Yocto Project provides various ancillary tools for the embedded + developer and also features the Sato reference User Interface, which + is optimized for stylus-driven, low-resolution screens. + + + + + + + + + + Here are some highlights for the Yocto Project: + + + + + Provides a recent Linux kernel along with a set of system + commands and libraries suitable for the embedded + environment. + + + Makes available system components such as X11, GTK+, Qt, + Clutter, and SDL (among others) so you can create a rich user + experience on devices that have display hardware. + For devices that do not have a display or where you wish to + use alternative UI frameworks, these components need not be + installed. + + + Creates a focused and stable core compatible with the + OpenEmbedded project with which you can easily and reliably + build and develop. + + + Fully supports a wide range of hardware and device emulation + through the Quick EMUlator (QEMU). + + + Provides a layer mechanism that allows you to easily extend + the system, make customizations, and keep them organized. + + + + + You can use the Yocto Project to generate images for many kinds + of devices. + As mentioned earlier, the Yocto Project supports creation of + reference images that you can boot within and emulate using QEMU. + The standard example machines target QEMU full-system + emulation for 32-bit and 64-bit variants of x86, ARM, MIPS, and + PowerPC architectures. + Beyond emulation, you can use the layer mechanism to extend + support to just about any platform that Linux can run on and that + a toolchain can target. + + + + Another Yocto Project feature is the Sato reference User + Interface. + This optional UI that is based on GTK+ is intended for devices with + restricted screen sizes and is included as part of the + OpenEmbedded Core layer so that developers can test parts of the + software stack. + + + + While the Yocto Project does not provide a strict testing framework, + it does provide or generate for you artifacts that let you perform + target-level and emulated testing and debugging. + Additionally, if you are an + Eclipse IDE user, you can + install an Eclipse Yocto Plug-in to allow you to develop within that + familiar environment. + + + + By default, using the Yocto Project to build an image creates a Poky + distribution. + However, you can create your own distribution by providing key + Metadata. + A good example is Angstrom, which has had a distribution + based on the Yocto Project since its inception. + Other examples include commercial distributions like + Wind River Linux, + Mentor Embedded Linux, + ENEA Linux + and others. + See the "Creating Your Own Distribution" + section in the Yocto Project Development Tasks Manual for more + information. + +
+ +
+ Open Source Philosophy + + + Open source philosophy is characterized by software development + directed by peer production and collaboration through an active + community of developers. + Contrast this to the more standard centralized development models + used by commercial software companies where a finite set of developers + produces a product for sale using a defined set of procedures that + ultimately result in an end product whose architecture and source + material are closed to the public. + + + + Open source projects conceptually have differing concurrent agendas, + approaches, and production. + These facets of the development process can come from anyone in the + public (community) that has a stake in the software project. + The open source environment contains new copyright, licensing, domain, + and consumer issues that differ from the more traditional development + environment. + In an open source environment, the end product, source material, + and documentation are all available to the public at no cost. + + + + A benchmark example of an open source project is the Linux kernel, + which was initially conceived and created by Finnish computer science + student Linus Torvalds in 1991. + Conversely, a good example of a non-open source project is the + Windows family of operating + systems developed by + Microsoft Corporation. + + + + Wikipedia has a good historical description of the Open Source + Philosophy + here. + You can also find helpful information on how to participate in the + Linux Community + here. + +
+ +
+ Workflows + + + This section provides workflow concepts using the Yocto Project and + Git. + In particular, the information covers basic practices that describe + roles and actions in a collaborative development environment. + + If you are familiar with this type of development environment, you + might not want to read this section. + + + + + The Yocto Project files are maintained using Git in "master" + branches whose Git histories track every change and whose structures + provides branches for all diverging functionality. + Although there is no need to use Git, many open source projects do so. + + + + For the Yocto Project, a key individual called the "maintainer" is + responsible for the "master" branch of a given Git repository. + The "master" branch is the “upstream†repository from which final or + most recent builds of the project occur. + The maintainer is responsible for accepting changes from other + developers and for organizing the underlying branch structure to + reflect release strategies and so forth. + For information on finding out who is responsible for (maintains) + a particular area of code, see the + "Submitting a Change to the Yocto Project" + section of the Yocto Project Development Tasks Manual. + + + + + The Yocto Project poky Git repository also has an + upstream contribution Git repository named + poky-contrib. + You can see all the branches in this repository using the web interface + of the + Source Repositories organized + within the "Poky Support" area. + These branches temporarily hold changes to the project that have been + submitted or committed by the Yocto Project development team and by + community members who contribute to the project. + The maintainer determines if the changes are qualified to be moved + from the "contrib" branches into the "master" branch of the Git + repository. + + + + Developers (including contributing community members) create and + maintain cloned repositories of the upstream "master" branch. + The cloned repositories are local to their development platforms and + are used to develop changes. + When a developer is satisfied with a particular feature or change, + they "push" the changes to the appropriate "contrib" repository. + + + + Developers are responsible for keeping their local repository + up-to-date with "master". + They are also responsible for straightening out any conflicts that + might arise within files that are being worked on simultaneously by + more than one person. + All this work is done locally on the developer’s machine before + anything is pushed to a "contrib" area and examined at the maintainer’s + level. + + + + A somewhat formal method exists by which developers commit changes + and push them into the "contrib" area and subsequently request that + the maintainer include them into "master". + This process is called “submitting a patch†or "submitting a change." + For information on submitting patches and changes, see the + "Submitting a Change to the Yocto Project" + section in the Yocto Project Development Tasks Manual. + + + + To summarize the development workflow: a single point of entry + exists for changes into the project’s "master" branch of the + Git repository, which is controlled by the project’s maintainer. + And, a set of developers exist who independently develop, test, and + submit changes to "contrib" areas for the maintainer to examine. + The maintainer then chooses which changes are going to become a + permanent part of the project. + + + + + + + + While each development environment is unique, there are some best + practices or methods that help development run smoothly. + The following list describes some of these practices. + For more information about Git workflows, see the workflow topics in + the + Git Community Book. + + + Make Small Changes: + It is best to keep the changes you commit small as compared to + bundling many disparate changes into a single commit. + This practice not only keeps things manageable but also allows + the maintainer to more easily include or refuse changes. + + It is also good practice to leave the repository in a + state that allows you to still successfully build your project. + In other words, do not commit half of a feature, + then add the other half as a separate, later commit. + Each commit should take you from one buildable project state + to another buildable state. + + + Use Branches Liberally: + It is very easy to create, use, and delete local branches in + your working Git repository. + You can name these branches anything you like. + It is helpful to give them names associated with the particular + feature or change on which you are working. + Once you are done with a feature or change and have merged it + into your local master branch, simply discard the temporary + branch. + + + Merge Changes: + The git merge command allows you to take + the changes from one branch and fold them into another branch. + This process is especially helpful when more than a single + developer might be working on different parts of the same + feature. + Merging changes also automatically identifies any collisions + or "conflicts" that might happen as a result of the same lines + of code being altered by two different developers. + + + Manage Branches: + Because branches are easy to use, you should use a system + where branches indicate varying levels of code readiness. + For example, you can have a "work" branch to develop in, a + "test" branch where the code or change is tested, a "stage" + branch where changes are ready to be committed, and so forth. + As your project develops, you can merge code across the + branches to reflect ever-increasing stable states of the + development. + + + Use Push and Pull: + The push-pull workflow is based on the concept of developers + "pushing" local commits to a remote repository, which is + usually a contribution repository. + This workflow is also based on developers "pulling" known + states of the project down into their local development + repositories. + The workflow easily allows you to pull changes submitted by + other developers from the upstream repository into your + work area ensuring that you have the most recent software + on which to develop. + The Yocto Project has two scripts named + create-pull-request and + send-pull-request that ship with the + release to facilitate this workflow. + You can find these scripts in the scripts + folder of the + Source Directory. + For information on how to use these scripts, see the + "Using Scripts to Push a Change Upstream and Request a Pull" + section in the Yocto Project Development Tasks Manual. + + + Patch Workflow: + This workflow allows you to notify the maintainer through an + email that you have a change (or patch) you would like + considered for the "master" branch of the Git repository. + To send this type of change, you format the patch and then + send the email using the Git commands + git format-patch and + git send-email. + For information on how to use these scripts, see the + "Submitting a Change to the Yocto Project" + section in the Yocto Project Development Tasks Manual. + + + +
+ +
+ Git + + + The Yocto Project makes extensive use of Git, which is a + free, open source distributed version control system. + Git supports distributed development, non-linear development, + and can handle large projects. + It is best that you have some fundamental understanding + of how Git tracks projects and how to work with Git if + you are going to use the Yocto Project for development. + This section provides a quick overview of how Git works and + provides you with a summary of some essential Git commands. + Notes + + + For more information on Git, see + . + + + If you need to download Git, it is recommended that you add + Git to your system through your distribution's "software + store" (e.g. for Ubuntu, use the Ubuntu Software feature). + For the Git download page, see + . + + + For examples beyond the limited few in this section on how + to use Git with the Yocto Project, see the + "Working With Yocto Project Source Files" + section in the Yocto Project Development Tasks Manual. + + + + + +
+ Repositories, Tags, and Branches + + + As mentioned briefly in the previous section and also in the + "Workflows" section, + the Yocto Project maintains source repositories at + . + If you look at this web-interface of the repositories, each item + is a separate Git repository. + + + + Git repositories use branching techniques that track content + change (not files) within a project (e.g. a new feature or updated + documentation). + Creating a tree-like structure based on project divergence allows + for excellent historical information over the life of a project. + This methodology also allows for an environment from which you can + do lots of local experimentation on projects as you develop + changes or new features. + + + + A Git repository represents all development efforts for a given + project. + For example, the Git repository poky contains + all changes and developments for Poky over the course of its + entire life. + That means that all changes that make up all releases are captured. + The repository maintains a complete history of changes. + + + + You can create a local copy of any repository by "cloning" it + with the git clone command. + When you clone a Git repository, you end up with an identical + copy of the repository on your development system. + Once you have a local copy of a repository, you can take steps to + develop locally. + For examples on how to clone Git repositories, see the + "Working With Yocto Project Source Files" + section in the Yocto Project Development Tasks Manual. + + + + It is important to understand that Git tracks content change and + not files. + Git uses "branches" to organize different development efforts. + For example, the poky repository has + several branches that include the current "&DISTRO_NAME_NO_CAP;" + branch, the "master" branch, and many branches for past + Yocto Project releases. + You can see all the branches by going to + and + clicking on the + [...] + link beneath the "Branch" heading. + + + + Each of these branches represents a specific area of development. + The "master" branch represents the current or most recent + development. + All other branches represent offshoots of the "master" branch. + + + + When you create a local copy of a Git repository, the copy has + the same set of branches as the original. + This means you can use Git to create a local working area + (also called a branch) that tracks a specific development branch + from the upstream source Git repository. + in other words, you can define your local Git environment to + work on any development branch in the repository. + To help illustrate, consider the following example Git commands: + + $ cd ~ + $ git clone git://git.yoctoproject.org/poky + $ cd poky + $ git checkout -b &DISTRO_NAME_NO_CAP; origin/&DISTRO_NAME_NO_CAP; + + In the previous example after moving to the home directory, the + git clone command creates a + local copy of the upstream poky Git repository. + By default, Git checks out the "master" branch for your work. + After changing the working directory to the new local repository + (i.e. poky), the + git checkout command creates + and checks out a local branch named "&DISTRO_NAME_NO_CAP;", which + tracks the upstream "origin/&DISTRO_NAME_NO_CAP;" branch. + Changes you make while in this branch would ultimately affect + the upstream "&DISTRO_NAME_NO_CAP;" branch of the + poky repository. + + + + It is important to understand that when you create and checkout a + local working branch based on a branch name, + your local environment matches the "tip" of that particular + development branch at the time you created your local branch, + which could be different from the files in the "master" branch + of the upstream repository. + In other words, creating and checking out a local branch based on + the "&DISTRO_NAME_NO_CAP;" branch name is not the same as + cloning and checking out the "master" branch if the repository. + Keep reading to see how you create a local snapshot of a Yocto + Project Release. + + + + Git uses "tags" to mark specific changes in a repository. + Typically, a tag is used to mark a special point such as the final + change before a project is released. + You can see the tags used with the poky Git + repository by going to + and + clicking on the + [...] + link beneath the "Tag" heading. + + + + Some key tags for the poky are + jethro-14.0.3, + morty-16.0.1, + pyro-17.0.0, and + &DISTRO_NAME_NO_CAP;-&POKYVERSION;. + These tags represent Yocto Project releases. + + + + When you create a local copy of the Git repository, you also + have access to all the tags in the upstream repository. + Similar to branches, you can create and checkout a local working + Git branch based on a tag name. + When you do this, you get a snapshot of the Git repository that + reflects the state of the files when the change was made associated + with that tag. + The most common use is to checkout a working branch that matches + a specific Yocto Project release. + Here is an example: + + $ cd ~ + $ git clone git://git.yoctoproject.org/poky + $ cd poky + $ git fetch --all --tags --prune + $ git checkout tags/pyro-17.0.0 -b my-pyro-17.0.0 + + In this example, the name of the top-level directory of your + local Yocto Project repository is poky. + After moving to the poky directory, the + git fetch command makes all the upstream + tags available locally in your repository. + Finally, the git checkout command + creates and checks out a branch named "my-pyro-17.0.0" that is + based on the specific change upstream in the repository + associated with the "pyro-17.0.0" tag. + The files in your repository now exactly match that particular + Yocto Project release as it is tagged in the upstream Git + repository. + It is important to understand that when you create and + checkout a local working branch based on a tag, your environment + matches a specific point in time and not the entire development + branch (i.e. the "tip" of the branch). + +
+ +
+ Basic Commands + + + Git has an extensive set of commands that lets you manage changes + and perform collaboration over the life of a project. + Conveniently though, you can manage with a small set of basic + operations and workflows once you understand the basic + philosophy behind Git. + You do not have to be an expert in Git to be functional. + A good place to look for instruction on a minimal set of Git + commands is + here. + + + + If you do not know much about Git, you should educate + yourself by visiting the links previously mentioned. + + + + The following list of Git commands briefly describes some basic + Git operations as a way to get started. + As with any set of commands, this list (in most cases) simply shows + the base command and omits the many arguments they support. + See the Git documentation for complete descriptions and strategies + on how to use these commands: + + + git init: + Initializes an empty Git repository. + You cannot use Git commands unless you have a + .git repository. + + + git clone: + Creates a local clone of a Git repository that is on + equal footing with a fellow developer’s Git repository + or an upstream repository. + + + git add: + Locally stages updated file contents to the index that + Git uses to track changes. + You must stage all files that have changed before you + can commit them. + + + git commit: + Creates a local "commit" that documents the changes you + made. + Only changes that have been staged can be committed. + Commits are used for historical purposes, for determining + if a maintainer of a project will allow the change, + and for ultimately pushing the change from your local + Git repository into the project’s upstream repository. + + + git status: + Reports any modified files that possibly need to be + staged and gives you a status of where you stand regarding + local commits as compared to the upstream repository. + + + git checkout branch-name: + Changes your working branch. + This command is analogous to "cd". + + git checkout –b working-branch: + Creates and checks out a working branch on your local + machine that you can use to isolate your work. + It is a good idea to use local branches when adding + specific features or changes. + Using isolated branches facilitates easy removal of + changes if they do not work out. + + git branch: + Displays the existing local branches associated with your + local repository. + The branch that you have currently checked out is noted + with an asterisk character. + + + git branch -D branch-name: + Deletes an existing local branch. + You need to be in a local branch other than the one you + are deleting in order to delete + branch-name. + + + git pull: + Retrieves information from an upstream Git repository + and places it in your local Git repository. + You use this command to make sure you are synchronized with + the repository from which you are basing changes + (.e.g. the "master" branch). + + + git push: + Sends all your committed local changes to the upstream Git + repository that your local repository is tracking + (e.g. a contribution repository). + The maintainer of the project draws from these repositories + to merge changes (commits) into the appropriate branch + of project's upstream repository. + + + git merge: + Combines or adds changes from one + local branch of your repository with another branch. + When you create a local Git repository, the default branch + is named "master". + A typical workflow is to create a temporary branch that is + based off "master" that you would use for isolated work. + You would make your changes in that isolated branch, + stage and commit them locally, switch to the "master" + branch, and then use the git merge + command to apply the changes from your isolated branch + into the currently checked out branch (e.g. "master"). + After the merge is complete and if you are done with + working in that isolated branch, you can safely delete + the isolated branch. + + + git cherry-pick: + Choose and apply specific commits from one branch + into another branch. + There are times when you might not be able to merge + all the changes in one branch with + another but need to pick out certain ones. + + + gitk: + Provides a GUI view of the branches and changes in your + local Git repository. + This command is a good way to graphically see where things + have diverged in your local repository. + + You need to install the gitk + package on your development system to use this + command. + + + + git log: + Reports a history of your commits to the repository. + This report lists all commits regardless of whether you + have pushed them upstream or not. + + + git diff: + Displays line-by-line differences between a local + working file and the same file as understood by Git. + This command is useful to see what you have changed + in any given file. + + + +
+
+ +
+ Yocto Project Source Repositories + + + The Yocto Project team maintains complete source repositories for all + Yocto Project files at + . + This web-based source code browser is organized into categories by + function such as IDE Plugins, Matchbox, Poky, Yocto Linux Kernel, and + so forth. + From the interface, you can click on any particular item in the "Name" + column and see the URL at the bottom of the page that you need to clone + a Git repository for that particular item. + Having a local Git repository of the + Source Directory, + which is usually named "poky", allows + you to make changes, contribute to the history, and ultimately enhance + the Yocto Project's tools, Board Support Packages, and so forth. + + + + For any supported release of Yocto Project, you can also go to the + Yocto Project Website and + select the "Downloads" tab and get a released tarball of the + poky repository or any supported BSP tarballs. + Unpacking these tarballs gives you a snapshot of the released + files. + Notes + + + The recommended method for setting up the Yocto Project + Source Directory + and the files for supported BSPs + (e.g., meta-intel) is to use + Git to create a local copy of + the upstream repositories. + + + Be sure to always work in matching branches for both + the selected BSP repository and the + Source Directory + (i.e. poky) repository. + For example, if you have checked out the "master" branch + of poky and you are going to use + meta-intel, be sure to checkout the + "master" branch of meta-intel. + + + + + + + In summary, here is where you can get the project files needed for + development: + + + + Source Repositories: + + This area contains IDE Plugins, Matchbox, Poky, Poky Support, + Tools, Yocto Linux Kernel, and Yocto Metadata Layers. + You can create local copies of Git repositories for each of + these areas. + + + + For steps on how to view and access these upstream Git + repositories, see the + "Accessing Source Repositories" + Section in the Yocto Project Development Tasks Manual. + + + + Index of /releases: + + This is an index of releases such as + the Eclipse + Yocto Plug-in, miscellaneous support, Poky, Pseudo, installers + for cross-development toolchains, and all released versions of + Yocto Project in the form of images or tarballs. + Downloading and extracting these files does not produce a local + copy of the Git repository but rather a snapshot of a + particular release or image. + + + + For steps on how to view and access these files, see the + "Accessing Index of Releases" + section in the Yocto Project Development Tasks Manual. + + + "Downloads" page for the + Yocto Project Website: + + + This section will change due to + reworking of the YP Website. + + The Yocto Project website includes a "Downloads" tab + that allows you to download any Yocto Project + release and Board Support Package (BSP) in tarball form. + The tarballs are similar to those found in the + Index of /releases: area. + + + + For steps on how to use the "Downloads" page, see the + "Using the Downloads Page" + section in the Yocto Project Development Tasks Manual. + + + +
+ +
+ Licensing + + + Because open source projects are open to the public, they have + different licensing structures in place. + License evolution for both Open Source and Free Software has an + interesting history. + If you are interested in this history, you can find basic information + here: + + + Open source license history + + + Free software license history + + + + + + In general, the Yocto Project is broadly licensed under the + Massachusetts Institute of Technology (MIT) License. + MIT licensing permits the reuse of software within proprietary + software as long as the license is distributed with that software. + MIT is also compatible with the GNU General Public License (GPL). + Patches to the Yocto Project follow the upstream licensing scheme. + You can find information on the MIT license + here. + You can find information on the GNU GPL + here. + + + + When you build an image using the Yocto Project, the build process + uses a known list of licenses to ensure compliance. + You can find this list in the + Source Directory + at meta/files/common-licenses. + Once the build completes, the list of all licenses found and used + during that build are kept in the + Build Directory + at tmp/deploy/licenses. + + + + If a module requires a license that is not in the base list, the + build process generates a warning during the build. + These tools make it easier for a developer to be certain of the + licenses with which their shipped products must comply. + However, even with these tools it is still up to the developer to + resolve potential licensing issues. + + + + The base list of licenses used by the build process is a combination + of the Software Package Data Exchange (SPDX) list and the Open + Source Initiative (OSI) projects. + SPDX Group is a working group of + the Linux Foundation that maintains a specification for a standard + format for communicating the components, licenses, and copyrights + associated with a software package. + OSI is a corporation + dedicated to the Open Source Definition and the effort for reviewing + and approving licenses that conform to the Open Source Definition + (OSD). + + + + You can find a list of the combined SPDX and OSI licenses that the + Yocto Project uses in the + meta/files/common-licenses directory in your + Source Directory. + + + + For information that can help you maintain compliance with various + open source licensing during the lifecycle of a product created using + the Yocto Project, see the + "Maintaining Open Source License Compliance During Your Product's Lifecycle" + section in the Yocto Project Development Tasks Manual. + +
+ +
+ Recipe Syntax + + + Understanding recipe file syntax is important for + writing recipes. + The following list overviews the basic items that make up a + BitBake recipe file. + For more complete BitBake syntax descriptions, see the + "Syntax and Operators" + chapter of the BitBake User Manual. + + Variable Assignments and Manipulations: + Variable assignments allow a value to be assigned to a + variable. + The assignment can be static text or might include + the contents of other variables. + In addition to the assignment, appending and prepending + operations are also supported. + The following example shows some of the ways + you can use variables in recipes: + + S = "${WORKDIR}/postfix-${PV}" + CFLAGS += "-DNO_ASM" + SRC_URI_append = " file://fixup.patch" + + + Functions: + Functions provide a series of actions to be performed. + You usually use functions to override the default + implementation of a task function or to complement + a default function (i.e. append or prepend to an + existing function). + Standard functions use sh shell + syntax, although access to OpenEmbedded variables and + internal methods are also available. + The following is an example function from the + sed recipe: + + do_install () { + autotools_do_install + install -d ${D}${base_bindir} + mv ${D}${bindir}/sed ${D}${base_bindir}/sed + rmdir ${D}${bindir}/ + } + + It is also possible to implement new functions that + are called between existing tasks as long as the + new functions are not replacing or complementing the + default functions. + You can implement functions in Python + instead of shell. + Both of these options are not seen in the majority of + recipes. + Keywords: + BitBake recipes use only a few keywords. + You use keywords to include common + functions (inherit), load parts + of a recipe from other files + (include and + require) and export variables + to the environment (export). + The following example shows the use of some of + these keywords: + + export POSTCONF = "${STAGING_BINDIR}/postconf" + inherit autoconf + require otherfile.inc + + + Comments: + Any lines that begin with the hash character + (#) are treated as comment lines + and are ignored: + + # This is a comment + + + + + + + This next list summarizes the most important and most commonly + used parts of the recipe syntax. + For more information on these parts of the syntax, you can + reference the + Syntax and Operators + chapter in the BitBake User Manual. + + Line Continuation: \ - + Use the backward slash (\) + character to split a statement over multiple lines. + Place the slash character at the end of the line that + is to be continued on the next line: + + VAR = "A really long \ + line" + + + You cannot have any characters including spaces + or tabs after the slash character. + + + + Using Variables: ${...} - + Use the ${VARNAME} syntax to + access the contents of a variable: + + SRC_URI = "${SOURCEFORGE_MIRROR}/libpng/zlib-${PV}.tar.gz" + + + It is important to understand that the value of a + variable expressed in this form does not get + substituted automatically. + The expansion of these expressions happens + on-demand later (e.g. usually when a function that + makes reference to the variable executes). + This behavior ensures that the values are most + appropriate for the context in which they are + finally used. + On the rare occasion that you do need the variable + expression to be expanded immediately, you can use + the := operator instead of + = when you make the + assignment, but this is not generally needed. + + + Quote All Assignments: "value" - + Use double quotes around the value in all variable + assignments. + + VAR1 = "${OTHERVAR}" + VAR2 = "The version is ${PV}" + + + Conditional Assignment: ?= - + Conditional assignment is used to assign a value to + a variable, but only when the variable is currently + unset. + Use the question mark followed by the equal sign + (?=) to make a "soft" assignment + used for conditional assignment. + Typically, "soft" assignments are used in the + local.conf file for variables + that are allowed to come through from the external + environment. + + Here is an example where + VAR1 is set to "New value" if + it is currently empty. + However, if VAR1 has already been + set, it remains unchanged: + + VAR1 ?= "New value" + + In this next example, VAR1 + is left with the value "Original value": + + VAR1 = "Original value" + VAR1 ?= "New value" + + + Appending: += - + Use the plus character followed by the equals sign + (+=) to append values to existing + variables. + + This operator adds a space between the existing + content of the variable and the new content. + + Here is an example: + + SRC_URI += "file://fix-makefile.patch" + + + Prepending: =+ - + Use the equals sign followed by the plus character + (=+) to prepend values to existing + variables. + + This operator adds a space between the new content + and the existing content of the variable. + + Here is an example: + + VAR =+ "Starts" + + + Appending: _append - + Use the _append operator to + append values to existing variables. + This operator does not add any additional space. + Also, the operator is applied after all the + +=, and + =+ operators have been applied and + after all = assignments have + occurred. + + The following example shows the space being + explicitly added to the start to ensure the appended + value is not merged with the existing value: + + SRC_URI_append = " file://fix-makefile.patch" + + You can also use the _append + operator with overrides, which results in the actions + only being performed for the specified target or + machine: + + SRC_URI_append_sh4 = " file://fix-makefile.patch" + + + Prepending: _prepend - + Use the _prepend operator to + prepend values to existing variables. + This operator does not add any additional space. + Also, the operator is applied after all the + +=, and + =+ operators have been applied and + after all = assignments have + occurred. + + The following example shows the space being + explicitly added to the end to ensure the prepended + value is not merged with the existing value: + + CFLAGS_prepend = "-I${S}/myincludes " + + You can also use the _prepend + operator with overrides, which results in the actions + only being performed for the specified target or + machine: + + CFLAGS_prepend_sh4 = "-I${S}/myincludes " + + + Overrides: - + You can use overrides to set a value conditionally, + typically based on how the recipe is being built. + For example, to set the + KBRANCH + variable's value to "standard/base" for any target + MACHINE, + except for qemuarm where it should be set to + "standard/arm-versatile-926ejs", you would do the + following: + + KBRANCH = "standard/base" + KBRANCH_qemuarm = "standard/arm-versatile-926ejs" + + Overrides are also used to separate alternate values + of a variable in other situations. + For example, when setting variables such as + FILES + and + RDEPENDS + that are specific to individual packages produced by + a recipe, you should always use an override that + specifies the name of the package. + + Indentation: + Use spaces for indentation rather than than tabs. + For shell functions, both currently work. + However, it is a policy decision of the Yocto Project + to use tabs in shell functions. + Realize that some layers have a policy to use spaces + for all indentation. + + Using Python for Complex Operations: ${@python_code} - + For more advanced processing, it is possible to use + Python code during variable assignments (e.g. + search and replacement on a variable). + You indicate Python code using the + ${@python_code} + syntax for the variable assignment: + + SRC_URI = "ftp://ftp.info-zip.org/pub/infozip/src/zip${@d.getVar('PV',1).replace('.', '')}.tgz + + + Shell Function Syntax: + Write shell functions as if you were writing a shell + script when you describe a list of actions to take. + You should ensure that your script works with a generic + sh and that it does not require + any bash or other shell-specific + functionality. + The same considerations apply to various system + utilities (e.g. sed, + grep, awk, + and so forth) that you might wish to use. + If in doubt, you should check with multiple + implementations - including those from BusyBox. + + + +
+ +
+ Development Concepts + + + This section takes a more detailed look inside the development + process. + The following diagram represents development at a high level. + The remainder of this chapter expands on the fundamental input, output, + process, and + Metadata) blocks + that make up development in the Yocto Project environment. + + + + + + + + In general, development consists of several functional areas: + + User Configuration: + Metadata you can use to control the build process. + + Metadata Layers: + Various layers that provide software, machine, and + distro Metadata. + Source Files: + Upstream releases, local projects, and SCMs. + Build System: + Processes under the control of + BitBake. + This block expands on how BitBake fetches source, applies + patches, completes compilation, analyzes output for package + generation, creates and tests packages, generates images, and + generates cross-development tools. + Package Feeds: + Directories containing output packages (RPM, DEB or IPK), + which are subsequently used in the construction of an image or + SDK, produced by the build system. + These feeds can also be copied and shared using a web server or + other means to facilitate extending or updating existing + images on devices at runtime if runtime package management is + enabled. + Images: + Images produced by the development process. + + Application Development SDK: + Cross-development tools that are produced along with an image + or separately with BitBake. + + + +
+ User Configuration + + + User configuration helps define the build. + Through user configuration, you can tell BitBake the + target architecture for which you are building the image, + where to store downloaded source, and other build properties. + + + + The following figure shows an expanded representation of the + "User Configuration" box of the + general Yocto Project Development Environment figure: + + + + + + + + BitBake needs some basic configuration files in order to complete + a build. + These files are *.conf files. + The minimally necessary ones reside as example files in the + Source Directory. + For simplicity, this section refers to the Source Directory as + the "Poky Directory." + + + + When you clone the poky Git repository or you + download and unpack a Yocto Project release, you can set up the + Source Directory to be named anything you want. + For this discussion, the cloned repository uses the default + name poky. + + The Poky repository is primarily an aggregation of existing + repositories. + It is not a canonical upstream source. + + + + + The meta-poky layer inside Poky contains + a conf directory that has example + configuration files. + These example files are used as a basis for creating actual + configuration files when you source the build environment + script + (i.e. + &OE_INIT_FILE;). + + + + Sourcing the build environment script creates a + Build Directory + if one does not already exist. + BitBake uses the Build Directory for all its work during builds. + The Build Directory has a conf directory that + contains default versions of your local.conf + and bblayers.conf configuration files. + These default configuration files are created only if versions + do not already exist in the Build Directory at the time you + source the build environment setup script. + + + + Because the Poky repository is fundamentally an aggregation of + existing repositories, some users might be familiar with running + the &OE_INIT_FILE; script in the context + of separate OpenEmbedded-Core and BitBake repositories rather than a + single Poky repository. + This discussion assumes the script is executed from within a cloned + or unpacked version of Poky. + + + + Depending on where the script is sourced, different sub-scripts + are called to set up the Build Directory (Yocto or OpenEmbedded). + Specifically, the script + scripts/oe-setup-builddir inside the + poky directory sets up the Build Directory and seeds the directory + (if necessary) with configuration files appropriate for the + Yocto Project development environment. + + The scripts/oe-setup-builddir script + uses the $TEMPLATECONF variable to + determine which sample configuration files to locate. + + + + + The local.conf file provides many + basic variables that define a build environment. + Here is a list of a few. + To see the default configurations in a local.conf + file created by the build environment script, see the + local.conf.sample in the + meta-poky layer: + + Parallelism Options: + Controlled by the + BB_NUMBER_THREADS, + PARALLEL_MAKE, + and + BB_NUMBER_PARSE_THREADS + variables. + Target Machine Selection: + Controlled by the + MACHINE + variable. + Download Directory: + Controlled by the + DL_DIR + variable. + Shared State Directory: + Controlled by the + SSTATE_DIR + variable. + Build Output: + Controlled by the + TMPDIR + variable. + + + Configurations set in the conf/local.conf + file can also be set in the + conf/site.conf and + conf/auto.conf configuration files. + + + + + The bblayers.conf file tells BitBake what + layers you want considered during the build. + By default, the layers listed in this file include layers + minimally needed by the build system. + However, you must manually add any custom layers you have created. + You can find more information on working with the + bblayers.conf file in the + "Enabling Your Layer" + section in the Yocto Project Development Tasks Manual. + + + + The files site.conf and + auto.conf are not created by the environment + initialization script. + If you want the site.conf file, you need to + create that yourself. + The auto.conf file is typically created by + an autobuilder: + + site.conf: + You can use the conf/site.conf + configuration file to configure multiple build directories. + For example, suppose you had several build environments and + they shared some common features. + You can set these default build properties here. + A good example is perhaps the packaging format to use + through the + PACKAGE_CLASSES + variable. + One useful scenario for using the + conf/site.conf file is to extend your + BBPATH + variable to include the path to a + conf/site.conf. + Then, when BitBake looks for Metadata using + BBPATH, it finds the + conf/site.conf file and applies your + common configurations found in the file. + To override configurations in a particular build directory, + alter the similar configurations within that build + directory's conf/local.conf file. + + auto.conf: + The file is usually created and written to by + an autobuilder. + The settings put into the file are typically the same as + you would find in the conf/local.conf + or the conf/site.conf files. + + + + + + You can edit all configuration files to further define + any particular build environment. + This process is represented by the "User Configuration Edits" + box in the figure. + + + + When you launch your build with the + bitbake target + command, BitBake sorts out the configurations to ultimately + define your build environment. + It is important to understand that the OpenEmbedded build system + reads the configuration files in a specific order: + site.conf, auto.conf, + and local.conf. + And, the build system applies the normal assignment statement + rules. + Because the files are parsed in a specific order, variable + assignments for the same variable could be affected. + For example, if the auto.conf file and + the local.conf set + variable1 to different values, because + the build system parses local.conf after + auto.conf, + variable1 is assigned the value from + the local.conf file. + +
+ +
+ Metadata, Machine Configuration, and Policy Configuration + + + The previous section described the user configurations that + define BitBake's global behavior. + This section takes a closer look at the layers the build system + uses to further control the build. + These layers provide Metadata for the software, machine, and + policy. + + + + In general, three types of layer input exist: + + Policy Configuration: + Distribution Layers provide top-level or general + policies for the image or SDK being built. + For example, this layer would dictate whether BitBake + produces RPM or IPK packages. + Machine Configuration: + Board Support Package (BSP) layers provide machine + configurations. + This type of information is specific to a particular + target architecture. + Metadata: + Software layers contain user-supplied recipe files, + patches, and append files. + + + + + + The following figure shows an expanded representation of the + Metadata, Machine Configuration, and Policy Configuration input + (layers) boxes of the + general Yocto Project Development Environment figure: + + + + + + + + In general, all layers have a similar structure. + They all contain a licensing file + (e.g. COPYING) if the layer is to be + distributed, a README file as good practice + and especially if the layer is to be distributed, a + configuration directory, and recipe directories. + + + + The Yocto Project has many layers that can be used. + You can see a web-interface listing of them on the + Source Repositories + page. + The layers are shown at the bottom categorized under + "Yocto Metadata Layers." + These layers are fundamentally a subset of the + OpenEmbedded Metadata Index, + which lists all layers provided by the OpenEmbedded community. + + Layers exist in the Yocto Project Source Repositories that + cannot be found in the OpenEmbedded Metadata Index. + These layers are either deprecated or experimental in nature. + + + + + BitBake uses the conf/bblayers.conf file, + which is part of the user configuration, to find what layers it + should be using as part of the build. + + + + For more information on layers, see the + "Understanding and Creating Layers" + section in the Yocto Project Development Tasks Manual. + + +
+ Distro Layer + + + The distribution layer provides policy configurations for your + distribution. + Best practices dictate that you isolate these types of + configurations into their own layer. + Settings you provide in + conf/distro/distro.conf override + similar + settings that BitBake finds in your + conf/local.conf file in the Build + Directory. + + + + The following list provides some explanation and references + for what you typically find in the distribution layer: + + classes: + Class files (.bbclass) hold + common functionality that can be shared among + recipes in the distribution. + When your recipes inherit a class, they take on the + settings and functions for that class. + You can read more about class files in the + "Classes" + section of the Yocto Reference Manual. + + conf: + This area holds configuration files for the + layer (conf/layer.conf), + the distribution + (conf/distro/distro.conf), + and any distribution-wide include files. + + recipes-*: + Recipes and append files that affect common + functionality across the distribution. + This area could include recipes and append files + to add distribution-specific configuration, + initialization scripts, custom image recipes, + and so forth. + + +
+ +
+ BSP Layer + + + The BSP Layer provides machine configurations. + Everything in this layer is specific to the machine for which + you are building the image or the SDK. + A common structure or form is defined for BSP layers. + You can learn more about this structure in the + Yocto Project Board Support Package (BSP) Developer's Guide. + + In order for a BSP layer to be considered compliant with the + Yocto Project, it must meet some structural requirements. + + + + + The BSP Layer's configuration directory contains + configuration files for the machine + (conf/machine/machine.conf) and, + of course, the layer (conf/layer.conf). + + + + The remainder of the layer is dedicated to specific recipes + by function: recipes-bsp, + recipes-core, + recipes-graphics, and + recipes-kernel. + Metadata can exist for multiple formfactors, graphics + support systems, and so forth. + + While the figure shows several recipes-* + directories, not all these directories appear in all + BSP layers. + + +
+ +
+ Software Layer + + + The software layer provides the Metadata for additional + software packages used during the build. + This layer does not include Metadata that is specific to the + distribution or the machine, which are found in their + respective layers. + + + + This layer contains any new recipes that your project needs + in the form of recipe files. + +
+
+ +
+ Sources + + + In order for the OpenEmbedded build system to create an image or + any target, it must be able to access source files. + The + general Yocto Project Development Environment figure + represents source files using the "Upstream Project Releases", + "Local Projects", and "SCMs (optional)" boxes. + The figure represents mirrors, which also play a role in locating + source files, with the "Source Mirror(s)" box. + + + + The method by which source files are ultimately organized is + a function of the project. + For example, for released software, projects tend to use tarballs + or other archived files that can capture the state of a release + guaranteeing that it is statically represented. + On the other hand, for a project that is more dynamic or + experimental in nature, a project might keep source files in a + repository controlled by a Source Control Manager (SCM) such as + Git. + Pulling source from a repository allows you to control + the point in the repository (the revision) from which you want to + build software. + Finally, a combination of the two might exist, which would give the + consumer a choice when deciding where to get source files. + + + + BitBake uses the + SRC_URI + variable to point to source files regardless of their location. + Each recipe must have a SRC_URI variable + that points to the source. + + + + Another area that plays a significant role in where source files + come from is pointed to by the + DL_DIR + variable. + This area is a cache that can hold previously downloaded source. + You can also instruct the OpenEmbedded build system to create + tarballs from Git repositories, which is not the default behavior, + and store them in the DL_DIR by using the + BB_GENERATE_MIRROR_TARBALLS + variable. + + + + Judicious use of a DL_DIR directory can + save the build system a trip across the Internet when looking + for files. + A good method for using a download directory is to have + DL_DIR point to an area outside of your + Build Directory. + Doing so allows you to safely delete the Build Directory + if needed without fear of removing any downloaded source file. + + + + The remainder of this section provides a deeper look into the + source files and the mirrors. + Here is a more detailed look at the source file area of the + base figure: + + + +
+ Upstream Project Releases + + + Upstream project releases exist anywhere in the form of an + archived file (e.g. tarball or zip file). + These files correspond to individual recipes. + For example, the figure uses specific releases each for + BusyBox, Qt, and Dbus. + An archive file can be for any released product that can be + built using a recipe. + +
+ +
+ Local Projects + + + Local projects are custom bits of software the user provides. + These bits reside somewhere local to a project - perhaps + a directory into which the user checks in items (e.g. + a local directory containing a development source tree + used by the group). + + + + The canonical method through which to include a local project + is to use the + externalsrc + class to include that local project. + You use either the local.conf or a + recipe's append file to override or set the + recipe to point to the local directory on your disk to pull + in the whole source tree. + + + + For information on how to use the + externalsrc class, see the + "externalsrc.bbclass" + section. + +
+ +
+ Source Control Managers (Optional) + + + Another place the build system can get source files from is + through an SCM such as Git or Subversion. + In this case, a repository is cloned or checked out. + The + do_fetch + task inside BitBake uses + the SRC_URI + variable and the argument's prefix to determine the correct + fetcher module. + + + + For information on how to have the OpenEmbedded build system + generate tarballs for Git repositories and place them in the + DL_DIR + directory, see the + BB_GENERATE_MIRROR_TARBALLS + variable. + + + + When fetching a repository, BitBake uses the + SRCREV + variable to determine the specific revision from which to + build. + +
+ +
+ Source Mirror(s) + + + Two kinds of mirrors exist: pre-mirrors and regular mirrors. + The + PREMIRRORS + and + MIRRORS + variables point to these, respectively. + BitBake checks pre-mirrors before looking upstream for any + source files. + Pre-mirrors are appropriate when you have a shared directory + that is not a directory defined by the + DL_DIR + variable. + A Pre-mirror typically points to a shared directory that is + local to your organization. + + + + Regular mirrors can be any site across the Internet that is + used as an alternative location for source code should the + primary site not be functioning for some reason or another. + +
+
+ +
+ Package Feeds + + + When the OpenEmbedded build system generates an image or an SDK, + it gets the packages from a package feed area located in the + Build Directory. + The + general Yocto Project Development Environment figure + shows this package feeds area in the upper-right corner. + + + + This section looks a little closer into the package feeds area used + by the build system. + Here is a more detailed look at the area: + + + + + Package feeds are an intermediary step in the build process. + The OpenEmbedded build system provides classes to generate + different package types, and you specify which classes to enable + through the + PACKAGE_CLASSES + variable. + Before placing the packages into package feeds, + the build process validates them with generated output quality + assurance checks through the + insane + class. + + + + The package feed area resides in the Build Directory. + The directory the build system uses to temporarily store packages + is determined by a combination of variables and the particular + package manager in use. + See the "Package Feeds" box in the illustration and note the + information to the right of that area. + In particular, the following defines where package files are + kept: + + DEPLOY_DIR: + Defined as tmp/deploy in the Build + Directory. + + DEPLOY_DIR_*: + Depending on the package manager used, the package type + sub-folder. + Given RPM, IPK, or DEB packaging and tarball creation, the + DEPLOY_DIR_RPM, + DEPLOY_DIR_IPK, + DEPLOY_DIR_DEB, + or + DEPLOY_DIR_TAR, + variables are used, respectively. + + PACKAGE_ARCH: + Defines architecture-specific sub-folders. + For example, packages could exist for the i586 or qemux86 + architectures. + + + + + + BitBake uses the do_package_write_* tasks to + generate packages and place them into the package holding area (e.g. + do_package_write_ipk for IPK packages). + See the + "do_package_write_deb", + "do_package_write_ipk", + "do_package_write_rpm", + and + "do_package_write_tar" + sections for additional information. + As an example, consider a scenario where an IPK packaging manager + is being used and package architecture support for both i586 + and qemux86 exist. + Packages for the i586 architecture are placed in + build/tmp/deploy/ipk/i586, while packages for + the qemux86 architecture are placed in + build/tmp/deploy/ipk/qemux86. + +
+ +
+ BitBake + + + The OpenEmbedded build system uses + BitBake + to produce images. + You can see from the + general Yocto Project Development Environment figure, + the BitBake area consists of several functional areas. + This section takes a closer look at each of those areas. + + + + Separate documentation exists for the BitBake tool. + See the + BitBake User Manual + for reference material on BitBake. + + +
+ Source Fetching + + + The first stages of building a recipe are to fetch and unpack + the source code: + + + + + The + do_fetch + and + do_unpack + tasks fetch the source files and unpack them into the work + directory. + + For every local file (e.g. file://) + that is part of a recipe's + SRC_URI + statement, the OpenEmbedded build system takes a checksum + of the file for the recipe and inserts the checksum into + the signature for the do_fetch. + If any local file has been modified, the + do_fetch task and all tasks that + depend on it are re-executed. + + By default, everything is accomplished in the + Build Directory, + which has a defined structure. + For additional general information on the Build Directory, + see the + "build/" + section in the Yocto Project Reference Manual. + + + + Unpacked source files are pointed to by the + S + variable. + Each recipe has an area in the Build Directory where the + unpacked source code resides. + The name of that directory for any given recipe is defined from + several different variables. + You can see the variables that define these directories + by looking at the figure: + + TMPDIR - + The base directory where the OpenEmbedded build system + performs all its work during the build. + + PACKAGE_ARCH - + The architecture of the built package or packages. + + TARGET_OS - + The operating system of the target device. + + PN - + The name of the built package. + + PV - + The version of the recipe used to build the package. + + PR - + The revision of the recipe used to build the package. + + WORKDIR - + The location within TMPDIR where + a specific package is built. + + S - + Contains the unpacked source files for a given recipe. + + + +
+ +
+ Patching + + + Once source code is fetched and unpacked, BitBake locates + patch files and applies them to the source files: + + + + + The + do_patch + task processes recipes by + using the + SRC_URI + variable to locate applicable patch files, which by default + are *.patch or + *.diff files, or any file if + "apply=yes" is specified for the file in + SRC_URI. + + + + BitBake finds and applies multiple patches for a single recipe + in the order in which it finds the patches. + Patches are applied to the recipe's source files located in the + S + directory. + + + + For more information on how the source directories are + created, see the + "Source Fetching" + section. + +
+ +
+ Configuration and Compilation + + + After source code is patched, BitBake executes tasks that + configure and compile the source code: + + + + + This step in the build process consists of three tasks: + + + do_prepare_recipe_sysroot: + This task sets up the two sysroots in + ${WORKDIR} + (i.e. recipe-sysroot and + recipe-sysroot-native) so that + the sysroots contain the contents of the + do_populate_sysroot + tasks of the recipes on which the recipe + containing the tasks depends. + A sysroot exists for both the target and for the native + binaries, which run on the host system. + + do_configure: + This task configures the source by enabling and + disabling any build-time and configuration options for + the software being built. + Configurations can come from the recipe itself as well + as from an inherited class. + Additionally, the software itself might configure itself + depending on the target for which it is being built. + + + The configurations handled by the + do_configure + task are specific + to source code configuration for the source code + being built by the recipe. + + If you are using the + autotools + class, + you can add additional configuration options by using + the + EXTRA_OECONF + or + PACKAGECONFIG_CONFARGS + variables. + For information on how this variable works within + that class, see the + meta/classes/autotools.bbclass file. + + do_compile: + Once a configuration task has been satisfied, BitBake + compiles the source using the + do_compile + task. + Compilation occurs in the directory pointed to by the + B + variable. + Realize that the B directory is, by + default, the same as the + S + directory. + do_install: + Once compilation is done, BitBake executes the + do_install + task. + This task copies files from the B + directory and places them in a holding area pointed to + by the + D + variable. + + +
+ +
+ Package Splitting + + + After source code is configured and compiled, the + OpenEmbedded build system analyzes + the results and splits the output into packages: + + + + + The + do_package + and + do_packagedata + tasks combine to analyze + the files found in the + D directory + and split them into subsets based on available packages and + files. + The analyzing process involves the following as well as other + items: splitting out debugging symbols, + looking at shared library dependencies between packages, + and looking at package relationships. + The do_packagedata task creates package + metadata based on the analysis such that the + OpenEmbedded build system can generate the final packages. + Working, staged, and intermediate results of the analysis + and package splitting process use these areas: + + PKGD - + The destination directory for packages before they are + split. + + PKGDATA_DIR - + A shared, global-state directory that holds data + generated during the packaging process. + + PKGDESTWORK - + A temporary work area used by the + do_package task. + + PKGDEST - + The parent directory for packages after they have + been split. + + + The FILES + variable defines the files that go into each package in + PACKAGES. + If you want details on how this is accomplished, you can + look at the + package + class. + + + + Depending on the type of packages being created (RPM, DEB, or + IPK), the do_package_write_* task + creates the actual packages and places them in the + Package Feed area, which is + ${TMPDIR}/deploy. + You can see the + "Package Feeds" + section for more detail on that part of the build process. + + Support for creating feeds directly from the + deploy/* directories does not exist. + Creating such feeds usually requires some kind of feed + maintenance mechanism that would upload the new packages + into an official package feed (e.g. the + Ångström distribution). + This functionality is highly distribution-specific + and thus is not provided out of the box. + + +
+ +
+ Image Generation + + + Once packages are split and stored in the Package Feeds area, + the OpenEmbedded build system uses BitBake to generate the + root filesystem image: + + + + + The image generation process consists of several stages and + depends on several tasks and variables. + The + do_rootfs + task creates the root filesystem (file and directory structure) + for an image. + This task uses several key variables to help create the list + of packages to actually install: + + IMAGE_INSTALL: + Lists out the base set of packages to install from + the Package Feeds area. + PACKAGE_EXCLUDE: + Specifies packages that should not be installed. + + IMAGE_FEATURES: + Specifies features to include in the image. + Most of these features map to additional packages for + installation. + PACKAGE_CLASSES: + Specifies the package backend to use and consequently + helps determine where to locate packages within the + Package Feeds area. + IMAGE_LINGUAS: + Determines the language(s) for which additional + language support packages are installed. + + PACKAGE_INSTALL: + The final list of packages passed to the package manager + for installation into the image. + + + + + + With + IMAGE_ROOTFS + pointing to the location of the filesystem under construction and + the PACKAGE_INSTALL variable providing the + final list of packages to install, the root file system is + created. + + + + Package installation is under control of the package manager + (e.g. dnf/rpm, opkg, or apt/dpkg) regardless of whether or + not package management is enabled for the target. + At the end of the process, if package management is not + enabled for the target, the package manager's data files + are deleted from the root filesystem. + As part of the final stage of package installation, postinstall + scripts that are part of the packages are run. + Any scripts that fail to run + on the build host are run on the target when the target system + is first booted. + If you are using a + read-only root filesystem, + all the post installation scripts must succeed during the + package installation phase since the root filesystem is + read-only. + + + + The final stages of the do_rootfs task + handle post processing. + Post processing includes creation of a manifest file and + optimizations. + + + + The manifest file (.manifest) resides + in the same directory as the root filesystem image. + This file lists out, line-by-line, the installed packages. + The manifest file is useful for the + testimage + class, for example, to determine whether or not to run + specific tests. + See the + IMAGE_MANIFEST + variable for additional information. + + + + Optimizing processes run across the image include + mklibs, prelink, + and any other post-processing commands as defined by the + ROOTFS_POSTPROCESS_COMMAND + variable. + The mklibs process optimizes the size + of the libraries, while the + prelink process optimizes the dynamic + linking of shared libraries to reduce start up time of + executables. + + + + After the root filesystem is built, processing begins on + the image through the + do_image + task. + The build system runs any pre-processing commands as defined + by the + IMAGE_PREPROCESS_COMMAND + variable. + This variable specifies a list of functions to call before + the OpenEmbedded build system creates the final image output + files. + + + + The OpenEmbedded build system dynamically creates + do_image_* tasks as needed, based + on the image types specified in the + IMAGE_FSTYPES + variable. + The process turns everything into an image file or a set of + image files and compresses the root filesystem image to reduce + the overall size of the image. + The formats used for the root filesystem depend on the + IMAGE_FSTYPES variable. + + + + As an example, a dynamically created task when creating a + particular image type would take the + following form: + + do_image_type[depends] + + So, if the type as specified by the + IMAGE_FSTYPES were + ext4, the dynamically generated task + would be as follows: + + do_image_ext4[depends] + + + + + The final task involved in image creation is the + do_image_complete + task. + This task completes the image by applying any image + post processing as defined through the + IMAGE_POSTPROCESS_COMMAND + variable. + The variable specifies a list of functions to call once the + OpenEmbedded build system has created the final image output + files. + + + + The entire image generation process is run under Pseudo. + Running under Pseudo ensures that the files in the root + filesystem have correct ownership. + +
+ +
+ SDK Generation + + + The OpenEmbedded build system uses BitBake to generate the + Software Development Kit (SDK) installer script for both the + standard and extensible SDKs: + + + + + For more information on the cross-development toolchain + generation, see the + "Cross-Development Toolchain Generation" + section. + For information on advantages gained when building a + cross-development toolchain using the + do_populate_sdk + task, see the + "Building an SDK Installer" + section in the Yocto Project Application Development and the + Extensible Software Development Kit (SDK) manual. + + + + Like image generation, the SDK script process consists of + several stages and depends on many variables. + The do_populate_sdk and + do_populate_sdk_ext tasks use these + key variables to help create the list of packages to actually + install. + For information on the variables listed in the figure, see the + "Application Development SDK" + section. + + + + The do_populate_sdk task helps create + the standard SDK and handles two parts: a target part and a + host part. + The target part is the part built for the target hardware and + includes libraries and headers. + The host part is the part of the SDK that runs on the + SDKMACHINE. + + + + The do_populate_sdk_ext task helps create + the extensible SDK and handles host and target parts + differently than its counter part does for the standard SDK. + For the extensible SDK, the task encapsulates the build system, + which includes everything needed (host and target) for the SDK. + + + + Regardless of the type of SDK being constructed, the + tasks perform some cleanup after which a cross-development + environment setup script and any needed configuration files + are created. + The final output is the Cross-development + toolchain installation script (.sh file), + which includes the environment setup script. + +
+ +
+ Stamp Files and the Rerunning of Tasks + + + For each task that completes successfully, BitBake writes a + stamp file into the + STAMPS_DIR + directory. + The beginning of the stamp file's filename is determined by the + STAMP + variable, and the end of the name consists of the task's name + and current + input checksum. + + This naming scheme assumes that + BB_SIGNATURE_HANDLER + is "OEBasicHash", which is almost always the case in + current OpenEmbedded. + + To determine if a task needs to be rerun, BitBake checks if a + stamp file with a matching input checksum exists for the task. + If such a stamp file exists, the task's output is assumed to + exist and still be valid. + If the file does not exist, the task is rerun. + + The stamp mechanism is more general than the shared + state (sstate) cache mechanism described in the + "Setscene Tasks and Shared State" + section. + BitBake avoids rerunning any task that has a valid + stamp file, not just tasks that can be accelerated through + the sstate cache. + However, you should realize that stamp files only + serve as a marker that some work has been done and that + these files do not record task output. + The actual task output would usually be somewhere in + TMPDIR + (e.g. in some recipe's + WORKDIR.) + What the sstate cache mechanism adds is a way to cache task + output that can then be shared between build machines. + + + Since STAMPS_DIR is usually a subdirectory + of TMPDIR, removing + TMPDIR will also remove + STAMPS_DIR, which means tasks will + properly be rerun to repopulate TMPDIR. + + + + If you want some task to always be considered "out of date", + you can mark it with the + nostamp + varflag. + If some other task depends on such a task, then that task will + also always be considered out of date, which might not be what + you want. + + + + For details on how to view information about a task's + signature, see the + "Viewing Task Variable Dependencies" + section in the Yocto Project Development Tasks Manual. + +
+ +
+ Setscene Tasks and Shared State + + + The description of tasks so far assumes that BitBake needs to + build everything and there are no prebuilt objects available. + BitBake does support skipping tasks if prebuilt objects are + available. + These objects are usually made available in the form of a + shared state (sstate) cache. + + For information on variables affecting sstate, see the + SSTATE_DIR + and + SSTATE_MIRRORS + variables. + + + + + The idea of a setscene task (i.e + do_taskname_setscene) + is a version of the task where + instead of building something, BitBake can skip to the end + result and simply place a set of files into specific locations + as needed. + In some cases, it makes sense to have a setscene task variant + (e.g. generating package files in the + do_package_write_* task). + In other cases, it does not make sense, (e.g. a + do_patch + task or + do_unpack + task) since the work involved would be equal to or greater than + the underlying task. + + + + In the OpenEmbedded build system, the common tasks that have + setscene variants are + do_package, + do_package_write_*, + do_deploy, + do_packagedata, + and + do_populate_sysroot. + Notice that these are most of the tasks whose output is an + end result. + + + + The OpenEmbedded build system has knowledge of the relationship + between these tasks and other tasks that precede them. + For example, if BitBake runs + do_populate_sysroot_setscene for + something, there is little point in running any of the + do_fetch, do_unpack, + do_patch, + do_configure, + do_compile, and + do_install tasks. + However, if do_package needs to be run, + BitBake would need to run those other tasks. + + + + It becomes more complicated if everything can come from an + sstate cache because some objects are simply not required at + all. + For example, you do not need a compiler or native tools, such + as quilt, if there is nothing to compile or patch. + If the do_package_write_* packages are + available from sstate, BitBake does not need the + do_package task data. + + + + To handle all these complexities, BitBake runs in two phases. + The first is the "setscene" stage. + During this stage, BitBake first checks the sstate cache for + any targets it is planning to build. + BitBake does a fast check to see if the object exists rather + than a complete download. + If nothing exists, the second phase, which is the setscene + stage, completes and the main build proceeds. + + + + If objects are found in the sstate cache, the OpenEmbedded + build system works backwards from the end targets specified + by the user. + For example, if an image is being built, the OpenEmbedded build + system first looks for the packages needed for that image and + the tools needed to construct an image. + If those are available, the compiler is not needed. + Thus, the compiler is not even downloaded. + If something was found to be unavailable, or the download or + setscene task fails, the OpenEmbedded build system then tries + to install dependencies, such as the compiler, from the cache. + + + + The availability of objects in the sstate cache is handled by + the function specified by the + BB_HASHCHECK_FUNCTION + variable and returns a list of the objects that are available. + The function specified by the + BB_SETSCENE_DEPVALID + variable is the function that determines whether a given + dependency needs to be followed, and whether for any given + relationship the function needs to be passed. + The function returns a True or False value. + +
+
+ +
+ Images + + + The images produced by the OpenEmbedded build system + are compressed forms of the + root filesystem that are ready to boot on a target device. + You can see from the + general Yocto Project Development Environment figure + that BitBake output, in part, consists of images. + This section is going to look more closely at this output: + + + + + For a list of example images that the Yocto Project provides, + see the + "Images" + chapter in the Yocto Project Reference Manual. + + + + Images are written out to the + Build Directory + inside the + tmp/deploy/images/machine/ + folder as shown in the figure. + This folder contains any files expected to be loaded on the + target device. + The + DEPLOY_DIR + variable points to the deploy directory, + while the + DEPLOY_DIR_IMAGE + variable points to the appropriate directory containing images for + the current configuration. + + kernel-image: + A kernel binary file. + The + KERNEL_IMAGETYPE + variable setting determines the naming scheme for the + kernel image file. + Depending on that variable, the file could begin with + a variety of naming strings. + The deploy/images/machine + directory can contain multiple image files for the + machine. + root-filesystem-image: + Root filesystems for the target device (e.g. + *.ext3 or *.bz2 + files). + The + IMAGE_FSTYPES + variable setting determines the root filesystem image + type. + The deploy/images/machine + directory can contain multiple root filesystems for the + machine. + kernel-modules: + Tarballs that contain all the modules built for the kernel. + Kernel module tarballs exist for legacy purposes and + can be suppressed by setting the + MODULE_TARBALL_DEPLOY + variable to "0". + The deploy/images/machine + directory can contain multiple kernel module tarballs + for the machine. + bootloaders: + Bootloaders supporting the image, if applicable to the + target machine. + The deploy/images/machine + directory can contain multiple bootloaders for the + machine. + symlinks: + The deploy/images/machine + folder contains + a symbolic link that points to the most recently built file + for each machine. + These links might be useful for external scripts that + need to obtain the latest version of each file. + + + +
+ +
+ Application Development SDK + + + In the + general Yocto Project Development Environment figure, + the output labeled "Application Development SDK" represents an + SDK. + The SDK generation process differs depending on whether you build + a standard SDK + (e.g. bitbake -c populate_sdk imagename) + or an extensible SDK + (e.g. bitbake -c populate_sdk_ext imagename). + This section is going to take a closer look at this output: + + + + + The specific form of this output is a self-extracting + SDK installer (*.sh) that, when run, + installs the SDK, which consists of a cross-development + toolchain, a set of libraries and headers, and an SDK + environment setup script. + Running this installer essentially sets up your + cross-development environment. + You can think of the cross-toolchain as the "host" + part because it runs on the SDK machine. + You can think of the libraries and headers as the "target" + part because they are built for the target hardware. + The environment setup script is added so that you can initialize + the environment before using the tools. + + + Notes + + + The Yocto Project supports several methods by which you can + set up this cross-development environment. + These methods include downloading pre-built SDK installers + or building and installing your own SDK installer. + + + For background information on cross-development toolchains + in the Yocto Project development environment, see the + "Cross-Development Toolchain Generation" + section. + + + For information on setting up a cross-development + environment, see the + Yocto Project Application Development and the Extensible Software Development Kit (eSDK) + manual. + + + + + + Once built, the SDK installers are written out to the + deploy/sdk folder inside the + Build Directory + as shown in the figure at the beginning of this section. + Depending on the type of SDK, several variables exist that help + configure these files. + The following list shows the variables associated with a standard + SDK: + + DEPLOY_DIR: + Points to the deploy + directory. + SDKMACHINE: + Specifies the architecture of the machine + on which the cross-development tools are run to + create packages for the target hardware. + + SDKIMAGE_FEATURES: + Lists the features to include in the "target" part + of the SDK. + + TOOLCHAIN_HOST_TASK: + Lists packages that make up the host + part of the SDK (i.e. the part that runs on + the SDKMACHINE). + When you use + bitbake -c populate_sdk imagename + to create the SDK, a set of default packages + apply. + This variable allows you to add more packages. + + TOOLCHAIN_TARGET_TASK: + Lists packages that make up the target part + of the SDK (i.e. the part built for the + target hardware). + + SDKPATH: + Defines the default SDK installation path offered by the + installation script. + + + This next list, shows the variables associated with an extensible + SDK: + + DEPLOY_DIR: + Points to the deploy directory. + + SDK_EXT_TYPE: + Controls whether or not shared state artifacts are copied + into the extensible SDK. + By default, all required shared state artifacts are copied + into the SDK. + + SDK_INCLUDE_PKGDATA: + Specifies whether or not packagedata will be included in + the extensible SDK for all recipes in the "world" target. + + SDK_INCLUDE_TOOLCHAIN: + Specifies whether or not the toolchain will be included + when building the extensible SDK. + + SDK_LOCAL_CONF_WHITELIST: + A list of variables allowed through from the build system + configuration into the extensible SDK configuration. + + SDK_LOCAL_CONF_BLACKLIST: + A list of variables not allowed through from the build + system configuration into the extensible SDK configuration. + + SDK_INHERIT_BLACKLIST: + A list of classes to remove from the + INHERIT + value globally within the extensible SDK configuration. + + + +
+
+ + + diff --git a/documentation/getting-started/getting-started-eclipse-customization.xsl b/documentation/getting-started/getting-started-eclipse-customization.xsl new file mode 100644 index 0000000000..17fff727f9 --- /dev/null +++ b/documentation/getting-started/getting-started-eclipse-customization.xsl @@ -0,0 +1,35 @@ + + + + + + + + + + + + + + + + + + + + + + + + diff --git a/documentation/getting-started/getting-started-intro.xml b/documentation/getting-started/getting-started-intro.xml new file mode 100644 index 0000000000..51a21b6e23 --- /dev/null +++ b/documentation/getting-started/getting-started-intro.xml @@ -0,0 +1,103 @@ + %poky; ] > + + + +The Yocto Project Overview Manual +
+ Welcome + + + Welcome to the Yocto Project Overview Manual! + This manual introduces the Yocto Project by providing concepts, + software overviews, best-known-methods (BKMs), and any other + high-level introductory information suitable for a new Yocto + Project user. + + + + The following list describes what you can get from this manual: + + + Major Topic: + Provide a high-level description of this major topic. + + + Major Topic: + Provide a high-level description of this major topic. + + + Major Topic: + Provide a high-level description of this major topic. + + + Major Topic: + Provide a high-level description of this major topic. + + + + + + This manual does not give you the following: + + + Step-by-step Instructions for Development Tasks: + Instructional procedures reside in other manuals within + the Yocto Project documentation set. + For example, the + Yocto Project Development Tasks Manual + provides examples on how to perform various development + tasks. + As another example, the + Yocto Project Application Development and the Extensible Software Development Kit (eSDK) + manual contains detailed instructions on how to install an + SDK, which is used to develop applications for target + hardware. + + + Reference Material: + This type of material resides in an appropriate reference + manual. + For example, system variables are documented in the + Yocto Project Reference Manual. + As another example, the + Yocto Project Board Support Package (BSP) Developer's Guide + contains reference information on BSPs. + + + Detailed Public Information Not Specific to the + Yocto Project: + For example, exhaustive information on how to use the + Source Control Manager Git is better covered with Internet + searches and official Git Documentation than through the + Yocto Project documentation. + + + +
+ +
+ Other Information + + + Because this manual presents information for many different + topics, supplemental information is recommended for full + comprehension. + For additional introductory information on the Yocto Project, see + the Yocto Project Website. + You can find an introductory to using the Yocto Project by working + through the + Yocto Project Quick Start. + + + + For a comprehensive list of links and other documentation, see the + "Links and Related Documentation" + section in the Yocto Project Reference Manual. + +
+ + diff --git a/documentation/getting-started/getting-started-style.css b/documentation/getting-started/getting-started-style.css new file mode 100644 index 0000000000..a03f7dc0c1 --- /dev/null +++ b/documentation/getting-started/getting-started-style.css @@ -0,0 +1,988 @@ +/* + Generic XHTML / DocBook XHTML CSS Stylesheet. + + Browser wrangling and typographic design by + Oyvind Kolas / pippin@gimp.org + + Customised for Poky by + Matthew Allum / mallum@o-hand.com + + Thanks to: + Liam R. E. Quin + William Skaggs + Jakub Steiner + + Structure + --------- + + The stylesheet is divided into the following sections: + + Positioning + Margins, paddings, width, font-size, clearing. + Decorations + Borders, style + Colors + Colors + Graphics + Graphical backgrounds + Nasty IE tweaks + Workarounds needed to make it work in internet explorer, + currently makes the stylesheet non validating, but up until + this point it is validating. + Mozilla extensions + Transparency for footer + Rounded corners on boxes + +*/ + + + /*************** / + / Positioning / +/ ***************/ + +body { + font-family: Verdana, Sans, sans-serif; + + min-width: 640px; + width: 80%; + margin: 0em auto; + padding: 2em 5em 5em 5em; + color: #333; +} + +h1,h2,h3,h4,h5,h6,h7 { + font-family: Arial, Sans; + color: #00557D; + clear: both; +} + +h1 { + font-size: 2em; + text-align: left; + padding: 0em 0em 0em 0em; + margin: 2em 0em 0em 0em; +} + +h2.subtitle { + margin: 0.10em 0em 3.0em 0em; + padding: 0em 0em 0em 0em; + font-size: 1.8em; + padding-left: 20%; + font-weight: normal; + font-style: italic; +} + +h2 { + margin: 2em 0em 0.66em 0em; + padding: 0.5em 0em 0em 0em; + font-size: 1.5em; + font-weight: bold; +} + +h3.subtitle { + margin: 0em 0em 1em 0em; + padding: 0em 0em 0em 0em; + font-size: 142.14%; + text-align: right; +} + +h3 { + margin: 1em 0em 0.5em 0em; + padding: 1em 0em 0em 0em; + font-size: 140%; + font-weight: bold; +} + +h4 { + margin: 1em 0em 0.5em 0em; + padding: 1em 0em 0em 0em; + font-size: 120%; + font-weight: bold; +} + +h5 { + margin: 1em 0em 0.5em 0em; + padding: 1em 0em 0em 0em; + font-size: 110%; + font-weight: bold; +} + +h6 { + margin: 1em 0em 0em 0em; + padding: 1em 0em 0em 0em; + font-size: 110%; + font-weight: bold; +} + +.authorgroup { + background-color: transparent; + background-repeat: no-repeat; + padding-top: 256px; + background-image: url("figures/getting-started-title.png"); + background-position: left top; + margin-top: -256px; + padding-right: 50px; + margin-left: 0px; + text-align: right; + width: 740px; +} + +h3.author { + margin: 0em 0me 0em 0em; + padding: 0em 0em 0em 0em; + font-weight: normal; + font-size: 100%; + color: #333; + clear: both; +} + +.author tt.email { + font-size: 66%; +} + +.titlepage hr { + width: 0em; + clear: both; +} + +.revhistory { + padding-top: 2em; + clear: both; +} + +.toc, +.list-of-tables, +.list-of-examples, +.list-of-figures { + padding: 1.33em 0em 2.5em 0em; + color: #00557D; +} + +.toc p, +.list-of-tables p, +.list-of-figures p, +.list-of-examples p { + padding: 0em 0em 0em 0em; + padding: 0em 0em 0.3em; + margin: 1.5em 0em 0em 0em; +} + +.toc p b, +.list-of-tables p b, +.list-of-figures p b, +.list-of-examples p b{ + font-size: 100.0%; + font-weight: bold; +} + +.toc dl, +.list-of-tables dl, +.list-of-figures dl, +.list-of-examples dl { + margin: 0em 0em 0.5em 0em; + padding: 0em 0em 0em 0em; +} + +.toc dt { + margin: 0em 0em 0em 0em; + padding: 0em 0em 0em 0em; +} + +.toc dd { + margin: 0em 0em 0em 2.6em; + padding: 0em 0em 0em 0em; 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+ font-size: 100%; + font-weight: normal; +} + +.mediaobject .caption, +.mediaobject .caption p { + text-align: center; + font-size: 80%; + padding-top: 0.5em; + padding-bottom: 0.5em; +} + +.epigraph { + padding-left: 55%; + margin-bottom: 1em; +} + +.epigraph p { + text-align: left; +} + +.epigraph .quote { + font-style: italic; +} +.epigraph .attribution { + font-style: normal; + text-align: right; +} + +span.application { + font-style: italic; +} + +.programlisting { + font-family: monospace; + font-size: 80%; + white-space: pre; + margin: 1.33em 0em; + padding: 1.33em; +} + +.tip, +.warning, +.caution, +.note { + margin-top: 1em; + margin-bottom: 1em; + +} + +/* force full width of table within div */ +.tip table, +.warning table, +.caution table, +.note table { + border: none; + width: 100%; +} + + +.tip table th, +.warning table th, +.caution table th, +.note table th { + padding: 0.8em 0.0em 0.0em 0.0em; + margin : 0em 0em 0em 0em; +} + +.tip p, +.warning p, +.caution p, +.note p { + margin-top: 0.5em; + margin-bottom: 0.5em; + padding-right: 1em; + text-align: left; +} + +.acronym { + text-transform: uppercase; +} + +b.keycap, +.keycap { + padding: 0.09em 0.3em; + margin: 0em; +} + +.itemizedlist li { + clear: none; +} + +.filename { + font-size: medium; + font-family: Courier, monospace; +} + + +div.navheader, div.heading{ + position: absolute; + left: 0em; + top: 0em; + width: 100%; + background-color: #cdf; + width: 100%; +} + +div.navfooter, div.footing{ + position: fixed; + left: 0em; + bottom: 0em; + background-color: #eee; + width: 100%; +} + + +div.navheader td, +div.navfooter td { + font-size: 66%; +} + +div.navheader table th { + /*font-family: Georgia, Times, serif;*/ + /*font-size: x-large;*/ + font-size: 80%; +} + +div.navheader table { + border-left: 0em; + border-right: 0em; + border-top: 0em; + width: 100%; +} + +div.navfooter table { + border-left: 0em; + border-right: 0em; + border-bottom: 0em; + width: 100%; +} + +div.navheader table td a, +div.navfooter table td a { + color: #777; + text-decoration: none; +} + +/* normal text in the footer */ +div.navfooter table td { + color: black; +} + +div.navheader table td a:visited, +div.navfooter table td a:visited { + color: #444; +} + + +/* links in header and footer */ +div.navheader table td a:hover, +div.navfooter table td a:hover { + text-decoration: underline; + background-color: transparent; + color: #33a; +} + +div.navheader hr, +div.navfooter hr { + display: none; +} + + +.qandaset tr.question td p { + margin: 0em 0em 1em 0em; + padding: 0em 0em 0em 0em; +} + +.qandaset tr.answer td p { + margin: 0em 0em 1em 0em; + padding: 0em 0em 0em 0em; +} +.answer td { + padding-bottom: 1.5em; +} + +.emphasis { + font-weight: bold; +} + + + /************* / + / decorations / +/ *************/ + +.titlepage { +} + +.part .title { +} + +.subtitle { + border: none; +} + +/* +h1 { + border: none; +} + +h2 { + border-top: solid 0.2em; + border-bottom: solid 0.06em; +} + +h3 { + border-top: 0em; + border-bottom: solid 0.06em; +} + +h4 { + border: 0em; + border-bottom: solid 0.06em; +} + +h5 { + border: 0em; +} +*/ + +.programlisting { + border: solid 1px; +} + +div.figure, +div.table, +div.informalfigure, +div.informaltable, +div.informalexample, +div.example { + border: 1px solid; +} + + + +.tip, +.warning, +.caution, +.note { + border: 1px solid; +} + +.tip table th, +.warning table th, +.caution table th, +.note table th { + border-bottom: 1px solid; +} + +.question td { + border-top: 1px solid black; +} + +.answer { +} + + +b.keycap, +.keycap { + border: 1px solid; +} + + +div.navheader, div.heading{ + border-bottom: 1px solid; +} + + +div.navfooter, div.footing{ + border-top: 1px solid; +} + + /********* / + / colors / +/ *********/ + +body { + color: #333; + background: white; +} + +a { + background: transparent; +} + +a:hover { + background-color: #dedede; +} + + +h1, +h2, +h3, +h4, +h5, +h6, +h7, +h8 { + background-color: transparent; +} + +hr { + border-color: #aaa; +} + + +.tip, .warning, .caution, .note { + border-color: #fff; +} + + +.tip table th, +.warning table th, +.caution table th, +.note table th { + border-bottom-color: #fff; +} + + +.warning { + background-color: #f0f0f2; +} + +.caution { + background-color: #f0f0f2; +} + +.tip { + background-color: #f0f0f2; +} + +.note { + background-color: #f0f0f2; +} + +.glossary dl dt, +.variablelist dl dt, +.variablelist dl dt span.term { + color: #044; +} + +div.figure, +div.table, +div.example, +div.informalfigure, +div.informaltable, +div.informalexample { + border-color: #aaa; +} + +pre.programlisting { + color: black; + background-color: #fff; + border-color: #aaa; + border-width: 2px; +} + +.guimenu, +.guilabel, +.guimenuitem { + background-color: #eee; +} + + +b.keycap, +.keycap { + background-color: #eee; + border-color: #999; +} + + +div.navheader { + border-color: black; +} + + +div.navfooter { + border-color: black; +} + +.writernotes { + color: red; +} + + + /*********** / + / graphics / +/ ***********/ + +/* +body { + background-image: url("images/body_bg.jpg"); + background-attachment: fixed; +} + +.navheader, +.note, +.tip { + background-image: url("images/note_bg.jpg"); + background-attachment: fixed; +} + +.warning, +.caution { + background-image: url("images/warning_bg.jpg"); + background-attachment: fixed; +} + +.figure, +.informalfigure, +.example, +.informalexample, +.table, +.informaltable { + background-image: url("images/figure_bg.jpg"); + background-attachment: fixed; +} + +*/ +h1, +h2, +h3, +h4, +h5, +h6, +h7{ +} + +/* +Example of how to stick an image as part of the title. + +div.article .titlepage .title +{ + background-image: url("figures/white-on-black.png"); + background-position: center; + background-repeat: repeat-x; +} +*/ + +div.preface .titlepage .title, +div.colophon .title, +div.chapter .titlepage .title, +div.article .titlepage .title +{ +} + +div.section div.section .titlepage .title, +div.sect2 .titlepage .title { + background: none; +} + + +h1.title { + background-color: transparent; + background-repeat: no-repeat; + height: 256px; + text-indent: -9000px; + overflow:hidden; +} + +h2.subtitle { + background-color: transparent; + text-indent: -9000px; + overflow:hidden; + width: 0px; + display: none; +} + + /*************************************** / + / pippin.gimp.org specific alterations / +/ ***************************************/ + +/* +div.heading, div.navheader { + color: #777; + font-size: 80%; + padding: 0; + margin: 0; + text-align: left; + position: absolute; + top: 0px; + left: 0px; + width: 100%; + height: 50px; + background: url('/gfx/heading_bg.png') transparent; + background-repeat: repeat-x; + background-attachment: fixed; + border: none; +} + +div.heading a { + color: #444; +} + +div.footing, div.navfooter { + border: none; + color: #ddd; + font-size: 80%; + text-align:right; + + width: 100%; + padding-top: 10px; + position: absolute; + bottom: 0px; + left: 0px; + + background: url('/gfx/footing_bg.png') transparent; +} +*/ + + + + /****************** / + / nasty ie tweaks / +/ ******************/ + +/* +div.heading, div.navheader { + width:expression(document.body.clientWidth + "px"); +} + +div.footing, div.navfooter { + width:expression(document.body.clientWidth + "px"); + margin-left:expression("-5em"); +} +body { + padding:expression("4em 5em 0em 5em"); +} +*/ + + /**************************************** / + / mozilla vendor specific css extensions / +/ ****************************************/ +/* +div.navfooter, div.footing{ + -moz-opacity: 0.8em; +} + +div.figure, +div.table, +div.informalfigure, +div.informaltable, +div.informalexample, +div.example, +.tip, +.warning, +.caution, +.note { + -moz-border-radius: 0.5em; +} + +b.keycap, +.keycap { + -moz-border-radius: 0.3em; +} +*/ + +table tr td table tr td { + display: none; +} + + +hr { + display: none; +} + +table { + border: 0em; +} + + .photo { + float: right; + margin-left: 1.5em; + margin-bottom: 1.5em; + margin-top: 0em; + max-width: 17em; + border: 1px solid gray; + padding: 3px; + background: white; +} + .seperator { + padding-top: 2em; + clear: both; + } + + #validators { + margin-top: 5em; + text-align: right; + color: #777; + } + @media print { + body { + font-size: 8pt; + } + .noprint { + display: none; + } + } + + +.tip, +.note { + background: #f0f0f2; + color: #333; + padding: 20px; + margin: 20px; +} + +.tip h3, +.note h3 { + padding: 0em; + margin: 0em; + font-size: 2em; + font-weight: bold; + color: #333; +} + +.tip a, +.note a { + color: #333; + text-decoration: underline; +} + +.footnote { + font-size: small; + color: #333; +} + +/* Changes the announcement text */ +.tip h3, +.warning h3, +.caution h3, +.note h3 { + font-size:large; + color: #00557D; +} diff --git a/documentation/getting-started/getting-started.html b/documentation/getting-started/getting-started.html new file mode 100644 index 0000000000..19c1384f8e --- /dev/null +++ b/documentation/getting-started/getting-started.html @@ -0,0 +1,3900 @@ + +Getting Started With Yocto Project

