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authorNicolas Dechesne <nicolas.dechesne@linaro.org>2020-06-26 19:10:51 +0200
committerRichard Purdie <richard.purdie@linuxfoundation.org>2020-09-17 10:09:33 +0100
commit9bd69b1f1d71a9692189beeac75af9dfbad816cc (patch)
tree305347fca899074aed5610e0e82eaec180bf630c /documentation/ref-manual/ref-terms.rst
parentc40a8d5904c29046f1cbbeb998e6cd7c24f9b206 (diff)
downloadpoky-9bd69b1f1d71a9692189beeac75af9dfbad816cc.tar.gz
sphinx: initial sphinx support
This commit is autogenerated pandoc to generate an inital set of reST files based on DocBook XML files. A .rst file is generated for each .xml files in all manuals with this command: cd <manual> for i in *.xml; do \ pandoc -f docbook -t rst --shift-heading-level-by=-1 \ $i -o $(basename $i .xml).rst \ done The conversion was done with: pandoc 2.9.2.1-91 (Arch Linux). Also created an initial top level index file for each document, and added all 'books' to the top leve index.rst file. The YP manuals layout is organized as: Book Chapter Section Section Section Sphinx uses section headers to create the document structure. ReStructuredText defines sections headers like that: To break longer text up into sections, you use section headers. These are a single line of text (one or more words) with adornment: an underline alone, or an underline and an overline together, in dashes "-----", equals "======", tildes "~~~~~~" or any of the non-alphanumeric characters = - ` : ' " ~ ^ _ * + # < > that you feel comfortable with. An underline-only adornment is distinct from an overline-and-underline adornment using the same character. The underline/overline must be at least as long as the title text. Be consistent, since all sections marked with the same adornment style are deemed to be at the same level: Let's define the following convention when converting from Docbook: Book => overline === (Title) Chapter => overline *** (1.) Section => ==== (1.1) Section => ---- (1.1.1) Section => ~~~~ (1.1.1.1) Section => ^^^^ (1.1.1.1.1) During the conversion with pandoc, we used --shift-heading-level=-1 to convert most of DocBook headings automatically. However with this setting, the Chapter header was removed, so I added it back manually. Without this setting all headings were off by one, which was more difficult to manually fix. At least with this change, we now have the same TOC with Sphinx and DocBook. (From yocto-docs rev: 3c73d64a476d4423ee4c6808c685fa94d88d7df8) Signed-off-by: Nicolas Dechesne <nicolas.dechesne@linaro.org> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
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1*******************
2Yocto Project Terms
3*******************
4
5Following is a list of terms and definitions users new to the Yocto
6Project development environment might find helpful. While some of these
7terms are universal, the list includes them just in case:
8
9- *Append Files:* Files that append build information to a recipe file.
10 Append files are known as BitBake append files and ``.bbappend``
11 files. The OpenEmbedded build system expects every append file to
12 have a corresponding recipe (``.bb``) file. Furthermore, the append
13 file and corresponding recipe file must use the same root filename.
14 The filenames can differ only in the file type suffix used (e.g.
15 ``formfactor_0.0.bb`` and ``formfactor_0.0.bbappend``).
16
17 Information in append files extends or overrides the information in
18 the similarly-named recipe file. For an example of an append file in
19 use, see the "`Using .bbappend Files in Your
20 Layer <&YOCTO_DOCS_DEV_URL;#using-bbappend-files>`__" section in the
21 Yocto Project Development Tasks Manual.
22
23 When you name an append file, you can use the "``%``" wildcard
24 character to allow for matching recipe names. For example, suppose
25 you have an append file named as follows: busybox_1.21.%.bbappend
26 That append file would match any ``busybox_1.21.``\ x\ ``.bb``
27 version of the recipe. So, the append file would match any of the
28 following recipe names: busybox_1.21.1.bb busybox_1.21.2.bb
29 busybox_1.21.3.bb busybox_1.21.10.bb busybox_1.21.25.bb
30
31 .. note::
32
33 The use of the "
34 %
35 " character is limited in that it only works directly in front of
36 the
37 .bbappend
38 portion of the append file's name. You cannot use the wildcard
39 character in any other location of the name.
40
41- *BitBake:* The task executor and scheduler used by the OpenEmbedded
42 build system to build images. For more information on BitBake, see
43 the `BitBake User Manual <&YOCTO_DOCS_BB_URL;>`__.
44
45- *Board Support Package (BSP):* A group of drivers, definitions, and
46 other components that provide support for a specific hardware
47 configuration. For more information on BSPs, see the `Yocto Project
48 Board Support Package (BSP) Developer's
49 Guide <&YOCTO_DOCS_BSP_URL;>`__.
50
51- *Build Directory:* This term refers to the area used by the
52 OpenEmbedded build system for builds. The area is created when you
53 ``source`` the setup environment script that is found in the Source
54 Directory (i.e. ````` <#structure-core-script>`__). The
55 ```TOPDIR`` <#var-TOPDIR>`__ variable points to the Build Directory.
