%poky; ] > This chapter lists common variables used in the OpenEmbedded build system and gives an overview of their function and contents. A B C D E F G H I K L M O P R S T U W ALLOW_EMPTY Specifies if an output package should still be produced if it is empty. By default, BitBake does not produce empty packages. This default behavior can cause issues when there is an RDEPENDS or some other hard runtime requirement on the existence of the package. Like all package-controlling variables, you must always use them in conjunction with a package name override, as in: ALLOW_EMPTY_${PN} = "1" ALLOW_EMPTY_${PN}-dev = "1" ALLOW_EMPTY_${PN}-staticdev = "1" ALTERNATIVE Lists commands in a package that need an alternative binary naming scheme. Sometimes the same command is provided in multiple packages. When this occurs, the OpenEmbedded build system needs to use the alternatives system to create a different binary naming scheme so the commands can co-exist. To use the variable, list out the package's commands that also exist as part of another package. For example, if the busybox package has four commands that also exist as part of another package, you identify them as follows: ALTERNATIVE_busybox = "sh sed test bracket" For more information on the alternatives system, see the "Alternatives - update-alternatives.bbclass" section. ALTERNATIVE_LINK_NAME Used by the alternatives system to map duplicated commands to actual locations. For example, if the bracket command provided by the busybox package is duplicated through another package, you must use the ALTERNATIVE_LINK_NAME variable to specify the actual location: ALTERNATIVE_LINK_NAME[bracket] = "/usr/bin/[" In this example, the binary for the bracket command (i.e. [) from the busybox package resides in /usr/bin/. If ALTERNATIVE_LINK_NAME is not defined, it defaults to ${bindir}/<name>. For more information on the alternatives system, see the "Alternatives - update-alternatives.bbclass" section. ALTERNATIVE_PRIORITY Used by the alternatives system to create default priorities for duplicated commands. You can use the variable to create a single default regardless of the command name or package, a default for specific duplicated commands regardless of the package, or a default for specific commands tied to particular packages. Here are the available syntax forms: ALTERNATIVE_PRIORITY = "<priority>" ALTERNATIVE_PRIORITY[<name>] = "<priority>" ALTERNATIVE_PRIORITY_<pkg>[<name>] = "<priority>" For more information on the alternatives system, see the "Alternatives - update-alternatives.bbclass" section. ALTERNATIVE_TARGET Used by the alternatives system to create default link locations for duplicated commands. You can use the variable to create a single default location for all duplicated commands regardless of the command name or package, a default for specific duplicated commands regardless of the package, or a default for specific commands tied to particular packages. Here are the available syntax forms: ALTERNATIVE_TARGET = "<target>" ALTERNATIVE_TARGET[<name>] = "<target>" ALTERNATIVE_TARGET_<pkg>[<name>] = "<target>" If ALTERNATIVE_TARGET is not defined, it inherits the value from the ALTERNATIVE_LINK_NAME variable. If ALTERNATIVE_LINK_NAME and ALTERNATIVE_TARGET are the same, the target for ALTERNATIVE_TARGET has ".{BPN}" appended to it. Finally, if the file referenced has not been renamed, the alternatives system will rename it to avoid the need to rename alternative files in the do_install task while retaining support for the command if necessary. For more information on the alternatives system, see the "Alternatives - update-alternatives.bbclass" section. APPEND An override list of append strings for each LABEL. See the grub-efi class for more information on how this variable is used. AUTHOR The email address used to contact the original author or authors in order to send patches and forward bugs. AUTOREV When SRCREV is set to the value of this variable, it specifies to use the latest source revision in the repository. Here is an example: SRCREV = "${AUTOREV}" B The directory within the Build Directory in which the OpenEmbedded build system places generated objects during a recipe's build process. By default, this directory is the same as the S directory, which is defined as: S = "${WORKDIR}/${BP}/" You can separate the (S) directory and the directory pointed to by the B variable. Most Autotools-based recipes support separating these directories. The build system defaults to using separate directories for gcc and some kernel recipes. BAD_RECOMMENDATIONS Lists "recommended-only" packages to not install. Recommended-only packages are packages installed only through the RRECOMMENDS variable. You can prevent any of these "recommended" packages from being installed by listing them with the BAD_RECOMMENDATIONS variable: BAD_RECOMMENDATIONS = "<package_name> <package_name> <package_name> ..." You can set this variable globally in your local.conf file or you can attach it to a specific image recipe by using the recipe name override: BAD_RECOMMENDATIONS_pn-<target_image> = "<package_name>" It is important to realize that if you choose to not install packages using this variable and some other packages are dependent on them (i.e. listed in a recipe's RDEPENDS variable), the OpenEmbedded build system ignores your request and will install the packages to avoid dependency errors. Support for this variable exists only when using the IPK and RPM packaging backend. Support does not exist for DEB. See the NO_RECOMMENDATIONS and the PACKAGE_EXCLUDE variables for related information. BB_DANGLINGAPPENDS_WARNONLY Defines how BitBake handles situations where an append file (.bbappend) has no corresponding recipe file (.bb). This condition often occurs when layers get out of sync (e.g. oe-core bumps a recipe version and the old recipe no longer exists and the other layer has not been updated to the new version of the recipe yet). The default fatal behavior is safest because it is the sane reaction given something is out of sync. It is important to realize when your changes are no longer being applied. You can change the default behavior by setting this variable to "1", "yes", or "true" in your local.conf file, which is located in the Build Directory: Here is an example: BB_DANGLINGAPPENDS_WARNONLY = "1" BB_DISKMON_DIRS Monitors disk space and available inodes during the build and allows you to control the build based on these parameters. Disk space monitoring is disabled by default. To enable monitoring, add the BB_DISKMON_DIRS variable to your conf/local.conf file found in the Build Directory. Use the following form: BB_DISKMON_DIRS = "<action>,<dir>,<threshold> [...]" where: <action> is: ABORT: Immediately abort the build when a threshold is broken. STOPTASKS: Stop the build after the currently executing tasks have finished when a threshold is broken. WARN: Issue a warning but continue the build when a threshold is broken. Subsequent warnings are issued as defined by the BB_DISKMON_WARNINTERVAL variable, which must be defined in the conf/local.conf file. <dir> is: Any directory you choose. You can specify one or more directories to monitor by separating the groupings with a space. If two directories are on the same device, only the first directory is monitored. <threshold> is: Either the minimum available disk space, the minimum number of free inodes, or both. You must specify at least one. To omit one or the other, simply omit the value. Specify the threshold using G, M, K for Gbytes, Mbytes, and Kbytes, respectively. If you do not specify G, M, or K, Kbytes is assumed by default. Do not use GB, MB, or KB. Here are some examples: BB_DISKMON_DIRS = "ABORT,${TMPDIR},1G,100K WARN,${SSTATE_DIR},1G,100K" BB_DISKMON_DIRS = "STOPTASKS,${TMPDIR},1G" BB_DISKMON_DIRS = "ABORT,${TMPDIR},,100K" The first example works only if you also provide the BB_DISKMON_WARNINTERVAL variable in the conf/local.conf. This example causes the build system to immediately abort when either the disk space in ${TMPDIR} drops below 1 Gbyte or the available free inodes drops below 100 Kbytes. Because two directories are provided with the variable, the build system also issue a warning when the disk space in the ${SSTATE_DIR} directory drops below 1 Gbyte or the number of free inodes drops below 100 Kbytes. Subsequent warnings are issued during intervals as defined by the BB_DISKMON_WARNINTERVAL variable. The second example stops the build after all currently executing tasks complete when the minimum disk space in the ${TMPDIR} directory drops below 1 Gbyte. No disk monitoring occurs for the free inodes in this case. The final example immediately aborts the build when the number of free inodes in the ${TMPDIR} directory drops below 100 Kbytes. No disk space monitoring for the directory itself occurs in this case. BB_DISKMON_WARNINTERVAL Defines the disk space and free inode warning intervals. To set these intervals, define the variable in your conf/local.conf file in the Build Directory. If you are going to use the BB_DISKMON_WARNINTERVAL variable, you must also use the BB_DISKMON_DIRS variable and define its action as "WARN". During the build, subsequent warnings are issued each time disk space or number of free inodes further reduces by the respective interval. If you do not provide a BB_DISKMON_WARNINTERVAL variable and you do use BB_DISKMON_DIRS with the "WARN" action, the disk monitoring interval defaults to the following: BB_DISKMON_WARNINTERVAL = "50M,5K" When specifying the variable in your configuration file, use the following form: BB_DISKMON_WARNINTERVAL = "<disk_space_interval>,<disk_inode_interval>" where: <disk_space_interval> is: An interval of memory expressed in either G, M, or K for Gbytes, Mbytes, or Kbytes, respectively. You cannot use GB, MB, or KB. <disk_inode_interval> is: An interval of free inodes expressed in either G, M, or K for Gbytes, Mbytes, or Kbytes, respectively. You cannot use GB, MB, or KB. Here is an example: BB_DISKMON_DIRS = "WARN,${SSTATE_DIR},1G,100K" BB_DISKMON_WARNINTERVAL = "50M,5K" These variables cause the OpenEmbedded build system to issue subsequent warnings each time the available disk space further reduces by 50 Mbytes or the number of free inodes further reduces by 5 Kbytes in the ${SSTATE_DIR} directory. Subsequent warnings based on the interval occur each time a respective interval is reached beyond the initial warning (i.e. 1 Gbytes and 100 Kbytes). BB_GENERATE_MIRROR_TARBALLS Causes tarballs of the Git repositories to be placed in the DL_DIR directory. For performance reasons, creating and placing tarballs of the Git repositories is not the default action by the OpenEmbedded build system. BB_GENERATE_MIRROR_TARBALLS = "1" Set this variable in your local.conf file in the Build Directory. BB_NUMBER_THREADS The maximum number of tasks BitBake should run in parallel at any one time. If your host development system supports multiple cores, a good rule of thumb is to set this variable to twice the number of cores. BBCLASSEXTEND Allows you to extend a recipe so that it builds variants of the software. Common variants for recipes exist such as "natives" like quilt-native, which is a copy of Quilt built to run on the build system; "crosses" such as gcc-cross, which is a compiler built to run on the build machine but produces binaries that run on the target MACHINE; "nativesdk", which targets the SDK machine instead of MACHINE; and "mulitlibs" in the form "multilib:<multilib_name>". To build a different variant of the recipe with a minimal amount of code, it usually is as simple as adding the following to your recipe: BBCLASSEXTEND =+ "native nativesdk" BBCLASSEXTEND =+ "multilib:<multilib_name>" BBFILE_COLLECTIONS Lists the names of configured layers. These names are used to find the other BBFILE_* variables. Typically, each layer will append its name to this variable in its conf/layer.conf file. BBFILE_PATTERN Variable that expands to match files from BBFILES in a particular layer. This variable is used in the conf/layer.conf file and must be suffixed with the name of the specific layer (e.g. BBFILE_PATTERN_emenlow). BBFILE_PRIORITY Assigns the priority for recipe files in each layer. This variable is useful in situations where the same recipe appears in more than one layer. Setting this variable allows you to prioritize a layer against other layers that contain the same recipe - effectively letting you control the precedence for the multiple layers. The precedence established through this variable stands regardless of a recipe's version (PV variable). For example, a layer that has a recipe with a higher PV value but for which the BBFILE_PRIORITY is set to have a lower precedence still has a lower precedence. A larger value for the BBFILE_PRIORITY variable results in a higher precedence. For example, the value 6 has a higher precedence than the value 5. If not specified, the BBFILE_PRIORITY variable is set based on layer dependencies (see the LAYERDEPENDS variable for more information. The default priority, if unspecified for a layer with no dependencies, is the lowest defined priority + 1 (or 1 if no priorities are defined). You can use the command bitbake-layers show-layers to list all configured layers along with their priorities. BBFILES List of recipe files used by BitBake to build software. BBINCLUDELOGS Variable that controls how BitBake displays logs on build failure. BBLAYERS Lists the layers to enable during the build. This variable is defined in the bblayers.conf configuration file in the Build Directory. Here is an example: BBLAYERS = " \ /home/scottrif/poky/meta \ /home/scottrif/poky/meta-yocto \ /home/scottrif/poky/meta-yocto-bsp \ /home/scottrif/poky/meta-mykernel \ " BBLAYERS_NON_REMOVABLE ?= " \ /home/scottrif/poky/meta \ /home/scottrif/poky/meta-yocto \ " This example enables four layers, one of which is a custom, user-defined layer named meta-mykernel. BBLAYERS_NON_REMOVABLE Lists core layers that cannot be removed from the bblayers.conf file during a build using the Hob. When building an image outside of Hob, this variable is ignored. In order for BitBake to build your image using Hob, your bblayers.conf file must include the meta and meta-yocto core layers. Here is an example that shows these two layers listed in the BBLAYERS_NON_REMOVABLE statement: BBLAYERS = " \ /home/scottrif/poky/meta \ /home/scottrif/poky/meta-yocto \ /home/scottrif/poky/meta-yocto-bsp \ /home/scottrif/poky/meta-mykernel \ " BBLAYERS_NON_REMOVABLE ?= " \ /home/scottrif/poky/meta \ /home/scottrif/poky/meta-yocto \ " BBMASK Prevents BitBake from processing recipes and recipe append files. Use the BBMASK variable from within the conf/local.conf file found in the Build Directory. You can use the BBMASK variable to "hide" these .bb and .bbappend files. BitBake ignores any recipe or recipe append files that match the expression. It is as if BitBake does not see them at all. Consequently, matching files are not parsed or otherwise used by BitBake. The value you provide is passed to Python's regular expression compiler. The expression is compared against the full paths to the files. For complete syntax information, see Python's documentation at . The following example uses a complete regular expression to tell BitBake to ignore all recipe and recipe append files in the meta-ti/recipes-misc/ directory: BBMASK = "meta-ti/recipes-misc/" If you want to mask out multiple directories or recipes, use the vertical bar to separate the regular expression fragments. This next example masks out multiple directories and individual recipes: BBMASK = "meta-ti/recipes-misc/|meta-ti/recipes-ti/packagegroup/" BBMASK .= "|.*meta-oe/recipes-support/" BBMASK .= "|.*openldap" BBMASK .= "|.*opencv" BBMASK .= "|.