+ Getting Started With Yocto Project +

+

Scott Rifenbark

+ Scotty's Documentation Services, INC
 +
+

Copyright © 2010-2018 Linux Foundation

+

+ Permission is granted to copy, distribute and/or modify this document under + the terms of the + Creative Commons Attribution-Share Alike 2.0 UK: England & Wales as published by + Creative Commons. +

+

Manual Notes

+

  • + This version of the + Yocto Project Overview Manual + is for the 2.5 release of the + Yocto Project. + To be sure you have the latest version of the manual + for this release, use the manual from the + Yocto Project documentation page. +

  • + For manuals associated with other releases of the Yocto + Project, go to the + Yocto Project documentation page + and use the drop-down "Active Releases" button + and choose the manual associated with the desired + Yocto Project. +

  • + To report any inaccuracies or problems with this + manual, send an email to the Yocto Project + discussion group at + yocto@yoctoproject.com or log into + the freenode #yocto channel. +

+
+
+ +
Revision History
Revision 2.5April 2018
The initial document released with the Yocto Project 2.5 Release.

Table of Contents

1. The Yocto Project Overview Manual
1.1. Welcome
1.2. Other Information
2. The Yocto Project Development Environment
2.1. Introduction
2.2. Open Source Philosophy
2.3. Workflows
2.4. Git
2.4.1. Repositories, Tags, and Branches
2.4.2. Basic Commands
2.5. Yocto Project Source Repositories
2.6. Licensing
2.7. Recipe Syntax
2.8. Development Concepts
2.8.1. User Configuration
2.8.2. Metadata, Machine Configuration, and Policy Configuration
2.8.3. Sources
2.8.4. Package Feeds
2.8.5. BitBake
2.8.6. Images
2.8.7. Application Development SDK
3. Yocto Project Concepts
3.1. Yocto Project Components
3.1.1. BitBake
3.1.2. Metadata (Recipes)
3.1.3. Metadata (Virtual Providers)
3.1.4. Classes
3.1.5. Configuration
3.2. Cross-Development Toolchain Generation
3.3. Shared State Cache
3.3.1. Overall Architecture
3.3.2. Checksums (Signatures)
3.3.3. Shared State
3.3.4. Tips and Tricks
3.4. Automatically Added Runtime Dependencies
3.5. Fakeroot and Pseudo
3.6. Wayland
3.6.1. Support
3.6.2. Enabling Wayland in an Image
3.6.3. Running Weston
3.7. Licenses
3.7.1. Tracking License Changes
3.7.2. Enabling Commercially Licensed Recipes
3.8. x32 psABI
+ + +

Chapter 1. The Yocto Project Overview Manual¶

Table of Contents

1.1. Welcome
1.2. Other Information

1.1. Welcome¶

+ Welcome to the Yocto Project Overview Manual! + This manual introduces the Yocto Project by providing concepts, + software overviews, best-known-methods (BKMs), and any other + high-level introductory information suitable for a new Yocto + Project user. +

+ The following list describes what you can get from this manual: +

  • + Major Topic: + Provide a high-level description of this major topic. +

  • + Major Topic: + Provide a high-level description of this major topic. +

  • + Major Topic: + Provide a high-level description of this major topic. +

  • + Major Topic: + Provide a high-level description of this major topic. +

+

+ This manual does not give you the following: +

  • + Step-by-step Instructions for Development Tasks: + Instructional procedures reside in other manuals within + the Yocto Project documentation set. + For example, the + Yocto Project Development Tasks Manual + provides examples on how to perform various development + tasks. + As another example, the + Yocto Project Application Development and the Extensible Software Development Kit (eSDK) + manual contains detailed instructions on how to install an + SDK, which is used to develop applications for target + hardware. +

  • + Reference Material: + This type of material resides in an appropriate reference + manual. + For example, system variables are documented in the + Yocto Project Reference Manual. + As another example, the + Yocto Project Board Support Package (BSP) Developer's Guide + contains reference information on BSPs. +

  • + Detailed Public Information Not Specific to the + Yocto Project: + For example, exhaustive information on how to use the + Source Control Manager Git is better covered with Internet + searches and official Git Documentation than through the + Yocto Project documentation. +

+

1.2. Other Information¶

+ Because this manual presents information for many different + topics, supplemental information is recommended for full + comprehension. + For additional introductory information on the Yocto Project, see + the Yocto Project Website. + You can find an introductory to using the Yocto Project by working + through the + Yocto Project Quick Start. +

+ For a comprehensive list of links and other documentation, see the + "Links and Related Documentation" + section in the Yocto Project Reference Manual. +

+ +

Chapter 2. The Yocto Project Development Environment¶

Table of Contents

2.1. Introduction
2.2. Open Source Philosophy
2.3. Workflows
2.4. Git
2.4.1. Repositories, Tags, and Branches
2.4.2. Basic Commands
2.5. Yocto Project Source Repositories
2.6. Licensing
2.7. Recipe Syntax
2.8. Development Concepts
2.8.1. User Configuration
2.8.2. Metadata, Machine Configuration, and Policy Configuration
2.8.3. Sources
2.8.4. Package Feeds
2.8.5. BitBake
2.8.6. Images
2.8.7. Application Development SDK

+ This chapter takes a look at the Yocto Project development + environment and also provides a detailed look at what goes on during + development in that environment. + The chapter provides Yocto Project Development environment concepts that + help you understand how work is accomplished in an open source environment, + which is very different as compared to work accomplished in a closed, + proprietary environment. +

+ Specifically, this chapter addresses open source philosophy, workflows, + Git, source repositories, licensing, recipe syntax, and development + syntax. +

2.1. Introduction¶

+ The Yocto Project is an open-source collaboration project whose + focus is for developers of embedded Linux systems. + Among other things, the Yocto Project uses an + OpenEmbedded build system. + The build system, which is based on the OpenEmbedded (OE) project and + uses the + BitBake tool, + constructs complete Linux images for architectures based on ARM, MIPS, + PowerPC, x86 and x86-64. +

Note

+ Historically, the OpenEmbedded build system, which is the + combination of BitBake and OE components, formed a reference + build host that was known as + "Poky" + (Pah-kee). + The term "Poky", as used throughout the Yocto Project Documentation + set, can have different meanings. +

+ The Yocto Project provides various ancillary tools for the embedded + developer and also features the Sato reference User Interface, which + is optimized for stylus-driven, low-resolution screens. +

+ Here are some highlights for the Yocto Project: +

  • + Provides a recent Linux kernel along with a set of system + commands and libraries suitable for the embedded + environment. +

  • + Makes available system components such as X11, GTK+, Qt, + Clutter, and SDL (among others) so you can create a rich user + experience on devices that have display hardware. + For devices that do not have a display or where you wish to + use alternative UI frameworks, these components need not be + installed. +

  • + Creates a focused and stable core compatible with the + OpenEmbedded project with which you can easily and reliably + build and develop. +

  • + Fully supports a wide range of hardware and device emulation + through the Quick EMUlator (QEMU). +

  • + Provides a layer mechanism that allows you to easily extend + the system, make customizations, and keep them organized. +

+ You can use the Yocto Project to generate images for many kinds + of devices. + As mentioned earlier, the Yocto Project supports creation of + reference images that you can boot within and emulate using QEMU. + The standard example machines target QEMU full-system + emulation for 32-bit and 64-bit variants of x86, ARM, MIPS, and + PowerPC architectures. + Beyond emulation, you can use the layer mechanism to extend + support to just about any platform that Linux can run on and that + a toolchain can target. +

+ Another Yocto Project feature is the Sato reference User + Interface. + This optional UI that is based on GTK+ is intended for devices with + restricted screen sizes and is included as part of the + OpenEmbedded Core layer so that developers can test parts of the + software stack. +

+ While the Yocto Project does not provide a strict testing framework, + it does provide or generate for you artifacts that let you perform + target-level and emulated testing and debugging. + Additionally, if you are an + Eclipseâ„¢ IDE user, you can + install an Eclipse Yocto Plug-in to allow you to develop within that + familiar environment. +

+ By default, using the Yocto Project to build an image creates a Poky + distribution. + However, you can create your own distribution by providing key + Metadata. + A good example is Angstrom, which has had a distribution + based on the Yocto Project since its inception. + Other examples include commercial distributions like + Wind River Linux, + Mentor Embedded Linux, + ENEA Linux + and others. + See the "Creating Your Own Distribution" + section in the Yocto Project Development Tasks Manual for more + information. +

2.2. Open Source Philosophy¶

+ Open source philosophy is characterized by software development + directed by peer production and collaboration through an active + community of developers. + Contrast this to the more standard centralized development models + used by commercial software companies where a finite set of developers + produces a product for sale using a defined set of procedures that + ultimately result in an end product whose architecture and source + material are closed to the public. +

+ Open source projects conceptually have differing concurrent agendas, + approaches, and production. + These facets of the development process can come from anyone in the + public (community) that has a stake in the software project. + The open source environment contains new copyright, licensing, domain, + and consumer issues that differ from the more traditional development + environment. + In an open source environment, the end product, source material, + and documentation are all available to the public at no cost. +

+ A benchmark example of an open source project is the Linux kernel, + which was initially conceived and created by Finnish computer science + student Linus Torvalds in 1991. + Conversely, a good example of a non-open source project is the + Windows® family of operating + systems developed by + Microsoft® Corporation. +

+ Wikipedia has a good historical description of the Open Source + Philosophy + here. + You can also find helpful information on how to participate in the + Linux Community + here. +

2.3. Workflows¶

+ This section provides workflow concepts using the Yocto Project and + Git. + In particular, the information covers basic practices that describe + roles and actions in a collaborative development environment. +

Note

+ If you are familiar with this type of development environment, you + might not want to read this section. +

+

+ The Yocto Project files are maintained using Git in "master" + branches whose Git histories track every change and whose structures + provides branches for all diverging functionality. + Although there is no need to use Git, many open source projects do so. +

+ +

+ For the Yocto Project, a key individual called the "maintainer" is + responsible for the "master" branch of a given Git repository. + The "master" branch is the “upstream†repository from which final or + most recent builds of the project occur. + The maintainer is responsible for accepting changes from other + developers and for organizing the underlying branch structure to + reflect release strategies and so forth. +

Note

For information on finding out who is responsible for (maintains) + a particular area of code, see the + "Submitting a Change to the Yocto Project" + section of the Yocto Project Development Tasks Manual. +

+

+ The Yocto Project poky Git repository also has an + upstream contribution Git repository named + poky-contrib. + You can see all the branches in this repository using the web interface + of the + Source Repositories organized + within the "Poky Support" area. + These branches temporarily hold changes to the project that have been + submitted or committed by the Yocto Project development team and by + community members who contribute to the project. + The maintainer determines if the changes are qualified to be moved + from the "contrib" branches into the "master" branch of the Git + repository. +

+ Developers (including contributing community members) create and + maintain cloned repositories of the upstream "master" branch. + The cloned repositories are local to their development platforms and + are used to develop changes. + When a developer is satisfied with a particular feature or change, + they "push" the changes to the appropriate "contrib" repository. +

+ Developers are responsible for keeping their local repository + up-to-date with "master". + They are also responsible for straightening out any conflicts that + might arise within files that are being worked on simultaneously by + more than one person. + All this work is done locally on the developer’s machine before + anything is pushed to a "contrib" area and examined at the maintainer’s + level. +

+ A somewhat formal method exists by which developers commit changes + and push them into the "contrib" area and subsequently request that + the maintainer include them into "master". + This process is called “submitting a patch†or "submitting a change." + For information on submitting patches and changes, see the + "Submitting a Change to the Yocto Project" + section in the Yocto Project Development Tasks Manual. +

+ To summarize the development workflow: a single point of entry + exists for changes into the project’s "master" branch of the + Git repository, which is controlled by the project’s maintainer. + And, a set of developers exist who independently develop, test, and + submit changes to "contrib" areas for the maintainer to examine. + The maintainer then chooses which changes are going to become a + permanent part of the project. +

+

+

+ While each development environment is unique, there are some best + practices or methods that help development run smoothly. + The following list describes some of these practices. + For more information about Git workflows, see the workflow topics in + the + Git Community Book. +

  • + Make Small Changes: + It is best to keep the changes you commit small as compared to + bundling many disparate changes into a single commit. + This practice not only keeps things manageable but also allows + the maintainer to more easily include or refuse changes.