56
57 You have a lot of flexibility when creating the Build Directory.
58 Following are some examples that show how to create the directory.
59 The examples assume your `Source Directory <#source-directory>`__ is
60 named ``poky``:
61
62 - Create the Build Directory inside your Source Directory and let
63 the name of the Build Directory default to ``build``: $ cd
64 $HOME/poky $ source OE_INIT_FILE
65
66 - Create the Build Directory inside your home directory and
67 specifically name it ``test-builds``: $ cd $HOME $ source
68 poky/OE_INIT_FILE test-builds
69
70 - Provide a directory path and specifically name the Build
71 Directory. Any intermediate folders in the pathname must exist.
72 This next example creates a Build Directory named
73 ``YP-POKYVERSION`` in your home directory within the existing
74 directory ``mybuilds``: $ cd $HOME $ source
75 $HOME/poky/OE_INIT_FILE $HOME/mybuilds/YP-POKYVERSION
76
77 .. note::
78
79 By default, the Build Directory contains
80 TMPDIR
81 , which is a temporary directory the build system uses for its
82 work.
83 TMPDIR
84 cannot be under NFS. Thus, by default, the Build Directory cannot
85 be under NFS. However, if you need the Build Directory to be under
86 NFS, you can set this up by setting
87 TMPDIR
88 in your
89 local.conf
90 file to use a local drive. Doing so effectively separates
91 TMPDIR
92 from
93 TOPDIR
94 , which is the Build Directory.
95
96- *Build Host:* The system used to build images in a Yocto Project
97 Development environment. The build system is sometimes referred to as
98 the development host.
99
100- *Classes:* Files that provide for logic encapsulation and inheritance
101 so that commonly used patterns can be defined once and then easily
102 used in multiple recipes. For reference information on the Yocto
103 Project classes, see the "`Classes <#ref-classes>`__" chapter. Class
104 files end with the ``.bbclass`` filename extension.
105
106- *Configuration File:* Files that hold global definitions of
107 variables, user-defined variables, and hardware configuration
108 information. These files tell the OpenEmbedded build system what to
109 build and what to put into the image to support a particular
110 platform.
111
112 Configuration files end with a ``.conf`` filename extension. The
113 ``conf/local.conf`` configuration file in the `Build
114 Directory <#build-directory>`__ contains user-defined variables that
115 affect every build. The ``meta-poky/conf/distro/poky.conf``
116 configuration file defines Yocto "distro" configuration variables
117 used only when building with this policy. Machine configuration
118 files, which are located throughout the `Source
119 Directory <#source-directory>`__, define variables for specific
120 hardware and are only used when building for that target (e.g. the
121 ``machine/beaglebone.conf`` configuration file defines variables for
122 the Texas Instruments ARM Cortex-A8 development board).
123
124- *Container Layer:* Layers that hold other layers. An example of a
125 container layer is OpenEmbedded's
126 ```meta-openembedded`` <https://github.com/openembedded/meta-openembedded>`__
127 layer. The ``meta-openembedded`` layer contains many ``meta-*``
128 layers.
129
130- *Cross-Development Toolchain:* In general, a cross-development
131 toolchain is a collection of software development tools and utilities
132 that run on one architecture and allow you to develop software for a
133 different, or targeted, architecture. These toolchains contain
134 cross-compilers, linkers, and debuggers that are specific to the
135 target architecture.
136
137 The Yocto Project supports two different cross-development
138 toolchains:
139
140 - A toolchain only used by and within BitBake when building an image
141 for a target architecture.
142
143 - A relocatable toolchain used outside of BitBake by developers when
144 developing applications that will run on a targeted device.
145
146 Creation of these toolchains is simple and automated. For information
147 on toolchain concepts as they apply to the Yocto Project, see the
148 "`Cross-Development Toolchain
149 Generation <&YOCTO_DOCS_OM_URL;#cross-development-toolchain-generation>`__"
150 section in the Yocto Project Overview and Concepts Manual. You can
151 also find more information on using the relocatable toolchain in the
152 `Yocto Project Application Development and the Extensible Software
153 Development Kit (eSDK) <&YOCTO_DOCS_SDK_URL;>`__ manual.
154
155- *Extensible Software Development Kit (eSDK):* A custom SDK for
156 application developers. This eSDK allows developers to incorporate
157 their library and programming changes back into the image to make
158 their code available to other application developers.