*lzma" Notice how the vertical bar is used to append the fragments. When specifying a directory name, use the trailing slash character to ensure you match just that directory name. BBPATH Used by BitBake to locate .bbclass and configuration files. This variable is analogous to the PATH variable. If you run BitBake from a directory outside of the Build Directory, you must be sure to set BBPATH to point to the Build Directory. Set the variable as you would any environment variable and then run BitBake: $ BBPATH = "<build_directory>" $ export BBPATH $ bitbake <target> BBSERVER Points to the server that runs memory-resident BitBake. This variable is set by the oe-init-build-env-memres setup script and should not be hand-edited. The variable is only used when you employ memory-resident BitBake. The setup script exports the value as follows: export BBSERVER=localhost:$port For more information on how the BBSERVER is used, see the oe-init-build-env-memres script, which is located in the Source Directory. BINCONFIG_GLOB When inheriting binconfig.bbclass from a recipe, this variable specifies a wildcard for configuration scripts that need editing. The scripts are edited to correct any paths that have been set up during compilation so that they are correct for use when installed into the sysroot and called by the build processes of other recipes. For more information on how this variable works, see meta/classes/binconfig.bbclass in the Source Directory. You can also find general information on the class in the "binconfig.bbclass" section. BP The base recipe name and version but without any special recipe name suffix (i.e. -native, lib64-, and so forth). BP is comprised of the following: ${BPN}-${PV} BPN The bare name of the recipe. This variable is a version of the PN variable but removes common suffixes such as "-native" and "-cross" as well as removes common prefixes such as multilib's "lib64-" and "lib32-". The exact list of suffixes removed is specified by the SPECIAL_PKGSUFFIX variable. The exact list of prefixes removed is specified by the MLPREFIX variable. Prefixes are removed for multilib and nativesdk cases. BUGTRACKER Specifies a URL for an upstream bug tracking website for a recipe. The OpenEmbedded build system does not use this variable. Rather, the variable is a useful pointer in case a bug in the software being built needs to be manually reported. BUILDDIR Points to the location of the Build Directory. You can define this directory indirectly through the &OE_INIT_FILE; and oe-init-build-env-memres scripts by passing in a Build Directory path when you run the scripts. If you run the scripts and do not provide a Build Directory path, the BUILDDIR defaults to build in the current directory. BUILDSTATS_BASE Points to the location of the directory that holds build statistics when you use and enable the buildstats class. The BUILDSTATS_BASE directory defaults to ${TMPDIR}/buildstats/. BUSYBOX_SPLIT_SUID For the BusyBox recipe, specifies whether to split the output executable file into two parts: one for features that require setuid root, and one for the remaining features (i.e. those that do not require setuid root). The BUSYBOX_SPLIT_SUID variable defaults to "1", which results in a single output executable file. Set the variable to "0" to split the output file. CFLAGS Flags passed to the C compiler for the target system. This variable evaluates to the same as TARGET_CFLAGS. CLASSOVERRIDE An internal variable specifying the special class override that should currently apply (e.g. "class-target", "class-native", and so forth). The classes that use this variable set it to appropriate values. You do not normally directly interact with this variable. The value for the CLASSOVERRIDE variable goes into OVERRIDES and then can be used as an override. Here is an example where "python-native" is added to DEPENDS only when building for the native case: DEPENDS_append_class-native = " python-native" COMBINED_FEATURES Provides a list of hardware features that are enabled in both MACHINE_FEATURES and DISTRO_FEATURES. This select list of features contains features that make sense to be controlled both at the machine and distribution configuration level. For example, the "bluetooth" feature requires hardware support but should also be optional at the distribution level, in case the hardware supports Bluetooth but you do not ever intend to use it. For more information, see the MACHINE_FEATURES and DISTRO_FEATURES variables. COMMON_LICENSE_DIR Points to meta/files/common-licenses in the Source Directory, which is where generic license files reside. COMPATIBLE_HOST A regular expression that resolves to one or more hosts (when the recipe is native) or one or more targets (when the recipe is non-native) with which a recipe is compatible. The regular expression is matched against HOST_SYS. You can use the variable to stop recipes from being built for classes of systems with which the recipes are not compatible. Stopping these builds is particularly useful with kernels. The variable also helps to increase parsing speed since the build system skips parsing recipes not compatible with the current system. COMPATIBLE_MACHINE A regular expression that resolves to one or more target machines with which a recipe is compatible. The regular expression is matched against MACHINEOVERRIDES. You can use the variable to stop recipes from being built for machines with which the recipes are not compatible. Stopping these builds is particularly useful with kernels. The variable also helps to increase parsing speed since the build system skips parsing recipes not compatible with the current machine. COMPLEMENTARY_GLOB Defines wildcards to match when installing a list of complementary packages for all the packages explicitly (or implicitly) installed in an image. The resulting list of complementary packages is associated with an item that can be added to IMAGE_FEATURES. An example usage of this is the "dev-pkgs" item that when added to IMAGE_FEATURES will install -dev packages (containing headers and other development files) for every package in the image. To add a new feature item pointing to a wildcard, use a variable flag to specify the feature item name and use the value to specify the wildcard. Here is an example: COMPLEMENTARY_GLOB[dev-pkgs] = '*-dev' CONFFILES Identifies editable or configurable files that are part of a package. If the Package Management System (PMS) is being used to update packages on the target system, it is possible that configuration files you have changed after the original installation and that you now want to remain unchanged are overwritten. In other words, editable files might exist in the package that you do not want reset as part of the package update process. You can use the CONFFILES variable to list the files in the package that you wish to prevent the PMS from overwriting during this update process. To use the CONFFILES variable, provide a package name override that identifies the resulting package. Then, provide a space-separated list of files. Here is an example: CONFFILES_${PN} += "${sysconfdir}/file1 \ ${sysconfdir}/file2 ${sysconfdir}/file3" A relationship exists between the CONFFILES and FILES variables. The files listed within CONFFILES must be a subset of the files listed within FILES. Because the configuration files you provide with CONFFILES are simply being identified so that the PMS will not overwrite them, it makes sense that the files must already be included as part of the package through the FILES variable. When specifying paths as part of the CONFFILES variable, it is good practice to use appropriate path variables. For example, ${sysconfdir} rather than /etc or ${bindir} rather than /usr/bin. You can find a list of these variables at the top of the meta/conf/bitbake.conf file in the Source Directory. CONFIG_SITE A list of files that contains autoconf test results relevant to the current build. This variable is used by the Autotools utilities when running configure. CONFLICT_DISTRO_FEATURES When a recipe inherits the distro_features_check class, this variable identifies distribution features that would be in conflict should the recipe be built. In other words, if the CONFLICT_DISTRO_FEATURES variable lists a feature that also appears in DISTRO_FEATURES within the current configuration, an error occurs and the build stops. CORE_IMAGE_EXTRA_INSTALL Specifies the list of packages to be added to the image. You should only set this variable in the local.conf configuration file found in the Build Directory. This variable replaces POKY_EXTRA_INSTALL, which is no longer supported. COREBASE Specifies the parent directory of the OpenEmbedded Core Metadata layer (i.e. meta). It is an important distinction that COREBASE points to the parent of this layer and not the layer itself. Consider an example where you have cloned the Poky Git repository and retained the poky name for your local copy of the repository. In this case, COREBASE points to the poky folder because it is the parent directory of the poky/meta layer. D The destination directory. DATETIME The date and time on which the current build started. The format is suitable for timestamps. DEBUG_BUILD Specifies to build packages with debugging information. This influences the value of the SELECTED_OPTIMIZATION variable. DEBUG_OPTIMIZATION The options to pass in TARGET_CFLAGS and CFLAGS when compiling a system for debugging. This variable defaults to "-O -fno-omit-frame-pointer ${DEBUG_FLAGS} -pipe". DEFAULT_PREFERENCE Specifies a weak bias for recipe selection priority. The most common usage of this is variable is to set it to "-1" within a recipe for a development version of a piece of software. Using the variable in this way causes the stable version of the recipe to build by default in the absence of PREFERRED_VERSION being used to build the development version. The bias provided by DEFAULT_PREFERENCE is weak and is overridden by BBFILE_PRIORITY if that variable is different between two layers that contain different versions of the same recipe. DEPENDS Lists a recipe's build-time dependencies (i.e. other recipe files). The system ensures that all the dependencies listed have been built and have their contents in the appropriate sysroots before the recipe's configure task is executed. Consider this simple example for two recipes named "a" and "b" that produce similarly named packages. In this example, the DEPENDS statement appears in the "a" recipe: DEPENDS = "b" Here, the dependency is such that the do_configure task for recipe "a" depends on the do_populate_sysroot task of recipe "b". This means anything that recipe "b" puts into sysroot is available when recipe "a" is configuring itself. For information on runtime dependencies, see the RDEPENDS variable. DEPLOY_DIR Points to the general area that the OpenEmbedded build system uses to place images, packages, SDKs and other output files that are ready to be used outside of the build system. By default, this directory resides within the Build Directory as ${TMPDIR}/deploy. For more information on the structure of the Build Directory, see "The Build Directory - build/" section. For more detail on the contents of the deploy directory, see the "Images" and "Application Development SDK" sections. DEPLOY_DIR_IMAGE Points to the area that the OpenEmbedded build system uses to place images and other associated output files that are ready to be deployed onto the target machine. The directory is machine-specific as it contains the ${MACHINE} name. By default, this directory resides within the Build Directory as ${DEPLOY_DIR}/images/${MACHINE}/. For more information on the structure of the Build Directory, see "The Build Directory - build/" section. For more detail on the contents of the deploy directory, see the "Images" and "Application Development SDK" sections. DESCRIPTION The package description used by package managers. If not set, DESCRIPTION takes the value of the SUMMARY variable. DISTRO The short name of the distribution. This variable corresponds to a distribution configuration file whose root name is the same as the variable's argument and whose filename extension is .conf. For example, the distribution configuration file for the Poky distribution is named poky.conf and resides in the meta-yocto/conf/distro directory of the Source Directory. Within that poky.conf file, the DISTRO variable is set as follows: DISTRO = "poky" Distribution configuration files are located in a conf/distro directory within the Metadata that contains the distribution configuration. The value for DISTRO must not contain spaces, and is typically all lower-case. If the DISTRO variable is blank, a set of default configurations are used, which are specified within meta/conf/distro/defaultsetup.conf also in the Source Directory. DISTRO_EXTRA_RDEPENDS Specifies a list of distro-specific packages to add to all images. This variable takes affect through packagegroup-base so the variable only really applies to the more full-featured images that include packagegroup-base. You can use this variable to keep distro policy out of generic images. As with all other distro variables, you set this variable in the distro .conf file. DISTRO_EXTRA_RRECOMMENDS Specifies a list of distro-specific packages to add to all images if the packages exist. The packages might not exist or be empty (e.g. kernel modules). The list of packages are automatically installed but you can remove them. DISTRO_FEATURES The software support you want in your distribution for various features. You define your distribution features in the distribution configuration file. In most cases, the presence or absence of a feature in DISTRO_FEATURES is translated to the appropriate option supplied to the configure script during do_configure for recipes that optionally support the feature. For example, specifying "x11" in DISTRO_FEATURES, causes every piece of software built for the target that can optionally support X11 to have its X11 support enabled. Two more examples are Bluetooth and NFS support. For a more complete list of features that ships with the Yocto Project and that you can provide with this variable, see the "Distro Features" section. DISTRO_FEATURES_BACKFILL Features to be added to DISTRO_FEATURES if not also present in DISTRO_FEATURES_BACKFILL_CONSIDERED. This variable is set in the meta/conf/bitbake.conf file. It is not intended to be user-configurable. It is best to just reference the variable to see which distro features are being backfilled for all distro configurations. See the Feature backfilling section for more information. DISTRO_FEATURES_BACKFILL_CONSIDERED Features from DISTRO_FEATURES_BACKFILL that should not be backfilled (i.e. added to DISTRO_FEATURES) during the build. See the "Feature Backfilling" section for more information. DISTRO_NAME The long name of the distribution. DISTRO_PN_ALIAS Alias names used for the recipe in various Linux distributions. See the "Handling a Package Name Alias" section in the Yocto Project Development Manual for more information. DISTRO_VERSION The version of the distribution. DISTROOVERRIDES This variable lists overrides specific to the current distribution. By default, the variable list includes the value of the DISTRO variable. You can extend the variable to apply any variable overrides you want as part of the distribution and are not already in OVERRIDES through some other means. DL_DIR The central download directory used by the build process to store downloads. By default, DL_DIR gets files suitable for mirroring for everything except Git repositories. If you want tarballs of Git repositories, use the BB_GENERATE_MIRROR_TARBALLS variable. You can set this directory by defining the DL_DIR variable in the conf/local.conf file. This directory is self-maintaining and you should not have to touch it. By default, the directory is downloads in the Build Directory. #DL_DIR ?