    It is also good practice to leave the repository in a + state that allows you to still successfully build your project. + In other words, do not commit half of a feature, + then add the other half as a separate, later commit. + Each commit should take you from one buildable project state + to another buildable state. +

  • + Use Branches Liberally: + It is very easy to create, use, and delete local branches in + your working Git repository. + You can name these branches anything you like. + It is helpful to give them names associated with the particular + feature or change on which you are working. + Once you are done with a feature or change and have merged it + into your local master branch, simply discard the temporary + branch. +

  • + Merge Changes: + The git merge command allows you to take + the changes from one branch and fold them into another branch. + This process is especially helpful when more than a single + developer might be working on different parts of the same + feature. + Merging changes also automatically identifies any collisions + or "conflicts" that might happen as a result of the same lines + of code being altered by two different developers. +

  • + Manage Branches: + Because branches are easy to use, you should use a system + where branches indicate varying levels of code readiness. + For example, you can have a "work" branch to develop in, a + "test" branch where the code or change is tested, a "stage" + branch where changes are ready to be committed, and so forth. + As your project develops, you can merge code across the + branches to reflect ever-increasing stable states of the + development. +

  • + Use Push and Pull: + The push-pull workflow is based on the concept of developers + "pushing" local commits to a remote repository, which is + usually a contribution repository. + This workflow is also based on developers "pulling" known + states of the project down into their local development + repositories. + The workflow easily allows you to pull changes submitted by + other developers from the upstream repository into your + work area ensuring that you have the most recent software + on which to develop. + The Yocto Project has two scripts named + create-pull-request and + send-pull-request that ship with the + release to facilitate this workflow. + You can find these scripts in the scripts + folder of the + Source Directory. + For information on how to use these scripts, see the + "Using Scripts to Push a Change Upstream and Request a Pull" + section in the Yocto Project Development Tasks Manual. +

  • + Patch Workflow: + This workflow allows you to notify the maintainer through an + email that you have a change (or patch) you would like + considered for the "master" branch of the Git repository. + To send this type of change, you format the patch and then + send the email using the Git commands + git format-patch and + git send-email. + For information on how to use these scripts, see the + "Submitting a Change to the Yocto Project" + section in the Yocto Project Development Tasks Manual. +

+

2.4. Git¶

+ The Yocto Project makes extensive use of Git, which is a + free, open source distributed version control system. + Git supports distributed development, non-linear development, + and can handle large projects. + It is best that you have some fundamental understanding + of how Git tracks projects and how to work with Git if + you are going to use the Yocto Project for development. + This section provides a quick overview of how Git works and + provides you with a summary of some essential Git commands. +

Notes

  • + For more information on Git, see + http://git-scm.com/documentation. +

  • + If you need to download Git, it is recommended that you add + Git to your system through your distribution's "software + store" (e.g. for Ubuntu, use the Ubuntu Software feature). + For the Git download page, see + http://git-scm.com/download. +

  • + For examples beyond the limited few in this section on how + to use Git with the Yocto Project, see the + "Working With Yocto Project Source Files" + section in the Yocto Project Development Tasks Manual. +

+

2.4.1. Repositories, Tags, and Branches¶

+ As mentioned briefly in the previous section and also in the + "Workflows" section, + the Yocto Project maintains source repositories at + http://git.yoctoproject.org/cgit.cgi. + If you look at this web-interface of the repositories, each item + is a separate Git repository. +

+ Git repositories use branching techniques that track content + change (not files) within a project (e.g. a new feature or updated + documentation). + Creating a tree-like structure based on project divergence allows + for excellent historical information over the life of a project. + This methodology also allows for an environment from which you can + do lots of local experimentation on projects as you develop + changes or new features. +

+ A Git repository represents all development efforts for a given + project. + For example, the Git repository poky contains + all changes and developments for Poky over the course of its + entire life. + That means that all changes that make up all releases are captured. + The repository maintains a complete history of changes. +

+ You can create a local copy of any repository by "cloning" it + with the git clone command. + When you clone a Git repository, you end up with an identical + copy of the repository on your development system. + Once you have a local copy of a repository, you can take steps to + develop locally. + For examples on how to clone Git repositories, see the + "Working With Yocto Project Source Files" + section in the Yocto Project Development Tasks Manual. +

+ It is important to understand that Git tracks content change and + not files. + Git uses "branches" to organize different development efforts. + For example, the poky repository has + several branches that include the current "sumo" + branch, the "master" branch, and many branches for past + Yocto Project releases. + You can see all the branches by going to + http://git.yoctoproject.org/cgit.cgi/poky/ and + clicking on the + [...] + link beneath the "Branch" heading. +

+ Each of these branches represents a specific area of development. + The "master" branch represents the current or most recent + development. + All other branches represent offshoots of the "master" branch. +

+ When you create a local copy of a Git repository, the copy has + the same set of branches as the original. + This means you can use Git to create a local working area + (also called a branch) that tracks a specific development branch + from the upstream source Git repository. + in other words, you can define your local Git environment to + work on any development branch in the repository. + To help illustrate, consider the following example Git commands: + 

+     $ cd ~
+     $ git clone git://git.yoctoproject.org/poky
+     $ cd poky
+     $ git checkout -b sumo origin/sumo
+

+ In the previous example after moving to the home directory, the + git clone command creates a + local copy of the upstream poky Git repository. + By default, Git checks out the "master" branch for your work. + After changing the working directory to the new local repository + (i.e. poky), the + git checkout command creates + and checks out a local branch named "sumo", which + tracks the upstream "origin/sumo" branch. + Changes you make while in this branch would ultimately affect + the upstream "sumo" branch of the + poky repository. +

+ It is important to understand that when you create and checkout a + local working branch based on a branch name, + your local environment matches the "tip" of that particular + development branch at the time you created your local branch, + which could be different from the files in the "master" branch + of the upstream repository. + In other words, creating and checking out a local branch based on + the "sumo" branch name is not the same as + cloning and checking out the "master" branch if the repository. + Keep reading to see how you create a local snapshot of a Yocto + Project Release. +

+ Git uses "tags" to mark specific changes in a repository. + Typically, a tag is used to mark a special point such as the final + change before a project is released. + You can see the tags used with the poky Git + repository by going to + http://git.yoctoproject.org/cgit.cgi/poky/ and + clicking on the + [...] + link beneath the "Tag" heading. +

+ Some key tags for the poky are + jethro-14.0.3, + morty-16.0.1, + pyro-17.0.0, and + sumo-20.0.0. + These tags represent Yocto Project releases. +

+ When you create a local copy of the Git repository, you also + have access to all the tags in the upstream repository. + Similar to branches, you can create and checkout a local working + Git branch based on a tag name. + When you do this, you get a snapshot of the Git repository that + reflects the state of the files when the change was made associated + with that tag. + The most common use is to checkout a working branch that matches + a specific Yocto Project release. + Here is an example: + 

+     $ cd ~
+     $ git clone git://git.yoctoproject.org/poky
+     $ cd poky
+     $ git fetch --all --tags --prune
+     $ git checkout tags/pyro-17.0.0 -b my-pyro-17.0.0
+

+ In this example, the name of the top-level directory of your + local Yocto Project repository is poky. + After moving to the poky directory, the + git fetch command makes all the upstream + tags available locally in your repository. + Finally, the git checkout command + creates and checks out a branch named "my-pyro-17.0.0" that is + based on the specific change upstream in the repository + associated with the "pyro-17.0.0" tag. + The files in your repository now exactly match that particular + Yocto Project release as it is tagged in the upstream Git + repository. + It is important to understand that when you create and + checkout a local working branch based on a tag, your environment + matches a specific point in time and not the entire development + branch (i.e. the "tip" of the branch). +

2.4.2. Basic Commands¶

+ Git has an extensive set of commands that lets you manage changes + and perform collaboration over the life of a project. + Conveniently though, you can manage with a small set of basic + operations and workflows once you understand the basic + philosophy behind Git. + You do not have to be an expert in Git to be functional. + A good place to look for instruction on a minimal set of Git + commands is + here. +

+ If you do not know much about Git, you should educate + yourself by visiting the links previously mentioned. +

+ The following list of Git commands briefly describes some basic + Git operations as a way to get started. + As with any set of commands, this list (in most cases) simply shows + the base command and omits the many arguments they support. + See the Git documentation for complete descriptions and strategies + on how to use these commands: +

  • + git init: + Initializes an empty Git repository. + You cannot use Git commands unless you have a + .git repository. +

  • + git clone: + Creates a local clone of a Git repository that is on + equal footing with a fellow developer’s Git repository + or an upstream repository. +

  • + git add: + Locally stages updated file contents to the index that + Git uses to track changes. + You must stage all files that have changed before you + can commit them. +

  • + git commit: + Creates a local "commit" that documents the changes you + made. + Only changes that have been staged can be committed. + Commits are used for historical purposes, for determining + if a maintainer of a project will allow the change, + and for ultimately pushing the change from your local + Git repository into the project’s upstream repository. +

  • + git status: + Reports any modified files that possibly need to be + staged and gives you a status of where you stand regarding + local commits as compared to the upstream repository. +

  • + git checkout branch-name: + Changes your working branch. + This command is analogous to "cd". +

  • git checkout –b working-branch: + Creates and checks out a working branch on your local + machine that you can use to isolate your work. + It is a good idea to use local branches when adding + specific features or changes. + Using isolated branches facilitates easy removal of + changes if they do not work out. +

  • git branch: + Displays the existing local branches associated with your + local repository. + The branch that you have currently checked out is noted + with an asterisk character. +

  • + git branch -D branch-name: + Deletes an existing local branch. + You need to be in a local branch other than the one you + are deleting in order to delete + branch-name. +

  • + git pull: + Retrieves information from an upstream Git repository + and places it in your local Git repository. + You use this command to make sure you are synchronized with + the repository from which you are basing changes + (.e.g. the "master" branch). +

  • + git push: + Sends all your committed local changes to the upstream Git + repository that your local repository is tracking + (e.g. a contribution repository). + The maintainer of the project draws from these repositories + to merge changes (commits) into the appropriate branch + of project's upstream repository. +

  • + git merge: + Combines or adds changes from one + local branch of your repository with another branch. + When you create a local Git repository, the default branch + is named "master". + A typical workflow is to create a temporary branch that is + based off "master" that you would use for isolated work. + You would make your changes in that isolated branch, + stage and commit them locally, switch to the "master" + branch, and then use the git merge + command to apply the changes from your isolated branch + into the currently checked out branch (e.g. "master"). + After the merge is complete and if you are done with + working in that isolated branch, you can safely delete + the isolated branch. +

  • + git cherry-pick: + Choose and apply specific commits from one branch + into another branch. + There are times when you might not be able to merge + all the changes in one branch with + another but need to pick out certain ones. +

  • + gitk: + Provides a GUI view of the branches and changes in your + local Git repository. + This command is a good way to graphically see where things + have diverged in your local repository. +

    Note

    + You need to install the gitk + package on your development system to use this + command. +

    +

  • + git log: + Reports a history of your commits to the repository. + This report lists all commits regardless of whether you + have pushed them upstream or not. +

  • + git diff: + Displays line-by-line differences between a local + working file and the same file as understood by Git. + This command is useful to see what you have changed + in any given file. +

+

2.5. Yocto Project Source Repositories¶

+ The Yocto Project team maintains complete source repositories for all + Yocto Project files at + http://git.yoctoproject.org/cgit/cgit.cgi. + This web-based source code browser is organized into categories by + function such as IDE Plugins, Matchbox, Poky, Yocto Linux Kernel, and + so forth. + From the interface, you can click on any particular item in the "Name" + column and see the URL at the bottom of the page that you need to clone + a Git repository for that particular item. + Having a local Git repository of the + Source Directory, + which is usually named "poky", allows + you to make changes, contribute to the history, and ultimately enhance + the Yocto Project's tools, Board Support Packages, and so forth. +

+ For any supported release of Yocto Project, you can also go to the + Yocto Project Website and + select the "Downloads" tab and get a released tarball of the + poky repository or any supported BSP tarballs. + Unpacking these tarballs gives you a snapshot of the released + files. +

Notes

  • + The recommended method for setting up the Yocto Project + Source Directory + and the files for supported BSPs + (e.g., meta-intel) is to use + Git to create a local copy of + the upstream repositories. +

  • + Be sure to always work in matching branches for both + the selected BSP repository and the + Source Directory + (i.e. poky) repository. + For example, if you have checked out the "master" branch + of poky and you are going to use + meta-intel, be sure to checkout the + "master" branch of meta-intel. +

+

+ In summary, here is where you can get the project files needed for + development: +

  • + + Source Repositories: + + This area contains IDE Plugins, Matchbox, Poky, Poky Support, + Tools, Yocto Linux Kernel, and Yocto Metadata Layers. + You can create local copies of Git repositories for each of + these areas.

    +

    + For steps on how to view and access these upstream Git + repositories, see the + "Accessing Source Repositories" + Section in the Yocto Project Development Tasks Manual. +

  • + + Index of /releases: + + This is an index of releases such as + the Eclipseâ„¢ + Yocto Plug-in, miscellaneous support, Poky, Pseudo, installers + for cross-development toolchains, and all released versions of + Yocto Project in the form of images or tarballs. + Downloading and extracting these files does not produce a local + copy of the Git repository but rather a snapshot of a + particular release or image.

    +

    + For steps on how to view and access these files, see the + "Accessing Index of Releases" + section in the Yocto Project Development Tasks Manual. +

  • + "Downloads" page for the + Yocto Project Website: +

    This section will change due to + reworking of the YP Website.

    The Yocto Project website includes a "Downloads" tab + that allows you to download any Yocto Project + release and Board Support Package (BSP) in tarball form. + The tarballs are similar to those found in the + Index of /releases: area.

    +

    + For steps on how to use the "Downloads" page, see the + "Using the Downloads Page" + section in the Yocto Project Development Tasks Manual. +

+

2.6. Licensing¶

+ Because open source projects are open to the public, they have + different licensing structures in place. + License evolution for both Open Source and Free Software has an + interesting history. + If you are interested in this history, you can find basic information + here: +

+

+ In general, the Yocto Project is broadly licensed under the + Massachusetts Institute of Technology (MIT) License. + MIT licensing permits the reuse of software within proprietary + software as long as the license is distributed with that software. + MIT is also compatible with the GNU General Public License (GPL). + Patches to the Yocto Project follow the upstream licensing scheme. + You can find information on the MIT license + here. + You can find information on the GNU GPL + here. +

+ When you build an image using the Yocto Project, the build process + uses a known list of licenses to ensure compliance. + You can find this list in the + Source Directory + at meta/files/common-licenses. + Once the build completes, the list of all licenses found and used + during that build are kept in the + Build Directory + at tmp/deploy/licenses. +

+ If a module requires a license that is not in the base list, the + build process generates a warning during the build. + These tools make it easier for a developer to be certain of the + licenses with which their shipped products must comply. + However, even with these tools it is still up to the developer to + resolve potential licensing issues. +

+ The base list of licenses used by the build process is a combination + of the Software Package Data Exchange (SPDX) list and the Open + Source Initiative (OSI) projects. + SPDX Group is a working group of + the Linux Foundation that maintains a specification for a standard + format for communicating the components, licenses, and copyrights + associated with a software package. + OSI is a corporation + dedicated to the Open Source Definition and the effort for reviewing + and approving licenses that conform to the Open Source Definition + (OSD). +

+ You can find a list of the combined SPDX and OSI licenses that the + Yocto Project uses in the + meta/files/common-licenses directory in your + Source Directory. +

+ For information that can help you maintain compliance with various + open source licensing during the lifecycle of a product created using + the Yocto Project, see the + "Maintaining Open Source License Compliance During Your Product's Lifecycle" + section in the Yocto Project Development Tasks Manual. +

2.7. Recipe Syntax¶

+ Understanding recipe file syntax is important for + writing recipes. + The following list overviews the basic items that make up a + BitBake recipe file. + For more complete BitBake syntax descriptions, see the + "Syntax and Operators" + chapter of the BitBake User Manual. +

  • Variable Assignments and Manipulations: + Variable assignments allow a value to be assigned to a + variable. + The assignment can be static text or might include + the contents of other variables. + In addition to the assignment, appending and prepending + operations are also supported.

    The following example shows some of the ways + you can use variables in recipes: + 

    +     S = "${WORKDIR}/postfix-${PV}"
+     CFLAGS += "-DNO_ASM"
+     SRC_URI_append = " file://fixup.patch"
+

    +

  • Functions: + Functions provide a series of actions to be performed. + You usually use functions to override the default + implementation of a task function or to complement + a default function (i.e. append or prepend to an + existing function). + Standard functions use sh shell + syntax, although access to OpenEmbedded variables and + internal methods are also available.

    The following is an example function from the + sed recipe: + 

    +     do_install () {
+         autotools_do_install
+         install -d ${D}${base_bindir}
+         mv ${D}${bindir}/sed ${D}${base_bindir}/sed
+         rmdir ${D}${bindir}/
+     }
+

    + It is also possible to implement new functions that + are called between existing tasks as long as the + new functions are not replacing or complementing the + default functions. + You can implement functions in Python + instead of shell. + Both of these options are not seen in the majority of + recipes.

  • Keywords: + BitBake recipes use only a few keywords. + You use keywords to include common + functions (inherit), load parts + of a recipe from other files + (include and + require) and export variables + to the environment (export).

    The following example shows the use of some of + these keywords: + 

    +     export POSTCONF = "${STAGING_BINDIR}/postconf"
+     inherit autoconf
+     require otherfile.inc
+

    +

  • Comments: + Any lines that begin with the hash character + (#) are treated as comment lines + and are ignored: + 

    +     # This is a comment
+

    +

+

+ This next list summarizes the most important and most commonly + used parts of the recipe syntax. + For more information on these parts of the syntax, you can + reference the + Syntax and Operators + chapter in the BitBake User Manual. +

  • Line Continuation: \ - + Use the backward slash (\) + character to split a statement over multiple lines. + Place the slash character at the end of the line that + is to be continued on the next line: + 

    +     VAR = "A really long \
+            line"
+

    +

    Note

    + You cannot have any characters including spaces + or tabs after the slash character. +

    +

  • + Using Variables: ${...} - + Use the ${VARNAME} syntax to + access the contents of a variable: + 

    +     SRC_URI = "${SOURCEFORGE_MIRROR}/libpng/zlib-${PV}.tar.gz"
+

    +

    Note

    + It is important to understand that the value of a + variable expressed in this form does not get + substituted automatically. + The expansion of these expressions happens + on-demand later (e.g. usually when a function that + makes reference to the variable executes). + This behavior ensures that the values are most + appropriate for the context in which they are + finally used. + On the rare occasion that you do need the variable + expression to be expanded immediately, you can use + the := operator instead of + = when you make the + assignment, but this is not generally needed. +

    +

  • Quote All Assignments: "value" - + Use double quotes around the value in all variable + assignments. + 

    +     VAR1 = "${OTHERVAR}"
+     VAR2 = "The version is ${PV}"
+

    +

  • Conditional Assignment: ?= - + Conditional assignment is used to assign a value to + a variable, but only when the variable is currently + unset. + Use the question mark followed by the equal sign + (?=) to make a "soft" assignment + used for conditional assignment. + Typically, "soft" assignments are used in the + local.conf file for variables + that are allowed to come through from the external + environment. +

    Here is an example where + VAR1 is set to "New value" if + it is currently empty. + However, if VAR1 has already been + set, it remains unchanged: + 

    +     VAR1 ?= "New value"
+

    + In this next example, VAR1 + is left with the value "Original value": + 

    +     VAR1 = "Original value"
+     VAR1 ?= "New value"
+

    +

  • Appending: += - + Use the plus character followed by the equals sign + (+=) to append values to existing + variables. +

    Note

    + This operator adds a space between the existing + content of the variable and the new content. +

    Here is an example: + 

    +     SRC_URI += "file://fix-makefile.patch"
+

    +

  • Prepending: =+ - + Use the equals sign followed by the plus character + (=+) to prepend values to existing + variables. +

    Note

    + This operator adds a space between the new content + and the existing content of the variable. +

    Here is an example: + 

    +     VAR =+ "Starts"
+

    +

  • Appending: _append - + Use the _append operator to + append values to existing variables. + This operator does not add any additional space. + Also, the operator is applied after all the + +=, and + =+ operators have been applied and + after all = assignments have + occurred. +

    The following example shows the space being + explicitly added to the start to ensure the appended + value is not merged with the existing value: + 

    +     SRC_URI_append = " file://fix-makefile.patch"
+

    + You can also use the _append + operator with overrides, which results in the actions + only being performed for the specified target or + machine: + 

    +     SRC_URI_append_sh4 = " file://fix-makefile.patch"
+

    +

  • Prepending: _prepend - + Use the _prepend operator to + prepend values to existing variables. + This operator does not add any additional space. + Also, the operator is applied after all the + +=, and + =+ operators have been applied and + after all = assignments have + occurred. +

    The following example shows the space being + explicitly added to the end to ensure the prepended + value is not merged with the existing value: + 

    +     CFLAGS_prepend = "-I${S}/myincludes "
+

    + You can also use the _prepend + operator with overrides, which results in the actions + only being performed for the specified target or + machine: + 

    +     CFLAGS_prepend_sh4 = "-I${S}/myincludes "
+

    +

  • Overrides: - + You can use overrides to set a value conditionally, + typically based on how the recipe is being built. + For example, to set the + KBRANCH + variable's value to "standard/base" for any target + MACHINE, + except for qemuarm where it should be set to + "standard/arm-versatile-926ejs", you would do the + following: + 

    +     KBRANCH = "standard/base"
+     KBRANCH_qemuarm  = "standard/arm-versatile-926ejs"
+

    + Overrides are also used to separate alternate values + of a variable in other situations. + For example, when setting variables such as + FILES + and + RDEPENDS + that are specific to individual packages produced by + a recipe, you should always use an override that + specifies the name of the package. +

  • Indentation: + Use spaces for indentation rather than than tabs. + For shell functions, both currently work. + However, it is a policy decision of the Yocto Project + to use tabs in shell functions. + Realize that some layers have a policy to use spaces + for all indentation. +

  • Using Python for Complex Operations: ${@python_code} - + For more advanced processing, it is possible to use + Python code during variable assignments (e.g. + search and replacement on a variable).

    You indicate Python code using the + ${@python_code} + syntax for the variable assignment: + 

    +     SRC_URI = "ftp://ftp.info-zip.org/pub/infozip/src/zip${@d.getVar('PV',1).replace('.', '')}.tgz
+

    +

  • Shell Function Syntax: + Write shell functions as if you were writing a shell + script when you describe a list of actions to take. + You should ensure that your script works with a generic + sh and that it does not require + any bash or other shell-specific + functionality. + The same considerations apply to various system + utilities (e.g. sed, + grep, awk, + and so forth) that you might wish to use. + If in doubt, you should check with multiple + implementations - including those from BusyBox. +

+

2.8. Development Concepts¶

+ This section takes a more detailed look inside the development + process. + The following diagram represents development at a high level. + The remainder of this chapter expands on the fundamental input, output, + process, and + Metadata) blocks + that make up development in the Yocto Project environment. +

+

+

+ In general, development consists of several functional areas: +

  • User Configuration: + Metadata you can use to control the build process. +

  • Metadata Layers: + Various layers that provide software, machine, and + distro Metadata.

  • Source Files: + Upstream releases, local projects, and SCMs.

  • Build System: + Processes under the control of + BitBake. + This block expands on how BitBake fetches source, applies + patches, completes compilation, analyzes output for package + generation, creates and tests packages, generates images, and + generates cross-development tools.

  • Package Feeds: + Directories containing output packages (RPM, DEB or IPK), + which are subsequently used in the construction of an image or + SDK, produced by the build system. + These feeds can also be copied and shared using a web server or + other means to facilitate extending or updating existing + images on devices at runtime if runtime package management is + enabled.

  • Images: + Images produced by the development process. +

  • Application Development SDK: + Cross-development tools that are produced along with an image + or separately with BitBake.

+

2.8.1. User Configuration¶

+ User configuration helps define the build. + Through user configuration, you can tell BitBake the + target architecture for which you are building the image, + where to store downloaded source, and other build properties. +

+ The following figure shows an expanded representation of the + "User Configuration" box of the + general Yocto Project Development Environment figure: +

+

+

+ BitBake needs some basic configuration files in order to complete + a build. + These files are *.conf files. + The minimally necessary ones reside as example files in the + Source Directory. + For simplicity, this section refers to the Source Directory as + the "Poky Directory." +

+ When you clone the poky Git repository or you + download and unpack a Yocto Project release, you can set up the + Source Directory to be named anything you want. + For this discussion, the cloned repository uses the default + name poky. +

Note

+ The Poky repository is primarily an aggregation of existing + repositories. + It is not a canonical upstream source. +

+

+ The meta-poky layer inside Poky contains + a conf directory that has example + configuration files. + These example files are used as a basis for creating actual + configuration files when you source the build environment + script + (i.e. + oe-init-build-env). +

+ Sourcing the build environment script creates a + Build Directory + if one does not already exist. + BitBake uses the Build Directory for all its work during builds. + The Build Directory has a conf directory that + contains default versions of your local.conf + and bblayers.conf configuration files. + These default configuration files are created only if versions + do not already exist in the Build Directory at the time you + source the build environment setup script. +

+ Because the Poky repository is fundamentally an aggregation of + existing repositories, some users might be familiar with running + the oe-init-build-env script in the context + of separate OpenEmbedded-Core and BitBake repositories rather than a + single Poky repository. + This discussion assumes the script is executed from within a cloned + or unpacked version of Poky. +

+ Depending on where the script is sourced, different sub-scripts + are called to set up the Build Directory (Yocto or OpenEmbedded). + Specifically, the script + scripts/oe-setup-builddir inside the + poky directory sets up the Build Directory and seeds the directory + (if necessary) with configuration files appropriate for the + Yocto Project development environment. +

Note

+ The scripts/oe-setup-builddir script + uses the $TEMPLATECONF variable to + determine which sample configuration files to locate. +

+

+ The local.conf file provides many + basic variables that define a build environment. + Here is a list of a few. + To see the default configurations in a local.conf + file created by the build environment script, see the + local.conf.sample in the + meta-poky layer: +

+

Note

+ Configurations set in the conf/local.conf + file can also be set in the + conf/site.conf and + conf/auto.conf configuration files. +

+

+ The bblayers.conf file tells BitBake what + layers you want considered during the build. + By default, the layers listed in this file include layers + minimally needed by the build system. + However, you must manually add any custom layers you have created. + You can find more information on working with the + bblayers.conf file in the + "Enabling Your Layer" + section in the Yocto Project Development Tasks Manual. +

+ The files site.conf and + auto.conf are not created by the environment + initialization script. + If you want the site.conf file, you need to + create that yourself. + The auto.conf file is typically created by + an autobuilder: +

  • site.conf: + You can use the conf/site.conf + configuration file to configure multiple build directories. + For example, suppose you had several build environments and + they shared some common features. + You can set these default build properties here. + A good example is perhaps the packaging format to use + through the + PACKAGE_CLASSES + variable.

    One useful scenario for using the + conf/site.conf file is to extend your + BBPATH + variable to include the path to a + conf/site.conf. + Then, when BitBake looks for Metadata using + BBPATH, it finds the + conf/site.conf file and applies your + common configurations found in the file. + To override configurations in a particular build directory, + alter the similar configurations within that build + directory's conf/local.conf file. +

  • auto.conf: + The file is usually created and written to by + an autobuilder. + The settings put into the file are typically the same as + you would find in the conf/local.conf + or the conf/site.conf files. +

+

+ You can edit all configuration files to further define + any particular build environment. + This process is represented by the "User Configuration Edits" + box in the figure. +

+ When you launch your build with the + bitbake target + command, BitBake sorts out the configurations to ultimately + define your build environment. + It is important to understand that the OpenEmbedded build system + reads the configuration files in a specific order: + site.conf, auto.conf, + and local.conf. + And, the build system applies the normal assignment statement + rules. + Because the files are parsed in a specific order, variable + assignments for the same variable could be affected. + For example, if the auto.conf file and + the local.conf set + variable1 to different values, because + the build system parses local.conf after + auto.conf, + variable1 is assigned the value from + the local.conf file. +

2.8.2. Metadata, Machine Configuration, and Policy Configuration¶

+ The previous section described the user configurations that + define BitBake's global behavior. + This section takes a closer look at the layers the build system + uses to further control the build. + These layers provide Metadata for the software, machine, and + policy. +

+ In general, three types of layer input exist: +

  • Policy Configuration: + Distribution Layers provide top-level or general + policies for the image or SDK being built. + For example, this layer would dictate whether BitBake + produces RPM or IPK packages.

  • Machine Configuration: + Board Support Package (BSP) layers provide machine + configurations. + This type of information is specific to a particular + target architecture.

  • Metadata: + Software layers contain user-supplied recipe files, + patches, and append files. +

+

+ The following figure shows an expanded representation of the + Metadata, Machine Configuration, and Policy Configuration input + (layers) boxes of the + general Yocto Project Development Environment figure: +

+

+

+ In general, all layers have a similar structure. + They all contain a licensing file + (e.g. COPYING) if the layer is to be + distributed, a README file as good practice + and especially if the layer is to be distributed, a + configuration directory, and recipe directories. +

+ The Yocto Project has many layers that can be used. + You can see a web-interface listing of them on the + Source Repositories + page. + The layers are shown at the bottom categorized under + "Yocto Metadata Layers." + These layers are fundamentally a subset of the + OpenEmbedded Metadata Index, + which lists all layers provided by the OpenEmbedded community. +

Note

+ Layers exist in the Yocto Project Source Repositories that + cannot be found in the OpenEmbedded Metadata Index. + These layers are either deprecated or experimental in nature. +

+

+ BitBake uses the conf/bblayers.conf file, + which is part of the user configuration, to find what layers it + should be using as part of the build. +

+ For more information on layers, see the + "Understanding and Creating Layers" + section in the Yocto Project Development Tasks Manual. +

2.8.2.1. Distro Layer¶

+ The distribution layer provides policy configurations for your + distribution. + Best practices dictate that you isolate these types of + configurations into their own layer. + Settings you provide in + conf/distro/distro.conf override + similar + settings that BitBake finds in your + conf/local.conf file in the Build + Directory. +

+ The following list provides some explanation and references + for what you typically find in the distribution layer: +

  • classes: + Class files (.bbclass) hold + common functionality that can be shared among + recipes in the distribution. + When your recipes inherit a class, they take on the + settings and functions for that class. + You can read more about class files in the + "Classes" + section of the Yocto Reference Manual. +

  • conf: + This area holds configuration files for the + layer (conf/layer.conf), + the distribution + (conf/distro/distro.conf), + and any distribution-wide include files. +

  • recipes-*: + Recipes and append files that affect common + functionality across the distribution. + This area could include recipes and append files + to add distribution-specific configuration, + initialization scripts, custom image recipes, + and so forth.

+

2.8.2.2. BSP Layer¶

+ The BSP Layer provides machine configurations. + Everything in this layer is specific to the machine for which + you are building the image or the SDK. + A common structure or form is defined for BSP layers. + You can learn more about this structure in the + Yocto Project Board Support Package (BSP) Developer's Guide. +

Note

+ In order for a BSP layer to be considered compliant with the + Yocto Project, it must meet some structural requirements. +

+

+ The BSP Layer's configuration directory contains + configuration files for the machine + (conf/machine/machine.conf) and, + of course, the layer (conf/layer.conf). +

+ The remainder of the layer is dedicated to specific recipes + by function: recipes-bsp, + recipes-core, + recipes-graphics, and + recipes-kernel. + Metadata can exist for multiple formfactors, graphics + support systems, and so forth. +

Note

+ While the figure shows several recipes-* + directories, not all these directories appear in all + BSP layers. +

+

2.8.2.3. Software Layer¶

+ The software layer provides the Metadata for additional + software packages used during the build. + This layer does not include Metadata that is specific to the + distribution or the machine, which are found in their + respective layers. +

+ This layer contains any new recipes that your project needs + in the form of recipe files. +

2.8.3. Sources¶

+ In order for the OpenEmbedded build system to create an image or + any target, it must be able to access source files. + The + general Yocto Project Development Environment figure + represents source files using the "Upstream Project Releases", + "Local Projects", and "SCMs (optional)" boxes. + The figure represents mirrors, which also play a role in locating + source files, with the "Source Mirror(s)" box. +

+ The method by which source files are ultimately organized is + a function of the project. + For example, for released software, projects tend to use tarballs + or other archived files that can capture the state of a release + guaranteeing that it is statically represented. + On the other hand, for a project that is more dynamic or + experimental in nature, a project might keep source files in a + repository controlled by a Source Control Manager (SCM) such as + Git. + Pulling source from a repository allows you to control + the point in the repository (the revision) from which you want to + build software. + Finally, a combination of the two might exist, which would give the + consumer a choice when deciding where to get source files. +

+ BitBake uses the + SRC_URI + variable to point to source files regardless of their location. + Each recipe must have a SRC_URI variable + that points to the source. +

+ Another area that plays a significant role in where source files + come from is pointed to by the + DL_DIR + variable. + This area is a cache that can hold previously downloaded source. + You can also instruct the OpenEmbedded build system to create + tarballs from Git repositories, which is not the default behavior, + and store them in the DL_DIR by using the + BB_GENERATE_MIRROR_TARBALLS + variable. +

+ Judicious use of a DL_DIR directory can + save the build system a trip across the Internet when looking + for files. + A good method for using a download directory is to have + DL_DIR point to an area outside of your + Build Directory. + Doing so allows you to safely delete the Build Directory + if needed without fear of removing any downloaded source file. +

+ The remainder of this section provides a deeper look into the + source files and the mirrors. + Here is a more detailed look at the source file area of the + base figure: +

+

2.8.3.1. Upstream Project Releases¶

+ Upstream project releases exist anywhere in the form of an + archived file (e.g. tarball or zip file). + These files correspond to individual recipes. + For example, the figure uses specific releases each for + BusyBox, Qt, and Dbus. + An archive file can be for any released product that can be + built using a recipe. +

2.8.3.2. Local Projects¶

+ Local projects are custom bits of software the user provides. + These bits reside somewhere local to a project - perhaps + a directory into which the user checks in items (e.g. + a local directory containing a development source tree + used by the group). +

+ The canonical method through which to include a local project + is to use the + externalsrc + class to include that local project. + You use either the local.conf or a + recipe's append file to override or set the + recipe to point to the local directory on your disk to pull + in the whole source tree. +

+ For information on how to use the + externalsrc class, see the + "externalsrc.bbclass" + section. +

2.8.3.3. Source Control Managers (Optional)¶

+ Another place the build system can get source files from is + through an SCM such as Git or Subversion. + In this case, a repository is cloned or checked out. + The + do_fetch + task inside BitBake uses + the SRC_URI + variable and the argument's prefix to determine the correct + fetcher module. +

Note

+ For information on how to have the OpenEmbedded build system + generate tarballs for Git repositories and place them in the + DL_DIR + directory, see the + BB_GENERATE_MIRROR_TARBALLS + variable. +

+ When fetching a repository, BitBake uses the + SRCREV + variable to determine the specific revision from which to + build. +

2.8.3.4. Source Mirror(s)¶

+ Two kinds of mirrors exist: pre-mirrors and regular mirrors. + The + PREMIRRORS + and + MIRRORS + variables point to these, respectively. + BitBake checks pre-mirrors before looking upstream for any + source files. + Pre-mirrors are appropriate when you have a shared directory + that is not a directory defined by the + DL_DIR + variable. + A Pre-mirror typically points to a shared directory that is + local to your organization. +

+ Regular mirrors can be any site across the Internet that is + used as an alternative location for source code should the + primary site not be functioning for some reason or another. +

2.8.4. Package Feeds¶

+ When the OpenEmbedded build system generates an image or an SDK, + it gets the packages from a package feed area located in the + Build Directory. + The + general Yocto Project Development Environment figure + shows this package feeds area in the upper-right corner. +

+ This section looks a little closer into the package feeds area used + by the build system. + Here is a more detailed look at the area: +

+

+ Package feeds are an intermediary step in the build process. + The OpenEmbedded build system provides classes to generate + different package types, and you specify which classes to enable + through the + PACKAGE_CLASSES + variable. + Before placing the packages into package feeds, + the build process validates them with generated output quality + assurance checks through the + insane + class. +

+ The package feed area resides in the Build Directory. + The directory the build system uses to temporarily store packages + is determined by a combination of variables and the particular + package manager in use. + See the "Package Feeds" box in the illustration and note the + information to the right of that area. + In particular, the following defines where package files are + kept: +

  • DEPLOY_DIR: + Defined as tmp/deploy in the Build + Directory. +

  • DEPLOY_DIR_*: + Depending on the package manager used, the package type + sub-folder. + Given RPM, IPK, or DEB packaging and tarball creation, the + DEPLOY_DIR_RPM, + DEPLOY_DIR_IPK, + DEPLOY_DIR_DEB, + or + DEPLOY_DIR_TAR, + variables are used, respectively. +

  • PACKAGE_ARCH: + Defines architecture-specific sub-folders. + For example, packages could exist for the i586 or qemux86 + architectures. +

+

+ BitBake uses the do_package_write_* tasks to + generate packages and place them into the package holding area (e.g. + do_package_write_ipk for IPK packages). + See the + "do_package_write_deb", + "do_package_write_ipk", + "do_package_write_rpm", + and + "do_package_write_tar" + sections for additional information. + As an example, consider a scenario where an IPK packaging manager + is being used and package architecture support for both i586 + and qemux86 exist. + Packages for the i586 architecture are placed in + build/tmp/deploy/ipk/i586, while packages for + the qemux86 architecture are placed in + build/tmp/deploy/ipk/qemux86. +

2.8.5. BitBake¶

+ The OpenEmbedded build system uses + BitBake + to produce images. + You can see from the + general Yocto Project Development Environment figure, + the BitBake area consists of several functional areas. + This section takes a closer look at each of those areas. +

+ Separate documentation exists for the BitBake tool. + See the + BitBake User Manual + for reference material on BitBake. +

2.8.5.1. Source Fetching¶

+ The first stages of building a recipe are to fetch and unpack + the source code: +

+

+ The + do_fetch + and + do_unpack + tasks fetch the source files and unpack them into the work + directory. +

Note

+ For every local file (e.g. file://) + that is part of a recipe's + SRC_URI + statement, the OpenEmbedded build system takes a checksum + of the file for the recipe and inserts the checksum into + the signature for the do_fetch. + If any local file has been modified, the + do_fetch task and all tasks that + depend on it are re-executed. +

+ By default, everything is accomplished in the + Build Directory, + which has a defined structure. + For additional general information on the Build Directory, + see the + "build/" + section in the Yocto Project Reference Manual. +

+ Unpacked source files are pointed to by the + S + variable. + Each recipe has an area in the Build Directory where the + unpacked source code resides. + The name of that directory for any given recipe is defined from + several different variables. + You can see the variables that define these directories + by looking at the figure: +

  • TMPDIR - + The base directory where the OpenEmbedded build system + performs all its work during the build. +

  • PACKAGE_ARCH - + The architecture of the built package or packages. +

  • TARGET_OS - + The operating system of the target device. +

  • PN - + The name of the built package. +

  • PV - + The version of the recipe used to build the package. +

  • PR - + The revision of the recipe used to build the package. +

  • WORKDIR - + The location within TMPDIR where + a specific package is built. +

  • S - + Contains the unpacked source files for a given recipe. +

+

2.8.5.2. Patching¶

+ Once source code is fetched and unpacked, BitBake locates + patch files and applies them to the source files: +

+

+ The + do_patch + task processes recipes by + using the + SRC_URI + variable to locate applicable patch files, which by default + are *.patch or + *.diff files, or any file if + "apply=yes" is specified for the file in + SRC_URI. +

+ BitBake finds and applies multiple patches for a single recipe + in the order in which it finds the patches. + Patches are applied to the recipe's source files located in the + S + directory. +

+ For more information on how the source directories are + created, see the + "Source Fetching" + section. +

2.8.5.3. Configuration and Compilation¶

+ After source code is patched, BitBake executes tasks that + configure and compile the source code: +

+

+ This step in the build process consists of three tasks: +

  • + do_prepare_recipe_sysroot: + This task sets up the two sysroots in + ${WORKDIR} + (i.e. recipe-sysroot and + recipe-sysroot-native) so that + the sysroots contain the contents of the + do_populate_sysroot + tasks of the recipes on which the recipe + containing the tasks depends. + A sysroot exists for both the target and for the native + binaries, which run on the host system. +

  • do_configure: + This task configures the source by enabling and + disabling any build-time and configuration options for + the software being built. + Configurations can come from the recipe itself as well + as from an inherited class. + Additionally, the software itself might configure itself + depending on the target for which it is being built. +

    The configurations handled by the + do_configure + task are specific + to source code configuration for the source code + being built by the recipe.