159
160 For information on the eSDK, see the `Yocto Project Application
161 Development and the Extensible Software Development Kit
162 (eSDK) <&YOCTO_DOCS_SDK_URL;>`__ manual.
163
164- *Image:* An image is an artifact of the BitBake build process given a
165 collection of recipes and related Metadata. Images are the binary
166 output that run on specific hardware or QEMU and are used for
167 specific use-cases. For a list of the supported image types that the
168 Yocto Project provides, see the "`Images <#ref-images>`__" chapter.
169
170- *Layer:* A collection of related recipes. Layers allow you to
171 consolidate related metadata to customize your build. Layers also
172 isolate information used when building for multiple architectures.
173 Layers are hierarchical in their ability to override previous
174 specifications. You can include any number of available layers from
175 the Yocto Project and customize the build by adding your layers after
176 them. You can search the Layer Index for layers used within Yocto
177 Project.
178
179 For introductory information on layers, see the "`The Yocto Project
180 Layer Model <&YOCTO_DOCS_OM_URL;#the-yocto-project-layer-model>`__"
181 section in the Yocto Project Overview and Concepts Manual. For more
182 detailed information on layers, see the "`Understanding and Creating
183 Layers <&YOCTO_DOCS_DEV_URL;#understanding-and-creating-layers>`__"
184 section in the Yocto Project Development Tasks Manual. For a
185 discussion specifically on BSP Layers, see the "`BSP
186 Layers <&YOCTO_DOCS_BSP_URL;#bsp-layers>`__" section in the Yocto
187 Project Board Support Packages (BSP) Developer's Guide.
188
189- *Metadata:* A key element of the Yocto Project is the Metadata that
190 is used to construct a Linux distribution and is contained in the
191 files that the `OpenEmbedded build system <#build-system-term>`__
192 parses when building an image. In general, Metadata includes recipes,
193 configuration files, and other information that refers to the build
194 instructions themselves, as well as the data used to control what
195 things get built and the effects of the build. Metadata also includes
196 commands and data used to indicate what versions of software are
197 used, from where they are obtained, and changes or additions to the
198 software itself (patches or auxiliary files) that are used to fix
199 bugs or customize the software for use in a particular situation.
200 OpenEmbedded-Core is an important set of validated metadata.
201
202 In the context of the kernel ("kernel Metadata"), the term refers to
203 the kernel config fragments and features contained in the
204 ```yocto-kernel-cache`` <&YOCTO_GIT_URL;/cgit/cgit.cgi/yocto-kernel-cache>`__
205 Git repository.
206
207- *OpenEmbedded-Core (OE-Core):* OE-Core is metadata comprised of
208 foundational recipes, classes, and associated files that are meant to
209 be common among many different OpenEmbedded-derived systems,
210 including the Yocto Project. OE-Core is a curated subset of an
211 original repository developed by the OpenEmbedded community that has
212 been pared down into a smaller, core set of continuously validated
213 recipes. The result is a tightly controlled and an quality-assured
214 core set of recipes.
215
216 You can see the Metadata in the ``meta`` directory of the Yocto
217 Project `Source
218 Repositories <http://git.yoctoproject.org/cgit/cgit.cgi>`__.
219
220- *OpenEmbedded Build System:* The build system specific to the Yocto
221 Project. The OpenEmbedded build system is based on another project
222 known as "Poky", which uses `BitBake <#bitbake-term>`__ as the task
223 executor. Throughout the Yocto Project documentation set, the
224 OpenEmbedded build system is sometimes referred to simply as "the
225 build system". If other build systems, such as a host or target build
226 system are referenced, the documentation clearly states the
227 difference.
228
229 .. note::
230
231 For some historical information about Poky, see the
232 Poky
233 term.
234
235- *Package:* In the context of the Yocto Project, this term refers to a
236 recipe's packaged output produced by BitBake (i.e. a "baked recipe").
237 A package is generally the compiled binaries produced from the
238 recipe's sources. You "bake" something by running it through BitBake.
239
240 It is worth noting that the term "package" can, in general, have
241 subtle meanings. For example, the packages referred to in the
242 "`Required Packages for the Build
243 Host <#required-packages-for-the-build-host>`__" section are compiled
244 binaries that, when installed, add functionality to your Linux
245 distribution.
246
247 Another point worth noting is that historically within the Yocto
248 Project, recipes were referred to as packages - thus, the existence
249 of several BitBake variables that are seemingly mis-named, (e.g.
250 ```PR`` <#var-PR>`__, ```PV`` <#var-PV>`__, and
251 ```PE`` <#var-PE>`__).
252
253- *Package Groups:* Arbitrary groups of software Recipes. You use
254 package groups to hold recipes that, when built, usually accomplish a
255 single task. For example, a package group could contain the recipes
256 for a company’s proprietary or value-add software. Or, the package
257 group could contain the recipes that enable graphics. A package group
258 is really just another recipe. Because package group files are
259 recipes, they end with the ``.bb`` filename extension.