= "${TOPDIR}/downloads" To specify a different download directory, simply remove the comment from the line and provide your directory. During a first build, the system downloads many different source code tarballs from various upstream projects. Downloading can take a while, particularly if your network connection is slow. Tarballs are all stored in the directory defined by DL_DIR and the build system looks there first to find source tarballs. When wiping and rebuilding, you can preserve this directory to speed up this part of subsequent builds. You can safely share this directory between multiple builds on the same development machine. For additional information on how the build process gets source files when working behind a firewall or proxy server, see this specific question in the "FAQ" chapter. ENABLE_BINARY_LOCALE_GENERATION Variable that controls which locales for eglibc are generated during the build (useful if the target device has 64Mbytes of RAM or less). ERROR_QA Specifies the quality assurance checks whose failures are reported as errors by the OpenEmbedded build system. You set this variable in your distribution configuration file. For a list of the checks you can control with this variable, see the "insane.bbclass" section. EXCLUDE_FROM_WORLD Directs BitBake to exclude a recipe from world builds (i.e. bitbake world). During world builds, BitBake locates, parses and builds all recipes found in every layer exposed in the bblayers.conf configuration file. To exclude a recipe from a world build using this variable, set the variable to "1" in the recipe. Recipes added to EXCLUDE_FROM_WORLD may still be built during a world build in order to satisfy dependencies of other recipes. Adding a recipe to EXCLUDE_FROM_WORLD only ensures that the recipe is not explicitly added to the list of build targets in a world build. EXTENDPE Used with file and pathnames to create a prefix for a recipe's version based on the recipe's PE value. If PE is set and greater than zero for a recipe, EXTENDPE becomes that value (e.g if PE is equal to "1" then EXTENDPE becomes "1_"). If a recipe's PE is not set (the default) or is equal to zero, EXTENDPE becomes "". See the STAMP variable for an example. EXTENDPKGV The full package version specification as it appears on the final packages produced by a recipe. The variable's value is normally used to fix a runtime dependency to the exact same version of another package in the same recipe: RDEPENDS_${PN}-additional-module = "${PN} (= ${EXTENDPKGV})" The dependency relationships are intended to force the package manager to upgrade these types of packages in lock-step. EXTERNALSRC If externalsrc.bbclass is inherited, this variable points to the source tree, which is outside of the OpenEmbedded build system. When set, this variable sets the S variable, which is what the OpenEmbedded build system uses to locate unpacked recipe source code. For more information on externalsrc.bbclass, see the "externalsrc.bbclass" section. You can also find information on how to use this variable in the "Building Software from an External Source" section in the Yocto Project Development Manual. EXTERNALSRC_BUILD If externalsrc.bbclass is inherited, this variable points to the directory in which the recipe's source code is built, which is outside of the OpenEmbedded build system. When set, this variable sets the B variable, which is what the OpenEmbedded build system uses to locate the Build Directory. For more information on externalsrc.bbclass, see the "externalsrc.bbclass" section. You can also find information on how to use this variable in the "Building Software from an External Source" section in the Yocto Project Development Manual. EXTRA_IMAGE_FEATURES The list of additional features to include in an image. Typically, you configure this variable in your local.conf file, which is found in the Build Directory. Although you can use this variable from within a recipe, best practices dictate that you do not. To enable primary features from within the image recipe, use the IMAGE_FEATURES variable. Here are some examples of features you can add: "dbg-pkgs" - Adds -dbg packages for all installed packages including symbol information for debugging and profiling. "debug-tweaks" - Makes an image suitable for development. For example, ssh root access has a blank password. You should remove this feature before you produce a production image. "dev-pkgs" - Adds -dev packages for all installed packages. This is useful if you want to develop against the libraries in the image. "read-only-rootfs" - Creates an image whose root filesystem is read-only. See the "Creating a Read-Only Root Filesystem" section in the Yocto Project Development Manual for more information "tools-debug" - Adds debugging tools such as gdb and strace. "tools-profile" - Adds profiling tools such as oprofile, exmap, lttng and valgrind (x86 only). "tools-sdk" - Adds development tools such as gcc, make, pkgconfig and so forth. "tools-testapps" - Adds useful testing tools such as ts_print, aplay, arecord and so forth. For a complete list of image features that ships with the Yocto Project, see the "Image Features" section. For an example that shows how to customize your image by using this variable, see the "Customizing Images Using Custom IMAGE_FEATURES and EXTRA_IMAGE_FEATURES" section in the Yocto Project Development Manual. EXTRA_IMAGEDEPENDS A list of recipes to build that do not provide packages for installing into the root filesystem. Sometimes a recipe is required to build the final image but is not needed in the root filesystem. You can use the EXTRA_IMAGEDEPENDS variable to list these recipes and thus specify the dependencies. A typical example is a required bootloader in a machine configuration. To add packages to the root filesystem, see the various *RDEPENDS and *RRECOMMENDS variables. EXTRA_OECMAKE Additional cmake options. EXTRA_OECONF Additional configure script options. EXTRA_OEMAKE Additional GNU make options. EXTRA_USERS_PARAMS When a recipe inherits the extrausers class, this variable provides image level user and group operations. This is a more global method of providing user and group configuration as compared to using the useradd class, which ties user and group configurations to a specific recipe. The set list of commands you can configure using the EXTRA_USERS_PARAMS is shown in the extrausers class. These commands map to the normal Unix commands of the same names: # EXTRA_USERS_PARAMS = "\ # useradd -p '' tester; \ # groupadd developers; \ # userdel nobody; \ # groupdel -g video; \ # groupmod -g 1020 developers; \ # usermod -s /bin/sh tester; \ # " FEED_DEPLOYDIR_BASE_URI Points to the base URL of the server and location within the document-root that provides the metadata and packages required by OPKG to support runtime package management of IPK packages. You set this variable in your local.conf file. Consider the following example: FEED_DEPLOYDIR_BASE_URI = "http://192.168.7.1/BOARD-dir" This example assumes you are serving your packages over HTTP and your databases are located in a directory named BOARD-dir, which is underneath your HTTP server's document-root. In this case, the OpenEmbedded build system generates a set of configuration files for you in your target that work with the feed. FILES The list of directories or files that are placed in packages. To use the FILES variable, provide a package name override that identifies the resulting package. Then, provide a space-separated list of files or paths that identifies the files you want included as part of the resulting package. Here is an example: FILES_${PN} += "${bindir}/mydir1/ ${bindir}/mydir2/myfile" When specifying paths as part of the FILES variable, it is good practice to use appropriate path variables. For example, use ${sysconfdir} rather than /etc, or ${bindir} rather than /usr/bin. You can find a list of these variables at the top of the meta/conf/bitbake.conf file in the Source Directory. If some of the files you provide with the FILES variable are editable and you know they should not be overwritten during the package update process by the Package Management System (PMS), you can identify these files so that the PMS will not overwrite them. See the CONFFILES variable for information on how to identify these files to the PMS. FILESEXTRAPATHS Extends the search path the OpenEmbedded build system uses when looking for files and patches as it processes recipes and append files. The default directories BitBake uses when it processes recipes are initially defined by the FILESPATH variable. You can extend FILESPATH variable by using FILESEXTRAPATHS. Best practices dictate that you accomplish this by using FILESEXTRAPATHS from within a .bbappend file and that you prepend paths as follows: FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:" In the above example, the build system first looks for files in a directory that has the same name as the corresponding append file. When extending FILESEXTRAPATHS, be sure to use the immediate expansion (:=) operator. Immediate expansion makes sure that BitBake evaluates THISDIR at the time the directive is encountered rather than at some later time when expansion might result in a directory that does not contain the files you need. Also, include the trailing separating colon character if you are prepending. The trailing colon character is necessary because you are directing BitBake to extend the path by prepending directories to the search path. Here is another common use: FILESEXTRAPATHS_prepend := "${THISDIR}/files:" In this example, the build system extends the FILESPATH variable to include a directory named files that is in the same directory as the corresponding append file. Here is a final example that specifically adds three paths: FILESEXTRAPATHS_prepend := "path_1:path_2:path_3:" By prepending paths in .bbappend files, you allow multiple append files that reside in different layers but are used for the same recipe to correctly extend the path. FILESOVERRIDES A subset of OVERRIDES used by the OpenEmbedded build system for creating FILESPATH. You can find more information on how overrides are handled in the BitBake Manual that is located at bitbake/doc/manual in the Source Directory. By default, the FILESOVERRIDES variable is defined as: FILESOVERRIDES = "${TRANSLATED_TARGET_ARCH}:${MACHINEOVERRIDES}:${DISTROOVERRIDES}" Do not hand-edit the FILESOVERRIDES variable. The values match up with expected overrides and are used in an expected manner by the build system. FILESPATH The default set of directories the OpenEmbedded build system uses when searching for patches and files. During the build process, BitBake searches each directory in FILESPATH in the specified order when looking for files and patches specified by each file:// URI in a recipe. The default value for the FILESPATH variable is defined in the base.bbclass class found in meta/classes in the Source Directory: FILESPATH = "${@base_set_filespath(["${FILE_DIRNAME}/${BP}", \ "${FILE_DIRNAME}/${BPN}", "${FILE_DIRNAME}/files"], d)}" Do not hand-edit the FILESPATH variable. If you want the build system to look in directories other than the defaults, extend the FILESPATH variable by using the FILESEXTRAPATHS variable. Be aware that the default FILESPATH directories do not map to directories in custom layers where append files (.bbappend) are used. If you want the build system to find patches or files that reside with your append files, you need to extend the FILESPATH variable by using the FILESEXTRAPATHS variable. FILESYSTEM_PERMS_TABLES Allows you to define your own file permissions settings table as part of your configuration for the packaging process. For example, suppose you need a consistent set of custom permissions for a set of groups and users across an entire work project. It is best to do this in the packages themselves but this is not always possible. By default, the OpenEmbedded build system uses the fs-perms.txt, which is located in the meta/files folder in the Source Directory. If you create your own file permissions setting table, you should place it in your layer or the distro's layer. You define the FILESYSTEM_PERMS_TABLES variable in the conf/local.conf file, which is found in the Build Directory, to point to your custom fs-perms.txt. You can specify more than a single file permissions setting table. The paths you specify to these files must be defined within the BBPATH variable. For guidance on how to create your own file permissions settings table file, examine the existing fs-perms.txt. FONT_PACKAGES When a recipe inherits the fontcache class, this variable identifies packages that contain fonts the OpenEmbedded build system installs. By default, installed fonts appear in the main package (i.e. ${PN}). Use this variable if fonts you need appear in a package other than that main package. FULL_OPTIMIZATION The options to pass in TARGET_CFLAGS and CFLAGS when compiling an optimized system. This variable defaults to "-O2 -pipe ${DEBUG_FLAGS}". GROUPADD_PARAM When a recipe inherits the useradd class, this variable specifies for a package what parameters should be passed to the groupadd command if you wish to add a group to the system when the package is installed. Here is an example from the dbus recipe: GROUPADD_PARAM_${PN} = "-r netdev" For information on the standard Linux shell command groupadd, see . GROUPMEMS_PARAM When a recipe inherits the useradd class, this variable specifies for a package what parameters should be passed to the groupmems command if you wish to modify the members of a group when the package is installed. For information on the standard Linux shell command groupmems, see . GRUB_GFXSERIAL Configures the GNU GRand Unified Bootloader (GRUB) to have graphics and serial in the boot menu. Set this variable to "1" in your local.conf or distribution configuration file to enable graphics and serial in the menu. See the grub-efi class for more information on how this variable is used. GRUB_OPTS Additional options to add to the GNU GRand Unified Bootloader (GRUB) configuration. Use a semi-colon character (;) to separate multiple options. The GRUB_OPTS variable is optional. See the grub-efi class for more information on how this variable is used. GRUB_TIMEOUT Specifies the timeout before executing the default LABEL in the GNU GRand Unified Bootloader (GRUB). The GRUB_TIMEOUT variable is optional. See the grub-efi class for more information on how this variable is used. GTKIMMODULES_PACKAGES Includes the packages that contain the GIMP Toolkit input method modules being installed when the modules are in packages other than the main package. See the gtk-immodules-cache class for more information on how this variable is used. HOMEPAGE Website where more information about the software the recipe is building can be found. HOST_SYS Specifies the system, including the architecture and the operating system, for with the build is occurring in the context of the current recipe. The OpenEmbedded build system automatically sets this variable. You do not need to set the variable yourself. Here are two examples: Given a native recipe on a 32-bit x86 machine running Linux, the value is "i686-linux". Given a recipe being built for a little-endian MIPS target running Linux, the value might be "mipsel-linux". ICECC_CC The path to the GNU C compiler gcc. This variable is used by the icecc class. You do not set this variable by hand. When the location for the GNU C compiler is not a symbolic link, the class sets the variable to the location of the compiler. ICECC_CXX The path to the GNU C++ compiler g++. This variable is used by the icecc class. You do not set this variable by hand. When the location for the GNU C++ compiler is not a symbolic link, the class sets the variable to the location of the compiler. ICECC_ENV_EXEC Points to the icecc-create-env script that you provide. This variable is used by the icecc class. You set this variable in your local.conf file. If you do not point to a script that you provide, the OpenEmbedded build system uses the default script provided by the icecc-create-env.bb recipe, which is a modified version and not the one that comes