    If you are using the + autotools + class, + you can add additional configuration options by using + the + EXTRA_OECONF + or + PACKAGECONFIG_CONFARGS + variables. + For information on how this variable works within + that class, see the + meta/classes/autotools.bbclass file. +

  • do_compile: + Once a configuration task has been satisfied, BitBake + compiles the source using the + do_compile + task. + Compilation occurs in the directory pointed to by the + B + variable. + Realize that the B directory is, by + default, the same as the + S + directory.

  • do_install: + Once compilation is done, BitBake executes the + do_install + task. + This task copies files from the B + directory and places them in a holding area pointed to + by the + D + variable.

+

2.8.5.4. Package Splitting¶

+ After source code is configured and compiled, the + OpenEmbedded build system analyzes + the results and splits the output into packages: +

+

+ The + do_package + and + do_packagedata + tasks combine to analyze + the files found in the + D directory + and split them into subsets based on available packages and + files. + The analyzing process involves the following as well as other + items: splitting out debugging symbols, + looking at shared library dependencies between packages, + and looking at package relationships. + The do_packagedata task creates package + metadata based on the analysis such that the + OpenEmbedded build system can generate the final packages. + Working, staged, and intermediate results of the analysis + and package splitting process use these areas: +

  • PKGD - + The destination directory for packages before they are + split. +

  • PKGDATA_DIR - + A shared, global-state directory that holds data + generated during the packaging process. +

  • PKGDESTWORK - + A temporary work area used by the + do_package task. +

  • PKGDEST - + The parent directory for packages after they have + been split. +

+ The FILES + variable defines the files that go into each package in + PACKAGES. + If you want details on how this is accomplished, you can + look at the + package + class. +

+ Depending on the type of packages being created (RPM, DEB, or + IPK), the do_package_write_* task + creates the actual packages and places them in the + Package Feed area, which is + ${TMPDIR}/deploy. + You can see the + "Package Feeds" + section for more detail on that part of the build process. +

Note

+ Support for creating feeds directly from the + deploy/* directories does not exist. + Creating such feeds usually requires some kind of feed + maintenance mechanism that would upload the new packages + into an official package feed (e.g. the + Ångström distribution). + This functionality is highly distribution-specific + and thus is not provided out of the box. +

+

2.8.5.5. Image Generation¶

+ Once packages are split and stored in the Package Feeds area, + the OpenEmbedded build system uses BitBake to generate the + root filesystem image: +

+

+ The image generation process consists of several stages and + depends on several tasks and variables. + The + do_rootfs + task creates the root filesystem (file and directory structure) + for an image. + This task uses several key variables to help create the list + of packages to actually install: +

  • IMAGE_INSTALL: + Lists out the base set of packages to install from + the Package Feeds area.

  • PACKAGE_EXCLUDE: + Specifies packages that should not be installed. +

  • IMAGE_FEATURES: + Specifies features to include in the image. + Most of these features map to additional packages for + installation.

  • PACKAGE_CLASSES: + Specifies the package backend to use and consequently + helps determine where to locate packages within the + Package Feeds area.

  • IMAGE_LINGUAS: + Determines the language(s) for which additional + language support packages are installed. +

  • PACKAGE_INSTALL: + The final list of packages passed to the package manager + for installation into the image. +

+

+ With + IMAGE_ROOTFS + pointing to the location of the filesystem under construction and + the PACKAGE_INSTALL variable providing the + final list of packages to install, the root file system is + created. +

+ Package installation is under control of the package manager + (e.g. dnf/rpm, opkg, or apt/dpkg) regardless of whether or + not package management is enabled for the target. + At the end of the process, if package management is not + enabled for the target, the package manager's data files + are deleted from the root filesystem. + As part of the final stage of package installation, postinstall + scripts that are part of the packages are run. + Any scripts that fail to run + on the build host are run on the target when the target system + is first booted. + If you are using a + read-only root filesystem, + all the post installation scripts must succeed during the + package installation phase since the root filesystem is + read-only. +

+ The final stages of the do_rootfs task + handle post processing. + Post processing includes creation of a manifest file and + optimizations. +

+ The manifest file (.manifest) resides + in the same directory as the root filesystem image. + This file lists out, line-by-line, the installed packages. + The manifest file is useful for the + testimage + class, for example, to determine whether or not to run + specific tests. + See the + IMAGE_MANIFEST + variable for additional information. +

+ Optimizing processes run across the image include + mklibs, prelink, + and any other post-processing commands as defined by the + ROOTFS_POSTPROCESS_COMMAND + variable. + The mklibs process optimizes the size + of the libraries, while the + prelink process optimizes the dynamic + linking of shared libraries to reduce start up time of + executables. +

+ After the root filesystem is built, processing begins on + the image through the + do_image + task. + The build system runs any pre-processing commands as defined + by the + IMAGE_PREPROCESS_COMMAND + variable. + This variable specifies a list of functions to call before + the OpenEmbedded build system creates the final image output + files. +

+ The OpenEmbedded build system dynamically creates + do_image_* tasks as needed, based + on the image types specified in the + IMAGE_FSTYPES + variable. + The process turns everything into an image file or a set of + image files and compresses the root filesystem image to reduce + the overall size of the image. + The formats used for the root filesystem depend on the + IMAGE_FSTYPES variable. +

+ As an example, a dynamically created task when creating a + particular image type would take the + following form: + 

+     do_image_type[depends]
+

+ So, if the type as specified by the + IMAGE_FSTYPES were + ext4, the dynamically generated task + would be as follows: + 

+     do_image_ext4[depends]
+

+

+ The final task involved in image creation is the + do_image_complete + task. + This task completes the image by applying any image + post processing as defined through the + IMAGE_POSTPROCESS_COMMAND + variable. + The variable specifies a list of functions to call once the + OpenEmbedded build system has created the final image output + files. +

Note

+ The entire image generation process is run under Pseudo. + Running under Pseudo ensures that the files in the root + filesystem have correct ownership. +

2.8.5.6. SDK Generation¶

+ The OpenEmbedded build system uses BitBake to generate the + Software Development Kit (SDK) installer script for both the + standard and extensible SDKs: + +

Note

+ For more information on the cross-development toolchain + generation, see the + "Cross-Development Toolchain Generation" + section. + For information on advantages gained when building a + cross-development toolchain using the + do_populate_sdk + task, see the + "Building an SDK Installer" + section in the Yocto Project Application Development and the + Extensible Software Development Kit (SDK) manual. +

+ Like image generation, the SDK script process consists of + several stages and depends on many variables. + The do_populate_sdk and + do_populate_sdk_ext tasks use these + key variables to help create the list of packages to actually + install. + For information on the variables listed in the figure, see the + "Application Development SDK" + section. +

+ The do_populate_sdk task helps create + the standard SDK and handles two parts: a target part and a + host part. + The target part is the part built for the target hardware and + includes libraries and headers. + The host part is the part of the SDK that runs on the + SDKMACHINE. +

+ The do_populate_sdk_ext task helps create + the extensible SDK and handles host and target parts + differently than its counter part does for the standard SDK. + For the extensible SDK, the task encapsulates the build system, + which includes everything needed (host and target) for the SDK. +

+ Regardless of the type of SDK being constructed, the + tasks perform some cleanup after which a cross-development + environment setup script and any needed configuration files + are created. + The final output is the Cross-development + toolchain installation script (.sh file), + which includes the environment setup script. +

2.8.5.7. Stamp Files and the Rerunning of Tasks¶

+ For each task that completes successfully, BitBake writes a + stamp file into the + STAMPS_DIR + directory. + The beginning of the stamp file's filename is determined by the + STAMP + variable, and the end of the name consists of the task's name + and current + input checksum. +

Note

+ This naming scheme assumes that + BB_SIGNATURE_HANDLER + is "OEBasicHash", which is almost always the case in + current OpenEmbedded. +

+ To determine if a task needs to be rerun, BitBake checks if a + stamp file with a matching input checksum exists for the task. + If such a stamp file exists, the task's output is assumed to + exist and still be valid. + If the file does not exist, the task is rerun. +

Note

The stamp mechanism is more general than the shared + state (sstate) cache mechanism described in the + "Setscene Tasks and Shared State" + section. + BitBake avoids rerunning any task that has a valid + stamp file, not just tasks that can be accelerated through + the sstate cache.

However, you should realize that stamp files only + serve as a marker that some work has been done and that + these files do not record task output. + The actual task output would usually be somewhere in + TMPDIR + (e.g. in some recipe's + WORKDIR.) + What the sstate cache mechanism adds is a way to cache task + output that can then be shared between build machines. +

+ Since STAMPS_DIR is usually a subdirectory + of TMPDIR, removing + TMPDIR will also remove + STAMPS_DIR, which means tasks will + properly be rerun to repopulate TMPDIR. +

+ If you want some task to always be considered "out of date", + you can mark it with the + nostamp + varflag. + If some other task depends on such a task, then that task will + also always be considered out of date, which might not be what + you want. +

+ For details on how to view information about a task's + signature, see the + "Viewing Task Variable Dependencies" + section in the Yocto Project Development Tasks Manual. +

2.8.5.8. Setscene Tasks and Shared State¶

+ The description of tasks so far assumes that BitBake needs to + build everything and there are no prebuilt objects available. + BitBake does support skipping tasks if prebuilt objects are + available. + These objects are usually made available in the form of a + shared state (sstate) cache. +

Note

+ For information on variables affecting sstate, see the + SSTATE_DIR + and + SSTATE_MIRRORS + variables. +

+

+ The idea of a setscene task (i.e + do_taskname_setscene) + is a version of the task where + instead of building something, BitBake can skip to the end + result and simply place a set of files into specific locations + as needed. + In some cases, it makes sense to have a setscene task variant + (e.g. generating package files in the + do_package_write_* task). + In other cases, it does not make sense, (e.g. a + do_patch + task or + do_unpack + task) since the work involved would be equal to or greater than + the underlying task. +

+ In the OpenEmbedded build system, the common tasks that have + setscene variants are + do_package, + do_package_write_*, + do_deploy, + do_packagedata, + and + do_populate_sysroot. + Notice that these are most of the tasks whose output is an + end result. +

+ The OpenEmbedded build system has knowledge of the relationship + between these tasks and other tasks that precede them. + For example, if BitBake runs + do_populate_sysroot_setscene for + something, there is little point in running any of the + do_fetch, do_unpack, + do_patch, + do_configure, + do_compile, and + do_install tasks. + However, if do_package needs to be run, + BitBake would need to run those other tasks. +

+ It becomes more complicated if everything can come from an + sstate cache because some objects are simply not required at + all. + For example, you do not need a compiler or native tools, such + as quilt, if there is nothing to compile or patch. + If the do_package_write_* packages are + available from sstate, BitBake does not need the + do_package task data. +

+ To handle all these complexities, BitBake runs in two phases. + The first is the "setscene" stage. + During this stage, BitBake first checks the sstate cache for + any targets it is planning to build. + BitBake does a fast check to see if the object exists rather + than a complete download. + If nothing exists, the second phase, which is the setscene + stage, completes and the main build proceeds. +

+ If objects are found in the sstate cache, the OpenEmbedded + build system works backwards from the end targets specified + by the user. + For example, if an image is being built, the OpenEmbedded build + system first looks for the packages needed for that image and + the tools needed to construct an image. + If those are available, the compiler is not needed. + Thus, the compiler is not even downloaded. + If something was found to be unavailable, or the download or + setscene task fails, the OpenEmbedded build system then tries + to install dependencies, such as the compiler, from the cache. +

+ The availability of objects in the sstate cache is handled by + the function specified by the + BB_HASHCHECK_FUNCTION + variable and returns a list of the objects that are available. + The function specified by the + BB_SETSCENE_DEPVALID + variable is the function that determines whether a given + dependency needs to be followed, and whether for any given + relationship the function needs to be passed. + The function returns a True or False value. +

2.8.6. Images¶

+ The images produced by the OpenEmbedded build system + are compressed forms of the + root filesystem that are ready to boot on a target device. + You can see from the + general Yocto Project Development Environment figure + that BitBake output, in part, consists of images. + This section is going to look more closely at this output: +

+

+ For a list of example images that the Yocto Project provides, + see the + "Images" + chapter in the Yocto Project Reference Manual. +

+ Images are written out to the + Build Directory + inside the + tmp/deploy/images/machine/ + folder as shown in the figure. + This folder contains any files expected to be loaded on the + target device. + The + DEPLOY_DIR + variable points to the deploy directory, + while the + DEPLOY_DIR_IMAGE + variable points to the appropriate directory containing images for + the current configuration. +

  • kernel-image: + A kernel binary file. + The + KERNEL_IMAGETYPE + variable setting determines the naming scheme for the + kernel image file. + Depending on that variable, the file could begin with + a variety of naming strings. + The deploy/images/machine + directory can contain multiple image files for the + machine.

  • root-filesystem-image: + Root filesystems for the target device (e.g. + *.ext3 or *.bz2 + files). + The + IMAGE_FSTYPES + variable setting determines the root filesystem image + type. + The deploy/images/machine + directory can contain multiple root filesystems for the + machine.

  • kernel-modules: + Tarballs that contain all the modules built for the kernel. + Kernel module tarballs exist for legacy purposes and + can be suppressed by setting the + MODULE_TARBALL_DEPLOY + variable to "0". + The deploy/images/machine + directory can contain multiple kernel module tarballs + for the machine.

  • bootloaders: + Bootloaders supporting the image, if applicable to the + target machine. + The deploy/images/machine + directory can contain multiple bootloaders for the + machine.

  • symlinks: + The deploy/images/machine + folder contains + a symbolic link that points to the most recently built file + for each machine. + These links might be useful for external scripts that + need to obtain the latest version of each file. +

+

2.8.7. Application Development SDK¶

+ In the + general Yocto Project Development Environment figure, + the output labeled "Application Development SDK" represents an + SDK. + The SDK generation process differs depending on whether you build + a standard SDK + (e.g. bitbake -c populate_sdk imagename) + or an extensible SDK + (e.g. bitbake -c populate_sdk_ext imagename). + This section is going to take a closer look at this output: +

+

+ The specific form of this output is a self-extracting + SDK installer (*.sh) that, when run, + installs the SDK, which consists of a cross-development + toolchain, a set of libraries and headers, and an SDK + environment setup script. + Running this installer essentially sets up your + cross-development environment. + You can think of the cross-toolchain as the "host" + part because it runs on the SDK machine. + You can think of the libraries and headers as the "target" + part because they are built for the target hardware. + The environment setup script is added so that you can initialize + the environment before using the tools. +

Notes

+ Once built, the SDK installers are written out to the + deploy/sdk folder inside the + Build Directory + as shown in the figure at the beginning of this section. + Depending on the type of SDK, several variables exist that help + configure these files. + The following list shows the variables associated with a standard + SDK: +

  • DEPLOY_DIR: + Points to the deploy + directory.

  • SDKMACHINE: + Specifies the architecture of the machine + on which the cross-development tools are run to + create packages for the target hardware. +

  • SDKIMAGE_FEATURES: + Lists the features to include in the "target" part + of the SDK. +

  • TOOLCHAIN_HOST_TASK: + Lists packages that make up the host + part of the SDK (i.e. the part that runs on + the SDKMACHINE). + When you use + bitbake -c populate_sdk imagename + to create the SDK, a set of default packages + apply. + This variable allows you to add more packages. +

  • TOOLCHAIN_TARGET_TASK: + Lists packages that make up the target part + of the SDK (i.e. the part built for the + target hardware). +

  • SDKPATH: + Defines the default SDK installation path offered by the + installation script. +

+ This next list, shows the variables associated with an extensible + SDK: +

  • DEPLOY_DIR: + Points to the deploy directory. +

  • SDK_EXT_TYPE: + Controls whether or not shared state artifacts are copied + into the extensible SDK. + By default, all required shared state artifacts are copied + into the SDK. +

  • SDK_INCLUDE_PKGDATA: + Specifies whether or not packagedata will be included in + the extensible SDK for all recipes in the "world" target. +

  • SDK_INCLUDE_TOOLCHAIN: + Specifies whether or not the toolchain will be included + when building the extensible SDK. +

  • SDK_LOCAL_CONF_WHITELIST: + A list of variables allowed through from the build system + configuration into the extensible SDK configuration. +

  • SDK_LOCAL_CONF_BLACKLIST: + A list of variables not allowed through from the build + system configuration into the extensible SDK configuration. +

  • SDK_INHERIT_BLACKLIST: + A list of classes to remove from the + INHERIT + value globally within the extensible SDK configuration. +

+

+ +

Chapter 3. Yocto Project Concepts¶

Table of Contents

3.1. Yocto Project Components
3.1.1. BitBake
3.1.2. Metadata (Recipes)
3.1.3. Metadata (Virtual Providers)
3.1.4. Classes
3.1.5. Configuration
3.2. Cross-Development Toolchain Generation
3.3. Shared State Cache
3.3.1. Overall Architecture
3.3.2. Checksums (Signatures)
3.3.3. Shared State
3.3.4. Tips and Tricks
3.4. Automatically Added Runtime Dependencies
3.5. Fakeroot and Pseudo
3.6. Wayland
3.6.1. Support
3.6.2. Enabling Wayland in an Image
3.6.3. Running Weston
3.7. Licenses
3.7.1. Tracking License Changes
3.7.2. Enabling Commercially Licensed Recipes
3.8. x32 psABI

+ This chapter describes concepts for various areas of the Yocto Project. + Currently, topics include Yocto Project components, cross-development + generation, shared state (sstate) cache, runtime dependencies, + Pseudo and Fakeroot, x32 psABI, Wayland support, and Licenses. +

3.1. Yocto Project Components¶

+ The + BitBake + task executor together with various types of configuration files + form the OpenEmbedded Core. + This section overviews these components by describing their use and + how they interact. +

+ BitBake handles the parsing and execution of the data files. + The data itself is of various types: +

  • + Recipes: + Provides details about particular pieces of software. +

  • + Class Data: + Abstracts common build information (e.g. how to build a + Linux kernel). +

  • + Configuration Data: + Defines machine-specific settings, policy decisions, and + so forth. + Configuration data acts as the glue to bind everything + together. +

+

+ BitBake knows how to combine multiple data sources together and + refers to each data source as a layer. + For information on layers, see the + "Understanding and Creating Layers" + section of the Yocto Project Development Tasks Manual. +

+ Following are some brief details on these core components. + For additional information on how these components interact during + a build, see the + "Development Concepts" + section. +

3.1.1. BitBake¶

+ BitBake is the tool at the heart of the OpenEmbedded build + system and is responsible for parsing the + Metadata, + generating a list of tasks from it, and then executing those + tasks. +

+ This section briefly introduces BitBake. + If you want more information on BitBake, see the + BitBake User Manual. +

+ To see a list of the options BitBake supports, use either of + the following commands: + 

+     $ bitbake -h
+     $ bitbake --help
+

+

+ The most common usage for BitBake is + bitbake packagename, + where packagename is the name of the + package you want to build (referred to as the "target" in this + manual). + The target often equates to the first part of a recipe's + filename (e.g. "foo" for a recipe named + foo_1.3.0-r0.bb). + So, to process the + matchbox-desktop_1.2.3.bb recipe file, you + might type the following: + 

+     $ bitbake matchbox-desktop
+

+ Several different versions of + matchbox-desktop might exist. + BitBake chooses the one selected by the distribution + configuration. + You can get more details about how BitBake chooses between + different target versions and providers in the + "Preferences" + section of the BitBake User Manual. +

+ BitBake also tries to execute any dependent tasks first. + So for example, before building + matchbox-desktop, BitBake would build a + cross compiler and glibc if they had not + already been built. +

+ A useful BitBake option to consider is the + -k or --continue + option. + This option instructs BitBake to try and continue processing + the job as long as possible even after encountering an error. + When an error occurs, the target that failed and those that + depend on it cannot be remade. + However, when you use this option other dependencies can + still be processed. +

3.1.2. Metadata (Recipes)¶

+ Files that have the .bb suffix are + "recipes" files. + In general, a recipe contains information about a single piece + of software. + This information includes the location from which to download + the unaltered source, any source patches to be applied to that + source (if needed), which special configuration options to + apply, how to compile the source files, and how to package the + compiled output. +

+ The term "package" is sometimes used to refer to recipes. + However, since the word "package" is used for the packaged + output from the OpenEmbedded build system (i.e. + .ipk or .deb files), + this document avoids using the term "package" when referring + to recipes. +

3.1.3. Metadata (Virtual Providers)¶

+ Prior to the build, if you know that several different recipes + provide the same functionality, you can use a virtual provider + (i.e. virtual/*) as a placeholder for the + actual provider. + The actual provider would be determined at build time. + In this case, you should add virtual/* + to + DEPENDS, + rather than listing the specified provider. + You would select the actual provider by setting the + PREFERRED_PROVIDER + variable (i.e. + PREFERRED_PROVIDER_virtual/*) + in the build's configuration file (e.g. + poky/build/conf/local.conf). +

Note

+ Any recipe that PROVIDES a virtual/* + item that is ultimately not selected through + PREFERRED_PROVIDER does not get built. + Preventing these recipes from building is usually the + desired behavior since this mechanism's purpose is to + select between mutually exclusive alternative providers. +

+

+ The following lists specific examples of virtual providers: +

  • + virtual/mesa: + Provides gbm.pc. +

  • + virtual/egl: + Provides egl.pc and possibly + wayland-egl.pc. +

  • + virtual/libgl: + Provides gl.pc (i.e. libGL). +

  • + virtual/libgles1: + Provides glesv1_cm.pc + (i.e. libGLESv1_CM). +

  • + virtual/libgles2: + Provides glesv2.pc + (i.e. libGLESv2). +

+

3.1.4. Classes¶

+ Class files (.bbclass) contain information + that is useful to share between + Metadata + files. + An example is the + autotools + class, which contains common settings for any application that + Autotools uses. + The + "Classes" + chapter in the Yocto Project Reference Manual provides + details about classes and how to use them. +

3.1.5. Configuration¶

+ The configuration files (.conf) define + various configuration variables that govern the OpenEmbedded + build process. + These files fall into several areas that define machine + configuration options, distribution configuration options, + compiler tuning options, general common configuration options, + and user configuration options in + local.conf, which is found in the + Build Directory. +

3.2. Cross-Development Toolchain Generation¶

+ The Yocto Project does most of the work for you when it comes to + creating + cross-development toolchains. + This section provides some technical background on how + cross-development toolchains are created and used. + For more information on toolchains, you can also see the + Yocto Project Application Development and the Extensible Software Development Kit (eSDK) + manual. +

+ In the Yocto Project development environment, cross-development + toolchains are used to build the image and applications that run + on the target hardware. + With just a few commands, the OpenEmbedded build system creates + these necessary toolchains for you. +

+ The following figure shows a high-level build environment regarding + toolchain construction and use. +

+

+

+ Most of the work occurs on the Build Host. + This is the machine used to build images and generally work within the + the Yocto Project environment. + When you run BitBake to create an image, the OpenEmbedded build system + uses the host gcc compiler to bootstrap a + cross-compiler named gcc-cross. + The gcc-cross compiler is what BitBake uses to + compile source files when creating the target image. + You can think of gcc-cross simply as an + automatically generated cross-compiler that is used internally within + BitBake only. +

Note

+ The extensible SDK does not use + gcc-cross-canadian since this SDK + ships a copy of the OpenEmbedded build system and the sysroot + within it contains gcc-cross. +

+

+ The chain of events that occurs when gcc-cross is + bootstrapped is as follows: + 

+     gcc -> binutils-cross -> gcc-cross-initial -> linux-libc-headers -> glibc-initial -> glibc -> gcc-cross -> gcc-runtime
+

+

  • + gcc: + The build host's GNU Compiler Collection (GCC). +

  • + binutils-cross: + The bare minimum binary utilities needed in order to run + the gcc-cross-initial phase of the + bootstrap operation. +

  • + gcc-cross-initial: + An early stage of the bootstrap process for creating + the cross-compiler. + This stage builds enough of the gcc-cross, + the C library, and other pieces needed to finish building the + final cross-compiler in later stages. + This tool is a "native" package (i.e. it is designed to run on + the build host). +

  • + linux-libc-headers: + Headers needed for the cross-compiler. +

  • + glibc-initial: + An initial version of the Embedded GLIBC needed to bootstrap + glibc. +

  • + gcc-cross: + The final stage of the bootstrap process for the + cross-compiler. + This stage results in the actual cross-compiler that + BitBake uses when it builds an image for a targeted + device. +

    Note

    + If you are replacing this cross compiler toolchain + with a custom version, you must replace + gcc-cross. +

    + This tool is also a "native" package (i.e. it is + designed to run on the build host). +

  • + gcc-runtime: + Runtime libraries resulting from the toolchain bootstrapping + process. + This tool produces a binary that consists of the + runtime libraries need for the targeted device. +

+

+ You can use the OpenEmbedded build system to build an installer for + the relocatable SDK used to develop applications. + When you run the installer, it installs the toolchain, which contains + the development tools (e.g., the + gcc-cross-canadian), + binutils-cross-canadian, and other + nativesdk-* tools, + which are tools native to the SDK (i.e. native to + SDK_ARCH), + you need to cross-compile and test your software. + The figure shows the commands you use to easily build out this + toolchain. + This cross-development toolchain is built to execute on the + SDKMACHINE, + which might or might not be the same + machine as the Build Host. +

Note

+ If your target architecture is supported by the Yocto Project, + you can take advantage of pre-built images that ship with the + Yocto Project and already contain cross-development toolchain + installers. +

+

+ Here is the bootstrap process for the relocatable toolchain: + 

+     gcc -> binutils-crosssdk -> gcc-crosssdk-initial -> linux-libc-headers ->
+        glibc-initial -> nativesdk-glibc -> gcc-crosssdk -> gcc-cross-canadian
+

+

  • + gcc: + The build host's GNU Compiler Collection (GCC). +

  • + binutils-crosssdk: + The bare minimum binary utilities needed in order to run + the gcc-crosssdk-initial phase of the + bootstrap operation. +

  • + gcc-crosssdk-initial: + An early stage of the bootstrap process for creating + the cross-compiler. + This stage builds enough of the + gcc-crosssdk and supporting pieces so that + the final stage of the bootstrap process can produce the + finished cross-compiler. + This tool is a "native" binary that runs on the build host. +

  • + linux-libc-headers: + Headers needed for the cross-compiler. +

  • + glibc-initial: + An initial version of the Embedded GLIBC needed to bootstrap + nativesdk-glibc. +

  • + nativesdk-glibc: + The Embedded GLIBC needed to bootstrap the + gcc-crosssdk. +

  • + gcc-crosssdk: + The final stage of the bootstrap process for the + relocatable cross-compiler. + The gcc-crosssdk is a transitory compiler + and never leaves the build host. + Its purpose is to help in the bootstrap process to create the + eventual relocatable gcc-cross-canadian + compiler, which is relocatable. + This tool is also a "native" package (i.e. it is + designed to run on the build host). +

  • + gcc-cross-canadian: + The final relocatable cross-compiler. + When run on the + SDKMACHINE, + this tool + produces executable code that runs on the target device. + Only one cross-canadian compiler is produced per architecture + since they can be targeted at different processor optimizations + using configurations passed to the compiler through the + compile commands. + This circumvents the need for multiple compilers and thus + reduces the size of the toolchains. +

+

Note

+ For information on advantages gained when building a + cross-development toolchain installer, see the + "Building an SDK Installer" + section in the Yocto Project Application Development and the + Extensible Software Development Kit (eSDK) manual. +

3.3. Shared State Cache¶

+ By design, the OpenEmbedded build system builds everything from + scratch unless BitBake can determine that parts do not need to be + rebuilt. + Fundamentally, building from scratch is attractive as it means all + parts are built fresh and there is no possibility of stale data + causing problems. + When developers hit problems, they typically default back to + building from scratch so they know the state of things from the + start. +

+ Building an image from scratch is both an advantage and a + disadvantage to the process. + As mentioned in the previous paragraph, building from scratch + ensures that everything is current and starts from a known state. + However, building from scratch also takes much longer as it + generally means rebuilding things that do not necessarily need + to be rebuilt. +

+ The Yocto Project implements shared state code that supports + incremental builds. + The implementation of the shared state code answers the following + questions that were fundamental roadblocks within the OpenEmbedded + incremental build support system: +

  • + What pieces of the system have changed and what pieces have + not changed? +

  • + How are changed pieces of software removed and replaced? +

  • + How are pre-built components that do not need to be rebuilt + from scratch used when they are available? +

+

+ For the first question, the build system detects changes in the + "inputs" to a given task by creating a checksum (or signature) of + the task's inputs. + If the checksum changes, the system assumes the inputs have changed + and the task needs to be rerun. + For the second question, the shared state (sstate) code tracks + which tasks add which output to the build process. + This means the output from a given task can be removed, upgraded + or otherwise manipulated. + The third question is partly addressed by the solution for the + second question assuming the build system can fetch the sstate + objects from remote locations and install them if they are deemed + to be valid. +

Note

+ The OpenEmbedded build system does not maintain + PR + information as part of the shared state packages. + Consequently, considerations exist that affect maintaining + shared state feeds. + For information on how the OpenEmbedded build system + works with packages and can track incrementing + PR information, see the + "Automatically Incrementing a Binary Package Revision Number" + section in the Yocto Project Development Tasks Manual. +

+

+ The rest of this section goes into detail about the overall + incremental build architecture, the checksums (signatures), shared + state, and some tips and tricks. +

3.3.1. Overall Architecture¶

+ When determining what parts of the system need to be built, + BitBake works on a per-task basis rather than a per-recipe + basis. + You might wonder why using a per-task basis is preferred over + a per-recipe basis. + To help explain, consider having the IPK packaging backend + enabled and then switching to DEB. + In this case, the + do_install + and + do_package + task outputs are still valid. + However, with a per-recipe approach, the build would not + include the .deb files. + Consequently, you would have to invalidate the whole build and + rerun it. + Rerunning everything is not the best solution. + Also, in this case, the core must be "taught" much about + specific tasks. + This methodology does not scale well and does not allow users + to easily add new tasks in layers or as external recipes + without touching the packaged-staging core. +

3.3.2. Checksums (Signatures)¶

+ The shared state code uses a checksum, which is a unique + signature of a task's inputs, to determine if a task needs to + be run again. + Because it is a change in a task's inputs that triggers a + rerun, the process needs to detect all the inputs to a given + task. + For shell tasks, this turns out to be fairly easy because + the build process generates a "run" shell script for each task + and it is possible to create a checksum that gives you a good + idea of when the task's data changes. +

+ To complicate the problem, there are things that should not be + included in the checksum. + First, there is the actual specific build path of a given + task - the + WORKDIR. + It does not matter if the work directory changes because it + should not affect the output for target packages. + Also, the build process has the objective of making native + or cross packages relocatable. +

Note

+ Both native and cross packages run on the build host. + However, cross packages generate output for the target + architecture. +

+ The checksum therefore needs to exclude + WORKDIR. + The simplistic approach for excluding the work directory is to + set WORKDIR to some fixed value and + create the checksum for the "run" script. +

+ Another problem results from the "run" scripts containing + functions that might or might not get called. + The incremental build solution contains code that figures out + dependencies between shell functions. + This code is used to prune the "run" scripts down to the + minimum set, thereby alleviating this problem and making the + "run" scripts much more readable as a bonus. +

+ So far we have solutions for shell scripts. + What about Python tasks? + The same approach applies even though these tasks are more + difficult. + The process needs to figure out what variables a Python + function accesses and what functions it calls. + Again, the incremental build solution contains code that first + figures out the variable and function dependencies, and then + creates a checksum for the data used as the input to the task. +

+ Like the WORKDIR case, situations exist + where dependencies should be ignored. + For these cases, you can instruct the build process to + ignore a dependency by using a line like the following: + 

+     PACKAGE_ARCHS[vardepsexclude] = "MACHINE"
+

+ This example ensures that the + PACKAGE_ARCHS + variable does not depend on the value of + MACHINE, + even if it does reference it. +

+ Equally, there are cases where we need to add dependencies + BitBake is not able to find. + You can accomplish this by using a line like the following: + 

+      PACKAGE_ARCHS[vardeps] = "MACHINE"
+

+ This example explicitly adds the MACHINE + variable as a dependency for + PACKAGE_ARCHS. +

+ Consider a case with in-line Python, for example, where + BitBake is not able to figure out dependencies. + When running in debug mode (i.e. using + -DDD), BitBake produces output when it + discovers something for which it cannot figure out dependencies. + The Yocto Project team has currently not managed to cover + those dependencies in detail and is aware of the need to fix + this situation. +

+ Thus far, this section has limited discussion to the direct + inputs into a task. + Information based on direct inputs is referred to as the + "basehash" in the code. + However, there is still the question of a task's indirect + inputs - the things that were already built and present in the + Build Directory. + The checksum (or signature) for a particular task needs to add + the hashes of all the tasks on which the particular task + depends. + Choosing which dependencies to add is a policy decision. + However, the effect is to generate a master checksum that + combines the basehash and the hashes of the task's + dependencies. +

+ At the code level, there are a variety of ways both the + basehash and the dependent task hashes can be influenced. + Within the BitBake configuration file, we can give BitBake + some extra information to help it construct the basehash. + The following statement effectively results in a list of + global variable dependency excludes - variables never + included in any checksum: + 

+     BB_HASHBASE_WHITELIST ?= "TMPDIR FILE PATH PWD BB_TASKHASH BBPATH DL_DIR \
+         SSTATE_DIR THISDIR FILESEXTRAPATHS FILE_DIRNAME HOME LOGNAME SHELL TERM \
+         USER FILESPATH STAGING_DIR_HOST STAGING_DIR_TARGET COREBASE PRSERV_HOST \
+         PRSERV_DUMPDIR PRSERV_DUMPFILE PRSERV_LOCKDOWN PARALLEL_MAKE \
+         CCACHE_DIR EXTERNAL_TOOLCHAIN CCACHE CCACHE_DISABLE LICENSE_PATH SDKPKGSUFFIX"
+

+ The previous example excludes + WORKDIR + since that variable is actually constructed as a path within + TMPDIR, + which is on the whitelist. +

+ The rules for deciding which hashes of dependent tasks to + include through dependency chains are more complex and are + generally accomplished with a Python function. + The code in meta/lib/oe/sstatesig.py shows + two examples of this and also illustrates how you can insert + your own policy into the system if so desired. + This file defines the two basic signature generators + OE-Core + uses: "OEBasic" and "OEBasicHash". + By default, there is a dummy "noop" signature handler enabled + in BitBake. + This means that behavior is unchanged from previous versions. + OE-Core uses the "OEBasicHash" signature handler by default + through this setting in the bitbake.conf + file: + 

+     BB_SIGNATURE_HANDLER ?= "OEBasicHash"
+

+ The "OEBasicHash" BB_SIGNATURE_HANDLER + is the same as the "OEBasic" version but adds the task hash to + the stamp files. + This results in any + Metadata + change that changes the task hash, automatically + causing the task to be run again. + This removes the need to bump + PR + values, and changes to Metadata automatically ripple across + the build. +

+ It is also worth noting that the end result of these + signature generators is to make some dependency and hash + information available to the build. + This information includes: +

  • + BB_BASEHASH_task-taskname: + The base hashes for each task in the recipe. +

  • + BB_BASEHASH_filename:taskname: + The base hashes for each dependent task. +

  • + BBHASHDEPS_filename:taskname: + The task dependencies for each task. +

  • + BB_TASKHASH: + The hash of the currently running task. +

+

3.3.3. Shared State¶

+ Checksums and dependencies, as discussed in the previous + section, solve half the problem of supporting a shared state. + The other part of the problem is being able to use checksum + information during the build and being able to reuse or rebuild + specific components. +

+ The + sstate + class is a relatively generic implementation of how to + "capture" a snapshot of a given task. + The idea is that the build process does not care about the + source of a task's output. + Output could be freshly built or it could be downloaded and + unpacked from somewhere - the build process does not need to + worry about its origin. +

+ There are two types of output, one is just about creating a + directory in + WORKDIR. + A good example is the output of either + do_install + or + do_package. + The other type of output occurs when a set of data is merged + into a shared directory tree such as the sysroot. +

+ The Yocto Project team has tried to keep the details of the + implementation hidden in sstate class. + From a user's perspective, adding shared state wrapping to a task + is as simple as this + do_deploy + example taken from the + deploy + class: + 

+     DEPLOYDIR = "${WORKDIR}/deploy-${PN}"
+     SSTATETASKS += "do_deploy"
+     do_deploy[sstate-inputdirs] = "${DEPLOYDIR}"
+     do_deploy[sstate-outputdirs] = "${DEPLOY_DIR_IMAGE}"
+
+     python do_deploy_setscene () {
+         sstate_setscene(d)
+     }
+     addtask do_deploy_setscene
+     do_deploy[dirs] = "${DEPLOYDIR} ${B}"
+

+ The following list explains the previous example: +

  • + Adding "do_deploy" to SSTATETASKS + adds some required sstate-related processing, which is + implemented in the + sstate + class, to before and after the + do_deploy + task. +

  • + The + do_deploy[sstate-inputdirs] = "${DEPLOYDIR}" + declares that do_deploy places its + output in ${DEPLOYDIR} when run + normally (i.e. when not using the sstate cache). + This output becomes the input to the shared state cache. +

  • + The + do_deploy[sstate-outputdirs] = "${DEPLOY_DIR_IMAGE}" + line causes the contents of the shared state cache to be + copied to ${DEPLOY_DIR_IMAGE}. +

    Note

    + If do_deploy is not already in + the shared state cache or if its input checksum + (signature) has changed from when the output was + cached, the task will be run to populate the shared + state cache, after which the contents of the shared + state cache is copied to + ${DEPLOY_DIR_IMAGE}. + If do_deploy is in the shared + state cache and its signature indicates that the + cached output is still valid (i.e. if no + relevant task inputs have changed), then the + contents of the shared state cache will be copied + directly to + ${DEPLOY_DIR_IMAGE} by the + do_deploy_setscene task + instead, skipping the + do_deploy task. +

    +

  • + The following task definition is glue logic needed to + make the previous settings effective: + 

    +     python do_deploy_setscene () {
+         sstate_setscene(d)
+     }
+     addtask do_deploy_setscene
+

    + sstate_setscene() takes the flags + above as input and accelerates the + do_deploy task through the + shared state cache if possible. + If the task was accelerated, + sstate_setscene() returns True. + Otherwise, it returns False, and the normal + do_deploy task runs. + For more information, see the + "setscene" + section in the BitBake User Manual. +

  • + The do_deploy[dirs] = "${DEPLOYDIR} ${B}" + line creates ${DEPLOYDIR} and + ${B} before the + do_deploy task runs, and also sets + the current working directory of + do_deploy to + ${B}. + For more information, see the + "Variable Flags" + section in the BitBake User Manual. +

    Note

    + In cases where + sstate-inputdirs and + sstate-outputdirs would be the + same, you can use + sstate-plaindirs. + For example, to preserve the + ${PKGD} and + ${PKGDEST} output from the + do_package + task, use the following: + 
    +     do_package[sstate-plaindirs] = "${PKGD} ${PKGDEST}"
+

    +

  • + sstate-inputdirs and + sstate-outputdirs can also be used + with multiple directories. + For example, the following declares + PKGDESTWORK and + SHLIBWORK as shared state + input directories, which populates the shared state + cache, and PKGDATA_DIR and + SHLIBSDIR as the corresponding + shared state output directories: + 

    +     do_package[sstate-inputdirs] = "${PKGDESTWORK} ${SHLIBSWORKDIR}"
+     do_package[sstate-outputdirs] = "${PKGDATA_DIR} ${SHLIBSDIR}"
+

    +

  • + These methods also include the ability to take a + lockfile when manipulating shared state directory + structures, for cases where file additions or removals + are sensitive: + 

    +     do_package[sstate-lockfile] = "${PACKAGELOCK}"
+

    +

+

+ Behind the scenes, the shared state code works by looking in + SSTATE_DIR + and + SSTATE_MIRRORS + for shared state files. + Here is an example: + 

+     SSTATE_MIRRORS ?= "\
+     file://.* http://someserver.tld/share/sstate/PATH;downloadfilename=PATH \n \
+     file://.* file:///some/local/dir/sstate/PATH"
+

+

Note

+ The shared state directory + (SSTATE_DIR) is organized into + two-character subdirectories, where the subdirectory + names are based on the first two characters of the hash. + If the shared state directory structure for a mirror has the + same structure as SSTATE_DIR, you must + specify "PATH" as part of the URI to enable the build system + to map to the appropriate subdirectory. +

+

+ The shared state package validity can be detected just by + looking at the filename since the filename contains the task + checksum (or signature) as described earlier in this section. + If a valid shared state package is found, the build process + downloads it and uses it to accelerate the task. +

+ The build processes use the *_setscene + tasks for the task acceleration phase. + BitBake goes through this phase before the main execution + code and tries to accelerate any tasks for which it can find + shared state packages. + If a shared state package for a task is available, the + shared state package is used. + This means the task and any tasks on which it is dependent + are not executed. +

+ As a real world example, the aim is when building an IPK-based + image, only the + do_package_write_ipk + tasks would have their shared state packages fetched and + extracted. + Since the sysroot is not used, it would never get extracted. + This is another reason why a task-based approach is preferred + over a recipe-based approach, which would have to install the + output from every task. +

3.3.4. Tips and Tricks¶

+ The code in the build system that supports incremental builds + is not simple code. + This section presents some tips and tricks that help you work + around issues related to shared state code. +

3.3.4.1. Debugging¶

+ Seeing what metadata went into creating the input signature + of a shared state (sstate) task can be a useful debugging + aid. + This information is available in signature information + (siginfo) files in + SSTATE_DIR. + For information on how to view and interpret information in + siginfo files, see the + "Viewing Task Variable Dependencies" + section in the Yocto Project Development Tasks Manual. +

3.3.4.2. Invalidating Shared State¶

+ The OpenEmbedded build system uses checksums and shared + state cache to avoid unnecessarily rebuilding tasks. + Collectively, this scheme is known as "shared state code." +

+ As with all schemes, this one has some drawbacks. + It is possible that you could make implicit changes to your + code that the checksum calculations do not take into + account. + These implicit changes affect a task's output but do not + trigger the shared state code into rebuilding a recipe. + Consider an example during which a tool changes its output. + Assume that the output of rpmdeps + changes. + The result of the change should be that all the + package and + package_write_rpm shared state cache + items become invalid. + However, because the change to the output is + external to the code and therefore implicit, + the associated shared state cache items do not become + invalidated. + In this case, the build process uses the cached items + rather than running the task again. + Obviously, these types of implicit changes can cause + problems. +

+ To avoid these problems during the build, you need to + understand the effects of any changes you make. + Realize that changes you make directly to a function + are automatically factored into the checksum calculation. + Thus, these explicit changes invalidate the associated + area of shared state cache. + However, you need to be aware of any implicit changes that + are not obvious changes to the code and could affect + the output of a given task. +

+ When you identify an implicit change, you can easily + take steps to invalidate the cache and force the tasks + to run. + The steps you can take are as simple as changing a + function's comments in the source code. + For example, to invalidate package shared state files, + change the comment statements of + do_package + or the comments of one of the functions it calls. + Even though the change is purely cosmetic, it causes the + checksum to be recalculated and forces the OpenEmbedded + build system to run the task again. +

Note

+ For an example of a commit that makes a cosmetic + change to invalidate shared state, see this + commit. +

+

3.4. Automatically Added Runtime Dependencies¶

+ The OpenEmbedded build system automatically adds common types of + runtime dependencies between packages, which means that you do not + need to explicitly declare the packages using + RDEPENDS. + Three automatic mechanisms exist (shlibdeps, + pcdeps, and depchains) + that handle shared libraries, package configuration (pkg-config) + modules, and -dev and + -dbg packages, respectively. + For other types of runtime dependencies, you must manually declare + the dependencies. +

  • + shlibdeps: + During the + do_package + task of each recipe, all shared libraries installed by the + recipe are located. + For each shared library, the package that contains the + shared library is registered as providing the shared + library. + More specifically, the package is registered as providing + the + soname + of the library. + The resulting shared-library-to-package mapping + is saved globally in + PKGDATA_DIR + by the + do_packagedata + task.