260
261- *Poky:* Poky, which is pronounced *Pock*-ee, is a reference embedded
262 distribution and a reference test configuration. Poky provides the
263 following:
264
265 - A base-level functional distro used to illustrate how to customize
266 a distribution.
267
268 - A means by which to test the Yocto Project components (i.e. Poky
269 is used to validate the Yocto Project).
270
271 - A vehicle through which you can download the Yocto Project.
272
273 Poky is not a product level distro. Rather, it is a good starting
274 point for customization.
275
276 .. note::
277
278 Poky began as an open-source project initially developed by
279 OpenedHand. OpenedHand developed Poky from the existing
280 OpenEmbedded build system to create a commercially supportable
281 build system for embedded Linux. After Intel Corporation acquired
282 OpenedHand, the poky project became the basis for the Yocto
283 Project's build system.
284
285- *Recipe:* A set of instructions for building packages. A recipe
286 describes where you get source code, which patches to apply, how to
287 configure the source, how to compile it and so on. Recipes also
288 describe dependencies for libraries or for other recipes. Recipes
289 represent the logical unit of execution, the software to build, the
290 images to build, and use the ``.bb`` file extension.
291
292- *Reference Kit:* A working example of a system, which includes a
293 `BSP <#board-support-package-bsp-term>`__ as well as a `build
294 host <#hardware-build-system-term>`__ and other components, that can
295 work on specific hardware.
296
297- *Source Directory:* This term refers to the directory structure
298 created as a result of creating a local copy of the ``poky`` Git
299 repository ``git://git.yoctoproject.org/poky`` or expanding a
300 released ``poky`` tarball.
301
302 .. note::
303
304 Creating a local copy of the
305 poky
306 Git repository is the recommended method for setting up your
307 Source Directory.
308
309 Sometimes you might hear the term "poky directory" used to refer to
310 this directory structure.
311
312 .. note::
313
314 The OpenEmbedded build system does not support file or directory
315 names that contain spaces. Be sure that the Source Directory you
316 use does not contain these types of names.
317
318 The Source Directory contains BitBake, Documentation, Metadata and
319 other files that all support the Yocto Project. Consequently, you
320 must have the Source Directory in place on your development system in
321 order to do any development using the Yocto Project.
322
323 When you create a local copy of the Git repository, you can name the
324 repository anything you like. Throughout much of the documentation,
325 "poky" is used as the name of the top-level folder of the local copy
326 of the poky Git repository. So, for example, cloning the ``poky`` Git
327 repository results in a local Git repository whose top-level folder
328 is also named "poky".
329
330 While it is not recommended that you use tarball expansion to set up
331 the Source Directory, if you do, the top-level directory name of the
332 Source Directory is derived from the Yocto Project release tarball.
333 For example, downloading and unpacking ```` results in a Source
334 Directory whose root folder is named ````.
335
336 It is important to understand the differences between the Source
337 Directory created by unpacking a released tarball as compared to
338 cloning ``git://git.yoctoproject.org/poky``. When you unpack a
339 tarball, you have an exact copy of the files based on the time of
340 release - a fixed release point. Any changes you make to your local
341 files in the Source Directory are on top of the release and will
342 remain local only. On the other hand, when you clone the ``poky`` Git
343 repository, you have an active development repository with access to
344 the upstream repository's branches and tags. In this case, any local
345 changes you make to the local Source Directory can be later applied
346 to active development branches of the upstream ``poky`` Git
347 repository.
348
349 For more information on concepts related to Git repositories,
350 branches, and tags, see the "`Repositories, Tags, and
351 Branches <&YOCTO_DOCS_OM_URL;#repositories-tags-and-branches>`__"
352 section in the Yocto Project Overview and Concepts Manual.
353
354- *Task:* A unit of execution for BitBake (e.g.
355 ```do_compile`` <#ref-tasks-compile>`__,
356 ```do_fetch`` <#ref-tasks-fetch>`__,
357 ```do_patch`` <#ref-tasks-patch>`__, and so forth).
358
359- *Toaster:* A web interface to the Yocto Project's `OpenEmbedded Build
360 System <#build-system-term>`__. The interface enables you to
361 configure and run your builds. Information about builds is collected
362 and stored in a database. For information on Toaster, see the
363 `Toaster User Manual <&YOCTO_DOCS_TOAST_URL;>`__.
364
365- *Upstream:* A reference to source code or repositories that are not
366 local to the development system but located in a master area that is
367 controlled by the maintainer of the source code. For example, in
368 order for a developer to work on a particular piece of code, they
369 need to first get a copy of it from an "upstream" source.