with icecc. ICECC_PATH The location of the icecc binary. You can set this variable in your local.conf file. If your local.conf file does not define this variable, the icecc class attempts to define it by locating icecc using which. ICECC_USER_CLASS_BL Identifies user classes that you do not want the Icecream distributed compile support to consider. This variable is used by the icecc class. You set this variable in your local.conf file. When you list classes using this variable, you are "blacklisting" them from distributed compilation across remote hosts. Any classes you list will be distributed and compiled locally. ICECC_USER_PACKAGE_BL Identifies user packages that you do not want the Icecream distributed compile support to consider. This variable is used by the icecc class. You set this variable in your local.conf file. When you list packages using this variable, you are "blacklisting" them from distributed compilation across remote hosts. Any packages you list will be distributed and compiled locally. ICECC_USER_PACKAGE_WL Identifies user packages that use an empty PARALLEL_MAKE variable that you want to force remote distributed compilation on using the Icecream distributed compile support. This variable is used by the icecc class. You set this variable in your local.conf file. ICECC_VERSION The version of the cross-compiler used in the cross-development toolchain. This variable is used by the icecc class. You do not set this variable by hand. IMAGE_BASENAME The base name of image output files. This variable defaults to the recipe name (${PN}). IMAGE_CLASSES A list of classes that all images should inherit. You typically use this variable to specify the list of classes that register the different types of images the OpenEmbedded build system creates. The default value for IMAGE_CLASSES is image_types. You can set this variable in your local.conf or in a distribution configuration file. For more information, see meta/classes/image_types.bbclass in the Source Directory. IMAGE_FEATURES The primary list of features to include in an image. Typically, you configure this variable in an image recipe. Although you can use this variable from your local.conf file, which is found in the Build Directory, best practices dictate that you do not. To enable extra features from outside the image recipe, use the EXTRA_IMAGE_FEATURES variable. For a list of image features that ships with the Yocto Project, see the "Image Features" section. For an example that shows how to customize your image by using this variable, see the "Customizing Images Using Custom IMAGE_FEATURES and EXTRA_IMAGE_FEATURES" section in the Yocto Project Development Manual. IMAGE_FSTYPES Specifies the formats the OpenEmbedded build system uses during the build when creating the root filesystem. For example, setting IMAGE_FSTYPES as follows causes the build system to create root filesystems using two formats: .ext3 and .tar.bz2: IMAGE_FSTYPES = "ext3 tar.bz2" For the complete list of supported image formats from which you can choose, see IMAGE_TYPES. If you add "live" to IMAGE_FSTYPES inside an image recipe, be sure that you do so prior to the "inherit image" line of the recipe or the live image will not build. Due to the way this variable is processed, it is not possible to update its contents using _append or _prepend. To add one or more additional options to this variable the += operator must be used. IMAGE_INSTALL Specifies the packages to install into an image. The IMAGE_INSTALL variable is a mechanism for an image recipe and you should use it with care to avoid ordering issues. Image recipes set IMAGE_INSTALL to specify the packages to install into an image through image.bbclass. Additionally, "helper" classes exist, such as core-image.bbclass, that can take IMAGE_FEATURES lists and turn these into auto-generated entries in IMAGE_INSTALL in addition to its default contents. Using IMAGE_INSTALL with the += operator from the /conf/local.conf file or from within an image recipe is not recommended as it can cause ordering issues. Since core-image.bbclass sets IMAGE_INSTALL to a default value using the ?= operator, using a += operation against IMAGE_INSTALL will result in unexpected behavior when used in conf/local.conf. Furthermore, the same operation from within an image recipe may or may not succeed depending on the specific situation. In both these cases, the behavior is contrary to how most users expect the += operator to work. When you use this variable, it is best to use it as follows: IMAGE_INSTALL_append = " package-name" Be sure to include the space between the quotation character and the start of the package name or names. IMAGE_LINGUAS Specifies the list of locales to install into the image during the root filesystem construction process. The OpenEmbedded build system automatically splits locale files, which are used for localization, into separate packages. Setting the IMAGE_LINGUAS variable ensures that any locale packages that correspond to packages already selected for installation into the image are also installed. Here is an example: IMAGE_LINGUAS = "pt-br de-de" In this example, the build system ensures any Brazilian Portuguese and German locale files that correspond to packages in the image are installed (i.e. *-locale-pt-br and *-locale-de-de as well as *-locale-pt and *-locale-de, since some software packages only provide locale files by language and not by country-specific language). IMAGE_NAME The name of the output image files minus the extension. This variable is derived using the IMAGE_BASENAME, MACHINE, and DATETIME variables: IMAGE_NAME = "${IMAGE_BASENAME}-${MACHINE}-${DATETIME}" IMAGE_OVERHEAD_FACTOR Defines a multiplier that the build system applies to the initial image size for cases when the multiplier times the returned disk usage value for the image is greater than the sum of IMAGE_ROOTFS_SIZE and IMAGE_ROOTFS_EXTRA_SPACE. The result of the multiplier applied to the initial image size creates free disk space in the image as overhead. By default, the build process uses a multiplier of 1.3 for this variable. This default value results in 30% free disk space added to the image when this method is used to determine the final generated image size. You should be aware that post install scripts and the package management system uses disk space inside this overhead area. Consequently, the multiplier does not produce an image with all the theoretical free disk space. See IMAGE_ROOTFS_SIZE for information on how the build system determines the overall image size. The default 30% free disk space typically gives the image enough room to boot and allows for basic post installs while still leaving a small amount of free disk space. If 30% free space is inadequate, you can increase the default value. For example, the following setting gives you 50% free space added to the image: IMAGE_OVERHEAD_FACTOR = "1.5" Alternatively, you can ensure a specific amount of free disk space is added to the image by using the IMAGE_ROOTFS_EXTRA_SPACE variable. IMAGE_POSTPROCESS_COMMAND Added by classes to run post processing commands once the OpenEmbedded build system has created the image. You can specify shell commands separated by semicolons: IMAGE_POSTPROCESS_COMMAND += "<shell_command>; ... " If you need to pass the path to the root filesystem within the command, you can use ${IMAGE_ROOTFS}, which points to the root filesystem image. IMAGE_ROOTFS The location of the root filesystem while it is under construction (i.e. during do_rootfs). This variable is not configurable. Do not change it. IMAGE_ROOTFS_EXTRA_SPACE Defines additional free disk space created in the image in Kbytes. By default, this variable is set to "0". This free disk space is added to the image after the build system determines the image size as described in IMAGE_ROOTFS_SIZE. This variable is particularly useful when you want to ensure that a specific amount of free disk space is available on a device after an image is installed and running. For example, to be sure 5 Gbytes of free disk space is available, set the variable as follows: IMAGE_ROOTFS_EXTRA_SPACE = "5242880" For example, the Yocto Project Build Appliance specifically requests 40 Gbytes of extra space with the line: IMAGE_ROOTFS_EXTRA_SPACE = "41943040" IMAGE_ROOTFS_SIZE Defines the size in Kbytes for the generated image. The OpenEmbedded build system determines the final size for the generated image using an algorithm that takes into account the initial disk space used for the generated image, a requested size for the image, and requested additional free disk space to be added to the image. Programatically, the build system determines the final size of the generated image as follows: if (image-du * overhead) < rootfs-size: internal-rootfs-size = rootfs-size + xspace else: internal-rootfs-size = (image-du * overhead) + xspace where: image-du = Returned value of the du command on the image. overhead = IMAGE_OVERHEAD_FACTOR rootfs-size = IMAGE_ROOTFS_SIZE internal-rootfs-size = Initial root filesystem size before any modifications. xspace = IMAGE_ROOTFS_EXTRA_SPACE See the IMAGE_OVERHEAD_FACTOR and IMAGE_ROOTFS_EXTRA_SPACE variables for related information. IMAGE_TYPES Specifies the complete list of supported image types by default: jffs2 sum.jffs2 cramfs ext2 ext2.gz ext2.bz2 ext3 ext3.gz ext2.lzma btrfs live squashfs squashfs-xz ubi ubifs tar tar.gz tar.bz2 tar.xz cpio cpio.gz cpio.xz cpio.lzma vmdk elf For more information on how these types of images, see meta/classes/image_types*.bbclass in the Source Directory. INC_PR Helps define the recipe revision for recipes that share a common include file. You can think of this variable as part of the recipe revision as set from within an include file. Suppose, for example, you have a set of recipes that are used across several projects. And, within each of those recipes the revision (its PR value) is set accordingly. In this case, when the revision of those recipes changes, the burden is on you to find all those recipes and be sure that they get changed to reflect the updated version of the recipe. In this scenario, it can get complicated when recipes that are used in many places and provide common functionality are upgraded to a new revision. A more efficient way of dealing with this situation is to set the INC_PR variable inside the include files that the recipes share and then expand the INC_PR variable within the recipes to help define the recipe revision. The following provides an example that shows how to use the INC_PR variable given a common include file that defines the variable. Once the variable is defined in the include file, you can use the variable to set the PR values in each recipe. You will notice that when you set a recipe's PR you can provide more granular revisioning by appending values to the INC_PR variable: recipes-graphics/xorg-font/xorg-font-common.inc:INC_PR = "r2" recipes-graphics/xorg-font/encodings_1.0.4.bb:PR = "${INC_PR}.1" recipes-graphics/xorg-font/font-util_1.3.0.bb:PR = "${INC_PR}.0" recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3" The first line of the example establishes the baseline revision to be used for all recipes that use the include file. The remaining lines in the example are from individual recipes and show how the PR value is set. INCOMPATIBLE_LICENSE Specifies a space-separated list of license names (as they would appear in LICENSE) that should be excluded from the build. Recipes that provide no alternatives to listed incompatible licenses are not built. Packages that are individually licensed with the specified incompatible licenses will be deleted. This functionality is only regularly tested using the following setting: INCOMPATIBLE_LICENSE = "GPLv3" Although you can use other settings, you might be required to remove dependencies on or provide alternatives to components that are required to produce a functional system image. INHIBIT_DEFAULT_DEPS Prevents the default dependencies, namely the C compiler and standard C library (libc), from being added to DEPENDS. This variable is usually used within recipes that do not require any compilation using the C compiler. Set the variable to "1" to prevent the default dependencies from being added. INHIBIT_PACKAGE_STRIP If set to "1", causes the build to not strip binaries in resulting packages. INHERIT Causes the named class to be inherited at this point during parsing. The variable is only valid in configuration files. INHERIT_DISTRO Lists classes that are inherited by default at the distribution level. It is unlikely that you want to edit this variable. The variable is set as follows in the meta/conf/distro/defaultsetup.conf file: INHERIT_DISTRO ?= "debian devshell sstate license" INITRAMFS_FSTYPES Defines the format for the output image of an initial RAM disk (initramfs), which is used during boot. Supported formats are the same as those supported by the IMAGE_FSTYPES variable. INITRD Indicates a filesystem image to use as an initial RAM disk (initrd). The INITRD variable is an optional variable used with the buildimg class. INITSCRIPT_NAME The filename of the initialization script as installed to ${sysconfdir}/init.d. This variable is used in recipes when using update-rc.d.bbclass. The variable is mandatory. INITSCRIPT_PACKAGES A list of the packages that contain initscripts. If multiple packages are specified, you need to append the package name to the other INITSCRIPT_* as an override. This variable is used in recipes when using update-rc.d.bbclass. The variable is optional and defaults to the PN variable. INITSCRIPT_PARAMS Specifies the options to pass to update-rc.d. Here is an example: INITSCRIPT_PARAMS = "start 99 5 2 . stop 20 0 1 6 ." In this example, the script has a runlevel of 99, starts the script in initlevels 2 and 5, and stops the script in levels 0, 1 and 6. The variable is mandatory and is used in recipes when using update-rc.d.bbclass. INSANE_SKIP Specifies the QA checks to skip for a specific package within a recipe. For example, to skip the check for symbolic link .so files in the main package of a recipe, add the following to the recipe. The package name override must be used, which in this example is ${PN}: INSANE_SKIP_${PN} += "dev-so" See the "insane.bbclass" section for a list of the valid QA checks you can specify using this variable. IPK_FEED_URIS When the IPK backend is in use and package management is enabled on the target, you can use this variable to set up opkg in the target image to point to package feeds on a nominated server. Once the feed is established, you can perform installations or upgrades using the package manager at runtime. KARCH Defines the kernel architecture used when assembling the configuration. Architectures supported for this release are: powerpc i386 x86_64 arm qemu mips You define the KARCH variable in the BSP Descriptions. KBRANCH A regular expression used by the build process to explicitly identify the kernel branch that is validated, patched and configured during a build. The KBRANCH variable is optional. You can use it to trigger checks to ensure the exact kernel branch you want is being used by the build process. Values for this variable are set in the kernel's recipe file and the kernel's append file. For example, if you are using the Yocto Project kernel that is based on the Linux 3.4 kernel, the kernel recipe file is the meta/recipes-kernel/linux/linux-yocto_3.4.bb file. Following is the default value for KBRANCH and the default override for the architectures the Yocto Project supports: KBRANCH_DEFAULT = "standard/base" KBRANCH = "${KBRANCH_DEFAULT}" This branch exists in the linux-yocto-3.4 kernel Git repository . This variable is also used from the kernel's append file to identify the kernel branch specific to a particular machine or target hardware. The kernel's append file is located in the BSP layer for a given machine. For example, the kernel append file for the Crown Bay BSP is in the