    Simultaneously, all executables and shared libraries + installed by the recipe are inspected to see what shared + libraries they link against. + For each shared library dependency that is found, + PKGDATA_DIR is queried to + see if some package (likely from a different recipe) + contains the shared library. + If such a package is found, a runtime dependency is added + from the package that depends on the shared library to the + package that contains the library.

    The automatically added runtime dependency also + includes a version restriction. + This version restriction specifies that at least the + current version of the package that provides the shared + library must be used, as if + "package (>= version)" + had been added to + RDEPENDS. + This forces an upgrade of the package containing the shared + library when installing the package that depends on the + library, if needed.

    If you want to avoid a package being registered as + providing a particular shared library (e.g. because the library + is for internal use only), then add the library to + PRIVATE_LIBS + inside the package's recipe. +

  • + pcdeps: + During the + do_package + task of each recipe, all pkg-config modules + (*.pc files) installed by the recipe + are located. + For each module, the package that contains the module is + registered as providing the module. + The resulting module-to-package mapping is saved globally in + PKGDATA_DIR + by the + do_packagedata + task.

    Simultaneously, all pkg-config modules installed by + the recipe are inspected to see what other pkg-config + modules they depend on. + A module is seen as depending on another module if it + contains a "Requires:" line that specifies the other module. + For each module dependency, + PKGDATA_DIR is queried to see if some + package contains the module. + If such a package is found, a runtime dependency is added + from the package that depends on the module to the package + that contains the module. +

    Note

    + The pcdeps mechanism most often + infers dependencies between -dev + packages. +

    +

  • + depchains: + If a package foo depends on a package + bar, then foo-dev + and foo-dbg are also made to depend on + bar-dev and + bar-dbg, respectively. + Taking the -dev packages as an + example, the bar-dev package might + provide headers and shared library symlinks needed by + foo-dev, which shows the need + for a dependency between the packages.

    The dependencies added by + depchains are in the form of + RRECOMMENDS. +

    Note

    + By default, foo-dev also has an + RDEPENDS-style dependency on + foo, because the default value of + RDEPENDS_${PN}-dev (set in + bitbake.conf) includes + "${PN}". +

    To ensure that the dependency chain is never broken, + -dev and -dbg + packages are always generated by default, even if the + packages turn out to be empty. + See the + ALLOW_EMPTY + variable for more information. +

+

+ The do_package task depends on the + do_packagedata + task of each recipe in + DEPENDS + through use of a + [deptask] + declaration, which guarantees that the required + shared-library/module-to-package mapping information will be available + when needed as long as DEPENDS has been + correctly set. +

3.5. Fakeroot and Pseudo¶

+ Some tasks are easier to implement when allowed to perform certain + operations that are normally reserved for the root user (e.g. + do_install, + do_package_write*, + do_rootfs, + and + do_image*). + For example, the do_install task benefits + from being able to set the UID and GID of installed files to + arbitrary values. +

+ One approach to allowing tasks to perform root-only operations + would be to require BitBake to run as root. + However, this method is cumbersome and has security issues. + The approach that is actually used is to run tasks that benefit + from root privileges in a "fake" root environment. + Within this environment, the task and its child processes believe + that they are running as the root user, and see an internally + consistent view of the filesystem. + As long as generating the final output (e.g. a package or an image) + does not require root privileges, the fact that some earlier + steps ran in a fake root environment does not cause problems. +

+ The capability to run tasks in a fake root environment is known as + "fakeroot", + which is derived from the BitBake keyword/variable + flag that requests a fake root environment for a task. +

+ In the OpenEmbedded build system, the program that implements + fakeroot is known as Pseudo. + Pseudo overrides system calls by using the environment variable + LD_PRELOAD, which results in the illusion + of running as root. + To keep track of "fake" file ownership and permissions resulting + from operations that require root permissions, Pseudo uses + an SQLite 3 database. + This database is stored in + ${WORKDIR}/pseudo/files.db + for individual recipes. + Storing the database in a file as opposed to in memory + gives persistence between tasks and builds, which is not + accomplished using fakeroot. +

Caution

+ If you add your own task that manipulates the same files or + directories as a fakeroot task, then that task also needs to + run under fakeroot. + Otherwise, the task cannot run root-only operations, and + cannot see the fake file ownership and permissions set by the + other task. + You need to also add a dependency on + virtual/fakeroot-native:do_populate_sysroot, + giving the following: + 
+       fakeroot do_mytask () {
+           ...
+       }
+       do_mytask[depends] += "virtual/fakeroot-native:do_populate_sysroot"
+

+ For more information, see the + FAKEROOT* + variables in the BitBake User Manual. + You can also reference the + "Pseudo" + and + "Why Not Fakeroot?" + articles for background information on Pseudo. +

3.6. Wayland¶

+ Wayland + is a computer display server protocol that + provides a method for compositing window managers to communicate + directly with applications and video hardware and expects them to + communicate with input hardware using other libraries. + Using Wayland with supporting targets can result in better control + over graphics frame rendering than an application might otherwise + achieve. +

+ The Yocto Project provides the Wayland protocol libraries and the + reference + Weston + compositor as part of its release. + This section describes what you need to do to implement Wayland and + use the compositor when building an image for a supporting target. +

3.6.1. Support¶

+ The Wayland protocol libraries and the reference Weston + compositor ship as integrated packages in the + meta layer of the + Source Directory. + Specifically, you can find the recipes that build both Wayland + and Weston at + meta/recipes-graphics/wayland. +

+ You can build both the Wayland and Weston packages for use only + with targets that accept the + Mesa 3D and Direct Rendering Infrastructure, + which is also known as Mesa DRI. + This implies that you cannot build and use the packages if your + target uses, for example, the + Intel® Embedded Media + and Graphics Driver + (Intel® EMGD) that + overrides Mesa DRI. +

Note

+ Due to lack of EGL support, Weston 1.0.3 will not run + directly on the emulated QEMU hardware. + However, this version of Weston will run under X emulation + without issues. +

+

3.6.2. Enabling Wayland in an Image¶

+ To enable Wayland, you need to enable it to be built and enable + it to be included in the image. +

3.6.2.1. Building¶

+ To cause Mesa to build the wayland-egl + platform and Weston to build Wayland with Kernel Mode + Setting + (KMS) + support, include the "wayland" flag in the + DISTRO_FEATURES + statement in your local.conf file: + 

+     DISTRO_FEATURES_append = " wayland"
+

+

Note

+ If X11 has been enabled elsewhere, Weston will build + Wayland with X11 support +

+

3.6.2.2. Installing¶

+ To install the Wayland feature into an image, you must + include the following + CORE_IMAGE_EXTRA_INSTALL + statement in your local.conf file: + 

+     CORE_IMAGE_EXTRA_INSTALL += "wayland weston"
+

+

3.6.3. Running Weston¶

+ To run Weston inside X11, enabling it as described earlier and + building a Sato image is sufficient. + If you are running your image under Sato, a Weston Launcher + appears in the "Utility" category. +

+ Alternatively, you can run Weston through the command-line + interpretor (CLI), which is better suited for development work. + To run Weston under the CLI, you need to do the following after + your image is built: +

  1. + Run these commands to export + XDG_RUNTIME_DIR: + 

    +     mkdir -p /tmp/$USER-weston
+     chmod 0700 /tmp/$USER-weston
+     export XDG_RUNTIME_DIR=/tmp/$USER-weston
+

    +

  2. + Launch Weston in the shell: + 

    +     weston
+

+

3.7. Licenses¶

+ This section describes the mechanism by which the OpenEmbedded + build system tracks changes to licensing text. + The section also describes how to enable commercially licensed + recipes, which by default are disabled. +

+ For information that can help you maintain compliance with + various open source licensing during the lifecycle of the product, + see the + "Maintaining Open Source License Compliance During Your Project's Lifecycle" + section in the Yocto Project Development Tasks Manual. +

3.7.1. Tracking License Changes¶

+ The license of an upstream project might change in the future. + In order to prevent these changes going unnoticed, the + LIC_FILES_CHKSUM + variable tracks changes to the license text. The checksums are + validated at the end of the configure step, and if the + checksums do not match, the build will fail. +

3.7.1.1. Specifying the LIC_FILES_CHKSUM Variable¶

+ The LIC_FILES_CHKSUM + variable contains checksums of the license text in the + source code for the recipe. + Following is an example of how to specify + LIC_FILES_CHKSUM: + 

+     LIC_FILES_CHKSUM = "file://COPYING;md5=xxxx \
+                         file://licfile1.txt;beginline=5;endline=29;md5=yyyy \
+                         file://licfile2.txt;endline=50;md5=zzzz \
+                         ..."
+

+

Notes

  • + When using "beginline" and "endline", realize + that line numbering begins with one and not + zero. + Also, the included lines are inclusive (i.e. + lines five through and including 29 in the + previous example for + licfile1.txt). +

  • + When a license check fails, the selected license + text is included as part of the QA message. + Using this output, you can determine the exact + start and finish for the needed license text. +

+

+ The build system uses the + S + variable as the default directory when searching files + listed in LIC_FILES_CHKSUM. + The previous example employs the default directory. +

+ Consider this next example: + 

+     LIC_FILES_CHKSUM = "file://src/ls.c;beginline=5;endline=16;\
+                                         md5=bb14ed3c4cda583abc85401304b5cd4e"
+     LIC_FILES_CHKSUM = "file://${WORKDIR}/license.html;md5=5c94767cedb5d6987c902ac850ded2c6"
+

+

+ The first line locates a file in + ${S}/src/ls.c and isolates lines five + through 16 as license text. + The second line refers to a file in + WORKDIR. +

+ Note that LIC_FILES_CHKSUM variable is + mandatory for all recipes, unless the + LICENSE variable is set to "CLOSED". +

3.7.1.2. Explanation of Syntax¶

+ As mentioned in the previous section, the + LIC_FILES_CHKSUM variable lists all + the important files that contain the license text for the + source code. + It is possible to specify a checksum for an entire file, + or a specific section of a file (specified by beginning and + ending line numbers with the "beginline" and "endline" + parameters, respectively). + The latter is useful for source files with a license + notice header, README documents, and so forth. + If you do not use the "beginline" parameter, then it is + assumed that the text begins on the first line of the file. + Similarly, if you do not use the "endline" parameter, + it is assumed that the license text ends with the last + line of the file. +

+ The "md5" parameter stores the md5 checksum of the license + text. + If the license text changes in any way as compared to + this parameter then a mismatch occurs. + This mismatch triggers a build failure and notifies + the developer. + Notification allows the developer to review and address + the license text changes. + Also note that if a mismatch occurs during the build, + the correct md5 checksum is placed in the build log and + can be easily copied to the recipe. +

+ There is no limit to how many files you can specify using + the LIC_FILES_CHKSUM variable. + Generally, however, every project requires a few + specifications for license tracking. + Many projects have a "COPYING" file that stores the + license information for all the source code files. + This practice allows you to just track the "COPYING" + file as long as it is kept up to date. +

Tips

  • + If you specify an empty or invalid "md5" + parameter, BitBake returns an md5 mis-match + error and displays the correct "md5" parameter + value during the build. + The correct parameter is also captured in + the build log. +

  • + If the whole file contains only license text, + you do not need to use the "beginline" and + "endline" parameters. +

+

3.7.2. Enabling Commercially Licensed Recipes¶

+ By default, the OpenEmbedded build system disables + components that have commercial or other special licensing + requirements. + Such requirements are defined on a + recipe-by-recipe basis through the + LICENSE_FLAGS + variable definition in the affected recipe. + For instance, the + poky/meta/recipes-multimedia/gstreamer/gst-plugins-ugly + recipe contains the following statement: + 

+     LICENSE_FLAGS = "commercial"
+

+ Here is a slightly more complicated example that contains both + an explicit recipe name and version (after variable expansion): + 

+     LICENSE_FLAGS = "license_${PN}_${PV}"
+

+ In order for a component restricted by a + LICENSE_FLAGS definition to be enabled and + included in an image, it needs to have a matching entry in the + global + LICENSE_FLAGS_WHITELIST + variable, which is a variable typically defined in your + local.conf file. + For example, to enable the + poky/meta/recipes-multimedia/gstreamer/gst-plugins-ugly + package, you could add either the string + "commercial_gst-plugins-ugly" or the more general string + "commercial" to LICENSE_FLAGS_WHITELIST. + See the + "License Flag Matching" + section for a full + explanation of how LICENSE_FLAGS matching + works. + Here is the example: + 

+     LICENSE_FLAGS_WHITELIST = "commercial_gst-plugins-ugly"
+

+ Likewise, to additionally enable the package built from the + recipe containing + LICENSE_FLAGS = "license_${PN}_${PV}", + and assuming that the actual recipe name was + emgd_1.10.bb, the following string would + enable that package as well as the original + gst-plugins-ugly package: + 

+     LICENSE_FLAGS_WHITELIST = "commercial_gst-plugins-ugly license_emgd_1.10"
+

+ As a convenience, you do not need to specify the complete + license string in the whitelist for every package. + You can use an abbreviated form, which consists + of just the first portion or portions of the license + string before the initial underscore character or characters. + A partial string will match any license that contains the + given string as the first portion of its license. + For example, the following whitelist string will also match + both of the packages previously mentioned as well as any other + packages that have licenses starting with "commercial" or + "license". + 

+     LICENSE_FLAGS_WHITELIST = "commercial license"
+

+

3.7.2.1. License Flag Matching¶

+ License flag matching allows you to control what recipes + the OpenEmbedded build system includes in the build. + Fundamentally, the build system attempts to match + LICENSE_FLAGS + strings found in recipes against + LICENSE_FLAGS_WHITELIST + strings found in the whitelist. + A match causes the build system to include a recipe in the + build, while failure to find a match causes the build + system to exclude a recipe. +

+ In general, license flag matching is simple. + However, understanding some concepts will help you + correctly and effectively use matching. +

+ Before a flag + defined by a particular recipe is tested against the + contents of the whitelist, the expanded string + _${PN} is appended to the flag. + This expansion makes each + LICENSE_FLAGS value recipe-specific. + After expansion, the string is then matched against the + whitelist. + Thus, specifying + LICENSE_FLAGS = "commercial" + in recipe "foo", for example, results in the string + "commercial_foo". + And, to create a match, that string must appear in the + whitelist. +

+ Judicious use of the LICENSE_FLAGS + strings and the contents of the + LICENSE_FLAGS_WHITELIST variable + allows you a lot of flexibility for including or excluding + recipes based on licensing. + For example, you can broaden the matching capabilities by + using license flags string subsets in the whitelist. +

Note

+ When using a string subset, be sure to use the part of + the expanded string that precedes the appended + underscore character (e.g. + usethispart_1.3, + usethispart_1.4, and so forth). +

+ For example, simply specifying the string "commercial" in + the whitelist matches any expanded + LICENSE_FLAGS definition that starts + with the string "commercial" such as "commercial_foo" and + "commercial_bar", which are the strings the build system + automatically generates for hypothetical recipes named + "foo" and "bar" assuming those recipes simply specify the + following: + 

+     LICENSE_FLAGS = "commercial"
+

+ Thus, you can choose to exhaustively + enumerate each license flag in the whitelist and + allow only specific recipes into the image, or + you can use a string subset that causes a broader range of + matches to allow a range of recipes into the image. +

+ This scheme works even if the + LICENSE_FLAGS string already + has _${PN} appended. + For example, the build system turns the license flag + "commercial_1.2_foo" into "commercial_1.2_foo_foo" and + would match both the general "commercial" and the specific + "commercial_1.2_foo" strings found in the whitelist, as + expected. +

+ Here are some other scenarios: +

  • + You can specify a versioned string in the recipe + such as "commercial_foo_1.2" in a "foo" recipe. + The build system expands this string to + "commercial_foo_1.2_foo". + Combine this license flag with a whitelist that has + the string "commercial" and you match the flag + along with any other flag that starts with the + string "commercial". +

  • + Under the same circumstances, you can use + "commercial_foo" in the whitelist and the build + system not only matches "commercial_foo_1.2" but + also matches any license flag with the string + "commercial_foo", regardless of the version. +

  • + You can be very specific and use both the + package and version parts in the whitelist (e.g. + "commercial_foo_1.2") to specifically match a + versioned recipe. +

+

+ Other helpful variables related to commercial + license handling exist and are defined in the + poky/meta/conf/distro/include/default-distrovars.inc file: + 

+     COMMERCIAL_AUDIO_PLUGINS ?= ""
+     COMMERCIAL_VIDEO_PLUGINS ?= ""
+

+ If you want to enable these components, you can do so by + making sure you have statements similar to the following + in your local.conf configuration file: + 

+     COMMERCIAL_AUDIO_PLUGINS = "gst-plugins-ugly-mad \
+        gst-plugins-ugly-mpegaudioparse"
+     COMMERCIAL_VIDEO_PLUGINS = "gst-plugins-ugly-mpeg2dec \
+        gst-plugins-ugly-mpegstream gst-plugins-bad-mpegvideoparse"
+     LICENSE_FLAGS_WHITELIST = "commercial_gst-plugins-ugly commercial_gst-plugins-bad commercial_qmmp"
+

+ Of course, you could also create a matching whitelist + for those components using the more general "commercial" + in the whitelist, but that would also enable all the + other packages with + LICENSE_FLAGS + containing "commercial", which you may or may not want: + 

+     LICENSE_FLAGS_WHITELIST = "commercial"
+

+

+ Specifying audio and video plug-ins as part of the + COMMERCIAL_AUDIO_PLUGINS and + COMMERCIAL_VIDEO_PLUGINS statements + (along with the enabling + LICENSE_FLAGS_WHITELIST) includes the + plug-ins or components into built images, thus adding + support for media formats or components. +

3.8. x32 psABI¶

+ x32 processor-specific Application Binary Interface + (x32 psABI) + is a native 32-bit processor-specific ABI for + Intel® 64 (x86-64) + architectures. + An ABI defines the calling conventions between functions in a + processing environment. + The interface determines what registers are used and what the sizes are + for various C data types. +

+ Some processing environments prefer using 32-bit applications even + when running on Intel 64-bit platforms. + Consider the i386 psABI, which is a very old 32-bit ABI for Intel + 64-bit platforms. + The i386 psABI does not provide efficient use and access of the + Intel 64-bit processor resources, leaving the system underutilized. + Now consider the x86_64 psABI. + This ABI is newer and uses 64-bits for data sizes and program + pointers. + The extra bits increase the footprint size of the programs, + libraries, and also increases the memory and file system size + requirements. + Executing under the x32 psABI enables user programs to utilize CPU + and system resources more efficiently while keeping the memory + footprint of the applications low. + Extra bits are used for registers but not for addressing mechanisms. +

+ The Yocto Project supports the final specifications of x32 psABI + as follows: +

  • + You can create packages and images in x32 psABI format on + x86_64 architecture targets. +

  • + You can successfully build recipes with the x32 toolchain. +

  • + You can create and boot + core-image-minimal and + core-image-sato images. +

  • + RPM Package Manager (RPM) support exists for x32 binaries. +

  • + Support for large images exists. +

+

+ For steps on how to use x32 psABI, see the + "Using x32 psABI" + section in the Yocto Project Development Tasks Manual. +

+ +
\ No newline at end of file diff --git a/documentation/getting-started/getting-started.tgz b/documentation/getting-started/getting-started.tgz new file mode 100644 index 0000000000..829706d5d3 Binary files /dev/null and b/documentation/getting-started/getting-started.tgz differ diff --git a/documentation/getting-started/getting-started.xml b/documentation/getting-started/getting-started.xml new file mode 100644 index 0000000000..930a202e1a --- /dev/null +++ b/documentation/getting-started/getting-started.xml @@ -0,0 +1,94 @@ + %poky; ] > + + + + + + + + + + + + Getting Started With Yocto Project + + + + + Scott Rifenbark + + Scotty's Documentation Services, INC + + srifenbark@gmail.com + + + + + + 2.5 + April 2018 + The initial document released with the Yocto Project 2.5 Release. + + + + + ©RIGHT_YEAR; + Linux Foundation + + + + + Permission is granted to copy, distribute and/or modify this document under + the terms of the + Creative Commons Attribution-Share Alike 2.0 UK: England & Wales as published by + Creative Commons. + + Manual Notes + + + This version of the + Yocto Project Overview Manual + is for the &YOCTO_DOC_VERSION; release of the + Yocto Project. + To be sure you have the latest version of the manual + for this release, use the manual from the + Yocto Project documentation page. + + + For manuals associated with other releases of the Yocto + Project, go to the + Yocto Project documentation page + and use the drop-down "Active Releases" button + and choose the manual associated with the desired + Yocto Project. + + + To report any inaccuracies or problems with this + manual, send an email to the Yocto Project + discussion group at + yocto@yoctoproject.com or log into + the freenode #yocto channel. + + + + + + + + + + + + + + + diff --git a/documentation/kernel-dev/kernel-dev-advanced.xml b/documentation/kernel-dev/kernel-dev-advanced.xml index 11ab37ffaf..8b4ce45d7d 100644 --- a/documentation/kernel-dev/kernel-dev-advanced.xml +++ b/documentation/kernel-dev/kernel-dev-advanced.xml @@ -21,7 +21,7 @@ Kernel Metadata exists in many places. One area in the Yocto Project - Source Repositories + Source Repositories is the yocto-kernel-cache Git repository. You can find this repository grouped under the "Yocto Linux Kernel" heading in the diff --git a/documentation/kernel-dev/kernel-dev-common.xml b/documentation/kernel-dev/kernel-dev-common.xml index 5b392a144c..d4bed076aa 100644 --- a/documentation/kernel-dev/kernel-dev-common.xml +++ b/documentation/kernel-dev/kernel-dev-common.xml @@ -79,7 +79,7 @@ The previous commands assume the - Source Repositories + Source Repositories (i.e. poky) have been cloned using Git and the local repository is named "poky". @@ -303,7 +303,7 @@ The previous commands assume the - Source Repositories + Source Repositories (i.e. poky) have been cloned using Git and the local repository is named "poky". diff --git a/documentation/kernel-dev/kernel-dev-concepts-appx.xml b/documentation/kernel-dev/kernel-dev-concepts-appx.xml index 231ef9a43d..db692edfab 100644 --- a/documentation/kernel-dev/kernel-dev-concepts-appx.xml +++ b/documentation/kernel-dev/kernel-dev-concepts-appx.xml @@ -49,7 +49,7 @@ You can find a web interface to the Yocto Linux kernels in the - Source Repositories + Source Repositories at . If you look at the interface, you will see to the left a @@ -239,7 +239,7 @@ . You can also get an introduction to Git as it applies to the Yocto Project in the - "Git" + "Git" section in the Yocto Project Overview Manual. The latter reference provides an overview of Git and presents a minimal set of Git commands @@ -381,7 +381,7 @@ generic kernel just for conceptual purposes. Also keep in mind that this structure represents the Yocto Project - Source Repositories + Source Repositories that are either pulled from during the build or established on the host development system prior to the build by either cloning a particular kernel's Git repository or by diff --git a/documentation/mega-manual/figures/getting-started-title.png b/documentation/mega-manual/figures/getting-started-title.png new file mode 100644 index 0000000000..f38b078ab7 Binary files /dev/null and b/documentation/mega-manual/figures/getting-started-title.png differ diff --git a/documentation/mega-manual/figures/overview-title.png b/documentation/mega-manual/figures/overview-title.png deleted file mode 100644 index c5ec87242e..0000000000 Binary files a/documentation/mega-manual/figures/overview-title.png and /dev/null differ diff --git a/documentation/mega-manual/mega-manual.xml b/documentation/mega-manual/mega-manual.xml index f44e8c4e65..0533530a1c 100644 --- 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100644 index 5770be6883..0000000000 Binary files a/documentation/overview-manual/figures/yp-download.png and /dev/null differ diff --git a/documentation/overview-manual/overview-concepts.xml b/documentation/overview-manual/overview-concepts.xml deleted file mode 100644 index 59741d2e35..0000000000 --- a/documentation/overview-manual/overview-concepts.xml +++ /dev/null @@ -1,1929 +0,0 @@ - %poky; ] > - - -Yocto Project Concepts - - - This chapter describes concepts for various areas of the Yocto Project. - Currently, topics include Yocto Project components, cross-development - generation, shared state (sstate) cache, runtime dependencies, - Pseudo and Fakeroot, x32 psABI, Wayland support, and Licenses. - - -
- Yocto Project Components - - - The - BitBake - task executor together with various types of configuration files - form the OpenEmbedded Core. - This section overviews these components by describing their use and - how they interact. - - - - BitBake handles the parsing and execution of the data files. - The data itself is of various types: - - - Recipes: - Provides details about particular pieces of software. - - - Class Data: - Abstracts common build information (e.g. how to build a - Linux kernel). - - - Configuration Data: - Defines machine-specific settings, policy decisions, and - so forth. - Configuration data acts as the glue to bind everything - together. - - - - - - BitBake knows how to combine multiple data sources together and - refers to each data source as a layer. - For information on layers, see the - "Understanding and Creating Layers" - section of the Yocto Project Development Tasks Manual. - - - - Following are some brief details on these core components. - For additional information on how these components interact during - a build, see the - "Development Concepts" - section. - - -
- BitBake - - - BitBake is the tool at the heart of the OpenEmbedded build - system and is responsible for parsing the - Metadata, - generating a list of tasks from it, and then executing those - tasks. - - - - This section briefly introduces BitBake. - If you want more information on BitBake, see the - BitBake User Manual. - - - - To see a list of the options BitBake supports, use either of - the following commands: - - $ bitbake -h - $ bitbake --help - - - - - The most common usage for BitBake is - bitbake packagename, - where packagename is the name of the - package you want to build (referred to as the "target" in this - manual). - The target often equates to the first part of a recipe's - filename (e.g. "foo" for a recipe named - foo_1.3.0-r0.bb). - So, to process the - matchbox-desktop_1.2.3.bb recipe file, you - might type the following: - - $ bitbake matchbox-desktop - - Several different versions of - matchbox-desktop might exist. - BitBake chooses the one selected by the distribution - configuration. - You can get more details about how BitBake chooses between - different target versions and providers in the - "Preferences" - section of the BitBake User Manual. - - - - BitBake also tries to execute any dependent tasks first. - So for example, before building - matchbox-desktop, BitBake would build a - cross compiler and glibc if they had not - already been built. - - - - A useful BitBake option to consider is the - -k or --continue - option. - This option instructs BitBake to try and continue processing - the job as long as possible even after encountering an error. - When an error occurs, the target that failed and those that - depend on it cannot be remade. - However, when you use this option other dependencies can - still be processed. - -
- -
- Metadata (Recipes) - - - Files that have the .bb suffix are - "recipes" files. - In general, a recipe contains information about a single piece - of software. - This information includes the location from which to download - the unaltered source, any source patches to be applied to that - source (if needed), which special configuration options to - apply, how to compile the source files, and how to package the - compiled output. - - - - The term "package" is sometimes used to refer to recipes. - However, since the word "package" is used for the packaged - output from the OpenEmbedded build system (i.e. - .ipk or .deb files), - this document avoids using the term "package" when referring - to recipes. - -
- -
- Metadata (Virtual Providers) - - - Prior to the build, if you know that several different recipes - provide the same functionality, you can use a virtual provider - (i.e. virtual/*) as a placeholder for the - actual provider. - The actual provider would be determined at build time. - In this case, you should add virtual/* - to - DEPENDS, - rather than listing the specified provider. - You would select the actual provider by setting the - PREFERRED_PROVIDER - variable (i.e. - PREFERRED_PROVIDER_virtual/*) - in the build's configuration file (e.g. - poky/build/conf/local.conf). - - Any recipe that PROVIDES a virtual/* - item that is ultimately not selected through - PREFERRED_PROVIDER does not get built. - Preventing these recipes from building is usually the - desired behavior since this mechanism's purpose is to - select between mutually exclusive alternative providers. - - - - - The following lists specific examples of virtual providers: - - - virtual/mesa: - Provides gbm.pc. - - - virtual/egl: - Provides egl.pc and possibly - wayland-egl.pc. - - - virtual/libgl: - Provides gl.pc (i.e. libGL). - - - virtual/libgles1: - Provides glesv1_cm.pc - (i.e. libGLESv1_CM). - - - virtual/libgles2: - Provides glesv2.pc - (i.e. libGLESv2). - - - -
- -
- Classes - - - Class files (.bbclass) contain information - that is useful to share between - Metadata - files. - An example is the - autotools - class, which contains common settings for any application that - Autotools uses. - The - "Classes" - chapter in the Yocto Project Reference Manual provides - details about classes and how to use them. - -
- -
- Configuration - - - The configuration files (.conf) define - various configuration variables that govern the OpenEmbedded - build process. - These files fall into several areas that define machine - configuration options, distribution configuration options, - compiler tuning options, general common configuration options, - and user configuration options in - local.conf, which is found in the - Build Directory. - -
-
- -
- Cross-Development Toolchain Generation - - - The Yocto Project does most of the work for you when it comes to - creating - cross-development toolchains. - This section provides some technical background on how - cross-development toolchains are created and used. - For more information on toolchains, you can also see the - Yocto Project Application Development and the Extensible Software Development Kit (eSDK) - manual. - - - - In the Yocto Project development environment, cross-development - toolchains are used to build the image and applications that run - on the target hardware. - With just a few commands, the OpenEmbedded build system creates - these necessary toolchains for you. - - - - The following figure shows a high-level build environment regarding - toolchain construction and use. - - - - - - - - Most of the work occurs on the Build Host. - This is the machine used to build images and generally work within the - the Yocto Project environment. - When you run BitBake to create an image, the OpenEmbedded build system - uses the host gcc compiler to bootstrap a - cross-compiler named gcc-cross. - The gcc-cross compiler is what BitBake uses to - compile source files when creating the target image. - You can think of gcc-cross simply as an - automatically generated cross-compiler that is used internally within - BitBake only. - - The extensible SDK does not use - gcc-cross-canadian since this SDK - ships a copy of the OpenEmbedded build system and the sysroot - within it contains gcc-cross. - - - - - The chain of events that occurs when gcc-cross is - bootstrapped is as follows: - - gcc -> binutils-cross -> gcc-cross-initial -> linux-libc-headers -> glibc-initial -> glibc -> gcc-cross -> gcc-runtime - - - - gcc: - The build host's GNU Compiler Collection (GCC). - - - binutils-cross: - The bare minimum binary utilities needed in order to run - the gcc-cross-initial phase of the - bootstrap operation. - - - gcc-cross-initial: - An early stage of the bootstrap process for creating - the cross-compiler. - This stage builds enough of the gcc-cross, - the C library, and other pieces needed to finish building the - final cross-compiler in later stages. - This tool is a "native" package (i.e. it is designed to run on - the build host). - - - linux-libc-headers: - Headers needed for the cross-compiler. - - - glibc-initial: - An initial version of the Embedded GLIBC needed to bootstrap - glibc. - - - gcc-cross: - The final stage of the bootstrap process for the - cross-compiler. - This stage results in the actual cross-compiler that - BitBake uses when it builds an image for a targeted - device. - - If you are replacing this cross compiler toolchain - with a custom version, you must replace - gcc-cross. - - This tool is also a "native" package (i.e. it is - designed to run on the build host). - - - gcc-runtime: - Runtime libraries resulting from the toolchain bootstrapping - process. - This tool produces a binary that consists of the - runtime libraries need for the targeted device. - - - - - - You can use the OpenEmbedded build system to build an installer for - the relocatable SDK used to develop applications. - When you run the installer, it installs the toolchain, which contains - the development tools (e.g., the - gcc-cross-canadian), - binutils-cross-canadian, and other - nativesdk-* tools, - which are tools native to the SDK (i.e. native to - SDK_ARCH), - you need to cross-compile and test your software. - The figure shows the commands you use to easily build out this - toolchain. - This cross-development toolchain is built to execute on the - SDKMACHINE, - which might or might not be the same - machine as the Build Host. - - If your target architecture is supported by the Yocto Project, - you can take advantage of pre-built images that ship with the - Yocto Project and already contain cross-development toolchain - installers. - - - - - Here is the bootstrap process for the relocatable toolchain: - - gcc -> binutils-crosssdk -> gcc-crosssdk-initial -> linux-libc-headers -> - glibc-initial -> nativesdk-glibc -> gcc-crosssdk -> gcc-cross-canadian - - - - gcc: - The build host's GNU Compiler Collection (GCC). - - - binutils-crosssdk: - The bare minimum binary utilities needed in order to run - the gcc-crosssdk-initial phase of the - bootstrap operation. - - - gcc-crosssdk-initial: - An early stage of the bootstrap process for creating - the cross-compiler. - This stage builds enough of the - gcc-crosssdk and supporting pieces so that - the final stage of the bootstrap process can produce the - finished cross-compiler. - This tool is a "native" binary that runs on the build host. - - - linux-libc-headers: - Headers needed for the cross-compiler. - - - glibc-initial: - An initial version of the Embedded GLIBC needed to bootstrap - nativesdk-glibc. - - - nativesdk-glibc: - The Embedded GLIBC needed to bootstrap the - gcc-crosssdk. - - - gcc-crosssdk: - The final stage of the bootstrap process for the - relocatable cross-compiler. - The gcc-crosssdk is a transitory compiler - and never leaves the build host. - Its purpose is to help in the bootstrap process to create the - eventual relocatable gcc-cross-canadian - compiler, which is relocatable. - This tool is also a "native" package (i.e. it is - designed to run on the build host). - - - gcc-cross-canadian: - The final relocatable cross-compiler. - When run on the - SDKMACHINE, - this tool - produces executable code that runs on the target device. - Only one cross-canadian compiler is produced per architecture - since they can be targeted at different processor optimizations - using configurations passed to the compiler through the - compile commands. - This circumvents the need for multiple compilers and thus - reduces the size of the toolchains. - - - - - - For information on advantages gained when building a - cross-development toolchain installer, see the - "Building an SDK Installer" - section in the Yocto Project Application Development and the - Extensible Software Development Kit (eSDK) manual. - -
- - - - -
- Shared State Cache - - - By design, the OpenEmbedded build system builds everything from - scratch unless BitBake can determine that parts do not need to be - rebuilt. - Fundamentally, building from scratch is attractive as it means all - parts are built fresh and there is no possibility of stale data - causing problems. - When developers hit problems, they typically default back to - building from scratch so they know the state of things from the - start. - - - - Building an image from scratch is both an advantage and a - disadvantage to the process. - As mentioned in the previous paragraph, building from scratch - ensures that everything is current and starts from a known state. - However, building from scratch also takes much longer as it - generally means rebuilding things that do not necessarily need - to be rebuilt. - - - - The Yocto Project implements shared state code that supports - incremental builds. - The implementation of the shared state code answers the following - questions that were fundamental roadblocks within the OpenEmbedded - incremental build support system: - - - What pieces of the system have changed and what pieces have - not changed? - - - How are changed pieces of software removed and replaced? - - - How are pre-built components that do not need to be rebuilt - from scratch used when they are available? - - - - - - For the first question, the build system detects changes in the - "inputs" to a given task by creating a checksum (or signature) of - the task's inputs. - If the checksum changes, the system assumes the inputs have changed - and the task needs to be rerun. - For the second question, the shared state (sstate) code tracks - which tasks add which output to the build process. - This means the output from a given task can be removed, upgraded - or otherwise manipulated. - The third question is partly addressed by the solution for the - second question assuming the build system can fetch the sstate - objects from remote locations and install them if they are deemed - to be valid. - - The OpenEmbedded build system does not maintain - PR - information as part of the shared state packages. - Consequently, considerations exist that affect maintaining - shared state feeds. - For information on how the OpenEmbedded build system - works with packages and can track incrementing - PR information, see the - "Automatically Incrementing a Binary Package Revision Number" - section in the Yocto Project Development Tasks Manual. - - - - - The rest of this section goes into detail about the overall - incremental build architecture, the checksums (signatures), shared - state, and some tips and tricks. - - -
- Overall Architecture - - - When determining what parts of the system need to be built, - BitBake works on a per-task basis rather than a per-recipe - basis. - You might wonder why using a per-task basis is preferred over - a per-recipe basis. - To help explain, consider having the IPK packaging backend - enabled and then switching to DEB. - In this case, the - do_install - and - do_package - task outputs are still valid. - However, with a per-recipe approach, the build would not - include the .deb files. - Consequently, you would have to invalidate the whole build and - rerun it. - Rerunning everything is not the best solution. - Also, in this case, the core must be "taught" much about - specific tasks. - This methodology does not scale well and does not allow users - to easily add new tasks in layers or as external recipes - without touching the packaged-staging core. - -
- -
- Checksums (Signatures) - - - The shared state code uses a checksum, which is a unique - signature of a task's inputs, to determine if a task needs to - be run again. - Because it is a change in a task's inputs that triggers a - rerun, the process needs to detect all the inputs to a given - task. - For shell tasks, this turns out to be fairly easy because - the build process generates a "run" shell script for each task - and it is possible to create a checksum that gives you a good - idea of when the task's data changes. - - - - To complicate the problem, there are things that should not be - included in the checksum. - First, there is the actual specific build path of a given - task - the - WORKDIR. - It does not matter if the work directory changes because it - should not affect the output for target packages. - Also, the build process has the objective of making native - or cross packages relocatable. - - Both native and cross packages run on the build host. - However, cross packages generate output for the target - architecture. - - The checksum therefore needs to exclude - WORKDIR. - The simplistic approach for excluding the work directory is to - set WORKDIR to some fixed value and - create the checksum for the "run" script. - - - - Another problem results from the "run" scripts containing - functions that might or might not get called. - The incremental build solution contains code that figures out - dependencies between shell functions. - This code is used to prune the "run" scripts down to the - minimum set, thereby alleviating this problem and making the - "run" scripts much more readable as a bonus. - - - - So far we have solutions for shell scripts. - What about Python tasks? - The same approach applies even though these tasks are more - difficult. - The process needs to figure out what variables a Python - function accesses and what functions it calls. - Again, the incremental build solution contains code that first - figures out the variable and function dependencies, and then - creates a checksum for the data used as the input to the task. - - - - Like the WORKDIR case, situations exist - where dependencies should be ignored. - For these cases, you can instruct the build process to - ignore a dependency by using a line like the following: - - PACKAGE_ARCHS[vardepsexclude] = "MACHINE" - - This example ensures that the - PACKAGE_ARCHS - variable does not depend on the value of - MACHINE, - even if it does reference it. - - - - Equally, there are cases where we need to add dependencies - BitBake is not able to find. - You can accomplish this by using a line like the following: - - PACKAGE_ARCHS[vardeps] = "MACHINE" - - This example explicitly adds the MACHINE - variable as a dependency for - PACKAGE_ARCHS. - - - - Consider a case with in-line Python, for example, where - BitBake is not able to figure out dependencies. - When running in debug mode (i.e. using - -DDD), BitBake produces output when it - discovers something for which it cannot figure out dependencies. - The Yocto Project team has currently not managed to cover - those dependencies in detail and is aware of the need to fix - this situation. - - - - Thus far, this section has limited discussion to the direct - inputs into a task. - Information based on direct inputs is referred to as the - "basehash" in the code. - However, there is still the question of a task's indirect - inputs - the things that were already built and present in the - Build Directory. - The checksum (or signature) for a particular task needs to add - the hashes of all the tasks on which the particular task - depends. - Choosing which dependencies to add is a policy decision. - However, the effect is to generate a master checksum that - combines the basehash and the hashes of the task's - dependencies. - - - - At the code level, there are a variety of ways both the - basehash and the dependent task hashes can be influenced. - Within the BitBake configuration file, we can give BitBake - some extra information to help it construct the basehash. - The following statement effectively results in a list of - global variable dependency excludes - variables never - included in any checksum: - - BB_HASHBASE_WHITELIST ?= "TMPDIR FILE PATH PWD BB_TASKHASH BBPATH DL_DIR \ - SSTATE_DIR THISDIR FILESEXTRAPATHS FILE_DIRNAME HOME LOGNAME SHELL TERM \ - USER FILESPATH STAGING_DIR_HOST STAGING_DIR_TARGET COREBASE PRSERV_HOST \ - PRSERV_DUMPDIR PRSERV_DUMPFILE PRSERV_LOCKDOWN PARALLEL_MAKE \ - CCACHE_DIR EXTERNAL_TOOLCHAIN CCACHE CCACHE_DISABLE LICENSE_PATH SDKPKGSUFFIX" - - The previous example excludes - WORKDIR - since that variable is actually constructed as a path within - TMPDIR, - which is on the whitelist. - - - - The rules for deciding which hashes of dependent tasks to - include through dependency chains are more complex and are - generally accomplished with a Python function. - The code in meta/lib/oe/sstatesig.py shows - two examples of this and also illustrates how you can insert - your own policy into the system if so desired. - This file defines the two basic signature generators - OE-Core - uses: "OEBasic" and "OEBasicHash". - By default, there is a dummy "noop" signature handler enabled - in BitBake. - This means that behavior is unchanged from previous versions. - OE-Core uses the "OEBasicHash" signature handler by default - through this setting in the bitbake.conf - file: - - BB_SIGNATURE_HANDLER ?= "OEBasicHash" - - The "OEBasicHash" BB_SIGNATURE_HANDLER - is the same as the "OEBasic" version but adds the task hash to - the stamp files. - This results in any - Metadata - change that changes the task hash, automatically - causing the task to be run again. - This removes the need to bump - PR - values, and changes to Metadata automatically ripple across - the build. - - - - It is also worth noting that the end result of these - signature generators is to make some dependency and hash - information available to the build. - This information includes: - - - BB_BASEHASH_task-taskname: - The base hashes for each task in the recipe. - - - BB_BASEHASH_filename:taskname: - The base hashes for each dependent task. - - - BBHASHDEPS_filename:taskname: - The task dependencies for each task. - - - BB_TASKHASH: - The hash of the currently running task. - - - -
- -
- Shared State - - - Checksums and dependencies, as discussed in the previous - section, solve half the problem of supporting a shared state. - The other part of the problem is being able to use checksum - information during the build and being able to reuse or rebuild - specific components. - - - - The - sstate - class is a relatively generic implementation of how to - "capture" a snapshot of a given task. - The idea is that the build process does not care about the - source of a task's output. - Output could be freshly built or it could be downloaded and - unpacked from somewhere - the build process does not need to - worry about its origin. - - - - There are two types of output, one is just about creating a - directory in - WORKDIR. - A good example is the output of either - do_install - or - do_package. - The other type of output occurs when a set of data is merged - into a shared directory tree such as the sysroot. - - - - The Yocto Project team has tried to keep the details of the - implementation hidden in sstate class. - From a user's perspective, adding shared state wrapping to a task - is as simple as this - do_deploy - example taken from the - deploy - class: - - DEPLOYDIR = "${WORKDIR}/deploy-${PN}" - SSTATETASKS += "do_deploy" - do_deploy[sstate-inputdirs] = "${DEPLOYDIR}" - do_deploy[sstate-outputdirs] = "${DEPLOY_DIR_IMAGE}" - - python do_deploy_setscene () { - sstate_setscene(d) - } - addtask do_deploy_setscene - do_deploy[dirs] = "${DEPLOYDIR} ${B}" - - The following list explains the previous example: - - - Adding "do_deploy" to SSTATETASKS - adds some required sstate-related processing, which is - implemented in the - sstate - class, to before and after the - do_deploy - task. - - - The - do_deploy[sstate-inputdirs] = "${DEPLOYDIR}" - declares that do_deploy places its - output in ${DEPLOYDIR} when run - normally (i.e. when not using the sstate cache). - This output becomes the input to the shared state cache. - - - The - do_deploy[sstate-outputdirs] = "${DEPLOY_DIR_IMAGE}" - line causes the contents of the shared state cache to be - copied to ${DEPLOY_DIR_IMAGE}. - - If do_deploy is not already in - the shared state cache or if its input checksum - (signature) has changed from when the output was - cached, the task will be run to populate the shared - state cache, after which the contents of the shared - state cache is copied to - ${DEPLOY_DIR_IMAGE}. - If do_deploy is in the shared - state cache and its signature indicates that the - cached output is still valid (i.e. if no - relevant task inputs have changed), then the - contents of the shared state cache will be copied - directly to - ${DEPLOY_DIR_IMAGE} by the - do_deploy_setscene task - instead, skipping the - do_deploy task. - - - - The following task definition is glue logic needed to - make the previous settings effective: - - python do_deploy_setscene () { - sstate_setscene(d) - } - addtask do_deploy_setscene - - sstate_setscene() takes the flags - above as input and accelerates the - do_deploy task through the - shared state cache if possible. - If the task was accelerated, - sstate_setscene() returns True. - Otherwise, it returns False, and the normal - do_deploy task runs. - For more information, see the - "setscene" - section in the BitBake User Manual. - - - The do_deploy[dirs] = "${DEPLOYDIR} ${B}" - line creates ${DEPLOYDIR} and - ${B} before the - do_deploy task runs, and also sets - the current working directory of - do_deploy to - ${B}. - For more information, see the - "Variable Flags" - section in the BitBake User Manual. - - In cases where - sstate-inputdirs and - sstate-outputdirs would be the - same, you can use - sstate-plaindirs. - For example, to preserve the - ${PKGD} and - ${PKGDEST} output from the - do_package - task, use the following: - - do_package[sstate-plaindirs] = "${PKGD} ${PKGDEST}" - - - - - sstate-inputdirs and - sstate-outputdirs can also be used - with multiple directories. - For example, the following declares - PKGDESTWORK and - SHLIBWORK as shared state - input directories, which populates the shared state - cache, and PKGDATA_DIR and - SHLIBSDIR as the corresponding - shared state output directories: - - do_package[sstate-inputdirs] = "${PKGDESTWORK} ${SHLIBSWORKDIR}" - do_package[sstate-outputdirs] = "${PKGDATA_DIR} ${SHLIBSDIR}" - - - - These methods also include the ability to take a - lockfile when manipulating shared state directory - structures, for cases where file additions or removals - are sensitive: - - do_package[sstate-lockfile] = "${PACKAGELOCK}" - - - - - - - Behind the scenes, the shared state code works by looking in - SSTATE_DIR - and - SSTATE_MIRRORS - for shared state files. - Here is an example: - - SSTATE_MIRRORS ?= "\ - file://.* http://someserver.tld/share/sstate/PATH;downloadfilename=PATH \n \ - file://.* file:///some/local/dir/sstate/PATH" - - - The shared state directory - (SSTATE_DIR) is organized into - two-character subdirectories, where the subdirectory - names are based on the first two characters of the hash. - If the shared state directory structure for a mirror has the - same structure as SSTATE_DIR, you must - specify "PATH" as part of the URI to enable the build system - to map to the appropriate subdirectory. - - - - - The shared state package validity can be detected just by - looking at the filename since the filename contains the task - checksum (or signature) as described earlier in this section. - If a valid shared state package is found, the build process - downloads it and uses it to accelerate the task. - - - - The build processes use the *_setscene - tasks for the task acceleration phase. - BitBake goes through this phase before the main execution - code and tries to accelerate any tasks for which it can find - shared state packages. - If a shared state package for a task is available, the - shared state package is used. - This means the task and any tasks on which it is dependent - are not executed. - - - - As a real world example, the aim is when building an IPK-based - image, only the - do_package_write_ipk - tasks would have their shared state packages fetched and - extracted. - Since the sysroot is not used, it would never get extracted. - This is another reason why a task-based approach is preferred - over a recipe-based approach, which would have to install the - output from every task. - -
- -
- Tips and Tricks - - - The code in the build system that supports incremental builds - is not simple code. - This section presents some tips and tricks that help you work - around issues related to shared state code. - - -
- Debugging - - - Seeing what metadata went into creating the input signature - of a shared state (sstate) task can be a useful debugging - aid. - This information is available in signature information - (siginfo) files in - SSTATE_DIR. - For information on how to view and interpret information in - siginfo files, see the - "Viewing Task Variable Dependencies" - section in the Yocto Project Development Tasks Manual. - -
- -
- Invalidating Shared State - - - The OpenEmbedded build system uses checksums and shared - state cache to avoid unnecessarily rebuilding tasks. - Collectively, this scheme is known as "shared state code." - - - - As with all schemes, this one has some drawbacks. - It is possible that you could make implicit changes to your - code that the checksum calculations do not take into - account. - These implicit changes affect a task's output but do not - trigger the shared state code into rebuilding a recipe. - Consider an example during which a tool changes its output. - Assume that the output of rpmdeps - changes. - The result of the change should be that all the - package and - package_write_rpm shared state cache - items become invalid. - However, because the change to the output is - external to the code and therefore implicit, - the associated shared state cache items do not become - invalidated. - In this case, the build process uses the cached items - rather than running the task again. - Obviously, these types of implicit changes can cause - problems. - - - - To avoid these problems during the build, you need to - understand the effects of any changes you make. - Realize that changes you make directly to a function - are automatically factored into the checksum calculation. - Thus, these explicit changes invalidate the associated - area of shared state cache. - However, you need to be aware of any implicit changes that - are not obvious changes to the code and could affect - the output of a given task. - - - - When you identify an implicit change, you can easily - take steps to invalidate the cache and force the tasks - to run. - The steps you can take are as simple as changing a - function's comments in the source code. - For example, to invalidate package shared state files, - change the comment statements of - do_package - or the comments of one of the functions it calls. - Even though the change is purely cosmetic, it causes the - checksum to be recalculated and forces the OpenEmbedded - build system to run the task again. - - For an example of a commit that makes a cosmetic - change to invalidate shared state, see this - commit. - - -
-
-
- -
- Automatically Added Runtime Dependencies - - - The OpenEmbedded build system automatically adds common types of - runtime dependencies between packages, which means that you do not - need to explicitly declare the packages using - RDEPENDS. - Three automatic mechanisms exist (shlibdeps, - pcdeps, and depchains) - that handle shared libraries, package configuration (pkg-config) - modules, and -dev and - -dbg packages, respectively. - For other types of runtime dependencies, you must manually declare - the dependencies. - - - shlibdeps: - During the - do_package - task of each recipe, all shared libraries installed by the - recipe are located. - For each shared library, the package that contains the - shared library is registered as providing the shared - library. - More specifically, the package is registered as providing - the - soname - of the library. - The resulting shared-library-to-package mapping - is saved globally in - PKGDATA_DIR - by the - do_packagedata - task. - - Simultaneously, all executables and shared libraries - installed by the recipe are inspected to see what shared - libraries they link against. - For each shared library dependency that is found, - PKGDATA_DIR is queried to - see if some package (likely from a different recipe) - contains the shared library. - If such a package is found, a runtime dependency is added - from the package that depends on the shared library to the - package that contains the library. - - The automatically added runtime dependency also - includes a version restriction. - This version restriction specifies that at least the - current version of the package that provides the shared - library must be used, as if - "package (>= version)" - had been added to - RDEPENDS. - This forces an upgrade of the package containing the shared - library when installing the package that depends on the - library, if needed. - - If you want to avoid a package being registered as - providing a particular shared library (e.g. because the library - is for internal use only), then add the library to - PRIVATE_LIBS - inside the package's recipe. - - - pcdeps: - During the - do_package - task of each recipe, all pkg-config modules - (*.pc files) installed by the recipe - are located. - For each module, the package that contains the module is - registered as providing the module. - The resulting module-to-package mapping is saved globally in - PKGDATA_DIR - by the - do_packagedata - task. - - Simultaneously, all pkg-config modules installed by - the recipe are inspected to see what other pkg-config - modules they depend on. - A module is seen as depending on another module if it - contains a "Requires:" line that specifies the other module. - For each module dependency, - PKGDATA_DIR is queried to see if some - package contains the module. - If such a package is found, a runtime dependency is added - from the package that depends on the module to the package - that contains the module. - - The pcdeps mechanism most often - infers dependencies between -dev - packages. - - - - depchains: - If a package foo depends on a package - bar, then foo-dev - and foo-dbg are also made to depend on - bar-dev and - bar-dbg, respectively. - Taking the -dev packages as an - example, the bar-dev package might - provide headers and shared library symlinks needed by - foo-dev, which shows the need - for a dependency between the packages. - - The dependencies added by - depchains are in the form of - RRECOMMENDS. - - By default, foo-dev also has an - RDEPENDS-style dependency on - foo, because the default value of - RDEPENDS_${PN}-dev (set in - bitbake.conf) includes - "${PN}". - - - To ensure that the dependency chain is never broken, - -dev and -dbg - packages are always generated by default, even if the - packages turn out to be empty. - See the - ALLOW_EMPTY - variable for more information. - - - - - - The do_package task depends on the - do_packagedata - task of each recipe in - DEPENDS - through use of a - [deptask] - declaration, which guarantees that the required - shared-library/module-to-package mapping information will be available - when needed as long as DEPENDS has been - correctly set. - -
- -
- Fakeroot and Pseudo - - - Some tasks are easier to implement when allowed to perform certain - operations that are normally reserved for the root user (e.g. - do_install, - do_package_write*, - do_rootfs, - and - do_image*). - For example, the do_install task benefits - from being able to set the UID and GID of installed files to - arbitrary values. - - - - One approach to allowing tasks to perform root-only operations - would be to require BitBake to run as root. - However, this method is cumbersome and has security issues. - The approach that is actually used is to run tasks that benefit - from root privileges in a "fake" root environment. - Within this environment, the task and its child processes believe - that they are running as the root user, and see an internally - consistent view of the filesystem. - As long as generating the final output (e.g. a package or an image) - does not require root privileges, the fact that some earlier - steps ran in a fake root environment does not cause problems. - - - - The capability to run tasks in a fake root environment is known as - "fakeroot", - which is derived from the BitBake keyword/variable - flag that requests a fake root environment for a task. - - - - In the OpenEmbedded build system, the program that implements - fakeroot is known as Pseudo. - Pseudo overrides system calls by using the environment variable - LD_PRELOAD, which results in the illusion - of running as root. - To keep track of "fake" file ownership and permissions resulting - from operations that require root permissions, Pseudo uses - an SQLite 3 database. - This database is stored in - ${WORKDIR}/pseudo/files.db - for individual recipes. - Storing the database in a file as opposed to in memory - gives persistence between tasks and builds, which is not - accomplished using fakeroot. - Caution - If you add your own task that manipulates the same files or - directories as a fakeroot task, then that task also needs to - run under fakeroot. - Otherwise, the task cannot run root-only operations, and - cannot see the fake file ownership and permissions set by the - other task. - You need to also add a dependency on - virtual/fakeroot-native:do_populate_sysroot, - giving the following: - - fakeroot do_mytask () { - ... - } - do_mytask[depends] += "virtual/fakeroot-native:do_populate_sysroot" - - - For more information, see the - FAKEROOT* - variables in the BitBake User Manual. - You can also reference the - "Pseudo" - and - "Why Not Fakeroot?" - articles for background information on Pseudo. - -
- -
- Wayland - - - Wayland - is a computer display server protocol that - provides a method for compositing window managers to communicate - directly with applications and video hardware and expects them to - communicate with input hardware using other libraries. - Using Wayland with supporting targets can result in better control - over graphics frame rendering than an application might otherwise - achieve. - - - - The Yocto Project provides the Wayland protocol libraries and the - reference - Weston - compositor as part of its release. - This section describes what you need to do to implement Wayland and - use the compositor when building an image for a supporting target. - - -
- Support - - - The Wayland protocol libraries and the reference Weston - compositor ship as integrated packages in the - meta layer of the - Source Directory. - Specifically, you can find the recipes that build both Wayland - and Weston at - meta/recipes-graphics/wayland. - - - - You can build both the Wayland and Weston packages for use only - with targets that accept the - Mesa 3D and Direct Rendering Infrastructure, - which is also known as Mesa DRI. - This implies that you cannot build and use the packages if your - target uses, for example, the - Intel Embedded Media - and Graphics Driver - (Intel EMGD) that - overrides Mesa DRI. - - Due to lack of EGL support, Weston 1.0.3 will not run - directly on the emulated QEMU hardware. - However, this version of Weston will run under X emulation - without issues. - - -
- -
- Enabling Wayland in an Image - - - To enable Wayland, you need to enable it to be built and enable - it to be included in the image. - - -
- Building - - - To cause Mesa to build the wayland-egl - platform and Weston to build Wayland with Kernel Mode - Setting - (KMS) - support, include the "wayland" flag in the - DISTRO_FEATURES - statement in your local.conf file: - - DISTRO_FEATURES_append = " wayland" - - - If X11 has been enabled elsewhere, Weston will build - Wayland with X11 support - - -
- -
- Installing - - - To install the Wayland feature into an image, you must - include the following - CORE_IMAGE_EXTRA_INSTALL - statement in your local.conf file: - - CORE_IMAGE_EXTRA_INSTALL += "wayland weston" - - -
-
- -
- Running Weston - - - To run Weston inside X11, enabling it as described earlier and - building a Sato image is sufficient. - If you are running your image under Sato, a Weston Launcher - appears in the "Utility" category. - - - - Alternatively, you can run Weston through the command-line - interpretor (CLI), which is better suited for development work. - To run Weston under the CLI, you need to do the following after - your image is built: - - - Run these commands to export - XDG_RUNTIME_DIR: - - mkdir -p /tmp/$USER-weston - chmod 0700 /tmp/$USER-weston - export XDG_RUNTIME_DIR=/tmp/$USER-weston - - - - Launch Weston in the shell: - - weston - - - -
-
- -
- Licenses - - - This section describes the mechanism by which the OpenEmbedded - build system tracks changes to licensing text. - The section also describes how to enable commercially licensed - recipes, which by default are disabled. - - - - For information that can help you maintain compliance with - various open source licensing during the lifecycle of the product, - see the - "Maintaining Open Source License Compliance During Your Project's Lifecycle" - section in the Yocto Project Development Tasks Manual. - - -
- Tracking License Changes - - - The license of an upstream project might change in the future. - In order to prevent these changes going unnoticed, the - LIC_FILES_CHKSUM - variable tracks changes to the license text. The checksums are - validated at the end of the configure step, and if the - checksums do not match, the build will fail. - - -
- Specifying the <filename>LIC_FILES_CHKSUM</filename> Variable - - - The LIC_FILES_CHKSUM - variable contains checksums of the license text in the - source code for the recipe. - Following is an example of how to specify - LIC_FILES_CHKSUM: - - LIC_FILES_CHKSUM = "file://COPYING;md5=xxxx \ - file://licfile1.txt;beginline=5;endline=29;md5=yyyy \ - file://licfile2.txt;endline=50;md5=zzzz \ - ..." - - Notes - - - When using "beginline" and "endline", realize - that line numbering begins with one and not - zero. - Also, the included lines are inclusive (i.e. - lines five through and including 29 in the - previous example for - licfile1.txt). - - - When a license check fails, the selected license - text is included as part of the QA message. - Using this output, you can determine the exact - start and finish for the needed license text. - - - - - - - The build system uses the - S - variable as the default directory when searching files - listed in LIC_FILES_CHKSUM. - The previous example employs the default directory. - - - - Consider this next example: - - LIC_FILES_CHKSUM = "file://src/ls.c;beginline=5;endline=16;\ - md5=bb14ed3c4cda583abc85401304b5cd4e" - LIC_FILES_CHKSUM = "file://${WORKDIR}/license.html;md5=5c94767cedb5d6987c902ac850ded2c6" - - - - - The first line locates a file in - ${S}/src/ls.c and isolates lines five - through 16 as license text. - The second line refers to a file in - WORKDIR. - - - - Note that LIC_FILES_CHKSUM variable is - mandatory for all recipes, unless the - LICENSE variable is set to "CLOSED". - -
- -
- Explanation of Syntax - - - As mentioned in the previous section, the - LIC_FILES_CHKSUM variable lists all - the important files that contain the license text for the - source code. - It is possible to specify a checksum for an entire file, - or a specific section of a file (specified by beginning and - ending line numbers with the "beginline" and "endline" - parameters, respectively). - The latter is useful for source files with a license - notice header, README documents, and so forth. - If you do not use the "beginline" parameter, then it is - assumed that the text begins on the first line of the file. - Similarly, if you do not use the "endline" parameter, - it is assumed that the license text ends with the last - line of the file. - - - - The "md5" parameter stores the md5 checksum of the license - text. - If the license text changes in any way as compared to - this parameter then a mismatch occurs. - This mismatch triggers a build failure and notifies - the developer. - Notification allows the developer to review and address - the license text changes. - Also note that if a mismatch occurs during the build, - the correct md5 checksum is placed in the build log and - can be easily copied to the recipe. - - - - There is no limit to how many files you can specify using - the LIC_FILES_CHKSUM variable. - Generally, however, every project requires a few - specifications for license tracking. - Many projects have a "COPYING" file that stores the - license information for all the source code files. - This practice allows you to just track the "COPYING" - file as long as it is kept up to date. - Tips - - - If you specify an empty or invalid "md5" - parameter, BitBake returns an md5 mis-match - error and displays the correct "md5" parameter - value during the build. - The correct parameter is also captured in - the build log. - - - If the whole file contains only license text, - you do not need to use the "beginline" and - "endline" parameters. - - - - -
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- -
- Enabling Commercially Licensed Recipes - - - By default, the OpenEmbedded build system disables - components that have commercial or other special licensing - requirements. - Such requirements are defined on a - recipe-by-recipe basis through the - LICENSE_FLAGS - variable definition in the affected recipe. - For instance, the - poky/meta/recipes-multimedia/gstreamer/gst-plugins-ugly - recipe contains the following statement: - - LICENSE_FLAGS = "commercial" - - Here is a slightly more complicated example that contains both - an explicit recipe name and version (after variable expansion): - - LICENSE_FLAGS = "license_${PN}_${PV}" - - In order for a component restricted by a - LICENSE_FLAGS definition to be enabled and - included in an image, it needs to have a matching entry in the - global - LICENSE_FLAGS_WHITELIST - variable, which is a variable typically defined in your - local.conf file. - For example, to enable the - poky/meta/recipes-multimedia/gstreamer/gst-plugins-ugly - package, you could add either the string - "commercial_gst-plugins-ugly" or the more general string - "commercial" to LICENSE_FLAGS_WHITELIST. - See the - "License Flag Matching" - section for a full - explanation of how LICENSE_FLAGS matching - works. - Here is the example: - - LICENSE_FLAGS_WHITELIST = "commercial_gst-plugins-ugly" - - Likewise, to additionally enable the package built from the - recipe containing - LICENSE_FLAGS = "license_${PN}_${PV}", - and assuming that the actual recipe name was - emgd_1.10.bb, the following string would - enable that package as well as the original - gst-plugins-ugly package: - - LICENSE_FLAGS_WHITELIST = "commercial_gst-plugins-ugly license_emgd_1.10" - - As a convenience, you do not need to specify the complete - license string in the whitelist for every package. - You can use an abbreviated form, which consists - of just the first portion or portions of the license - string before the initial underscore character or characters. - A partial string will match any license that contains the - given string as the first portion of its license. - For example, the following whitelist string will also match - both of the packages previously mentioned as well as any other - packages that have licenses starting with "commercial" or - "license". - - LICENSE_FLAGS_WHITELIST = "commercial license" - - - -
- License Flag Matching - - - License flag matching allows you to control what recipes - the OpenEmbedded build system includes in the build. - Fundamentally, the build system attempts to match - LICENSE_FLAGS - strings found in recipes against - LICENSE_FLAGS_WHITELIST - strings found in the whitelist. - A match causes the build system to include a recipe in the - build, while failure to find a match causes the build - system to exclude a recipe. - - - - In general, license flag matching is simple. - However, understanding some concepts will help you - correctly and effectively use matching. - - - - Before a flag - defined by a particular recipe is tested against the - contents of the whitelist, the expanded string - _${PN} is appended to the flag. - This expansion makes each - LICENSE_FLAGS value recipe-specific. - After expansion, the string is then matched against the - whitelist. - Thus, specifying - LICENSE_FLAGS = "commercial" - in recipe "foo", for example, results in the string - "commercial_foo". - And, to create a match, that string must appear in the - whitelist. - - - - Judicious use of the LICENSE_FLAGS - strings and the contents of the - LICENSE_FLAGS_WHITELIST variable - allows you a lot of flexibility for including or excluding - recipes based on licensing. - For example, you can broaden the matching capabilities by - using license flags string subsets in the whitelist. - - When using a string subset, be sure to use the part of - the expanded string that precedes the appended - underscore character (e.g. - usethispart_1.3, - usethispart_1.4, and so forth). - - For example, simply specifying the string "commercial" in - the whitelist matches any expanded - LICENSE_FLAGS definition that starts - with the string "commercial" such as "commercial_foo" and - "commercial_bar", which are the strings the build system - automatically generates for hypothetical recipes named - "foo" and "bar" assuming those recipes simply specify the - following: - - LICENSE_FLAGS = "commercial" - - Thus, you can choose to exhaustively - enumerate each license flag in the whitelist and - allow only specific recipes into the image, or - you can use a string subset that causes a broader range of - matches to allow a range of recipes into the image. - - - - This scheme works even if the - LICENSE_FLAGS string already - has _${PN} appended. - For example, the build system turns the license flag - "commercial_1.2_foo" into "commercial_1.2_foo_foo" and - would match both the general "commercial" and the specific - "commercial_1.2_foo" strings found in the whitelist, as - expected. - - - - Here are some other scenarios: - - - You can specify a versioned string in the recipe - such as "commercial_foo_1.2" in a "foo" recipe. - The build system expands this string to - "commercial_foo_1.2_foo". - Combine this license flag with a whitelist that has - the string "commercial" and you match the flag - along with any other flag that starts with the - string "commercial". - - - Under the same circumstances, you can use - "commercial_foo" in the whitelist and the build - system not only matches "commercial_foo_1.2" but - also matches any license flag with the string - "commercial_foo", regardless of the version. - - - You can be very specific and use both the - package and version parts in the whitelist (e.g. - "commercial_foo_1.2") to specifically match a - versioned recipe. - - - -
- - -
-
- -
- x32 psABI - - - x32 processor-specific Application Binary Interface - (x32 psABI) - is a native 32-bit processor-specific ABI for - Intel 64 (x86-64) - architectures. - An ABI defines the calling conventions between functions in a - processing environment. - The interface determines what registers are used and what the sizes are - for various C data types. - - - - Some processing environments prefer using 32-bit applications even - when running on Intel 64-bit platforms. - Consider the i386 psABI, which is a very old 32-bit ABI for Intel - 64-bit platforms. - The i386 psABI does not provide efficient use and access of the - Intel 64-bit processor resources, leaving the system underutilized. - Now consider the x86_64 psABI. - This ABI is newer and uses 64-bits for data sizes and program - pointers. - The extra bits increase the footprint size of the programs, - libraries, and also increases the memory and file system size - requirements. - Executing under the x32 psABI enables user programs to utilize CPU - and system resources more efficiently while keeping the memory - footprint of the applications low. - Extra bits are used for registers but not for addressing mechanisms. - - - - The Yocto Project supports the final specifications of x32 psABI - as follows: - - - You can create packages and images in x32 psABI format on - x86_64 architecture targets. - - - You can successfully build recipes with the x32 toolchain. - - - You can create and boot - core-image-minimal and - core-image-sato images. - - - RPM Package Manager (RPM) support exists for x32 binaries. - - - Support for large images exists. - - - - - - For steps on how to use x32 psABI, see the - "Using x32 psABI" - section in the Yocto Project Development Tasks Manual. - -
- - diff --git a/documentation/overview-manual/overview-development-environment.xml b/documentation/overview-manual/overview-development-environment.xml deleted file mode 100644 index 7d177cecca..0000000000 --- a/documentation/overview-manual/overview-development-environment.xml +++ /dev/null @@ -1,2890 +0,0 @@ - %poky; ] > - - -The Yocto Project Development Environment - - - This chapter takes a look at the Yocto Project development - environment and also provides a detailed look at what goes on during - development in that environment. - The chapter provides Yocto Project Development environment concepts that - help you understand how work is accomplished in an open source environment, - which is very different as compared to work accomplished in a closed, - proprietary environment. - - - - Specifically, this chapter addresses open source philosophy, workflows, - Git, source repositories, licensing, recipe syntax, and development - syntax. - - -
- Introduction - - - The Yocto Project is an open-source collaboration project whose - focus is for developers of embedded Linux systems. - Among other things, the Yocto Project uses an - OpenEmbedded build system. - The build system, which is based on the OpenEmbedded (OE) project and - uses the - BitBake tool, - constructs complete Linux images for architectures based on ARM, MIPS, - PowerPC, x86 and x86-64. - - Historically, the OpenEmbedded build system, which is the - combination of BitBake and OE components, formed a reference - build host that was known as - "Poky" - (Pah-kee). - The term "Poky", as used throughout the Yocto Project Documentation - set, can have different meanings. - - The Yocto Project provides various ancillary tools for the embedded - developer and also features the Sato reference User Interface, which - is optimized for stylus-driven, low-resolution screens. - - - - - - - - - - Here are some highlights for the Yocto Project: - - - - - Provides a recent Linux kernel along with a set of system - commands and libraries suitable for the embedded - environment. - - - Makes available system components such as X11, GTK+, Qt, - Clutter, and SDL (among others) so you can create a rich user - experience on devices that have display hardware. - For devices that do not have a display or where you wish to - use alternative UI frameworks, these components need not be - installed. - - - Creates a focused and stable core compatible with the - OpenEmbedded project with which you can easily and reliably - build and develop. - - - Fully supports a wide range of hardware and device emulation - through the Quick EMUlator (QEMU). - - - Provides a layer mechanism that allows you to easily extend - the system, make customizations, and keep them organized. - - - - - You can use the Yocto Project to generate images for many kinds - of devices. - As mentioned earlier, the Yocto Project supports creation of - reference images that you can boot within and emulate using QEMU. - The standard example machines target QEMU full-system - emulation for 32-bit and 64-bit variants of x86, ARM, MIPS, and - PowerPC architectures. - Beyond emulation, you can use the layer mechanism to extend - support to just about any platform that Linux can run on and that - a toolchain can target. - - - - Another Yocto Project feature is the Sato reference User - Interface. - This optional UI that is based on GTK+ is intended for devices with - restricted screen sizes and is included as part of the - OpenEmbedded Core layer so that developers can test parts of the - software stack. - - - - While the Yocto Project does not provide a strict testing framework, - it does provide or generate for you artifacts that let you perform - target-level and emulated testing and debugging. - Additionally, if you are an - Eclipse IDE user, you can - install an Eclipse Yocto Plug-in to allow you to develop within that - familiar environment. - - - - By default, using the Yocto Project to build an image creates a Poky - distribution. - However, you can create your own distribution by providing key - Metadata. - A good example is Angstrom, which has had a distribution - based on the Yocto Project since its inception. - Other examples include commercial distributions like - Wind River Linux, - Mentor Embedded Linux, - ENEA Linux - and others. - See the "Creating Your Own Distribution" - section in the Yocto Project Development Tasks Manual for more - information. - -