meta-intel Git repository and is named meta-crownbay/recipes-kernel/linux/linux-yocto_3.4.bbappend. Here are the related statements from the append file: COMPATIBLE_MACHINE_crownbay = "crownbay" KMACHINE_crownbay = "crownbay" KBRANCH_crownbay = "standard/crownbay" COMPATIBLE_MACHINE_crownbay-noemgd = "crownbay-noemgd" KMACHINE_crownbay-noemgd = "crownbay" KBRANCH_crownbay-noemgd = "standard/crownbay" The KBRANCH_* statements identify the kernel branch to use when building for the Crown Bay BSP. In this case there are two identical statements: one for each type of Crown Bay machine. KBRANCH_DEFAULT Defines the Linux kernel source repository's default branch used to build the Linux kernel. The KBRANCH_DEFAULT value is the default value for KBRANCH. Unless you specify otherwise, KBRANCH_DEFAULT initializes to "master". KERNEL_EXTRA_ARGS Specifies additional make command-line arguments the OpenEmbedded build system passes on when compiling the kernel. KERNEL_FEATURES Includes additional metadata from the Yocto Project kernel Git repository. In the OpenEmbedded build system, the default Board Support Packages (BSPs) Metadata is provided through the KMACHINE and KBRANCH variables. You can use the KERNEL_FEATURES variable to further add metadata for all BSPs. The metadata you add through this variable includes config fragments and features descriptions, which usually includes patches as well as config fragments. You typically override the KERNEL_FEATURES variable for a specific machine. In this way, you can provide validated, but optional, sets of kernel configurations and features. For example, the following adds netfilter to all the Yocto Project kernels and adds sound support to the qemux86 machine: # Add netfilter to all linux-yocto kernels KERNEL_FEATURES="features/netfilter" # Add sound support to the qemux86 machine KERNEL_FEATURES_append_qemux86=" cfg/sound" KERNEL_IMAGETYPE The type of kernel to build for a device, usually set by the machine configuration files and defaults to "zImage". This variable is used when building the kernel and is passed to make as the target to build. KERNEL_PATH The location of the kernel sources. This variable is set to the value of the STAGING_KERNEL_DIR within the module.bbclass class. For information on how this variable is used, see the "Incorporating Out-of-Tree Modules" section. The KERNEL_SRC variable is identical to the KERNEL_PATH variable. KERNEL_SRC The location of the kernel sources. This variable is set to the value of the STAGING_KERNEL_DIR within the module.bbclass class. For information on how this variable is used, see the "Incorporating Out-of-Tree Modules" section. The KERNEL_PATH variable is identical to the KERNEL_SRC variable. KFEATURE_DESCRIPTION Provides a short description of a configuration fragment. You use this variable in the .scc file that describes a configuration fragment file. Here is the variable used in a file named smp.scc to describe SMP being enabled: define KFEATURE_DESCRIPTION "Enable SMP" KMACHINE The machine as known by the kernel. Sometimes the machine name used by the kernel does not match the machine name used by the OpenEmbedded build system. For example, the machine name that the OpenEmbedded build system understands as qemuarm goes by a different name in the Linux Yocto kernel. The kernel understands that machine as arm_versatile926ejs. For cases like these, the KMACHINE variable maps the kernel machine name to the OpenEmbedded build system machine name. Kernel machine names are initially defined in the Yocto Linux Kernel's meta branch. From the meta branch, look in the meta/cfg/kernel-cache/bsp/<bsp_name>/<bsp-name>-<kernel-type>.scc file. For example, from the meta branch in the linux-yocto-3.0 kernel, the meta/cfg/kernel-cache/bsp/cedartrail/cedartrail-standard.scc file has the following: define KMACHINE cedartrail define KTYPE standard define KARCH i386 include ktypes/standard branch cedartrail include cedartrail.scc You can see that the kernel understands the machine name for the Cedar Trail Board Support Package (BSP) as cedartrail. If you look in the Cedar Trail BSP layer in the meta-intel Source Repositories at meta-cedartrail/recipes-kernel/linux/linux-yocto_3.0.bbappend, you will find the following statements among others: COMPATIBLE_MACHINE_cedartrail = "cedartrail" KMACHINE_cedartrail = "cedartrail" KBRANCH_cedartrail = "yocto/standard/cedartrail" KERNEL_FEATURES_append_cedartrail += "bsp/cedartrail/cedartrail-pvr-merge.scc" KERNEL_FEATURES_append_cedartrail += "cfg/efi-ext.scc" COMPATIBLE_MACHINE_cedartrail-nopvr = "cedartrail" KMACHINE_cedartrail-nopvr = "cedartrail" KBRANCH_cedartrail-nopvr = "yocto/standard/cedartrail" KERNEL_FEATURES_append_cedartrail-nopvr += " cfg/smp.scc" The KMACHINE statements in the kernel's append file make sure that the OpenEmbedded build system and the Yocto Linux kernel understand the same machine names. This append file uses two KMACHINE statements. The first is not really necessary but does ensure that the machine known to the OpenEmbedded build system as cedartrail maps to the machine in the kernel also known as cedartrail: KMACHINE_cedartrail = "cedartrail" The second statement is a good example of why the KMACHINE variable is needed. In this example, the OpenEmbedded build system uses the cedartrail-nopvr machine name to refer to the Cedar Trail BSP that does not support the proprietary PowerVR driver. The kernel, however, uses the machine name cedartrail. Thus, the append file must map the cedartrail-nopvr machine name to the kernel's cedartrail name: KMACHINE_cedartrail-nopvr = "cedartrail" BSPs that ship with the Yocto Project release provide all mappings between the Yocto Project kernel machine names and the OpenEmbedded machine names. Be sure to use the KMACHINE if you create a BSP and the machine name you use is different than that used in the kernel. KTYPE Defines the kernel type to be used in assembling the configuration. The linux-yocto recipes define "standard", "tiny", and "preempt-rt" kernel types. See the "Kernel Types" section in the Yocto Project Linux Kernel Development Manual for more information on kernel types. You define the KTYPE variable in the BSP Descriptions. The value you use must match the value used for the LINUX_KERNEL_TYPE value used by the kernel recipe. LABELS Provides a list of targets for automatic configuration. See the grub-efi class for more information on how this variable is used. LAYERDEPENDS Lists the layers that this recipe depends upon, separated by spaces. Optionally, you can specify a specific layer version for a dependency by adding it to the end of the layer name with a colon, (e.g. "anotherlayer:3" to be compared against LAYERVERSION_anotherlayer in this case). An error will be produced if any dependency is missing or the version numbers do not match exactly (if specified). This variable is used in the conf/layer.conf file and must be suffixed with the name of the specific layer (e.g. LAYERDEPENDS_mylayer). LAYERDIR When used inside the layer.conf configuration file, this variable provides the path of the current layer. This variable is not available outside of layer.conf and references are expanded immediately when parsing of the file completes. LAYERVERSION Optionally specifies the version of a layer as a single number. You can use this within LAYERDEPENDS for another layer in order to depend on a specific version of the layer. This variable is used in the conf/layer.conf file and must be suffixed with the name of the specific layer (e.g. LAYERVERSION_mylayer). LIC_FILES_CHKSUM Checksums of the license text in the recipe source code. This variable tracks changes in license text of the source code files. If the license text is changed, it will trigger a build failure, which gives the developer an opportunity to review any license change. This variable must be defined for all recipes (unless LICENSE is set to "CLOSED") For more information, see the Tracking License Changes section LICENSE The list of source licenses for the recipe. Follow these rules: Do not use spaces within individual license names. Separate license names using | (pipe) when there is a choice between licenses. Separate license names using & (ampersand) when multiple licenses exist that cover different parts of the source. You can use spaces between license names. Here are some examples: LICENSE = "LGPLv2.1 | GPLv3" LICENSE = "MPL-1 & LGPLv2.1" LICENSE = "GPLv2+" The first example is from the recipes for Qt, which the user may choose to distribute under either the LGPL version 2.1 or GPL version 3. The second example is from Cairo where two licenses cover different parts of the source code. The final example is from sysstat, which presents a single license. You can also specify licenses on a per-package basis to handle situations where components of the output have different licenses. For example, a piece of software whose code is licensed under GPLv2 but has accompanying documentation licensed under the GNU Free Documentation License 1.2 could be specified as follows: LICENSE = "GFDL-1.2 & GPLv2" LICENSE_${PN} = "GPLv2" LICENSE_${PN}-doc = "GFDL-1.2" LICENSE_PATH Path to additional licenses used during the build. By default, the OpenEmbedded build system uses COMMON_LICENSE_DIR to define the directory that holds common license text used during the build. The LICENSE_PATH variable allows you to extend that location to other areas that have additional licenses: LICENSE_PATH += "/path/to/additional/common/licenses" LINUX_KERNEL_TYPE Defines the kernel type to be used in assembling the configuration. The linux-yocto recipes define "standard", "tiny", and "preempt-rt" kernel types. See the "Kernel Types" section in the Yocto Project Linux Kernel Development Manual for more information on kernel types. If you do not specify a LINUX_KERNEL_TYPE, it defaults to "standard". Together with KMACHINE, the LINUX_KERNEL_TYPE variable defines the search arguments used by the kernel tools to find the appropriate description within the kernel Metadata with which to build out the sources and configuration. LINUX_VERSION The Linux version from kernel.org on which the Linux kernel image being built using the OpenEmbedded build system is based. You define this variable in the kernel recipe. For example, the linux-yocto-3.4.bb kernel recipe found in meta/recipes-kernel/linux defines the variables as follows: LINUX_VERSION ?= "3.4.24" The LINUX_VERSION variable is used to define PV for the recipe: PV = "${LINUX_VERSION}+git${SRCPV}" LINUX_VERSION_EXTENSION A string extension compiled into the version string of the Linux kernel built with the OpenEmbedded build system. You define this variable in the kernel recipe. For example, the linux-yocto kernel recipes all define the variable as follows: LINUX_VERSION_EXTENSION ?= "-yocto-${LINUX_KERNEL_TYPE}" Defining this variable essentially sets the Linux kernel configuration item CONFIG_LOCALVERSION, which is visible through the uname command. Here is an example that shows the extension assuming it was set as previously shown: $ uname -r 3.7.0-rc8-custom LOG_DIR Specifies the directory to which the OpenEmbedded build system writes overall log files. The default directory is ${TMPDIR}/log. For the directory containing logs specific to each task, see the T variable. MACHINE Specifies the target device for which the image is built. You define MACHINE in the local.conf file found in the Build Directory. By default, MACHINE is set to "qemux86", which is an x86-based architecture machine to be emulated using QEMU: MACHINE ?= "qemux86" The variable corresponds to a machine configuration file of the same name, through which machine-specific configurations are set. Thus, when MACHINE is set to "qemux86" there exists the corresponding qemux86.conf machine configuration file, which can be found in the Source Directory in meta/conf/machine. The list of machines supported by the Yocto Project as shipped include the following: MACHINE ?= "qemuarm" MACHINE ?= "qemumips" MACHINE ?= "qemuppc" MACHINE ?= "qemux86" MACHINE ?= "qemux86-64" MACHINE ?= "genericx86" MACHINE ?= "genericx86-64" MACHINE ?= "beagleboard" MACHINE ?= "mpc8315e-rdb" MACHINE ?= "routerstationpro" The last five are Yocto Project reference hardware boards, which are provided in the meta-yocto-bsp layer. Adding additional Board Support Package (BSP) layers to your configuration adds new possible settings for MACHINE. MACHINE_ESSENTIAL_EXTRA_RDEPENDS A list of required machine-specific packages to install as part of the image being built. The build process depends on these packages being present. Furthermore, because this is a "machine essential" variable, the list of packages are essential for the machine to boot. The impact of this variable affects images based on packagegroup-core-boot, including the core-image-minimal image. This variable is similar to the MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS variable with the exception that the image being built has a build dependency on the variable's list of packages. In other words, the image will not build if a file in this list is not found. As an example, suppose the machine for which you are building requires example-init to be run during boot to initialize the hardware. In this case, you would use the following in the machine's .conf configuration file: MACHINE_ESSENTIAL_EXTRA_RDEPENDS += "example-init" MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS A list of recommended machine-specific packages to install as part of the image being built. The build process does not depend on these packages being present. However, because this is a "machine essential" variable, the list of packages are essential for the machine to boot. The impact of this variable affects images based on packagegroup-core-boot, including the core-image-minimal image. This variable is similar to the MACHINE_ESSENTIAL_EXTRA_RDEPENDS variable with the exception that the image being built does not have a build dependency on the variable's list of packages. In other words, the image will still build if a package in this list is not found. Typically, this variable is used to handle essential kernel modules, whose functionality may be selected to be built into the kernel rather than as a module, in which case a package will not be produced. Consider an example where you have a custom kernel where a specific touchscreen driver is required for the machine to be usable. However, the driver can be built as a module or into the kernel depending on the kernel configuration. If the driver is built as a module, you want it to be installed. But, when the driver is built into the kernel, you still want the build to succeed. This variable sets up a "recommends" relationship so that in the latter case, the build will not fail due to the missing package. To accomplish this, assuming the package for the module was called kernel-module-ab123, you would use the following in the machine's .conf configuration file: MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS += "kernel-module-ab123" Some examples of these machine essentials are flash, screen, keyboard, mouse, or touchscreen drivers (depending on the machine). MACHINE_EXTRA_RDEPENDS A list of machine-specific packages to install as part of the image being built that are not essential for the machine to boot. However, the build process for more fully-featured images depends on the packages being present. This variable affects all images based on packagegroup-base, which does not include the core-image-minimal or core-image-basic images. The variable is similar to the MACHINE_EXTRA_RRECOMMENDS variable with the exception that the image being built has a build dependency on the variable's list of packages. In other words, the image will not build if a file in this list is not found. An example is a machine that has WiFi capability but is not essential for the machine to boot the image. However, if you are building a more