- -
- Open Source Philosophy - - - Open source philosophy is characterized by software development - directed by peer production and collaboration through an active - community of developers. - Contrast this to the more standard centralized development models - used by commercial software companies where a finite set of developers - produces a product for sale using a defined set of procedures that - ultimately result in an end product whose architecture and source - material are closed to the public. - - - - Open source projects conceptually have differing concurrent agendas, - approaches, and production. - These facets of the development process can come from anyone in the - public (community) that has a stake in the software project. - The open source environment contains new copyright, licensing, domain, - and consumer issues that differ from the more traditional development - environment. - In an open source environment, the end product, source material, - and documentation are all available to the public at no cost. - - - - A benchmark example of an open source project is the Linux kernel, - which was initially conceived and created by Finnish computer science - student Linus Torvalds in 1991. - Conversely, a good example of a non-open source project is the - Windows family of operating - systems developed by - Microsoft Corporation. - - - - Wikipedia has a good historical description of the Open Source - Philosophy - here. - You can also find helpful information on how to participate in the - Linux Community - here. - -
- -
- Workflows - - - This section provides workflow concepts using the Yocto Project and - Git. - In particular, the information covers basic practices that describe - roles and actions in a collaborative development environment. - - If you are familiar with this type of development environment, you - might not want to read this section. - - - - - The Yocto Project files are maintained using Git in "master" - branches whose Git histories track every change and whose structures - provides branches for all diverging functionality. - Although there is no need to use Git, many open source projects do so. - - - - For the Yocto Project, a key individual called the "maintainer" is - responsible for the "master" branch of a given Git repository. - The "master" branch is the “upstream†repository from which final or - most recent builds of the project occur. - The maintainer is responsible for accepting changes from other - developers and for organizing the underlying branch structure to - reflect release strategies and so forth. - For information on finding out who is responsible for (maintains) - a particular area of code, see the - "Submitting a Change to the Yocto Project" - section of the Yocto Project Development Tasks Manual. - - - - - The Yocto Project poky Git repository also has an - upstream contribution Git repository named - poky-contrib. - You can see all the branches in this repository using the web interface - of the - Source Repositories organized - within the "Poky Support" area. - These branches temporarily hold changes to the project that have been - submitted or committed by the Yocto Project development team and by - community members who contribute to the project. - The maintainer determines if the changes are qualified to be moved - from the "contrib" branches into the "master" branch of the Git - repository. - - - - Developers (including contributing community members) create and - maintain cloned repositories of the upstream "master" branch. - The cloned repositories are local to their development platforms and - are used to develop changes. - When a developer is satisfied with a particular feature or change, - they "push" the changes to the appropriate "contrib" repository. - - - - Developers are responsible for keeping their local repository - up-to-date with "master". - They are also responsible for straightening out any conflicts that - might arise within files that are being worked on simultaneously by - more than one person. - All this work is done locally on the developer’s machine before - anything is pushed to a "contrib" area and examined at the maintainer’s - level. - - - - A somewhat formal method exists by which developers commit changes - and push them into the "contrib" area and subsequently request that - the maintainer include them into "master". - This process is called “submitting a patch†or "submitting a change." - For information on submitting patches and changes, see the - "Submitting a Change to the Yocto Project" - section in the Yocto Project Development Tasks Manual. - - - - To summarize the development workflow: a single point of entry - exists for changes into the project’s "master" branch of the - Git repository, which is controlled by the project’s maintainer. - And, a set of developers exist who independently develop, test, and - submit changes to "contrib" areas for the maintainer to examine. - The maintainer then chooses which changes are going to become a - permanent part of the project. - - - - - - - - While each development environment is unique, there are some best - practices or methods that help development run smoothly. - The following list describes some of these practices. - For more information about Git workflows, see the workflow topics in - the - Git Community Book. - - - Make Small Changes: - It is best to keep the changes you commit small as compared to - bundling many disparate changes into a single commit. - This practice not only keeps things manageable but also allows - the maintainer to more easily include or refuse changes. - - It is also good practice to leave the repository in a - state that allows you to still successfully build your project. - In other words, do not commit half of a feature, - then add the other half as a separate, later commit. - Each commit should take you from one buildable project state - to another buildable state. - - - Use Branches Liberally: - It is very easy to create, use, and delete local branches in - your working Git repository. - You can name these branches anything you like. - It is helpful to give them names associated with the particular - feature or change on which you are working. - Once you are done with a feature or change and have merged it - into your local master branch, simply discard the temporary - branch. - - - Merge Changes: - The git merge command allows you to take - the changes from one branch and fold them into another branch. - This process is especially helpful when more than a single - developer might be working on different parts of the same - feature. - Merging changes also automatically identifies any collisions - or "conflicts" that might happen as a result of the same lines - of code being altered by two different developers. - - - Manage Branches: - Because branches are easy to use, you should use a system - where branches indicate varying levels of code readiness. - For example, you can have a "work" branch to develop in, a - "test" branch where the code or change is tested, a "stage" - branch where changes are ready to be committed, and so forth. - As your project develops, you can merge code across the - branches to reflect ever-increasing stable states of the - development. - - - Use Push and Pull: - The push-pull workflow is based on the concept of developers - "pushing" local commits to a remote repository, which is - usually a contribution repository. - This workflow is also based on developers "pulling" known - states of the project down into their local development - repositories. - The workflow easily allows you to pull changes submitted by - other developers from the upstream repository into your - work area ensuring that you have the most recent software - on which to develop. - The Yocto Project has two scripts named - create-pull-request and - send-pull-request that ship with the - release to facilitate this workflow. - You can find these scripts in the scripts - folder of the - Source Directory. - For information on how to use these scripts, see the - "Using Scripts to Push a Change Upstream and Request a Pull" - section in the Yocto Project Development Tasks Manual. - - - Patch Workflow: - This workflow allows you to notify the maintainer through an - email that you have a change (or patch) you would like - considered for the "master" branch of the Git repository. - To send this type of change, you format the patch and then - send the email using the Git commands - git format-patch and - git send-email. - For information on how to use these scripts, see the - "Submitting a Change to the Yocto Project" - section in the Yocto Project Development Tasks Manual. - - - -
- -
- Git - - - The Yocto Project makes extensive use of Git, which is a - free, open source distributed version control system. - Git supports distributed development, non-linear development, - and can handle large projects. - It is best that you have some fundamental understanding - of how Git tracks projects and how to work with Git if - you are going to use the Yocto Project for development. - This section provides a quick overview of how Git works and - provides you with a summary of some essential Git commands. - Notes - - - For more information on Git, see - . - - - If you need to download Git, it is recommended that you add - Git to your system through your distribution's "software - store" (e.g. for Ubuntu, use the Ubuntu Software feature). - For the Git download page, see - . - - - For examples beyond the limited few in this section on how - to use Git with the Yocto Project, see the - "Working With Yocto Project Source Files" - section in the Yocto Project Development Tasks Manual. - - - - - -
- Repositories, Tags, and Branches - - - As mentioned briefly in the previous section and also in the - "Workflows" section, - the Yocto Project maintains source repositories at - . - If you look at this web-interface of the repositories, each item - is a separate Git repository. - - - - Git repositories use branching techniques that track content - change (not files) within a project (e.g. a new feature or updated - documentation). - Creating a tree-like structure based on project divergence allows - for excellent historical information over the life of a project. - This methodology also allows for an environment from which you can - do lots of local experimentation on projects as you develop - changes or new features. - - - - A Git repository represents all development efforts for a given - project. - For example, the Git repository poky contains - all changes and developments for Poky over the course of its - entire life. - That means that all changes that make up all releases are captured. - The repository maintains a complete history of changes. - - - - You can create a local copy of any repository by "cloning" it - with the git clone command. - When you clone a Git repository, you end up with an identical - copy of the repository on your development system. - Once you have a local copy of a repository, you can take steps to - develop locally. - For examples on how to clone Git repositories, see the - "Working With Yocto Project Source Files" - section in the Yocto Project Development Tasks Manual. - - - - It is important to understand that Git tracks content change and - not files. - Git uses "branches" to organize different development efforts. - For example, the poky repository has - several branches that include the current "&DISTRO_NAME_NO_CAP;" - branch, the "master" branch, and many branches for past - Yocto Project releases. - You can see all the branches by going to - and - clicking on the - [...] - link beneath the "Branch" heading. - - - - Each of these branches represents a specific area of development. - The "master" branch represents the current or most recent - development. - All other branches represent offshoots of the "master" branch. - - - - When you create a local copy of a Git repository, the copy has - the same set of branches as the original. - This means you can use Git to create a local working area - (also called a branch) that tracks a specific development branch - from the upstream source Git repository. - in other words, you can define your local Git environment to - work on any development branch in the repository. - To help illustrate, consider the following example Git commands: - - $ cd ~ - $ git clone git://git.yoctoproject.org/poky - $ cd poky - $ git checkout -b &DISTRO_NAME_NO_CAP; origin/&DISTRO_NAME_NO_CAP; - - In the previous example after moving to the home directory, the - git clone command creates a - local copy of the upstream poky Git repository. - By default, Git checks out the "master" branch for your work. - After changing the working directory to the new local repository - (i.e. poky), the - git checkout command creates - and checks out a local branch named "&DISTRO_NAME_NO_CAP;", which - tracks the upstream "origin/&DISTRO_NAME_NO_CAP;" branch. - Changes you make while in this branch would ultimately affect - the upstream "&DISTRO_NAME_NO_CAP;" branch of the - poky repository. - - - - It is important to understand that when you create and checkout a - local working branch based on a branch name, - your local environment matches the "tip" of that particular - development branch at the time you created your local branch, - which could be different from the files in the "master" branch - of the upstream repository. - In other words, creating and checking out a local branch based on - the "&DISTRO_NAME_NO_CAP;" branch name is not the same as - cloning and checking out the "master" branch if the repository. - Keep reading to see how you create a local snapshot of a Yocto - Project Release. - - - - Git uses "tags" to mark specific changes in a repository. - Typically, a tag is used to mark a special point such as the final - change before a project is released. - You can see the tags used with the poky Git - repository by going to - and - clicking on the - [...] - link beneath the "Tag" heading. - - - - Some key tags for the poky are - jethro-14.0.3, - morty-16.0.1, - pyro-17.0.0, and - &DISTRO_NAME_NO_CAP;-&POKYVERSION;. - These tags represent Yocto Project releases. - - - - When you create a local copy of the Git repository, you also - have access to all the tags in the upstream repository. - Similar to branches, you can create and checkout a local working - Git branch based on a tag name. - When you do this, you get a snapshot of the Git repository that - reflects the state of the files when the change was made associated - with that tag. - The most common use is to checkout a working branch that matches - a specific Yocto Project release. - Here is an example: - - $ cd ~ - $ git clone git://git.yoctoproject.org/poky - $ cd poky - $ git fetch --all --tags --prune - $ git checkout tags/pyro-17.0.0 -b my-pyro-17.0.0 - - In this example, the name of the top-level directory of your - local Yocto Project repository is poky. - After moving to the poky directory, the - git fetch command makes all the upstream - tags available locally in your repository. - Finally, the git checkout command - creates and checks out a branch named "my-pyro-17.0.0" that is - based on the specific change upstream in the repository - associated with the "pyro-17.0.0" tag. - The files in your repository now exactly match that particular - Yocto Project release as it is tagged in the upstream Git - repository. - It is important to understand that when you create and - checkout a local working branch based on a tag, your environment - matches a specific point in time and not the entire development - branch (i.e. the "tip" of the branch). - -
- -
- Basic Commands - - - Git has an extensive set of commands that lets you manage changes - and perform collaboration over the life of a project. - Conveniently though, you can manage with a small set of basic - operations and workflows once you understand the basic - philosophy behind Git. - You do not have to be an expert in Git to be functional. - A good place to look for instruction on a minimal set of Git - commands is - here. - - - - If you do not know much about Git, you should educate - yourself by visiting the links previously mentioned. - - - - The following list of Git commands briefly describes some basic - Git operations as a way to get started. - As with any set of commands, this list (in most cases) simply shows - the base command and omits the many arguments they support. - See the Git documentation for complete descriptions and strategies - on how to use these commands: - - - git init: - Initializes an empty Git repository. - You cannot use Git commands unless you have a - .git repository. - - - git clone: - Creates a local clone of a Git repository that is on - equal footing with a fellow developer’s Git repository - or an upstream repository. - - - git add: - Locally stages updated file contents to the index that - Git uses to track changes. - You must stage all files that have changed before you - can commit them. - - - git commit: - Creates a local "commit" that documents the changes you - made. - Only changes that have been staged can be committed. - Commits are used for historical purposes, for determining - if a maintainer of a project will allow the change, - and for ultimately pushing the change from your local - Git repository into the project’s upstream repository. - - - git status: - Reports any modified files that possibly need to be - staged and gives you a status of where you stand regarding - local commits as compared to the upstream repository. - - - git checkout branch-name: - Changes your working branch. - This command is analogous to "cd". - - git checkout –b working-branch: - Creates and checks out a working branch on your local - machine that you can use to isolate your work. - It is a good idea to use local branches when adding - specific features or changes. - Using isolated branches facilitates easy removal of - changes if they do not work out. - - git branch: - Displays the existing local branches associated with your - local repository. - The branch that you have currently checked out is noted - with an asterisk character. - - - git branch -D branch-name: - Deletes an existing local branch. - You need to be in a local branch other than the one you - are deleting in order to delete - branch-name. - - - git pull: - Retrieves information from an upstream Git repository - and places it in your local Git repository. - You use this command to make sure you are synchronized with - the repository from which you are basing changes - (.e.g. the "master" branch). - - - git push: - Sends all your committed local changes to the upstream Git - repository that your local repository is tracking - (e.g. a contribution repository). - The maintainer of the project draws from these repositories - to merge changes (commits) into the appropriate branch - of project's upstream repository. - - - git merge: - Combines or adds changes from one - local branch of your repository with another branch. - When you create a local Git repository, the default branch - is named "master". - A typical workflow is to create a temporary branch that is - based off "master" that you would use for isolated work. - You would make your changes in that isolated branch, - stage and commit them locally, switch to the "master" - branch, and then use the git merge - command to apply the changes from your isolated branch - into the currently checked out branch (e.g. "master"). - After the merge is complete and if you are done with - working in that isolated branch, you can safely delete - the isolated branch. - - - git cherry-pick: - Choose and apply specific commits from one branch - into another branch. - There are times when you might not be able to merge - all the changes in one branch with - another but need to pick out certain ones. - - - gitk: - Provides a GUI view of the branches and changes in your - local Git repository. - This command is a good way to graphically see where things - have diverged in your local repository. - - You need to install the gitk - package on your development system to use this - command. - - - - git log: - Reports a history of your commits to the repository. - This report lists all commits regardless of whether you - have pushed them upstream or not. - - - git diff: - Displays line-by-line differences between a local - working file and the same file as understood by Git. - This command is useful to see what you have changed - in any given file. - - - -
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- -
- Yocto Project Source Repositories - - - The Yocto Project team maintains complete source repositories for all - Yocto Project files at - . - This web-based source code browser is organized into categories by - function such as IDE Plugins, Matchbox, Poky, Yocto Linux Kernel, and - so forth. - From the interface, you can click on any particular item in the "Name" - column and see the URL at the bottom of the page that you need to clone - a Git repository for that particular item. - Having a local Git repository of the - Source Directory, - which is usually named "poky", allows - you to make changes, contribute to the history, and ultimately enhance - the Yocto Project's tools, Board Support Packages, and so forth. - - - - For any supported release of Yocto Project, you can also go to the - Yocto Project Website and - select the "Downloads" tab and get a released tarball of the - poky repository or any supported BSP tarballs. - Unpacking these tarballs gives you a snapshot of the released - files. - Notes - - - The recommended method for setting up the Yocto Project - Source Directory - and the files for supported BSPs - (e.g., meta-intel) is to use - Git to create a local copy of - the upstream repositories. - - - Be sure to always work in matching branches for both - the selected BSP repository and the - Source Directory - (i.e. poky) repository. - For example, if you have checked out the "master" branch - of poky and you are going to use - meta-intel, be sure to checkout the - "master" branch of meta-intel. - - - - - - - In summary, here is where you can get the project files needed for - development: - - - - Source Repositories: - - This area contains IDE Plugins, Matchbox, Poky, Poky Support, - Tools, Yocto Linux Kernel, and Yocto Metadata Layers. - You can create local copies of Git repositories for each of - these areas. - - - - For steps on how to view and access these upstream Git - repositories, see the - "Accessing Source Repositories" - Section in the Yocto Project Development Tasks Manual. - - - - Index of /releases: - - This is an index of releases such as - the Eclipse - Yocto Plug-in, miscellaneous support, Poky, Pseudo, installers - for cross-development toolchains, and all released versions of - Yocto Project in the form of images or tarballs. - Downloading and extracting these files does not produce a local - copy of the Git repository but rather a snapshot of a - particular release or image. - - - - For steps on how to view and access these files, see the - "Accessing Index of Releases" - section in the Yocto Project Development Tasks Manual. - - - "Downloads" page for the - Yocto Project Website: - - - This section will change due to - reworking of the YP Website. - - The Yocto Project website includes a "Downloads" tab - that allows you to download any Yocto Project - release and Board Support Package (BSP) in tarball form. - The tarballs are similar to those found in the - Index of /releases: area. - - - - For steps on how to use the "Downloads" page, see the - "Using the Downloads Page" - section in the Yocto Project Development Tasks Manual. - - - -
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- Licensing - - - Because open source projects are open to the public, they have - different licensing structures in place. - License evolution for both Open Source and Free Software has an - interesting history. - If you are interested in this history, you can find basic information - here: - - - Open source license history - - - Free software license history - - - - - - In general, the Yocto Project is broadly licensed under the - Massachusetts Institute of Technology (MIT) License. - MIT licensing permits the reuse of software within proprietary - software as long as the license is distributed with that software. - MIT is also compatible with the GNU General Public License (GPL). - Patches to the Yocto Project follow the upstream licensing scheme. - You can find information on the MIT license - here. - You can find information on the GNU GPL - here. - - - - When you build an image using the Yocto Project, the build process - uses a known list of licenses to ensure compliance. - You can find this list in the - Source Directory - at meta/files/common-licenses. - Once the build completes, the list of all licenses found and used - during that build are kept in the - Build Directory - at tmp/deploy/licenses. - - - - If a module requires a license that is not in the base list, the - build process generates a warning during the build. - These tools make it easier for a developer to be certain of the - licenses with which their shipped products must comply. - However, even with these tools it is still up to the developer to - resolve potential licensing issues. - - - - The base list of licenses used by the build process is a combination - of the Software Package Data Exchange (SPDX) list and the Open - Source Initiative (OSI) projects. - SPDX Group is a working group of - the Linux Foundation that maintains a specification for a standard - format for communicating the components, licenses, and copyrights - associated with a software package. - OSI is a corporation - dedicated to the Open Source Definition and the effort for reviewing - and approving licenses that conform to the Open Source Definition - (OSD). - - - - You can find a list of the combined SPDX and OSI licenses that the - Yocto Project uses in the - meta/files/common-licenses directory in your - Source Directory. - - - - For information that can help you maintain compliance with various - open source licensing during the lifecycle of a product created using - the Yocto Project, see the - "Maintaining Open Source License Compliance During Your Product's Lifecycle" - section in the Yocto Project Development Tasks Manual. - -
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- Recipe Syntax - - - Understanding recipe file syntax is important for - writing recipes. - The following list overviews the basic items that make up a - BitBake recipe file. - For more complete BitBake syntax descriptions, see the - "Syntax and Operators" - chapter of the BitBake User Manual. - - Variable Assignments and Manipulations: - Variable assignments allow a value to be assigned to a - variable. - The assignment can be static text or might include - the contents of other variables. - In addition to the assignment, appending and prepending - operations are also supported. - The following example shows some of the ways - you can use variables in recipes: - - S = "${WORKDIR}/postfix-${PV}" - CFLAGS += "-DNO_ASM" - SRC_URI_append = " file://fixup.patch" - - - Functions: - Functions provide a series of actions to be performed. - You usually use functions to override the default - implementation of a task function or to complement - a default function (i.e. append or prepend to an - existing function). - Standard functions use sh shell - syntax, although access to OpenEmbedded variables and - internal methods are also available. - The following is an example function from the - sed recipe: - - do_install () { - autotools_do_install - install -d ${D}${base_bindir} - mv ${D}${bindir}/sed ${D}${base_bindir}/sed - rmdir ${D}${bindir}/ - } - - It is also possible to implement new functions that - are called between existing tasks as long as the - new functions are not replacing or complementing the - default functions. - You can implement functions in Python - instead of shell. - Both of these options are not seen in the majority of - recipes. - Keywords: - BitBake recipes use only a few keywords. - You use keywords to include common - functions (inherit), load parts - of a recipe from other files - (include and - require) and export variables - to the environment (export). - The following example shows the use of some of - these keywords: - - export POSTCONF = "${STAGING_BINDIR}/postconf" - inherit autoconf - require otherfile.inc - - - Comments: - Any lines that begin with the hash character - (#) are treated as comment lines - and are ignored: - - # This is a comment - - - - - - - This next list summarizes the most important and most commonly - used parts of the recipe syntax. - For more information on these parts of the syntax, you can - reference the - Syntax and Operators - chapter in the BitBake User Manual. - - Line Continuation: \ - - Use the backward slash (\) - character to split a statement over multiple lines. - Place the slash character at the end of the line that - is to be continued on the next line: - - VAR = "A really long \ - line" - - - You cannot have any characters including spaces - or tabs after the slash character. - - - - Using Variables: ${...} - - Use the ${VARNAME} syntax to - access the contents of a variable: - - SRC_URI = "${SOURCEFORGE_MIRROR}/libpng/zlib-${PV}.tar.gz" - - - It is important to understand that the value of a - variable expressed in this form does not get - substituted automatically. - The expansion of these expressions happens - on-demand later (e.g. usually when a function that - makes reference to the variable executes). - This behavior ensures that the values are most - appropriate for the context in which they are - finally used. - On the rare occasion that you do need the variable - expression to be expanded immediately, you can use - the := operator instead of - = when you make the - assignment, but this is not generally needed. - - - Quote All Assignments: "value" - - Use double quotes around the value in all variable - assignments. - - VAR1 = "${OTHERVAR}" - VAR2 = "The version is ${PV}" - - - Conditional Assignment: ?= - - Conditional assignment is used to assign a value to - a variable, but only when the variable is currently - unset. - Use the question mark followed by the equal sign - (?=) to make a "soft" assignment - used for conditional assignment. - Typically, "soft" assignments are used in the - local.conf file for variables - that are allowed to come through from the external - environment. - - Here is an example where - VAR1 is set to "New value" if - it is currently empty. - However, if VAR1 has already been - set, it remains unchanged: - - VAR1 ?= "New value" - - In this next example, VAR1 - is left with the value "Original value": - - VAR1 = "Original value" - VAR1 ?= "New value" - - - Appending: += - - Use the plus character followed by the equals sign - (+=) to append values to existing - variables. - - This operator adds a space between the existing - content of the variable and the new content. - - Here is an example: - - SRC_URI += "file://fix-makefile.patch" - - - Prepending: =+ - - Use the equals sign followed by the plus character - (=+) to prepend values to existing - variables. - - This operator adds a space between the new content - and the existing content of the variable. - - Here is an example: - - VAR =+ "Starts" - - - Appending: _append - - Use the _append operator to - append values to existing variables. - This operator does not add any additional space. - Also, the operator is applied after all the - +=, and - =+ operators have been applied and - after all = assignments have - occurred. - - The following example shows the space being - explicitly added to the start to ensure the appended - value is not merged with the existing value: - - SRC_URI_append = " file://fix-makefile.patch" - - You can also use the _append - operator with overrides, which results in the actions - only being performed for the specified target or - machine: - - SRC_URI_append_sh4 = " file://fix-makefile.patch" - - - Prepending: _prepend - - Use the _prepend operator to - prepend values to existing variables. - This operator does not add any additional space. - Also, the operator is applied after all the - +=, and - =+ operators have been applied and - after all = assignments have - occurred. - - The following example shows the space being - explicitly added to the end to ensure the prepended - value is not merged with the existing value: - - CFLAGS_prepend = "-I${S}/myincludes " - - You can also use the _prepend - operator with overrides, which results in the actions - only being performed for the specified target or - machine: - - CFLAGS_prepend_sh4 = "-I${S}/myincludes " - - - Overrides: - - You can use overrides to set a value conditionally, - typically based on how the recipe is being built. - For example, to set the - KBRANCH - variable's value to "standard/base" for any target - MACHINE, - except for qemuarm where it should be set to - "standard/arm-versatile-926ejs", you would do the - following: - - KBRANCH = "standard/base" - KBRANCH_qemuarm = "standard/arm-versatile-926ejs" - - Overrides are also used to separate alternate values - of a variable in other situations. - For example, when setting variables such as - FILES - and - RDEPENDS - that are specific to individual packages produced by - a recipe, you should always use an override that - specifies the name of the package. - - Indentation: - Use spaces for indentation rather than than tabs. - For shell functions, both currently work. - However, it is a policy decision of the Yocto Project - to use tabs in shell functions. - Realize that some layers have a policy to use spaces - for all indentation. - - Using Python for Complex Operations: ${@python_code} - - For more advanced processing, it is possible to use - Python code during variable assignments (e.g. - search and replacement on a variable). - You indicate Python code using the - ${@python_code} - syntax for the variable assignment: - - SRC_URI = "ftp://ftp.info-zip.org/pub/infozip/src/zip${@d.getVar('PV',1).replace('.', '')}.tgz - - - Shell Function Syntax: - Write shell functions as if you were writing a shell - script when you describe a list of actions to take. - You should ensure that your script works with a generic - sh and that it does not require - any bash or other shell-specific - functionality. - The same considerations apply to various system - utilities (e.g. sed, - grep, awk, - and so forth) that you might wish to use. - If in doubt, you should check with multiple - implementations - including those from BusyBox. - - - -
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- Development Concepts - - - This section takes a more detailed look inside the development - process. - The following diagram represents development at a high level. - The remainder of this chapter expands on the fundamental input, output, - process, and - Metadata) blocks - that make up development in the Yocto Project environment. - - - - - - - - In general, development consists of several functional areas: - - User Configuration: - Metadata you can use to control the build process. - - Metadata Layers: - Various layers that provide software, machine, and - distro Metadata. - Source Files: - Upstream releases, local projects, and SCMs. - Build System: - Processes under the control of - BitBake. - This block expands on how BitBake fetches source, applies - patches, completes compilation, analyzes output for package - generation, creates and tests packages, generates images, and - generates cross-development tools. - Package Feeds: - Directories containing output packages (RPM, DEB or IPK), - which are subsequently used in the construction of an image or - SDK, produced by the build system. - These feeds can also be copied and shared using a web server or - other means to facilitate extending or updating existing - images on devices at runtime if runtime package management is - enabled. - Images: - Images produced by the development process. - - Application Development SDK: - Cross-development tools that are produced along with an image - or separately with BitBake. - - - -
- User Configuration - - - User configuration helps define the build. - Through user configuration, you can tell BitBake the - target architecture for which you are building the image, - where to store downloaded source, and other build properties. - - - - The following figure shows an expanded representation of the - "User Configuration" box of the - general Yocto Project Development Environment figure: - - - - - - - - BitBake needs some basic configuration files in order to complete - a build. - These files are *.conf files. - The minimally necessary ones reside as example files in the - Source Directory. - For simplicity, this section refers to the Source Directory as - the "Poky Directory." - - - - When you clone the poky Git repository or you - download and unpack a Yocto Project release, you can set up the - Source Directory to be named anything you want. - For this discussion, the cloned repository uses the default - name poky. - - The Poky repository is primarily an aggregation of existing - repositories. - It is not a canonical upstream source. - - - - - The meta-poky layer inside Poky contains - a conf directory that has example - configuration files. - These example files are used as a basis for creating actual - configuration files when you source the build environment - script - (i.e. - &OE_INIT_FILE;). - - - - Sourcing the build environment script creates a - Build Directory - if one does not already exist. - BitBake uses the Build Directory for all its work during builds. - The Build Directory has a conf directory that - contains default versions of your local.conf - and bblayers.conf configuration files. - These default configuration files are created only if versions - do not already exist in the Build Directory at the time you - source the build environment setup script. - - - - Because the Poky repository is fundamentally an aggregation of - existing repositories, some users might be familiar with running - the &OE_INIT_FILE; script in the context - of separate OpenEmbedded-Core and BitBake repositories rather than a - single Poky repository. - This discussion assumes the script is executed from within a cloned - or unpacked version of Poky. - - - - Depending on where the script is sourced, different sub-scripts - are called to set up the Build Directory (Yocto or OpenEmbedded). - Specifically, the script - scripts/oe-setup-builddir inside the - poky directory sets up the Build Directory and seeds the directory - (if necessary) with configuration files appropriate for the - Yocto Project development environment. - - The scripts/oe-setup-builddir script - uses the $TEMPLATECONF variable to - determine which sample configuration files to locate. - - - - - The local.conf file provides many - basic variables that define a build environment. - Here is a list of a few. - To see the default configurations in a local.conf - file created by the build environment script, see the - local.conf.sample in the - meta-poky layer: - - Parallelism Options: - Controlled by the - BB_NUMBER_THREADS, - PARALLEL_MAKE, - and - BB_NUMBER_PARSE_THREADS - variables. - Target Machine Selection: - Controlled by the - MACHINE - variable. - Download Directory: - Controlled by the - DL_DIR - variable. - Shared State Directory: - Controlled by the - SSTATE_DIR - variable. - Build Output: - Controlled by the - TMPDIR - variable. - - - Configurations set in the conf/local.conf - file can also be set in the - conf/site.conf and - conf/auto.conf configuration files. - - - - - The bblayers.conf file tells BitBake what - layers you want considered during the build. - By default, the layers listed in this file include layers - minimally needed by the build system. - However, you must manually add any custom layers you have created. - You can find more information on working with the - bblayers.conf file in the - "Enabling Your Layer" - section in the Yocto Project Development Tasks Manual. - - - - The files site.conf and - auto.conf are not created by the environment - initialization script. - If you want the site.conf file, you need to - create that yourself. - The auto.conf file is typically created by - an autobuilder: - - site.conf: - You can use the conf/site.conf - configuration file to configure multiple build directories. - For example, suppose you had several build environments and - they shared some common features. - You can set these default build properties here. - A good example is perhaps the packaging format to use - through the - PACKAGE_CLASSES - variable. - One useful scenario for using the - conf/site.conf file is to extend your - BBPATH - variable to include the path to a - conf/site.conf. - Then, when BitBake looks for Metadata using - BBPATH, it finds the - conf/site.conf file and applies your - common configurations found in the file. - To override configurations in a particular build directory, - alter the similar configurations within that build - directory's conf/local.conf file. - - auto.conf: - The file is usually created and written to by - an autobuilder. - The settings put into the file are typically the same as - you would find in the conf/local.conf - or the conf/site.conf files. - - - - - - You can edit all configuration files to further define - any particular build environment. - This process is represented by the "User Configuration Edits" - box in the figure. - - - - When you launch your build with the - bitbake target - command, BitBake sorts out the configurations to ultimately - define your build environment. - It is important to understand that the OpenEmbedded build system - reads the configuration files in a specific order: - site.conf, auto.conf, - and local.conf. - And, the build system applies the normal assignment statement - rules. - Because the files are parsed in a specific order, variable - assignments for the same variable could be affected. - For example, if the auto.conf file and - the local.conf set - variable1 to different values, because - the build system parses local.conf after - auto.conf, - variable1 is assigned the value from - the local.conf file. - -
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- Metadata, Machine Configuration, and Policy Configuration - - - The previous section described the user configurations that - define BitBake's global behavior. - This section takes a closer look at the layers the build system - uses to further control the build. - These layers provide Metadata for the software, machine, and - policy. - - - - In general, three types of layer input exist: - - Policy Configuration: - Distribution Layers provide top-level or general - policies for the image or SDK being built. - For example, this layer would dictate whether BitBake - produces RPM or IPK packages. - Machine Configuration: - Board Support Package (BSP) layers provide machine - configurations. - This type of information is specific to a particular - target architecture. - Metadata: - Software layers contain user-supplied recipe files, - patches, and append files. - - - - - - The following figure shows an expanded representation of the - Metadata, Machine Configuration, and Policy Configuration input - (layers) boxes of the - general Yocto Project Development Environment figure: - - - - - - - - In general, all layers have a similar structure. - They all contain a licensing file - (e.g. COPYING) if the layer is to be - distributed, a README file as good practice - and especially if the layer is to be distributed, a - configuration directory, and recipe directories. - - - - The Yocto Project has many layers that can be used. - You can see a web-interface listing of them on the - Source Repositories - page. - The layers are shown at the bottom categorized under - "Yocto Metadata Layers." - These layers are fundamentally a subset of the - OpenEmbedded Metadata Index, - which lists all layers provided by the OpenEmbedded community. - - Layers exist in the Yocto Project Source Repositories that - cannot be found in the OpenEmbedded Metadata Index. - These layers are either deprecated or experimental in nature. - - - - - BitBake uses the conf/bblayers.conf file, - which is part of the user configuration, to find what layers it - should be using as part of the build. - - - - For more information on layers, see the - "Understanding and Creating Layers" - section in the Yocto Project Development Tasks Manual. - - -
- Distro Layer - - - The distribution layer provides policy configurations for your - distribution. - Best practices dictate that you isolate these types of - configurations into their own layer. - Settings you provide in - conf/distro/distro.conf override - similar - settings that BitBake finds in your - conf/local.conf file in the Build - Directory. - - - - The following list provides some explanation and references - for what you typically find in the distribution layer: - - classes: - Class files (.bbclass) hold - common functionality that can be shared among - recipes in the distribution. - When your recipes inherit a class, they take on the - settings and functions for that class. - You can read more about class files in the - "Classes" - section of the Yocto Reference Manual. - - conf: - This area holds configuration files for the - layer (conf/layer.conf), - the distribution - (conf/distro/distro.conf), - and any distribution-wide include files. - - recipes-*: - Recipes and append files that affect common - functionality across the distribution. - This area could include recipes and append files - to add distribution-specific configuration, - initialization scripts, custom image recipes, - and so forth. - - -
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- BSP Layer - - - The BSP Layer provides machine configurations. - Everything in this layer is specific to the machine for which - you are building the image or the SDK. - A common structure or form is defined for BSP layers. - You can learn more about this structure in the - Yocto Project Board Support Package (BSP) Developer's Guide. - - In order for a BSP layer to be considered compliant with the - Yocto Project, it must meet some structural requirements. - - - - - The BSP Layer's configuration directory contains - configuration files for the machine - (conf/machine/machine.conf) and, - of course, the layer (conf/layer.conf). - - - - The remainder of the layer is dedicated to specific recipes - by function: recipes-bsp, - recipes-core, - recipes-graphics, and - recipes-kernel. - Metadata can exist for multiple formfactors, graphics - support systems, and so forth. - - While the figure shows several recipes-* - directories, not all these directories appear in all - BSP layers. - - -
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- Software Layer - - - The software layer provides the Metadata for additional - software packages used during the build. - This layer does not include Metadata that is specific to the - distribution or the machine, which are found in their - respective layers. - - - - This layer contains any new recipes that your project needs - in the form of recipe files. - -
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- Sources - - - In order for the OpenEmbedded build system to create an image or - any target, it must be able to access source files. - The - general Yocto Project Development Environment figure - represents source files using the "Upstream Project Releases", - "Local Projects", and "SCMs (optional)" boxes. - The figure represents mirrors, which also play a role in locating - source files, with the "Source Mirror(s)" box. - - - - The method by which source files are ultimately organized is - a function of the project. - For example, for released software, projects tend to use tarballs - or other archived files that can capture the state of a release - guaranteeing that it is statically represented. - On the other hand, for a project that is more dynamic or - experimental in nature, a project might keep source files in a - repository controlled by a Source Control Manager (SCM) such as - Git. - Pulling source from a repository allows you to control - the point in the repository (the revision) from which you want to - build software. - Finally, a combination of the two might exist, which would give the - consumer a choice when deciding where to get source files. - - - - BitBake uses the - SRC_URI - variable to point to source files regardless of their location. - Each recipe must have a SRC_URI variable - that points to the source. - - - - Another area that plays a significant role in where source files - come from is pointed to by the - DL_DIR - variable. - This area is a cache that can hold previously downloaded source. - You can also instruct the OpenEmbedded build system to create - tarballs from Git repositories, which is not the default behavior, - and store them in the DL_DIR by using the - BB_GENERATE_MIRROR_TARBALLS - variable. - - - - Judicious use of a DL_DIR directory can - save the build system a trip across the Internet when looking - for files. - A good method for using a download directory is to have - DL_DIR point to an area outside of your - Build Directory. - Doing so allows you to safely delete the Build Directory - if needed without fear of removing any downloaded source file. - - - - The remainder of this section provides a deeper look into the - source files and the mirrors. - Here is a more detailed look at the source file area of the - base figure: - - - -
- Upstream Project Releases - - - Upstream project releases exist anywhere in the form of an - archived file (e.g. tarball or zip file). - These files correspond to individual recipes. - For example, the figure uses specific releases each for - BusyBox, Qt, and Dbus. - An archive file can be for any released product that can be - built using a recipe. - -
- -
- Local Projects - - - Local projects are custom bits of software the user provides. - These bits reside somewhere local to a project - perhaps - a directory into which the user checks in items (e.g. - a local directory containing a development source tree - used by the group). - - - - The canonical method through which to include a local project - is to use the - externalsrc - class to include that local project. - You use either the local.conf or a - recipe's append file to override or set the - recipe to point to the local directory on your disk to pull - in the whole source tree. - - - - For information on how to use the - externalsrc class, see the - "externalsrc.bbclass" - section. - -
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- Source Control Managers (Optional) - - - Another place the build system can get source files from is - through an SCM such as Git or Subversion. - In this case, a repository is cloned or checked out. - The - do_fetch - task inside BitBake uses - the SRC_URI - variable and the argument's prefix to determine the correct - fetcher module. - - - - For information on how to have the OpenEmbedded build system - generate tarballs for Git repositories and place them in the - DL_DIR - directory, see the - BB_GENERATE_MIRROR_TARBALLS - variable. - - - - When fetching a repository, BitBake uses the - SRCREV - variable to determine the specific revision from which to - build. - -
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- Source Mirror(s) - - - Two kinds of mirrors exist: pre-mirrors and regular mirrors. - The - PREMIRRORS - and - MIRRORS - variables point to these, respectively. - BitBake checks pre-mirrors before looking upstream for any - source files. - Pre-mirrors are appropriate when you have a shared directory - that is not a directory defined by the - DL_DIR - variable. - A Pre-mirror typically points to a shared directory that is - local to your organization. - - - - Regular mirrors can be any site across the Internet that is - used as an alternative location for source code should the - primary site not be functioning for some reason or another. - -
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- -
- Package Feeds - - - When the OpenEmbedded build system generates an image or an SDK, - it gets the packages from a package feed area located in the - Build Directory. - The - general Yocto Project Development Environment figure - shows this package feeds area in the upper-right corner. - - - - This section looks a little closer into the package feeds area used - by the build system. - Here is a more detailed look at the area: - - - - - Package feeds are an intermediary step in the build process. - The OpenEmbedded build system provides classes to generate - different package types, and you specify which classes to enable - through the - PACKAGE_CLASSES - variable. - Before placing the packages into package feeds, - the build process validates them with generated output quality - assurance checks through the - insane - class. - - - - The package feed area resides in the Build Directory. - The directory the build system uses to temporarily store packages - is determined by a combination of variables and the particular - package manager in use. - See the "Package Feeds" box in the illustration and note the - information to the right of that area. - In particular, the following defines where package files are - kept: - - DEPLOY_DIR: - Defined as tmp/deploy in the Build - Directory. - - DEPLOY_DIR_*: - Depending on the package manager used, the package type - sub-folder. - Given RPM, IPK, or DEB packaging and tarball creation, the - DEPLOY_DIR_RPM, - DEPLOY_DIR_IPK, - DEPLOY_DIR_DEB, - or - DEPLOY_DIR_TAR, - variables are used, respectively. - - PACKAGE_ARCH: - Defines architecture-specific sub-folders. - For example, packages could exist for the i586 or qemux86 - architectures. - - - - - - BitBake uses the do_package_write_* tasks to - generate packages and place them into the package holding area (e.g. - do_package_write_ipk for IPK packages). - See the - "do_package_write_deb", - "do_package_write_ipk", - "do_package_write_rpm", - and - "do_package_write_tar" - sections for additional information. - As an example, consider a scenario where an IPK packaging manager - is being used and package architecture support for both i586 - and qemux86 exist. - Packages for the i586 architecture are placed in - build/tmp/deploy/ipk/i586, while packages for - the qemux86 architecture are placed in - build/tmp/deploy/ipk/qemux86. - -
- -
- BitBake - - - The OpenEmbedded build system uses - BitBake - to produce images. - You can see from the - general Yocto Project Development Environment figure, - the BitBake area consists of several functional areas. - This section takes a closer look at each of those areas. - - - - Separate documentation exists for the BitBake tool. - See the - BitBake User Manual - for reference material on BitBake. - - -
- Source Fetching - - - The first stages of building a recipe are to fetch and unpack - the source code: - - - - - The - do_fetch - and - do_unpack - tasks fetch the source files and unpack them into the work - directory. - - For every local file (e.g. file://) - that is part of a recipe's - SRC_URI - statement, the OpenEmbedded build system takes a checksum - of the file for the recipe and inserts the checksum into - the signature for the do_fetch. - If any local file has been modified, the - do_fetch task and all tasks that - depend on it are re-executed. - - By default, everything is accomplished in the - Build Directory, - which has a defined structure. - For additional general information on the Build Directory, - see the - "build/" - section in the Yocto Project Reference Manual. - - - - Unpacked source files are pointed to by the - S - variable. - Each recipe has an area in the Build Directory where the - unpacked source code resides. - The name of that directory for any given recipe is defined from - several different variables. - You can see the variables that define these directories - by looking at the figure: - - TMPDIR - - The base directory where the OpenEmbedded build system - performs all its work during the build. - - PACKAGE_ARCH - - The architecture of the built package or packages. - - TARGET_OS - - The operating system of the target device. - - PN - - The name of the built package. - - PV - - The version of the recipe used to build the package. - - PR - - The revision of the recipe used to build the package. - - WORKDIR - - The location within TMPDIR where - a specific package is built. - - S - - Contains the unpacked source files for a given recipe. - - - -
- -
- Patching - - - Once source code is fetched and unpacked, BitBake locates - patch files and applies them to the source files: - - - - - The - do_patch - task processes recipes by - using the - SRC_URI - variable to locate applicable patch files, which by default - are *.patch or - *.diff files, or any file if - "apply=yes" is specified for the file in - SRC_URI. - - - - BitBake finds and applies multiple patches for a single recipe - in the order in which it finds the patches. - Patches are applied to the recipe's source files located in the - S - directory. - - - - For more information on how the source directories are - created, see the - "Source Fetching" - section. - -
- -
- Configuration and Compilation - - - After source code is patched, BitBake executes tasks that - configure and compile the source code: - - - - - This step in the build process consists of three tasks: - - - do_prepare_recipe_sysroot: - This task sets up the two sysroots in - ${WORKDIR} - (i.e. recipe-sysroot and - recipe-sysroot-native) so that - the sysroots contain the contents of the - do_populate_sysroot - tasks of the recipes on which the recipe - containing the tasks depends. - A sysroot exists for both the target and for the native - binaries, which run on the host system. - - do_configure: - This task configures the source by enabling and - disabling any build-time and configuration options for - the software being built. - Configurations can come from the recipe itself as well - as from an inherited class. - Additionally, the software itself might configure itself - depending on the target for which it is being built. - - - The configurations handled by the - do_configure - task are specific - to source code configuration for the source code - being built by the recipe. - - If you are using the - autotools - class, - you can add additional configuration options by using - the - EXTRA_OECONF - or - PACKAGECONFIG_CONFARGS - variables. - For information on how this variable works within - that class, see the - meta/classes/autotools.bbclass file. - - do_compile: - Once a configuration task has been satisfied, BitBake - compiles the source using the - do_compile - task. - Compilation occurs in the directory pointed to by the - B - variable. - Realize that the B directory is, by - default, the same as the - S - directory. - do_install: - Once compilation is done, BitBake executes the - do_install - task. - This task copies files from the B - directory and places them in a holding area pointed to - by the - D - variable. - - -