fully-featured image, you want to enable the WiFi. The package containing the firmware for the WiFi hardware is always expected to exist, so it is acceptable for the build process to depend upon finding the package. In this case, assuming the package for the firmware was called wifidriver-firmware, you would use the following in the .conf file for the machine: MACHINE_EXTRA_RDEPENDS += "wifidriver-firmware" MACHINE_EXTRA_RRECOMMENDS A list of machine-specific packages to install as part of the image being built that are not essential for booting the machine. The image being built has no build dependency on this list of packages. This variable affects only images based on packagegroup-base, which does not include the core-image-minimal or core-image-basic images. This variable is similar to the MACHINE_EXTRA_RDEPENDS variable with the exception that the image being built does not have a build dependency on the variable's list of packages. In other words, the image will build if a file in this list is not found. An example is a machine that has WiFi capability but is not essential For the machine to boot the image. However, if you are building a more fully-featured image, you want to enable WiFi. In this case, the package containing the WiFi kernel module will not be produced if the WiFi driver is built into the kernel, in which case you still want the build to succeed instead of failing as a result of the package not being found. To accomplish this, assuming the package for the module was called kernel-module-examplewifi, you would use the following in the .conf file for the machine: MACHINE_EXTRA_RRECOMMENDS += "kernel-module-examplewifi" MACHINE_FEATURES Specifies the list of hardware features the MACHINE is capable of supporting. For related information on enabling features, see the DISTRO_FEATURES, COMBINED_FEATURES, and IMAGE_FEATURES variables. For a list of hardware features supported by the Yocto Project as shipped, see the "Machine Features" section. MACHINE_FEATURES_BACKFILL Features to be added to MACHINE_FEATURES if not also present in MACHINE_FEATURES_BACKFILL_CONSIDERED. This variable is set in the meta/conf/bitbake.conf file. It is not intended to be user-configurable. It is best to just reference the variable to see which machine features are being backfilled for all machine configurations. See the "Feature backfilling" section for more information. MACHINE_FEATURES_BACKFILL_CONSIDERED Features from MACHINE_FEATURES_BACKFILL that should not be backfilled (i.e. added to MACHINE_FEATURES) during the build. See the "Feature backfilling" section for more information. MACHINEOVERRIDES Lists overrides specific to the current machine. By default, this list includes the value of MACHINE. You can extend the list to apply variable overrides for classes of machines. For example, all QEMU emulated machines (e.g. qemuarm, qemux86, and so forth) include a common file named meta/conf/machine/include/qemu.inc that prepends MACHINEOVERRIDES with the following variable override: MACHINEOVERRIDES =. "qemuall:" Applying an override like qemuall affects all QEMU emulated machines elsewhere. Here is an example from the connman-conf recipe: SRC_URI_append_qemuall = "file://wired.config \ file://wired-setup \ " MAINTAINER The email address of the distribution maintainer. MIRRORS Specifies additional paths from which the OpenEmbedded build system gets source code. When the build system searches for source code, it first tries the local download directory. If that location fails, the build system tries locations defined by PREMIRRORS, the upstream source, and then locations specified by MIRRORS in that order. Assuming your distribution (DISTRO) is "poky", the default value for MIRRORS is defined in the conf/distro/poky.conf file in the meta-yocto Git repository. MLPREFIX Specifies a prefix has been added to PN to create a special version of a recipe or package, such as a Multilib version. The variable is used in places where the prefix needs to be added to or removed from a the name (e.g. the BPN variable). MLPREFIX gets set when a prefix has been added to PN. MODULE_TARBALL_DEPLOY Controls creation of the modules-*.tgz file. Set this variable to "0" to disable creation of this file, which contains all of the kernel modules resulting from a kernel build. MULTIMACH_TARGET_SYS Separates files for different machines such that you can build for multiple target machines using the same output directories. See the STAMP variable for an example. NATIVELSBSTRING A string identifying the host distribution. Strings consist of the host distributor ID followed by the release, as reported by the lsb_release tool or as read from /etc/lsb-release. For example, when running a build on Ubuntu 12.10, the value is "Ubuntu-12.10". If this information is unable to be determined, the value resolves to "Unknown". This variable is used by default to isolate native shared state packages for different distributions (e.g. to avoid problems with glibc version incompatibilities). Additionally, the variable is checked against SANITY_TESTED_DISTROS if that variable is set. NO_RECOMMENDATIONS Prevents installation of all "recommended-only" packages. Recommended-only packages are packages installed only through the RRECOMMENDS variable). Setting the NO_RECOMMENDATIONS variable to "1" turns this feature on: NO_RECOMMENDATIONS = "1" You can set this variable globally in your local.conf file or you can attach it to a specific image recipe by using the recipe name override: NO_RECOMMENDATIONS_pn-<target_image> = "<package_name>" It is important to realize that if you choose to not install packages using this variable and some other packages are dependent on them (i.e. listed in a recipe's RDEPENDS variable), the OpenEmbedded build system ignores your request and will install the packages to avoid dependency errors. Some recommended packages might be required for certain system functionality, such as kernel modules. It is up to you to add packages with the IMAGE_INSTALL variable. Support for this variable exists only when using the IPK and RPM packaging backend. Support does not exist for DEB. See the BAD_RECOMMENDATIONS and the PACKAGE_EXCLUDE variables for related information. NOHDD Causes the OpenEmbedded build system to skip building the .hddimg image. The NOHDD variable is used with the buildimg class. Set the variable to "1" to prevent the .hddimg image from being built. NOISO Causes the OpenEmbedded build system to skip building the ISO image. The NOISO variable is used with the buildimg class. Set the variable to "1" to prevent the ISO image from being built. OE_BINCONFIG_EXTRA_MANGLE When a recipe inherits the binconfig.bbclass class, this variable specifies additional arguments passed to the "sed" command. The sed command alters any paths in configuration scripts that have been set up during compilation. Inheriting this class results in all paths in these scripts being changed to point into the sysroots/ directory so that all builds that use the script will use the correct directories for the cross compiling layout. See the meta/classes/binconfig.bbclass in the Source Directory for details on how this class applies these additional sed command arguments. For general information on the binconfig.bbclass class, see the "Binary Configuration Scripts - binconfig.bbclass" section. OE_IMPORTS An internal variable used to tell the OpenEmbedded build system what Python modules to import for every Python function run by the system. Do not set this variable. It is for internal use only. OE_TERMINAL Controls how the OpenEmbedded build system spawns interactive terminals on the host development system (e.g. using the BitBake command with the -c devshell command-line option). For more information, see the "Using a Development Shell" section in the Yocto Project Development Manual. You can use the following values for the OE_TERMINAL variable: auto gnome xfce rxvt screen konsole none Konsole support only works for KDE 3.x. Also, "auto" is the default behavior for OE_TERMINAL OEROOT The directory from which the top-level build environment setup script is sourced. The Yocto Project makes two top-level build environment setup scripts available: &OE_INIT_FILE; and oe-init-build-env-memres. When you run one of these scripts, the OEROOT variable resolves to the directory that holds the script. For additional information on how this variable is used, see the initialization scripts. OLDEST_KERNEL Declares the oldest version of the Linux kernel that the produced binaries must support. This variable is passed into the build of the Embedded GNU C Library (eglibc). The default for this variable comes from the meta/conf/bitbake.conf configuration file. You can override this default by setting the variable in a custom distribution configuration file. OVERRIDES BitBake uses OVERRIDES to control what variables are overridden after BitBake parses recipes and configuration files. You can find more information on how overrides are handled in the BitBake Manual that is located at bitbake/doc/manual in the Source Directory. P The recipe name and version. P is comprised of the following: ${PN}-${PV} PACKAGE_ARCH The architecture of the resulting package or packages. PACKAGE_BEFORE_PN Enables easily adding packages to PACKAGES before ${PN} so that those added packages can pick up files that would normally be included in the default package. PACKAGE_CLASSES This variable, which is set in the local.conf configuration file found in the conf folder of the Source Directory, specifies the package manager to use when packaging data. You can provide one or more arguments for the variable with the first argument being the package manager used to create images: PACKAGE_CLASSES ?= "package_rpm package_deb package_ipk" For information on build performance effects as a result of the package manager use, see Packaging - package*.bbclass in this manual. PACKAGE_EXCLUDE Lists packages that should not be installed into an image. For example: PACKAGE_EXCLUDE = "<package_name> <package_name> <package_name> ..." You can set this variable globally in your local.conf file or you can attach it to a specific image recipe by using the recipe name override: PACKAGE_EXCLUDE_pn-<target_image> = "<package_name>" If you choose to not install a package using this variable and some other package is dependent on it (i.e. listed in a recipe's RDEPENDS variable), the OpenEmbedded build system generates a fatal installation error. Because the build system halts the process with a fatal error, you can use the variable with an iterative development process to remove specific components from a system. Support for this variable exists only when using the IPK and RPM packaging backend. Support does not exist for DEB. See the NO_RECOMMENDATIONS and the BAD_RECOMMENDATIONS variables for related information. PACKAGE_EXTRA_ARCHS Specifies the list of architectures compatible with the device CPU. This variable is useful when you build for several different devices that use miscellaneous processors such as XScale and ARM926-EJS). PACKAGE_GROUP Defines one or more packages to include in an image when a specific item is included in IMAGE_FEATURES. When setting the value, PACKAGE_GROUP should have the name of the feature item as an override. Here is an example: PACKAGE_GROUP_widget = "package1 package2" In this example, if "widget" were added to IMAGE_FEATURES, "package1" and "package2" would be included in the image. Packages installed by features defined through PACKAGE_GROUP are often package groups. While similarly named, you should not confuse the PACKAGE_GROUP variable with package groups, which are discussed elsewhere in the documentation. PACKAGE_INSTALL The final list of packages passed to the package manager for installation into the image. Because the package manager controls actual installation of all packages, the list of packages passed using PACKAGE_INSTALL is not the final list of packages that are actually installed. This variable is internal to the image construction code. Use the IMAGE_INSTALL variable to specify packages for installation. PACKAGECONFIG This variable provides a means of enabling or disabling features of a recipe on a per-recipe basis. PACKAGECONFIG blocks are defined in recipes when you specify features and then arguments that define feature behaviors. Here is the basic block structure: PACKAGECONFIG ??= "f1 f2 f3 ..." PACKAGECONFIG[f1] = "--with-f1,--without-f1,build-deps-f1,rt-deps-f1" PACKAGECONFIG[f2] = "--with-f2,--without-f2,build-deps-f2,rt-deps-f2" PACKAGECONFIG[f3] = "--with-f3,--without-f3,build-deps-f3,rt-deps-f3" The PACKAGECONFIG variable itself specifies a space-separated list of the features to enable. Following the features, you can determine the behavior of each feature by providing up to four order-dependent arguments, which are separated by commas. You can omit any argument you like but must retain the separating commas. The order is important and specifies the following: Extra arguments that should be added to the configure script argument list (EXTRA_OECONF) if the feature is enabled. Extra arguments that should be added to EXTRA_OECONF if the feature is disabled. Additional build dependencies (DEPENDS) that should be added if the feature is enabled. Additional runtime dependencies (RDEPENDS) that should be added if the feature is enabled. Consider the following PACKAGECONFIG block taken from the librsvg recipe. In this example the feature is croco, which has three arguments that determine the feature's behavior. PACKAGECONFIG ??= "croco" PACKAGECONFIG[croco] = "--with-croco,--without-croco,libcroco" The --with-croco and libcroco arguments apply only if the feature is enabled. In this case, --with-croco is added to the configure script argument list and libcroco is added to DEPENDS. On the other hand, if the feature is disabled say through a .bbappend file in another layer, then the second argument --without-croco is added to the configure script rather than --with-croco. The basic PACKAGECONFIG structure previously described holds true regardless of whether you are creating a block or changing a block. When creating a block, use the structure inside your recipe. If you want to change an existing PACKAGECONFIG block, you can do so one of two ways: Append file: Create an append file named <recipename>.bbappend in your layer and override the value of PACKAGECONFIG. You can either completely override the variable: PACKAGECONFIG="f4 f5" Or, you can just append the variable: PACKAGECONFIG_append = " f4" Configuration file: This method is identical to changing the block through an append file except you edit your local.conf or <mydistro>.conf file. As with append files previously described, you can either completely override the variable: PACKAGECONFIG_pn-<recipename>="f4 f5" Or, you can just amend the variable: PACKAGECONFIG_append_pn-<recipename> = " f4" PACKAGES The list of packages to be created from the recipe. The default value is the following: ${PN}-dbg ${PN}-staticdev ${PN}-dev ${PN}-doc ${PN}-locale ${PACKAGE_BEFORE_PN} ${PN} PACKAGES_DYNAMIC A promise that your recipe satisfies runtime dependencies for optional modules that are found in other recipes. PACKAGES_DYNAMIC does not actually satisfy the dependencies, it only states that they should be satisfied. For example, if a hard, runtime dependency (RDEPENDS) of another package is satisfied at build time through the PACKAGES_DYNAMIC variable, but a package with the module name is never actually produced, then the other package will be broken. Thus, if you attempt to include that package in an image, you will get a dependency failure from the packaging system during do_rootfs. Typically, if there is a chance that such a situation can occur and the package that is not created is valid without the dependency being satisfied, then you should use RRECOMMENDS (a soft runtime dependency) instead of RDEPENDS. For an example of how to use the PACKAGES_DYNAMIC variable when you are splitting packages, see the "Handling Optional Module Packaging" section in the Yocto Project Development Manual. PARALLEL_MAKE Extra options that are passed to the make command during the do_compile task in order to specify parallel compilation. This variable is usually in the form -j 4, where the number represents the maximum number of parallel threads make can run. If you development host supports multiple cores a good rule of thumb is to set this variable to twice the number of cores on the host. Individual recipes might clear out this variable if the software being built has problems running its make process in parallel. PARALLEL_MAKEINST Extra options passed to the make install command during the do_install task in order to specify parallel installation. This variable defaults to the value of PARALLEL_MAKE. Individual recipes might clear out this variable if the software being built has problems running its make install process in parallel. PATCHRESOLVE Determines the action to take when a patch fails. You can set this variable to one of two values: "noop" and "user". The default value of "noop" causes the build to simply fail when the OpenEmbedded build system cannot successfully apply a patch. Setting the value to "user" causes the build system to launch a shell and places you in the right location so that you can manually resolve the conflicts. Set this variable in your local.conf file. PATCHTOOL Specifies the utility used to apply patches for a recipe during do_patch. You can specify one of three utilities: "patch", "quilt", or "git". The default utility used is "quilt" except for the quilt-native recipe itself. Because the quilt tool is not available at the time quilt-native is being patched, it uses "patch". If you wish to use an alternative patching tool, set the variable in the recipe using one of the following: PATCHTOOL = "patch" PATCHTOOL = "quilt" PATCHTOOL = "git" PE the epoch of the recipe. By default, this variable is unset. The field is used to make upgrades possible when the versioning scheme changes in some backwards incompatible way. PF Specifies the recipe or package name and includes all version and revision numbers (i.e. eglibc-2.13-r20+svnr15508/ and bash-4.2-r1/). This variable is comprised of the following: ${PN}-${EXTENDPE}${PV}-${PR} PKGD Points to the destination directory for files to be packaged before they are split into individual packages. This directory defaults to the following: ${WORKDIR}/package Do not change this default. PKGDATA_DIR Points to a shared, global-state directory that holds data generated during the packaging process. During the packaging process, the do_packagedata task packages data for each recipe and installs it into this temporary, shared area. This directory defaults to the following: ${STAGING_DIR_HOST}/pkgdata Do not change this default. PKGDEST Points to the parent directory for files to be packaged after they have been split into individual packages. This directory defaults to the following: ${WORKDIR}/packages-split Under this directory, the build system creates directories for each package specified in PACKAGES. Do not change this default. PKGDESTWORK Points to a temporary work area used by the do_package task to write output from the do_packagedata task. The PKGDESTWORK location defaults to the following: ${WORKDIR}/pkgdata The do_packagedata task then packages the data in the temporary work area and installs it into a shared directory pointed to by PKGDATA_DIR. Do not change this default. PN This variable can have two separate functions depending on the context: a recipe name or a resulting package name. PN refers to a recipe name in the context of a file used by the OpenEmbedded build system as input to create a package. The name is normally extracted from the recipe file name. For example, if the recipe is named expat_2.0.1.bb, then the default value of PN will be "expat". The variable refers to a package name in the context of a file created or produced by the OpenEmbedded build system. If applicable, the PN variable also contains any special suffix or prefix. For example, using bash to build packages for the native machine, PN is bash-native. Using bash to build packages for the target and for Multilib, PN would be bash and lib64-bash, respectively. PNBLACKLIST Lists recipes you do not want the OpenEmbedded build system to build. This variable works in conjunction with the blacklist class, which the recipe must inherit globally. To prevent a recipe from being built, inherit the class globally and use the variable in your local.conf file. Here is an example that prevents myrecipe from being built: INHERIT += "blacklist" PNBLACKLIST[myrecipe] = "Not supported by our organization." PR The revision of the recipe. The default value for this variable is "r0". PREFERRED_PROVIDER If multiple recipes provide an item, this variable determines which recipe should be given preference. You should always suffix the variable with the name of the provided item, and you should set it to the PN of the recipe to which you want to give precedence. Some examples: PREFERRED_PROVIDER_virtual/kernel ?= "linux-yocto" PREFERRED_PROVIDER_virtual/xserver = "xserver-xf86" PREFERRED_PROVIDER_virtual/libgl ?= "mesa" PREFERRED_VERSION If there are multiple versions of recipes available, this variable determines which recipe should be given preference. You must always suffix the variable with the PN you want to select, and you should set the PV accordingly for precedence. You can use the "%" character as a wildcard to match any number of characters, which can be useful when specifying versions that contain long revision numbers that could potentially change. Here are two examples: PREFERRED_VERSION_python = "2.7.3" PREFERRED_VERSION_linux-yocto = "3.10%" PREMIRRORS Specifies additional paths from which the OpenEmbedded build system gets source code. When the build system searches for source code, it first tries the local download directory. If that location fails, the build system tries locations defined by PREMIRRORS, the upstream source, and then locations specified by MIRRORS in that order. Assuming your distribution (DISTRO) is "poky", the default value for PREMIRRORS is defined in the conf/distro/poky.conf file in the meta-yocto Git repository. Typically, you could add a specific server for the build system to attempt before any others by adding something like the following to the local.conf configuration file in the Build Directory: PREMIRRORS_prepend = "\ git://.*/.* http://www.yoctoproject.org/sources/ \n \ ftp://.*/.* http://www.yoctoproject.org/sources/ \n \ http://.*/.* http://www.yoctoproject.org/sources/ \n \ https://.*/.* http://www.yoctoproject.org/sources/ \n" These changes cause the build system to intercept Git, FTP, HTTP, and HTTPS requests and direct them to the http:// sources mirror. You can use file:// URLs to point to local directories or network shares as well. PRINC Causes the PR variable of .bbappend files to dynamically increment. This increment minimizes the impact of layer ordering. In order to ensure multiple .bbappend files can co-exist, PRINC should be self-referencing. This variable defaults to 0. Following is an example that increments PR by two: PRINC := "${@int(PRINC) + 2}" It is advisable not to use strings such as ".= '.1'" with the variable because this usage is very sensitive to layer ordering. You should avoid explicit assignments as they cannot adequately represent multiple .bbappend files. PROVIDES A list of aliases that a recipe also provides. These aliases are useful for satisfying dependencies of other recipes during the build (as specified by DEPENDS). A recipe's own PN is implicitly already in its PROVIDES list. PV The version of the recipe. The version is normally extracted from the recipe filename. For example, if the recipe is named expat_2.0.1.bb, then the default value of PV will be "2.0.1". PV is generally not overridden within a recipe unless it is building an unstable (i.e. development) version from a source code repository (e.g. Git or Subversion). RCONFLICTS The list of packages that conflict with packages. Note that packages will not be installed if conflicting packages are not first removed. Like all package-controlling variables, you must always use them in conjunction with a package name override. Here is an example: RCONFLICTS_${PN} = "another-conflicting-package-name" BitBake, which the OpenEmbedded build system uses, supports specifying versioned dependencies. Although the syntax varies depending on the packaging format, BitBake hides these differences from you. Here is the general syntax to specify versions with the RCONFLICTS variable: RCONFLICTS_${PN} = "<package> (<operator> <version>)" For operator, you can specify the following: = < > <= >= For example, the following sets up a dependency on version 1.2 or greater of the package foo: RCONFLICTS_${PN} = "foo (>= 1.2)" RDEPENDS Lists a package's runtime dependencies (i.e. other packages) that must be installed in order for the built package to run correctly. If a package in this list cannot be found during the build, you will get a build error. When you use the RDEPENDS variable in a recipe, you are essentially stating that the recipe's do_build task depends on the existence of a specific package. Consider this simple example for two recipes named "a" and "b" that produce similarly named packages. In this example, the RDEPENDS statement appears in the "a" recipe: RDEPENDS_${PN} = "b" Here, the dependency is such that the do_build task for recipe "a" depends on the do_package_write task of recipe "b". This means the package file for "b" must be available when the output for recipe "a" has been completely built. More importantly, package "a" will be marked as depending on package "b" in a manner that is understood by the package manager in use (i.e. rpm, opkg, or dpkg). The names of the packages you list within RDEPENDS must be the names of other packages - they cannot be recipe names. Although package names and recipe names usually match, the important point here is that you are providing package names within the RDEPENDS variable. For an example of the default list of packages created from a recipe, see the PACKAGES variable. Because the RDEPENDS variable applies to packages being built, you should always use the variable in a form with an attached package name. For example, suppose you are building a development package that depends on the perl package. In this case, you would use the following RDEPENDS statement: RDEPENDS_${PN}-dev += "perl" In the example, the development package depends on the perl package. Thus, the RDEPENDS variable has the ${PN}-dev package name as part of the variable. The package name you attach to the RDEPENDS variable must appear as it would in the PACKAGES namespace before any renaming of the output package by classes like debian.bbclass. In many cases you do not need to explicitly add runtime dependencies using RDEPENDS since some automatic handling occurs: shlibdeps: If a runtime package contains a shared library (.so), the build processes the library in order to determine other libraries to which it is dynamically linked. The build process adds these libraries to RDEPENDS when creating the runtime package. pcdeps: If the package ships a pkg-config information file, the build process uses this file to add items to the RDEPENDS variable to create the runtime packages. BitBake, which the OpenEmbedded build system uses, supports specifying versioned dependencies. Although the syntax varies depending on the packaging format, BitBake hides these differences from you. Here is the general syntax to specify versions with the RDEPENDS variable: RDEPENDS_${PN} = "<package> (<operator> <version>)" For operator, you can specify the following: = < > <= >= For example, the following sets up a dependency on version 1.2 or greater of the package foo: RDEPENDS_${PN} = "foo (>= 1.2)" For information on build-time dependencies, see the DEPENDS variable. REQUIRED_DISTRO_FEATURES When a recipe inherits the distro_features_check class, this variable identifies distribution features that must exist in the current configuration in order for the OpenEmbedded build system to build the recipe. In other words, if the REQUIRED_DISTRO_FEATURES variable lists a feature that does not appear in DISTRO_FEATURES within the current configuration, an error occurs and the build stops. RM_OLD_IMAGE Reclaims disk space by removing previously built versions of the same image from the images directory pointed to by the DEPLOY_DIR variable. Set this variable to "1" in your local.conf file to remove these images. RM_WORK_EXCLUDE With rm_work enabled, this variable specifies a list of recipes whose work directories should not be removed. See the "Removing Work Files During the Build - rm_work.bbclass" section for more details. ROOTFS Indicates a filesystem image to include as the root filesystem. The ROOTFS variable is an optional variable used with the buildimg class. ROOTFS_POSTPROCESS_COMMAND Added by classes to run post processing commands once the OpenEmbedded build system has created the root filesystem. You can specify shell commands separated by semicolons: ROOTFS_POSTPROCESS_COMMAND += "<shell_command>; ... " If you need to pass the path to the root filesystem within the command, you can use ${IMAGE_ROOTFS}, which points to the root filesystem image. RPROVIDES A list of package name aliases that a package also provides. These aliases are useful for satisfying runtime dependencies of other packages both during the build and on the target (as specified by RDEPENDS). A package's own name is implicitly already in its RPROVIDES list. As with all package-controlling variables, you must always use the variable in conjunction with a package name override. Here is an example: RPROVIDES_${PN} = "widget-abi-2" RRECOMMENDS A list of packages that extends the usability of a package being built. The package being built does not depend on this list of packages in order to successfully build, but needs them for the extended usability. To specify runtime dependencies for packages, see the RDEPENDS variable. The OpenEmbedded build process automatically installs the list of packages as part of the built package. However, you can remove these packages later if you want. If, during the build, a package from the RRECOMMENDS list cannot be found, the build process continues without an error. You can also prevent packages in the list from being installed by using several variables. See the BAD_RECOMMENDATIONS, NO_RECOMMENDATIONS, and PACKAGE_EXCLUDE variables for more information. Because the RRECOMMENDS variable applies to packages being built, you should always attach an override to the variable to specify the particular package whose usability is being extended. For example, suppose you are building a development package that is extended to support wireless functionality. In this case, you would use the following: RRECOMMENDS_${PN}-dev += "<wireless_package_name>" In the example, the package name (${PN}-dev) must appear as it would in the PACKAGES namespace before any renaming of the output package by classes such as debian.bbclass. BitBake, which the OpenEmbedded build system uses, supports specifying versioned recommends. Although the syntax varies depending on the packaging format, BitBake hides these differences from you. Here is the general syntax to specify versions with the RRECOMMENDS variable: RRECOMMENDS_${PN} = "<package> (<operator> <version>)" For operator, you can specify the following: = < > <= >= For example, the following sets up a recommend on version 1.2 or greater of the package foo: RRECOMMENDS_${PN} = "foo (>= 1.2)" RREPLACES A list of packages replaced by a package. The package manager uses this variable to determine which package should be installed to replace other package(s) during