- -
- Package Splitting - - - After source code is configured and compiled, the - OpenEmbedded build system analyzes - the results and splits the output into packages: - - - - - The - do_package - and - do_packagedata - tasks combine to analyze - the files found in the - D directory - and split them into subsets based on available packages and - files. - The analyzing process involves the following as well as other - items: splitting out debugging symbols, - looking at shared library dependencies between packages, - and looking at package relationships. - The do_packagedata task creates package - metadata based on the analysis such that the - OpenEmbedded build system can generate the final packages. - Working, staged, and intermediate results of the analysis - and package splitting process use these areas: - - PKGD - - The destination directory for packages before they are - split. - - PKGDATA_DIR - - A shared, global-state directory that holds data - generated during the packaging process. - - PKGDESTWORK - - A temporary work area used by the - do_package task. - - PKGDEST - - The parent directory for packages after they have - been split. - - - The FILES - variable defines the files that go into each package in - PACKAGES. - If you want details on how this is accomplished, you can - look at the - package - class. - - - - Depending on the type of packages being created (RPM, DEB, or - IPK), the do_package_write_* task - creates the actual packages and places them in the - Package Feed area, which is - ${TMPDIR}/deploy. - You can see the - "Package Feeds" - section for more detail on that part of the build process. - - Support for creating feeds directly from the - deploy/* directories does not exist. - Creating such feeds usually requires some kind of feed - maintenance mechanism that would upload the new packages - into an official package feed (e.g. the - Ångström distribution). - This functionality is highly distribution-specific - and thus is not provided out of the box. - - -
- -
- Image Generation - - - Once packages are split and stored in the Package Feeds area, - the OpenEmbedded build system uses BitBake to generate the - root filesystem image: - - - - - The image generation process consists of several stages and - depends on several tasks and variables. - The - do_rootfs - task creates the root filesystem (file and directory structure) - for an image. - This task uses several key variables to help create the list - of packages to actually install: - - IMAGE_INSTALL: - Lists out the base set of packages to install from - the Package Feeds area. - PACKAGE_EXCLUDE: - Specifies packages that should not be installed. - - IMAGE_FEATURES: - Specifies features to include in the image. - Most of these features map to additional packages for - installation. - PACKAGE_CLASSES: - Specifies the package backend to use and consequently - helps determine where to locate packages within the - Package Feeds area. - IMAGE_LINGUAS: - Determines the language(s) for which additional - language support packages are installed. - - PACKAGE_INSTALL: - The final list of packages passed to the package manager - for installation into the image. - - - - - - With - IMAGE_ROOTFS - pointing to the location of the filesystem under construction and - the PACKAGE_INSTALL variable providing the - final list of packages to install, the root file system is - created. - - - - Package installation is under control of the package manager - (e.g. dnf/rpm, opkg, or apt/dpkg) regardless of whether or - not package management is enabled for the target. - At the end of the process, if package management is not - enabled for the target, the package manager's data files - are deleted from the root filesystem. - As part of the final stage of package installation, postinstall - scripts that are part of the packages are run. - Any scripts that fail to run - on the build host are run on the target when the target system - is first booted. - If you are using a - read-only root filesystem, - all the post installation scripts must succeed during the - package installation phase since the root filesystem is - read-only. - - - - The final stages of the do_rootfs task - handle post processing. - Post processing includes creation of a manifest file and - optimizations. - - - - The manifest file (.manifest) resides - in the same directory as the root filesystem image. - This file lists out, line-by-line, the installed packages. - The manifest file is useful for the - testimage - class, for example, to determine whether or not to run - specific tests. - See the - IMAGE_MANIFEST - variable for additional information. - - - - Optimizing processes run across the image include - mklibs, prelink, - and any other post-processing commands as defined by the - ROOTFS_POSTPROCESS_COMMAND - variable. - The mklibs process optimizes the size - of the libraries, while the - prelink process optimizes the dynamic - linking of shared libraries to reduce start up time of - executables. - - - - After the root filesystem is built, processing begins on - the image through the - do_image - task. - The build system runs any pre-processing commands as defined - by the - IMAGE_PREPROCESS_COMMAND - variable. - This variable specifies a list of functions to call before - the OpenEmbedded build system creates the final image output - files. - - - - The OpenEmbedded build system dynamically creates - do_image_* tasks as needed, based - on the image types specified in the - IMAGE_FSTYPES - variable. - The process turns everything into an image file or a set of - image files and compresses the root filesystem image to reduce - the overall size of the image. - The formats used for the root filesystem depend on the - IMAGE_FSTYPES variable. - - - - As an example, a dynamically created task when creating a - particular image type would take the - following form: - - do_image_type[depends] - - So, if the type as specified by the - IMAGE_FSTYPES were - ext4, the dynamically generated task - would be as follows: - - do_image_ext4[depends] - - - - - The final task involved in image creation is the - do_image_complete - task. - This task completes the image by applying any image - post processing as defined through the - IMAGE_POSTPROCESS_COMMAND - variable. - The variable specifies a list of functions to call once the - OpenEmbedded build system has created the final image output - files. - - - - The entire image generation process is run under Pseudo. - Running under Pseudo ensures that the files in the root - filesystem have correct ownership. - -
- -
- SDK Generation - - - The OpenEmbedded build system uses BitBake to generate the - Software Development Kit (SDK) installer script for both the - standard and extensible SDKs: - - - - - For more information on the cross-development toolchain - generation, see the - "Cross-Development Toolchain Generation" - section. - For information on advantages gained when building a - cross-development toolchain using the - do_populate_sdk - task, see the - "Building an SDK Installer" - section in the Yocto Project Application Development and the - Extensible Software Development Kit (SDK) manual. - - - - Like image generation, the SDK script process consists of - several stages and depends on many variables. - The do_populate_sdk and - do_populate_sdk_ext tasks use these - key variables to help create the list of packages to actually - install. - For information on the variables listed in the figure, see the - "Application Development SDK" - section. - - - - The do_populate_sdk task helps create - the standard SDK and handles two parts: a target part and a - host part. - The target part is the part built for the target hardware and - includes libraries and headers. - The host part is the part of the SDK that runs on the - SDKMACHINE. - - - - The do_populate_sdk_ext task helps create - the extensible SDK and handles host and target parts - differently than its counter part does for the standard SDK. - For the extensible SDK, the task encapsulates the build system, - which includes everything needed (host and target) for the SDK. - - - - Regardless of the type of SDK being constructed, the - tasks perform some cleanup after which a cross-development - environment setup script and any needed configuration files - are created. - The final output is the Cross-development - toolchain installation script (.sh file), - which includes the environment setup script. - -
- -
- Stamp Files and the Rerunning of Tasks - - - For each task that completes successfully, BitBake writes a - stamp file into the - STAMPS_DIR - directory. - The beginning of the stamp file's filename is determined by the - STAMP - variable, and the end of the name consists of the task's name - and current - input checksum. - - This naming scheme assumes that - BB_SIGNATURE_HANDLER - is "OEBasicHash", which is almost always the case in - current OpenEmbedded. - - To determine if a task needs to be rerun, BitBake checks if a - stamp file with a matching input checksum exists for the task. - If such a stamp file exists, the task's output is assumed to - exist and still be valid. - If the file does not exist, the task is rerun. - - The stamp mechanism is more general than the shared - state (sstate) cache mechanism described in the - "Setscene Tasks and Shared State" - section. - BitBake avoids rerunning any task that has a valid - stamp file, not just tasks that can be accelerated through - the sstate cache. - However, you should realize that stamp files only - serve as a marker that some work has been done and that - these files do not record task output. - The actual task output would usually be somewhere in - TMPDIR - (e.g. in some recipe's - WORKDIR.) - What the sstate cache mechanism adds is a way to cache task - output that can then be shared between build machines. - - - Since STAMPS_DIR is usually a subdirectory - of TMPDIR, removing - TMPDIR will also remove - STAMPS_DIR, which means tasks will - properly be rerun to repopulate TMPDIR. - - - - If you want some task to always be considered "out of date", - you can mark it with the - nostamp - varflag. - If some other task depends on such a task, then that task will - also always be considered out of date, which might not be what - you want. - - - - For details on how to view information about a task's - signature, see the - "Viewing Task Variable Dependencies" - section in the Yocto Project Development Tasks Manual. - -
- -
- Setscene Tasks and Shared State - - - The description of tasks so far assumes that BitBake needs to - build everything and there are no prebuilt objects available. - BitBake does support skipping tasks if prebuilt objects are - available. - These objects are usually made available in the form of a - shared state (sstate) cache. - - For information on variables affecting sstate, see the - SSTATE_DIR - and - SSTATE_MIRRORS - variables. - - - - - The idea of a setscene task (i.e - do_taskname_setscene) - is a version of the task where - instead of building something, BitBake can skip to the end - result and simply place a set of files into specific locations - as needed. - In some cases, it makes sense to have a setscene task variant - (e.g. generating package files in the - do_package_write_* task). - In other cases, it does not make sense, (e.g. a - do_patch - task or - do_unpack - task) since the work involved would be equal to or greater than - the underlying task. - - - - In the OpenEmbedded build system, the common tasks that have - setscene variants are - do_package, - do_package_write_*, - do_deploy, - do_packagedata, - and - do_populate_sysroot. - Notice that these are most of the tasks whose output is an - end result. - - - - The OpenEmbedded build system has knowledge of the relationship - between these tasks and other tasks that precede them. - For example, if BitBake runs - do_populate_sysroot_setscene for - something, there is little point in running any of the - do_fetch, do_unpack, - do_patch, - do_configure, - do_compile, and - do_install tasks. - However, if do_package needs to be run, - BitBake would need to run those other tasks. - - - - It becomes more complicated if everything can come from an - sstate cache because some objects are simply not required at - all. - For example, you do not need a compiler or native tools, such - as quilt, if there is nothing to compile or patch. - If the do_package_write_* packages are - available from sstate, BitBake does not need the - do_package task data. - - - - To handle all these complexities, BitBake runs in two phases. - The first is the "setscene" stage. - During this stage, BitBake first checks the sstate cache for - any targets it is planning to build. - BitBake does a fast check to see if the object exists rather - than a complete download. - If nothing exists, the second phase, which is the setscene - stage, completes and the main build proceeds. - - - - If objects are found in the sstate cache, the OpenEmbedded - build system works backwards from the end targets specified - by the user. - For example, if an image is being built, the OpenEmbedded build - system first looks for the packages needed for that image and - the tools needed to construct an image. - If those are available, the compiler is not needed. - Thus, the compiler is not even downloaded. - If something was found to be unavailable, or the download or - setscene task fails, the OpenEmbedded build system then tries - to install dependencies, such as the compiler, from the cache. - - - - The availability of objects in the sstate cache is handled by - the function specified by the - BB_HASHCHECK_FUNCTION - variable and returns a list of the objects that are available. - The function specified by the - BB_SETSCENE_DEPVALID - variable is the function that determines whether a given - dependency needs to be followed, and whether for any given - relationship the function needs to be passed. - The function returns a True or False value. - -
-
- -
- Images - - - The images produced by the OpenEmbedded build system - are compressed forms of the - root filesystem that are ready to boot on a target device. - You can see from the - general Yocto Project Development Environment figure - that BitBake output, in part, consists of images. - This section is going to look more closely at this output: - - - - - For a list of example images that the Yocto Project provides, - see the - "Images" - chapter in the Yocto Project Reference Manual. - - - - Images are written out to the - Build Directory - inside the - tmp/deploy/images/machine/ - folder as shown in the figure. - This folder contains any files expected to be loaded on the - target device. - The - DEPLOY_DIR - variable points to the deploy directory, - while the - DEPLOY_DIR_IMAGE - variable points to the appropriate directory containing images for - the current configuration. - - kernel-image: - A kernel binary file. - The - KERNEL_IMAGETYPE - variable setting determines the naming scheme for the - kernel image file. - Depending on that variable, the file could begin with - a variety of naming strings. - The deploy/images/machine - directory can contain multiple image files for the - machine. - root-filesystem-image: - Root filesystems for the target device (e.g. - *.ext3 or *.bz2 - files). - The - IMAGE_FSTYPES - variable setting determines the root filesystem image - type. - The deploy/images/machine - directory can contain multiple root filesystems for the - machine. - kernel-modules: - Tarballs that contain all the modules built for the kernel. - Kernel module tarballs exist for legacy purposes and - can be suppressed by setting the - MODULE_TARBALL_DEPLOY - variable to "0". - The deploy/images/machine - directory can contain multiple kernel module tarballs - for the machine. - bootloaders: - Bootloaders supporting the image, if applicable to the - target machine. - The deploy/images/machine - directory can contain multiple bootloaders for the - machine. - symlinks: - The deploy/images/machine - folder contains - a symbolic link that points to the most recently built file - for each machine. - These links might be useful for external scripts that - need to obtain the latest version of each file. - - - -
- -
- Application Development SDK - - - In the - general Yocto Project Development Environment figure, - the output labeled "Application Development SDK" represents an - SDK. - The SDK generation process differs depending on whether you build - a standard SDK - (e.g. bitbake -c populate_sdk imagename) - or an extensible SDK - (e.g. bitbake -c populate_sdk_ext imagename). - This section is going to take a closer look at this output: - - - - - The specific form of this output is a self-extracting - SDK installer (*.sh) that, when run, - installs the SDK, which consists of a cross-development - toolchain, a set of libraries and headers, and an SDK - environment setup script. - Running this installer essentially sets up your - cross-development environment. - You can think of the cross-toolchain as the "host" - part because it runs on the SDK machine. - You can think of the libraries and headers as the "target" - part because they are built for the target hardware. - The environment setup script is added so that you can initialize - the environment before using the tools. - - - Notes - - - The Yocto Project supports several methods by which you can - set up this cross-development environment. - These methods include downloading pre-built SDK installers - or building and installing your own SDK installer. - - - For background information on cross-development toolchains - in the Yocto Project development environment, see the - "Cross-Development Toolchain Generation" - section. - - - For information on setting up a cross-development - environment, see the - Yocto Project Application Development and the Extensible Software Development Kit (eSDK) - manual. - - - - - - Once built, the SDK installers are written out to the - deploy/sdk folder inside the - Build Directory - as shown in the figure at the beginning of this section. - Depending on the type of SDK, several variables exist that help - configure these files. - The following list shows the variables associated with a standard - SDK: - - DEPLOY_DIR: - Points to the deploy - directory. - SDKMACHINE: - Specifies the architecture of the machine - on which the cross-development tools are run to - create packages for the target hardware. - - SDKIMAGE_FEATURES: - Lists the features to include in the "target" part - of the SDK. - - TOOLCHAIN_HOST_TASK: - Lists packages that make up the host - part of the SDK (i.e. the part that runs on - the SDKMACHINE). - When you use - bitbake -c populate_sdk imagename - to create the SDK, a set of default packages - apply. - This variable allows you to add more packages. - - TOOLCHAIN_TARGET_TASK: - Lists packages that make up the target part - of the SDK (i.e. the part built for the - target hardware). - - SDKPATH: - Defines the default SDK installation path offered by the - installation script. - - - This next list, shows the variables associated with an extensible - SDK: - - DEPLOY_DIR: - Points to the deploy directory. - - SDK_EXT_TYPE: - Controls whether or not shared state artifacts are copied - into the extensible SDK. - By default, all required shared state artifacts are copied - into the SDK. - - SDK_INCLUDE_PKGDATA: - Specifies whether or not packagedata will be included in - the extensible SDK for all recipes in the "world" target. - - SDK_INCLUDE_TOOLCHAIN: - Specifies whether or not the toolchain will be included - when building the extensible SDK. - - SDK_LOCAL_CONF_WHITELIST: - A list of variables allowed through from the build system - configuration into the extensible SDK configuration. - - SDK_LOCAL_CONF_BLACKLIST: - A list of variables not allowed through from the build - system configuration into the extensible SDK configuration. - - SDK_INHERIT_BLACKLIST: - A list of classes to remove from the - INHERIT - value globally within the extensible SDK configuration. - - - -
-
- - - diff --git a/documentation/overview-manual/overview-manual-customization.xsl b/documentation/overview-manual/overview-manual-customization.xsl deleted file mode 100644 index ccb7521259..0000000000 --- a/documentation/overview-manual/overview-manual-customization.xsl +++ /dev/null @@ -1,27 +0,0 @@ - - - - - - - - - - - - - - - - - - - - - diff --git a/documentation/overview-manual/overview-manual-eclipse-customization.xsl b/documentation/overview-manual/overview-manual-eclipse-customization.xsl deleted file mode 100644 index aaf99ea1ba..0000000000 --- a/documentation/overview-manual/overview-manual-eclipse-customization.xsl +++ /dev/null @@ -1,35 +0,0 @@ - - - - - - - - - - - - - - - - - - - - - - - - diff --git a/documentation/overview-manual/overview-manual-intro.xml b/documentation/overview-manual/overview-manual-intro.xml deleted file mode 100644 index 51a21b6e23..0000000000 --- a/documentation/overview-manual/overview-manual-intro.xml +++ /dev/null @@ -1,103 +0,0 @@ - %poky; ] > - - - -The Yocto Project Overview Manual -
- Welcome - - - Welcome to the Yocto Project Overview Manual! - This manual introduces the Yocto Project by providing concepts, - software overviews, best-known-methods (BKMs), and any other - high-level introductory information suitable for a new Yocto - Project user. - - - - The following list describes what you can get from this manual: - - - Major Topic: - Provide a high-level description of this major topic. - - - Major Topic: - Provide a high-level description of this major topic. - - - Major Topic: - Provide a high-level description of this major topic. - - - Major Topic: - Provide a high-level description of this major topic. - - - - - - This manual does not give you the following: - - - Step-by-step Instructions for Development Tasks: - Instructional procedures reside in other manuals within - the Yocto Project documentation set. - For example, the - Yocto Project Development Tasks Manual - provides examples on how to perform various development - tasks. - As another example, the - Yocto Project Application Development and the Extensible Software Development Kit (eSDK) - manual contains detailed instructions on how to install an - SDK, which is used to develop applications for target - hardware. - - - Reference Material: - This type of material resides in an appropriate reference - manual. - For example, system variables are documented in the - Yocto Project Reference Manual. - As another example, the - Yocto Project Board Support Package (BSP) Developer's Guide - contains reference information on BSPs. - - - Detailed Public Information Not Specific to the - Yocto Project: - For example, exhaustive information on how to use the - Source Control Manager Git is better covered with Internet - searches and official Git Documentation than through the - Yocto Project documentation. - - - -
- -
- Other Information - - - Because this manual presents information for many different - topics, supplemental information is recommended for full - comprehension. - For additional introductory information on the Yocto Project, see - the Yocto Project Website. - You can find an introductory to using the Yocto Project by working - through the - Yocto Project Quick Start. - - - - For a comprehensive list of links and other documentation, see the - "Links and Related Documentation" - section in the Yocto Project Reference Manual. - -
- - diff --git a/documentation/overview-manual/overview-manual.xml b/documentation/overview-manual/overview-manual.xml deleted file mode 100644 index fe021073da..0000000000 --- a/documentation/overview-manual/overview-manual.xml +++ /dev/null @@ -1,94 +0,0 @@ - %poky; ] > - - - - - - - - - - - - Yocto Project Overview Manual - - - - - Scott Rifenbark - - Scotty's Documentation Services, INC - - srifenbark@gmail.com - - - - - - 2.5 - April 2018 - The initial document released with the Yocto Project 2.5 Release. - - - - - ©RIGHT_YEAR; - Linux Foundation - - - - - Permission is granted to copy, distribute and/or modify this document under - the terms of the - Creative Commons Attribution-Share Alike 2.0 UK: England & Wales as published by - Creative Commons. - - Manual Notes - - - This version of the - Yocto Project Overview Manual - is for the &YOCTO_DOC_VERSION; release of the - Yocto Project. - To be sure you have the latest version of the manual - for this release, use the manual from the - Yocto Project documentation page. - - - For manuals associated with other releases of the Yocto - Project, go to the - Yocto Project documentation page - and use the drop-down "Active Releases" button - and choose the manual associated with the desired - Yocto Project. - - - To report any inaccuracies or problems with this - manual, send an email to the Yocto Project - discussion group at - yocto@yoctoproject.com or log into - the freenode #yocto channel. - - - - - - - - - - - - - - - diff --git a/documentation/overview-manual/overview-style.css b/documentation/overview-manual/overview-style.css deleted file mode 100644 index 9d7bf9e0d6..0000000000 --- a/documentation/overview-manual/overview-style.css +++ /dev/null @@ -1,988 +0,0 @@ -/* - Generic XHTML / DocBook XHTML CSS Stylesheet. - - Browser wrangling and typographic design by - Oyvind Kolas / pippin@gimp.org - - Customised for Poky by - Matthew Allum / mallum@o-hand.com - - Thanks to: - Liam R. E. Quin - William Skaggs - Jakub Steiner - - Structure - --------- - - The stylesheet is divided into the following sections: - - Positioning - Margins, paddings, width, font-size, clearing. - Decorations - Borders, style - Colors - Colors - Graphics - Graphical backgrounds - Nasty IE tweaks - Workarounds needed to make it work in internet explorer, - currently makes the stylesheet non validating, but up until - this point it is validating. - Mozilla extensions - Transparency for footer - Rounded corners on boxes - -*/ - - - /*************** / - / Positioning / -/ ***************/ - -body { - font-family: Verdana, Sans, sans-serif; - - min-width: 640px; - width: 80%; - margin: 0em auto; - padding: 2em 5em 5em 5em; - color: #333; -} - -h1,h2,h3,h4,h5,h6,h7 { - font-family: Arial, Sans; - color: #00557D; - clear: both; -} - -h1 { - font-size: 2em; - text-align: left; - padding: 0em 0em 0em 0em; - margin: 2em 0em 0em 0em; -} - -h2.subtitle { - margin: 0.10em 0em 3.0em 0em; - padding: 0em 0em 0em 0em; - font-size: 1.8em; - padding-left: 20%; - font-weight: normal; - font-style: italic; -} - -h2 { - margin: 2em 0em 0.66em 0em; - padding: 0.5em 0em 0em 0em; - font-size: 1.5em; - font-weight: bold; -} - -h3.subtitle { - margin: 0em 0em 1em 0em; - padding: 0em 0em 0em 0em; - font-size: 142.14%; - text-align: right; -} - -h3 { - margin: 1em 0em 0.5em 0em; - padding: 1em 0em 0em 0em; - font-size: 140%; - font-weight: bold; -} - -h4 { - margin: 1em 0em 0.5em 0em; - padding: 1em 0em 0em 0em; - font-size: 120%; - font-weight: bold; -} - -h5 { - margin: 1em 0em 0.5em 0em; - padding: 1em 0em 0em 0em; - font-size: 110%; - font-weight: bold; -} - -h6 { - margin: 1em 0em 0em 0em; - padding: 1em 0em 0em 0em; - font-size: 110%; - font-weight: bold; -} - -.authorgroup { - background-color: transparent; - background-repeat: no-repeat; - padding-top: 256px; - background-image: url("figures/overview-title.png"); - background-position: left top; - margin-top: -256px; - padding-right: 50px; - margin-left: 0px; - text-align: right; - width: 740px; -} - -h3.author { - margin: 0em 0me 0em 0em; - padding: 0em 0em 0em 0em; - font-weight: normal; - font-size: 100%; - color: #333; - clear: both; -} - -.author tt.email { - font-size: 66%; -} - -.titlepage hr { - width: 0em; - clear: both; -} - -.revhistory { - padding-top: 2em; - clear: both; -} - -.toc, -.list-of-tables, -.list-of-examples, -.list-of-figures { - padding: 1.33em 0em 2.5em 0em; - color: #00557D; -} - -.toc p, -.list-of-tables p, -.list-of-figures p, -.list-of-examples p { - padding: 0em 0em 0em 0em; - padding: 0em 0em 0.3em; - margin: 1.5em 0em 0em 0em; -} - -.toc p b, -.list-of-tables p b, -.list-of-figures p b, -.list-of-examples p b{ - font-size: 100.0%; - font-weight: bold; -} - -.toc dl, -.list-of-tables dl, -.list-of-figures dl, -.list-of-examples dl { - margin: 0em 0em 0.5em 0em; - padding: 0em 0em 0em 0em; -} - -.toc dt { - margin: 0em 0em 0em 0em; - padding: 0em 0em 0em 0em; -} - -.toc dd { - margin: 0em 0em 0em 2.6em; - padding: 0em 0em 0em 0em; -} - -div.glossary dl, -div.variablelist dl { -} - -.glossary dl dt, -.variablelist dl dt, -.variablelist dl dt span.term { - font-weight: normal; - width: 20em; - text-align: right; -} - -.variablelist dl dt { - margin-top: 0.5em; -} - -.glossary dl dd, -.variablelist dl dd { - margin-top: -1em; - margin-left: 25.5em; -} - -.glossary dd p, -.variablelist dd p { - margin-top: 0em; - margin-bottom: 1em; -} - - -div.calloutlist table td { - padding: 0em 0em 0em 0em; - margin: 0em 0em 0em 0em; -} - -div.calloutlist table td p { - margin-top: 0em; - margin-bottom: 1em; -} - -div p.copyright { - text-align: left; -} - -div.legalnotice p.legalnotice-title { - margin-bottom: 0em; -} - -p { - line-height: 1.5em; - margin-top: 0em; - -} - -dl { - padding-top: 0em; -} - -hr { - border: solid 1px; -} - - -.mediaobject, -.mediaobjectco { - text-align: center; -} - -img { - border: none; -} - -ul { - padding: 0em 0em 0em 1.5em; -} - -ul li { - padding: 0em 0em 0em 0em; -} - -ul li p { - text-align: left; -} - -table { - width :100%; -} - -th { - padding: 0.25em; - text-align: left; - font-weight: normal; - vertical-align: top; -} - -td { - padding: 0.25em; - vertical-align: top; -} - -p a[id] { - margin: 0px; - padding: 0px; - display: inline; - background-image: none; -} - -a { - text-decoration: underline; - color: #444; -} - -pre { - overflow: auto; -} - -a:hover { - text-decoration: underline; - /*font-weight: bold;*/ -} - -/* This style defines how the permalink character - appears by itself and when hovered over with - the mouse. */ - -[alt='Permalink'] { color: #eee; } -[alt='Permalink']:hover { color: black; } - - -div.informalfigure, -div.informalexample, -div.informaltable, -div.figure, -div.table, -div.example { - margin: 1em 0em; - padding: 1em; - page-break-inside: avoid; -} - - -div.informalfigure p.title b, -div.informalexample p.title b, -div.informaltable p.title b, -div.figure p.title b, -div.example p.title b, -div.table p.title b{ - padding-top: 0em; - margin-top: 0em; - font-size: 100%; - font-weight: normal; -} - -.mediaobject .caption, -.mediaobject .caption p { - text-align: center; - font-size: 80%; - padding-top: 0.5em; - padding-bottom: 0.5em; -} - -.epigraph { - padding-left: 55%; - margin-bottom: 1em; -} - -.epigraph p { - text-align: left; -} - -.epigraph .quote { - font-style: italic; -} -.epigraph .attribution { - font-style: normal; - text-align: right; -} - -span.application { - font-style: italic; -} - -.programlisting { - font-family: monospace; - font-size: 80%; - white-space: pre; - margin: 1.33em 0em; - padding: 1.33em; -} - -.tip, -.warning, -.caution, -.note { - margin-top: 1em; - margin-bottom: 1em; - -} - -/* force full width of table within div */ -.tip table, -.warning table, -.caution table, -.note table { - border: none; - width: 100%; -} - - -.tip table th, -.warning table th, -.caution table th, -.note table th { - padding: 0.8em 0.0em 0.0em 0.0em; - margin : 0em 0em 0em 0em; -} - -.tip p, -.warning p, -.caution p, -.note p { - margin-top: 0.5em; - margin-bottom: 0.5em; - padding-right: 1em; - text-align: left; -} - -.acronym { - text-transform: uppercase; -} - -b.keycap, -.keycap { - padding: 0.09em 0.3em; - margin: 0em; -} - -.itemizedlist li { - clear: none; -} - -.filename { - font-size: medium; - font-family: Courier, monospace; -} - - -div.navheader, div.heading{ - position: absolute; - left: 0em; - top: 0em; - width: 100%; - background-color: #cdf; - width: 100%; -} - -div.navfooter, div.footing{ - position: fixed; - left: 0em; - bottom: 0em; - background-color: #eee; - width: 100%; -} - - -div.navheader td, -div.navfooter td { - font-size: 66%; -} - -div.navheader table th { - /*font-family: Georgia, Times, serif;*/ - /*font-size: x-large;*/ - font-size: 80%; -} - -div.navheader table { - border-left: 0em; - border-right: 0em; - border-top: 0em; - width: 100%; -} - -div.navfooter table { - border-left: 0em; - border-right: 0em; - border-bottom: 0em; - width: 100%; -} - -div.navheader table td a, -div.navfooter table td a { - color: #777; - text-decoration: none; -} - -/* normal text in the footer */ -div.navfooter table td { - color: black; -} - -div.navheader table td a:visited, -div.navfooter table td a:visited { - color: #444; -} - - -/* links in header and footer */ -div.navheader table td a:hover, -div.navfooter table td a:hover { - text-decoration: underline; - background-color: transparent; - color: #33a; -} - -div.navheader hr, -div.navfooter hr { - display: none; -} - - -.qandaset tr.question td p { - margin: 0em 0em 1em 0em; - padding: 0em 0em 0em 0em; -} - -.qandaset tr.answer td p { - margin: 0em 0em 1em 0em; - padding: 0em 0em 0em 0em; -} -.answer td { - padding-bottom: 1.5em; -} - -.emphasis { - font-weight: bold; -} - - - /************* / - / decorations / -/ *************/ - -.titlepage { -} - -.part .title { -} - -.subtitle { - border: none; -} - -/* -h1 { - border: none; -} - -h2 { - border-top: solid 0.2em; - border-bottom: solid 0.06em; -} - -h3 { - border-top: 0em; - border-bottom: solid 0.06em; -} - -h4 { - border: 0em; - border-bottom: solid 0.06em; -} - -h5 { - border: 0em; -} -*/ - -.programlisting { - border: solid 1px; -} - -div.figure, -div.table, -div.informalfigure, -div.informaltable, -div.informalexample, -div.example { - border: 1px solid; -} - - - -.tip, -.warning, -.caution, -.note { - border: 1px solid; -} - -.tip table th, -.warning table th, -.caution table th, -.note table th { - border-bottom: 1px solid; -} - -.question td { - border-top: 1px solid black; -} - -.answer { -} - - -b.keycap, -.keycap { - border: 1px solid; -} - - -div.navheader, div.heading{ - border-bottom: 1px solid; -} - - -div.navfooter, div.footing{ - border-top: 1px solid; -} - - /********* / - / colors / -/ *********/ - -body { - color: #333; - background: white; -} - -a { - background: transparent; -} - -a:hover { - background-color: #dedede; -} - - -h1, -h2, -h3, -h4, -h5, -h6, -h7, -h8 { - background-color: transparent; -} - -hr { - border-color: #aaa; -} - - -.tip, .warning, .caution, .note { - border-color: #fff; -} - - -.tip table th, -.warning table th, -.caution table th, -.note table th { - border-bottom-color: #fff; -} - - -.warning { - background-color: #f0f0f2; -} - -.caution { - background-color: #f0f0f2; -} - -.tip { - background-color: #f0f0f2; -} - -.note { - background-color: #f0f0f2; -} - -.glossary dl dt, -.variablelist dl dt, -.variablelist dl dt span.term { - color: #044; -} - -div.figure, -div.table, -div.example, -div.informalfigure, -div.informaltable, -div.informalexample { - border-color: #aaa; -} - -pre.programlisting { - color: black; - background-color: #fff; - border-color: #aaa; - border-width: 2px; -} - -.guimenu, -.guilabel, -.guimenuitem { - background-color: #eee; -} - - -b.keycap, -.keycap { - background-color: #eee; - border-color: #999; -} - - -div.navheader { - border-color: black; -} - - -div.navfooter { - border-color: black; -} - -.writernotes { - color: red; -} - - - /*********** / - / graphics / -/ ***********/ - -/* -body { - background-image: url("images/body_bg.jpg"); - background-attachment: fixed; -} - -.navheader, -.note, -.tip { - background-image: url("images/note_bg.jpg"); - background-attachment: fixed; -} - -.warning, -.caution { - background-image: url("images/warning_bg.jpg"); - background-attachment: fixed; -} - -.figure, -.informalfigure, -.example, -.informalexample, -.table, -.informaltable { - background-image: url("images/figure_bg.jpg"); - background-attachment: fixed; -} - -*/ -h1, -h2, -h3, -h4, -h5, -h6, -h7{ -} - -/* -Example of how to stick an image as part of the title. - -div.article .titlepage .title -{ - background-image: url("figures/white-on-black.png"); - background-position: center; - background-repeat: repeat-x; -} -*/ - -div.preface .titlepage .title, -div.colophon .title, -div.chapter .titlepage .title, -div.article .titlepage .title -{ -} - -div.section div.section .titlepage .title, -div.sect2 .titlepage .title { - background: none; -} - - -h1.title { - background-color: transparent; - background-repeat: no-repeat; - height: 256px; - text-indent: -9000px; - overflow:hidden; -} - -h2.subtitle { - background-color: transparent; - text-indent: -9000px; - overflow:hidden; - width: 0px; - display: none; -} - - /*************************************** / - / pippin.gimp.org specific alterations / -/ ***************************************/ - -/* -div.heading, div.navheader { - color: #777; - font-size: 80%; - padding: 0; - margin: 0; - text-align: left; - position: absolute; - top: 0px; - left: 0px; - width: 100%; - height: 50px; - background: url('/gfx/heading_bg.png') transparent; - background-repeat: repeat-x; - background-attachment: fixed; - border: none; -} - -div.heading a { - color: #444; -} - -div.footing, div.navfooter { - border: none; - color: #ddd; - font-size: 80%; - text-align:right; - - width: 100%; - padding-top: 10px; - position: absolute; - bottom: 0px; - left: 0px; - - background: url('/gfx/footing_bg.png') transparent; -} -*/ - - - - /****************** / - / nasty ie tweaks / -/ ******************/ - -/* -div.heading, div.navheader { - width:expression(document.body.clientWidth + "px"); -} - -div.footing, div.navfooter { - width:expression(document.body.clientWidth + "px"); - margin-left:expression("-5em"); -} -body { - padding:expression("4em 5em 0em 5em"); -} -*/ - - /**************************************** / - / mozilla vendor specific css extensions / -/ ****************************************/ -/* -div.navfooter, div.footing{ - -moz-opacity: 0.8em; -} - -div.figure, -div.table, -div.informalfigure, -div.informaltable, -div.informalexample, -div.example, -.tip, -.warning, -.caution, -.note { - -moz-border-radius: 0.5em; -} - -b.keycap, -.keycap { - -moz-border-radius: 0.3em; -} -*/ - -table tr td table tr td { - display: none; -} - - -hr { - display: none; -} - -table { - border: 0em; -} - - .photo { - float: right; - margin-left: 1.5em; - margin-bottom: 1.5em; - margin-top: 0em; - max-width: 17em; - border: 1px solid gray; - padding: 3px; - background: white; -} - .seperator { - padding-top: 2em; - clear: both; - } - - #validators { - margin-top: 5em; - text-align: right; - color: #777; - } - @media print { - body { - font-size: 8pt; - } - .noprint { - display: none; - } - } - - -.tip, -.note { - background: #f0f0f2; - color: #333; - padding: 20px; - margin: 20px; -} - -.tip h3, -.note h3 { - padding: 0em; - margin: 0em; - font-size: 2em; - font-weight: bold; - color: #333; -} - -.tip a, -.note a { - color: #333; - text-decoration: underline; -} - -.footnote { - font-size: small; - color: #333; -} - -/* Changes the announcement text */ -.tip h3, -.warning h3, -.caution h3, -.note h3 { - font-size:large; - color: #00557D; -} diff --git a/documentation/poky.ent b/documentation/poky.ent index eb2e05151d..490fb96dc0 100644 --- a/documentation/poky.ent +++ b/documentation/poky.ent @@ -60,6 +60,7 @@ + diff --git a/documentation/ref-manual/faq.xml b/documentation/ref-manual/faq.xml index ddb5078454..ecc866cdb3 100644 --- a/documentation/ref-manual/faq.xml +++ b/documentation/ref-manual/faq.xml @@ -417,7 +417,7 @@ You can find more information on licensing in the - "Licensing" + "Licensing" section in the Yocto Project Overview Manual and also in the "Maintaining Open Source License Compliance During Your Product's Lifecycle" section in the Yocto Project Development Tasks Manual. diff --git a/documentation/ref-manual/migration.xml b/documentation/ref-manual/migration.xml index 01c5a982e2..bccbeed3b9 100644 --- a/documentation/ref-manual/migration.xml +++ b/documentation/ref-manual/migration.xml @@ -293,7 +293,7 @@ For the remainder, you can now find them in the meta-extras repository, which is in the Yocto Project - Source Repositories. + Source Repositories. @@ -1748,7 +1748,7 @@ The minimum - Git version + Git version required on the build host is now 1.7.8 because the --list option is now required by BitBake's Git fetcher. @@ -4038,7 +4038,7 @@ $ runqemu qemux86-64 tmp/deploy/images/qemux86-64/core-image-minimal-qemux86-64. For an example, see the pixbufcache class in meta/classes/ in the Yocto Project - Source Repositories. + Source Repositories. The SSTATEPOSTINSTFUNCS variable itself is now deprecated in favor of the diff --git a/documentation/ref-manual/ref-bitbake.xml b/documentation/ref-manual/ref-bitbake.xml index 7d1dd48128..e848de81b3 100644 --- a/documentation/ref-manual/ref-bitbake.xml +++ b/documentation/ref-manual/ref-bitbake.xml @@ -350,7 +350,7 @@ checksums. For information on this process, see the BB_HASHBASE_WHITELIST example in the - "Checksums (Signatures)" + "Checksums (Signatures)" section in the Yocto Project Overview Manual. diff --git a/documentation/ref-manual/ref-classes.xml b/documentation/ref-manual/ref-classes.xml index 3b7ac31e6a..39d740d7d4 100644 --- a/documentation/ref-manual/ref-classes.xml +++ b/documentation/ref-manual/ref-classes.xml @@ -568,7 +568,7 @@ provides support for the recipes that build the Canadian Cross-compilation tools for SDKs. See the - "Cross-Development Toolchain Generation" + "Cross-Development Toolchain Generation" section in the Yocto Project Overview Manual for more discussion on these cross-compilation tools. @@ -582,7 +582,7 @@ provides support for the recipes that build the cross-compilation tools used for building SDKs. See the - "Cross-Development Toolchain Generation" + "Cross-Development Toolchain Generation" section in the Yocto Project Overview Manual for more discussion on these cross-compilation tools. @@ -1251,7 +1251,7 @@ "Customizing Images" section in the Yocto Project Development Tasks Manual. For information on how images are created, see the - "Images" + "Images" section in the Yocto Project Overview Manual. @@ -2722,7 +2722,7 @@ This check was removed for YP 2.3 release For more information on the cross-development toolchain generation, see the - "Cross-Development Toolchain Generation" + "Cross-Development Toolchain Generation" section in the Yocto Project Overview Manual. For information on advantages gained when building a cross-development toolchain using the @@ -3020,7 +3020,7 @@ This check was removed for YP 2.3 release For information on how root filesystem images are created, see the - "Image Generation" + "Image Generation" section in the Yocto Project Overview Manual. @@ -3182,7 +3182,7 @@ This check was removed for YP 2.3 release For more information on sstate, see the - "Shared State Cache" + "Shared State Cache" section in the Yocto Project Overview Manual. diff --git a/documentation/ref-manual/ref-images.xml b/documentation/ref-manual/ref-images.xml index fd6d5aabe9..58f33cda2a 100644 --- a/documentation/ref-manual/ref-images.xml +++ b/documentation/ref-manual/ref-images.xml @@ -151,7 +151,7 @@ This image provides the Wayland protocol libraries and the reference Weston compositor. For more information, see the - "Wayland" + "Wayland" section in the Yocto Project Overview Manual. core-image-x11: diff --git a/documentation/ref-manual/ref-release-process.xml b/documentation/ref-manual/ref-release-process.xml index 1b36932e21..d8ead1399b 100644 --- a/documentation/ref-manual/ref-release-process.xml +++ b/documentation/ref-manual/ref-release-process.xml @@ -61,7 +61,7 @@ Each major release receives a codename that identifies the release in the - Yocto Project Source Repositories. + Yocto Project Source Repositories. The concept is that branches of Metadata with the same codename are likely to be compatible and thus @@ -217,7 +217,7 @@ in the poky repository. You can find all these branches in the Yocto Project - Source Repositories. + Source Repositories. Testing within these public branches ensures in a publicly visible way that all of the main supposed architectures and recipes in OE-Core diff --git a/documentation/ref-manual/ref-structure.xml b/documentation/ref-manual/ref-structure.xml index 7a2371d8b3..1dff8f81f9 100644 --- a/documentation/ref-manual/ref-structure.xml +++ b/documentation/ref-manual/ref-structure.xml @@ -520,9 +520,9 @@ variable points to this directory. For more detail on the contents of the deploy directory, see the - "Images" + "Images" and - "Application Development SDK" + "Application Development SDK" sections in the Yocto Project Overview Manual. @@ -696,7 +696,7 @@ For information on how BitBake uses stamp files to determine if a task should be rerun, see the - "Stamp Files and the Rerunning of Tasks" + "Stamp Files and the Rerunning of Tasks" section in the Yocto Project Overview Manual. diff --git a/documentation/ref-manual/ref-system-requirements.xml b/documentation/ref-manual/ref-system-requirements.xml index baeb116a26..4e4e0de514 100644 --- a/documentation/ref-manual/ref-system-requirements.xml +++ b/documentation/ref-manual/ref-system-requirements.xml @@ -21,7 +21,7 @@ For introductory information on the Yocto Project, see the Yocto Project Website and the - "Yocto Project Development Environment" + "Yocto Project Development Environment" chapter in the Yocto Project Overview Manual. diff --git a/documentation/ref-manual/ref-tasks.xml b/documentation/ref-manual/ref-tasks.xml index 4fa64c0d60..262dec8311 100644 --- a/documentation/ref-manual/ref-tasks.xml +++ b/documentation/ref-manual/ref-tasks.xml @@ -220,7 +220,7 @@ For more information on image creation, see the - "Image Generation" + "Image Generation" section in the Yocto Project Overview Manual. @@ -246,7 +246,7 @@ For more information on image creation, see the - "Image Generation" + "Image Generation" section in the Yocto Project Overview Manual. @@ -268,7 +268,7 @@ and do_rootfs), run under - fakeroot. + fakeroot. Caution @@ -342,7 +342,7 @@ For additional information, see the PKGDESTWORK variable and the - "Automatically Added Runtime Dependencies" + "Automatically Added Runtime Dependencies" section in the Yocto Project Overview Manual. @@ -367,7 +367,7 @@ ${DEPLOY_DIR_DEB} directory in the package feeds area. For more information, see the - "Package Feeds" + "Package Feeds" section in the Yocto Project Overview Manual. @@ -381,7 +381,7 @@ ${DEPLOY_DIR_IPK} directory in the package feeds area. For more information, see the - "Package Feeds" + "Package Feeds" section in the Yocto Project Overview Manual. @@ -395,7 +395,7 @@ ${DEPLOY_DIR_RPM} directory in the package feeds area. For more information, see the - "Package Feeds" + "Package Feeds" section in the Yocto Project Overview Manual. @@ -408,7 +408,7 @@ ${DEPLOY_DIR_TAR} directory in the package feeds area. For more information, see the - "Package Feeds" + "Package Feeds" section Yocto Project Overview Manual. @@ -431,7 +431,7 @@ Locates patch files and applies them to the source code. See the - "Patching" + "Patching" section in the Yocto Project Overview Manual for more information. @@ -451,7 +451,7 @@ Creates the file and directory structure for an installable SDK. See the - "SDK Generation" + "SDK Generation" section in the Yocto Project Overview Manual for more information. @@ -538,7 +538,7 @@ S variable also plays a role in where unpacked source files ultimately reside. For more information on how source files are unpacked, see the - "Source Fetching" + "Source Fetching" section in the Yocto Project Overview Manual and also see the WORKDIR and S variable descriptions. @@ -628,7 +628,7 @@ Running this task does not remove the - sstate + sstate cache files. Consequently, if no changes have been made and the recipe is rebuilt after cleaning, output files are simply restored from the @@ -645,7 +645,7 @@ Removes all output files, shared state - (sstate) + (sstate) cache, and downloaded source files for a target (i.e. the contents of DL_DIR). @@ -676,13 +676,13 @@ Removes all output files and shared state - (sstate) + (sstate) cache for a target. Essentially, the do_cleansstate task is identical to the do_clean task with the added removal of shared state - (sstate) + (sstate) cache. @@ -760,7 +760,7 @@ Creates or updates the index in the - Package Feeds + Package Feeds area. This task is not triggered with the @@ -812,7 +812,7 @@ Creates the root filesystem (file and directory structure) for an image. See the - "Image Generation" + "Image Generation" section in the Yocto Project Overview Manual for more information on how the root filesystem is created. diff --git a/documentation/ref-manual/ref-terms.xml b/documentation/ref-manual/ref-terms.xml index 237e765202..9e38e98693 100644 --- a/documentation/ref-manual/ref-terms.xml +++ b/documentation/ref-manual/ref-terms.xml @@ -181,7 +181,7 @@ Creation of these toolchains is simple and automated. For information on toolchain concepts as they apply to the Yocto Project, see the - "Cross-Development Toolchain Generation" + "Cross-Development Toolchain Generation" section in the Yocto Project Overview Manual. You can also find more information on using the relocatable toolchain in the @@ -399,7 +399,7 @@ For more information on concepts related to Git repositories, branches, and tags, see the - "Repositories, Tags, and Branches" + "Repositories, Tags, and Branches" section in the Yocto Project Overview Manual. Task: diff --git a/documentation/ref-manual/ref-variables.xml b/documentation/ref-manual/ref-variables.xml index 334336880b..f09e0b6ae4 100644 --- a/documentation/ref-manual/ref-variables.xml +++ b/documentation/ref-manual/ref-variables.xml @@ -3017,7 +3017,7 @@ Caution Tasks that read from or write to this directory should run under - fakeroot. + fakeroot. @@ -3264,7 +3264,7 @@ add any runtime dependencies between the packages produced by the two recipes. However, as explained in the - "Automatically Added Runtime Dependencies" + "Automatically Added Runtime Dependencies" section in the Yocto Project Overview Manual, runtime dependencies will often be added automatically, meaning @@ -3329,11 +3329,11 @@ section. For more detail on the contents of the deploy directory, see the - "Images" + "Images" section, the - "Package Feeds" + "Package Feeds" section, and the - "Application Development SDK" + "Application Development SDK" sections all in the Yocto Project Overview Manual. @@ -3373,7 +3373,7 @@ do_package_write_deb task writes Debian packages into the appropriate folder. For more information on how packaging works, see the - "Package Feeds" + "Package Feeds" section in the Yocto Project Overview Manual. @@ -3403,9 +3403,9 @@ section. For more detail on the contents of the deploy directory, see the - "Images" + "Images" and - "Application Development SDK" + "Application Development SDK" sections both in the Yocto Project Overview Manual. @@ -3444,7 +3444,7 @@ do_package_write_ipk task writes IPK packages into the appropriate folder. For more information on how packaging works, see the - "Package Feeds" + "Package Feeds" section in the Yocto Project Overview Manual. @@ -3483,7 +3483,7 @@ do_package_write_rpm task writes RPM packages into the appropriate folder. For more information on how packaging works, see the - "Package Feeds" + "Package Feeds" section. @@ -3522,7 +3522,7 @@ do_package_write_tar task writes TAR packages into the appropriate folder. For more information on how packaging works, see the - "Package Feeds" + "Package Feeds" section in the Yocto Project Overview Manual. @@ -4864,7 +4864,7 @@ The previous statement appears in the linux-yocto-dev.bbappend file, which is found in the Yocto Project - Source Repositories + Source Repositories in meta-intel/common/recipes-kernel/linux. Here, the machine override is a special @@ -6084,7 +6084,7 @@ variables. You can find information on how the image is created in the - "Image Generation" + "Image Generation" section in the Yocto Project Overview Manual. @@ -7911,7 +7911,7 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3" LICENSE is set to "CLOSED"). For more information, see the - "Tracking License Changes" + "Tracking License Changes" section in the Yocto Project Overview Manual. @@ -8047,7 +8047,7 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3" require additional licenses in order to be used in a commercial product. For more information, see the - "Enabling Commercially Licensed Recipes" + "Enabling Commercially Licensed Recipes" section in the Yocto Project Overview Manual. @@ -8067,7 +8067,7 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3" This practice is otherwise known as "whitelisting" license flags. For more information, see the - Enabling Commercially Licensed Recipes" + Enabling Commercially Licensed Recipes" section in the Yocto Project Overview Manual. @@ -10412,7 +10412,7 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3" ${STAGING_DIR_HOST}/pkgdata For examples of how this data is used, see the - "Automatically Added Runtime Dependencies" + "Automatically Added Runtime Dependencies" section in the Yocto Project Overview Manual and the "Viewing Package Information with oe-pkgdata-util" section in the Yocto Project Development Tasks Manual. @@ -10659,11 +10659,11 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3" PR to know when to rebuild a recipe. The build system uses the task - input checksums + input checksums along with the stamp and - shared state cache + shared state cache mechanisms. The PR variable primarily becomes @@ -10715,7 +10715,7 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3" PREFERRED_PROVIDER_virtual/libgl ?= "mesa" For more information, see the - "Metadata (Virtual Providers)" + "Metadata (Virtual Providers)" section in the Yocto Project Overview Manual. If you set PREFERRED_PROVIDER @@ -10919,7 +10919,7 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3" For more information, see the - "Automatically Added Runtime Dependencies" + "Automatically Added Runtime Dependencies" section in the Yocto Project Overview Manual. @@ -11236,7 +11236,7 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3" Therefore, most recipes do not need to set RDEPENDS. For more information, see the - "Automatically Added Runtime Dependencies" + "Automatically Added Runtime Dependencies" section in the Yocto Project Overview Manual. @@ -13695,7 +13695,7 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3" For information on how BitBake uses stamp files to determine if a task should be rerun, see the - "Stamp Files and the Rerunning of Tasks" + "Stamp Files and the Rerunning of Tasks" section in the Yocto Project Overview Manual. @@ -15187,7 +15187,7 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3" For background information on cross-development toolchains in the Yocto Project development environment, see the - "Cross-Development Toolchain Generation" + "Cross-Development Toolchain Generation" section in the Yocto Project Overview Manual. For information on setting up a cross-development environment, see the @@ -15246,7 +15246,7 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3" For background information on cross-development toolchains in the Yocto Project development environment, see the - "Cross-Development Toolchain Generation" + "Cross-Development Toolchain Generation" section in the Yocto Project Overview Manual. For information on setting up a cross-development environment, see the diff --git a/documentation/ref-manual/resources.xml b/documentation/ref-manual/resources.xml index 3076de2e5e..09feddd29f 100644 --- a/documentation/ref-manual/resources.xml +++ b/documentation/ref-manual/resources.xml @@ -167,7 +167,7 @@ - Yocto Project Overview Manual: + Yocto Project Overview Manual: This manual introduces the Yocto Project, provides development environment basics, and explains Yocto Project concepts. diff --git a/documentation/sdk-manual/sdk-appendix-obtain.xml b/documentation/sdk-manual/sdk-appendix-obtain.xml index d2da5924c2..d35cc0a3c9 100644 --- a/documentation/sdk-manual/sdk-appendix-obtain.xml +++ b/documentation/sdk-manual/sdk-appendix-obtain.xml @@ -327,7 +327,7 @@ Following is an example command that extracts the root filesystem from a previously built root filesystem image that was downloaded from the - Index of Releases. + Index of Releases. This command extracts the root filesystem into the core2-64-sato directory: diff --git a/documentation/sdk-manual/sdk-extensible.xml b/documentation/sdk-manual/sdk-extensible.xml index ac6fa367ba..6c4e5c2233 100644 --- a/documentation/sdk-manual/sdk-extensible.xml +++ b/documentation/sdk-manual/sdk-extensible.xml @@ -247,7 +247,7 @@ The devtool command line is organized similarly to - Git in that it + Git in that it has a number of sub-commands for each function. You can run devtool --help to see all the commands. diff --git a/documentation/tools/mega-manual.sed b/documentation/tools/mega-manual.sed index 3f95569642..a34ff97d5e 100644 --- a/documentation/tools/mega-manual.sed +++ b/documentation/tools/mega-manual.sed @@ -16,7 +16,7 @@ s/\"ulink\" href=\"http:\/\/www.yoctoproject.org\/docs\/2.5\/poky-ref-manual\/po s/\"ulink\" href=\"http:\/\/www.yoctoproject.org\/docs\/2.5\/sdk-manual\/sdk-manual.html#/\"link\" href=\"#/g s/\"ulink\" href=\"http:\/\/www.yoctoproject.org\/docs\/2.5\/bsp-guide\/bsp-guide.html#/\"link\" href=\"#/g s/\"ulink\" href=\"http:\/\/www.yoctoproject.org\/docs\/2.5\/dev-manual\/dev-manual.html#/\"link\" href=\"#/g -s/\"ulink\" href=\"http:\/\/www.yoctoproject.org\/docs\/2.5\/overview-manual\/overview-manual.html#/\"link\" href=\"#/g +s/\"ulink\" href=\"http:\/\/www.yoctoproject.org\/docs\/2.5\/getting-started\/getting-started.html#/\"link\" href=\"#/g s/\"ulink\" href=\"http:\/\/www.yoctoproject.org\/docs\/2.5\/kernel-dev\/kernel-dev.html#/\"link\" href=\"#/g s/\"ulink\" href=\"http:\/\/www.yoctoproject.org\/docs\/2.5\/profile-manual\/profile-manual.html#/\"link\" href=\"#/g s/\"ulink\" href=\"http:\/\/www.yoctoproject.org\/docs\/2.5\/ref-manual\/ref-manual.html#/\"link\" href=\"#/g @@ -25,7 +25,7 @@ s/\"ulink\" href=\"http:\/\/www.yoctoproject.org\/docs\/2.5\/toaster-manual\/toa # Process cases where just an external manual is referenced without an id anchor s/Yocto Project Quick Start<\/a>/Yocto Project Quick Start/g s/Yocto Project Development Tasks Manual<\/a>/Yocto Project Development Tasks Manual/g -s/Yocto Project Overview Manual<\/a>/Yocto Project Overview Manual/g +s/Yocto Project Overview Manual<\/a>/Yocto Project Overview Manual/g s/Yocto Project Application Development and the Extensible Software Development Kit (eSDK)<\/a>/Yocto Project Application Development and the Extensible Software Development Kit (eSDK)/g s/Yocto Project Board Support Package (BSP) Developer's Guide<\/a>/Yocto Project Board Support Package (BSP) Developer's Guide/g s/Yocto Project Profiling and Tracing Manual<\/a>/Yocto Project Profiling and Tracing Manual/g diff --git a/documentation/yocto-project-qs/qs.xml b/documentation/yocto-project-qs/qs.xml index 3989fa06ca..bd5941f03e 100644 --- a/documentation/yocto-project-qs/qs.xml +++ b/documentation/yocto-project-qs/qs.xml @@ -48,7 +48,7 @@ For more introductory and conceptual information on the Yocto Project, see the - Yocto Project Overview Manual. + Yocto Project Overview Manual. For guidance on where to look for information beyond @@ -308,7 +308,7 @@ (CROPS), you need to get a copy of the Yocto Project. It is recommended that you get the latest Yocto Project release by setting up (cloning in - Git + Git terms) a local copy of the poky Git repository on your build host and then checking out the latest release. @@ -603,7 +603,7 @@ For information on using the bitbake command, see the - "BitBake" + "BitBake" section in the Yocto Project Overview Manual, or see the "BitBake Command" @@ -1078,7 +1078,7 @@ used by the OpenEmbedded build system during the image generation process. For information on Fakeroot and Pseudo, see the - "Fakeroot and Pseudo" + "Fakeroot and Pseudo" section in the Yocto Project Overview Manual. -- cgit v1.2.3-54-g00ecf