an upgrade. In order to also have the other package(s) removed at the same time, you must add the name of the other package to the RCONFLICTS variable. As with all package-controlling variables, you must use this variable in conjunction with a package name override. Here is an example: RREPLACES_${PN} = "other-package-being-replaced" BitBake, which the OpenEmbedded build system uses, supports specifying versioned replacements. Although the syntax varies depending on the packaging format, BitBake hides these differences from you. Here is the general syntax to specify versions with the RREPLACES variable: RREPLACES_${PN} = "<package> (<operator> <version>)" For operator, you can specify the following: = < > <= >= For example, the following sets up a replacement using version 1.2 or greater of the package foo: RREPLACES_${PN} = "foo (>= 1.2)" RSUGGESTS A list of additional packages that you can suggest for installation by the package manager at the time a package is installed. Not all package managers support this functionality. As with all package-controlling variables, you must always use this variable in conjunction with a package name override. Here is an example: RSUGGESTS_${PN} = "useful-package another-package" S The location in the Build Directory where unpacked recipe source code resides. This location is within the work directory (WORKDIR), which is not static. The unpacked source location depends on the recipe name (PN) and recipe version (PV) as follows: ${WORKDIR}/${PN}-${PV} As an example, assume a Source Directory top-level folder named poky and a default Build Directory at poky/build. In this case, the work directory the build system uses to keep the unpacked recipe for db is the following: poky/build/tmp/work/qemux86-poky-linux/db/5.1.19-r3/db-5.1.19 SANITY_TESTED_DISTROS A list of the host distribution identifiers that the build system has been tested against. Identifiers consist of the host distributor ID followed by the release, as reported by the lsb_release tool or as read from /etc/lsb-release. Separate the list items with explicit newline characters (\n). If SANITY_TESTED_DISTROS is not empty and the current value of NATIVELSBSTRING does not appear in the list, then the build system reports a warning that indicates the current host distribution has not been tested as a build host. SDK_ARCH The target architecture for the SDK. Typically, you do not directly set this variable. Instead, use SDKMACHINE. SDK_NAME The base name for SDK output files. The name is derived from the DISTRO, TCLIBC, SDK_ARCH, IMAGE_BASENAME, and TUNE_PKGARCH variables: SDK_NAME = "${DISTRO}-${TCLIBC}-${SDK_ARCH}-${IMAGE_BASENAME}-${TUNE_PKGARCH}" SDKIMAGE_FEATURES Equivalent to IMAGE_FEATURES. However, this variable applies to the SDK generated from an image using the following command: $ bitbake -c populate_sdk imagename SDKMACHINE The architecture of the machine that runs Application Development Toolkit (ADT) items. In other words, packages are built so that they will run on the target you specify with the argument. This implies that you can build out ADT/SDK items that run on an architecture other than that of your build host. For example, you can use an x86_64-based build host to create packages that will run on an i686-based SDK Machine. You can use "i686" and "x86_64" as possible values for this variable. The variable defaults to "i686" and is set in the local.conf file in the Build Directory. SDKMACHINE ?= "i686" SECTION The section in which packages should be categorized. Package management utilities can make use of this variable. SELECTED_OPTIMIZATION The variable takes the value of FULL_OPTIMIZATION unless DEBUG_BUILD = "1". In this case the value of DEBUG_OPTIMIZATION is used. SERIAL_CONSOLE Defines a serial console (TTY) to enable using getty. Provide a value that specifies the baud rate followed by the TTY device name separated by a space. You cannot specify more than one TTY device: SERIAL_CONSOLE = "115200 ttyS0" The SERIAL_CONSOLE variable is deprecated. Please use the SERIAL_CONSOLES variable. SERIAL_CONSOLES Defines the serial consoles (TTYs) to enable using getty. Provide a value that specifies the baud rate followed by the TTY device name separated by a semicolon. Use spaces to separate multiple devices: SERIAL_CONSOLES = "115200;ttyS0 115200;ttyS1" SERIAL_CONSOLES_CHECK Similar to SERIAL_CONSOLES except the device is checked for existence before attempting to enable it. This variable is currently only supported with SysVinit (i.e. not with systemd). SIGGEN_EXCLUDE_SAFE_RECIPE_DEPS A list of recipe dependencies that should not be used to determine signatures of tasks from one recipe when they depend on tasks from another recipe. For example: SIGGEN_EXCLUDE_SAFE_RECIPE_DEPS += "intone->mplayer2" In this example, intone depends on mplayer2. Use of this variable is one mechanism to remove dependencies that affect task signatures and thus force rebuilds when a recipe changes. If you add an inappropriate dependency for a recipe relationship, the software might break during runtime if the interface of the second recipe was changed after the first recipe had been built. SIGGEN_EXCLUDERECIPES_ABISAFE A list of recipes that are completely stable and will never change. The ABI for the recipes in the list are presented by output from the tasks run to build the recipe. Use of this variable is one way to remove dependencies from one recipe on another that affect task signatures and thus force rebuilds when the recipe changes. If you add an inappropriate variable to this list, the software might break at runtime if the interface of the recipe was changed after the other had been built. SITEINFO_BITS Specifies the number of bits for the target system CPU. The value should be either "32" or "64". SITEINFO_ENDIANNESS Specifies the endian byte order of the target system. The value should be either "le" for little-endian or "be" for big-endian. SOC_FAMILY Groups together machines based upon the same family of SOC (System On Chip). You typically set this variable in a common .inc file that you include in the configuration files of all the machines. You must include conf/machine/include/soc-family.inc for this variable to appear in MACHINEOVERRIDES. SOLIBS Defines the suffix for shared libraries used on the target platform. By default, this suffix is ".so.*" for all Linux-based systems and is defined in the meta/conf/bitbake.conf configuration file. You will see this variable referenced in the default values of FILES_${PN}. SOLIBSDEV Defines the suffix for the development symbolic link (symlink) for shared libraries on the target platform. By default, this suffix is ".so" for Linux-based systems and is defined in the meta/conf/bitbake.conf configuration file. You will see this variable referenced in the default values of FILES_${PN}-dev. SPECIAL_PKGSUFFIX A list of prefixes for PN used by the OpenEmbedded build system to create variants of recipes or packages. The list specifies the prefixes to strip off during certain circumstances such as the generation of the BPN variable. SRC_URI The list of source files - local or remote. This variable tells the OpenEmbedded build system which bits to pull in for the build and how to pull them in. For example, if the recipe or append file only needs to fetch a tarball from the Internet, the recipe or append file uses a single SRC_URI entry. On the other hand, if the recipe or append file needs to fetch a tarball, apply two patches, and include a custom file, the recipe or append file would include four instances of the variable. The following list explains the available URI protocols: file:// - Fetches files, which are usually files shipped with the Metadata, from the local machine. The path is relative to the FILESPATH variable. Thus, the build system searches, in order, from the following directories, which are assumed to be a subdirectories of the directory in which the recipe file (.bb) or append file (.bbappend) resides: ${BPN} - The base recipe name without any special suffix or version numbers. ${BP} - ${BPN}-${PV}. The base recipe name and version but without any special package name suffix. files - Files within a directory, which is named files and is also alongside the recipe or append file. If you want the build system to pick up files specified through a SRC_URI statement from your append file, you need to be sure to extend the FILESPATH variable by also using the FILESEXTRAPATHS variable from within your append file. bzr:// - Fetches files from a Bazaar revision control repository. git:// - Fetches files from a Git revision control repository. osc:// - Fetches files from an OSC (OpenSUSE Build service) revision control repository. repo:// - Fetches files from a repo (Git) repository. svk:// - Fetches files from an SVK revision control repository. http:// - Fetches files from the Internet using http. https:// - Fetches files from the Internet using https. ftp:// - Fetches files from the Internet using ftp. cvs:// - Fetches files from a CVS revision control repository. hg:// - Fetches files from a Mercurial (hg) revision control repository. p4:// - Fetches files from a Perforce (p4) revision control repository. ssh:// - Fetches files from a secure shell. svn:// - Fetches files from a Subversion (svn) revision control repository. Standard and recipe-specific options for SRC_URI exist. Here are standard options: apply - Whether to apply the patch or not. The default action is to apply the patch. striplevel - Which striplevel to use when applying the patch. The default level is 1. patchdir - Specifies the directory in which the patch should be applied. The default is ${S}. Here are options specific to recipes building code from a revision control system: mindate - Apply the patch only if SRCDATE is equal to or greater than mindate. maxdate - Apply the patch only if SRCDATE is not later than mindate. minrev - Apply the patch only if SRCREV is equal to or greater than minrev. maxrev - Apply the patch only if SRCREV is not later than maxrev. rev - Apply the patch only if SRCREV is equal to rev. notrev - Apply the patch only if SRCREV is not equal to rev. Here are some additional options worth mentioning: unpack - Controls whether or not to unpack the file if it is an archive. The default action is to unpack the file. subdir - Places the file (or extracts its contents) into the specified subdirectory of WORKDIR. This option is useful for unusual tarballs or other archives that do not have their files already in a subdirectory within the archive. name - Specifies a name to be used for association with SRC_URI checksums when you have more than one file specified in SRC_URI. downloadfilename - Specifies the filename used when storing the downloaded file. SRC_URI_OVERRIDES_PACKAGE_ARCH By default, the OpenEmbedded build system automatically detects whether SRC_URI contains files that are machine-specific. If so, the build system automatically changes PACKAGE_ARCH. Setting this variable to "0" disables this behavior. SRCDATE The date of the source code used to build the package. This variable applies only if the source was fetched from a Source Code Manager (SCM). SRCPV Returns the version string of the current package. This string is used to help define the value of PV. The SRCPV variable is defined in the meta/conf/bitbake.conf configuration file in the Source Directory as follows: SRCPV = "${@bb.fetch2.get_srcrev(d)}" Recipes that need to define PV do so with the help of the SRCPV. For example, the ofono recipe (ofono_git.bb) located in meta/recipes-connectivity in the Source Directory defines PV as follows: PV = "0.12-git${SRCPV}" SRCREV The revision of the source code used to build the package. This variable applies to Subversion, Git, Mercurial and Bazaar only. Note that if you wish to build a fixed revision and you wish to avoid performing a query on the remote repository every time BitBake parses your recipe, you should specify a SRCREV that is a full revision identifier and not just a tag. SSTATE_DIR The directory for the shared state cache. SSTATE_MIRRORS Configures the OpenEmbedded build system to search other mirror locations for prebuilt cache data objects before building out the data. This variable works like fetcher MIRRORS and PREMIRRORS and points to the cache locations to check for the shared objects. You can specify a filesystem directory or a remote URL such as HTTP or FTP. The locations you specify need to contain the shared state cache (sstate-cache) results from previous builds. The sstate-cache you point to can also be from builds on other machines. If a mirror uses the same structure as SSTATE_DIR, you need to add "PATH" at the end as shown in the examples below. The build system substitutes the correct path within the directory structure. SSTATE_MIRRORS ?= "\ file://.* http://someserver.tld/share/sstate/PATH \n \ file://.* file:///some/local/dir/sstate/PATH" STAGING_KERNEL_DIR The directory with kernel headers that are required to build out-of-tree modules. STAMP Specifies the base path used to create recipe stamp files. The path to an actual stamp file is constructed by evaluating this string and then appending additional information. Currently, the default assignment for STAMP as set in the meta/conf/bitbake.conf file is: STAMP = "${STAMPS_DIR}/${MULTIMACH_TARGET_SYS}/${PN}/${EXTENDPE}${PV}-${PR}" See STAMPS_DIR, MULTIMACH_TARGET_SYS, PN, EXTENDPE, PV, and PR for related variable information. STAMPS_DIR Specifies the base directory in which the OpenEmbedded build system places stamps. The default directory is ${TMPDIR}/stamps. SUMMARY The short (72 characters or less) summary of the binary package for packaging systems such as opkg, rpm or dpkg. By default, SUMMARY is used to define the DESCRIPTION variable if DESCRIPTION is not set in the recipe. SYSROOT_PREPROCESS_FUNCS A list of functions to execute after files are staged into the sysroot. These functions are usually used to apply additional processing on the staged files, or to stage additional files. T This variable points to a directory were BitBake places temporary files, which consist mostly of task logs and scripts, when building a particular recipe. The variable is typically set as follows: T = "${WORKDIR}/temp" The WORKDIR is the directory into which BitBake unpacks and builds the recipe. The default bitbake.conf file sets this variable. The T variable is not to be confused with the TMPDIR variable, which points to the root of the directory tree where BitBake places the output of an entire build. TARGET_ARCH The target machine's architecture. The OpenEmbedded build system supports many architectures. Here is an example list of architectures supported. This list is by no means complete as the architecture is configurable: arm i586 x86_64 powerpc powerpc64 mips mipsel TARGET_CFLAGS Flags passed to the C compiler for the target system. This variable evaluates to the same as CFLAGS. TARGET_FPU Specifies the method for handling FPU code. For FPU-less targets, which include most ARM CPUs, the variable must be set to "soft". If not, the kernel emulation gets used, which results in a performance penalty. TARGET_OS Specifies the target's operating system. The variable can be set to "linux" for eglibc-based systems and to "linux-uclibc" for uclibc. For ARM/EABI targets, there are also "linux-gnueabi" and "linux-uclibc-gnueabi" values possible. TCLIBC Specifies which variant of the GNU standard C library (libc) to use during the build process. This variable replaces POKYLIBC, which is no longer supported. You can select eglibc or uclibc. This release of the Yocto Project does not support the glibc implementation of libc. TCMODE The toolchain selector. This variable replaces POKYMODE, which is no longer supported. The TCMODE variable selects the external toolchain built using the OpenEmbedded build system or a few supported combinations of the upstream GCC or CodeSourcery Labs toolchain. The variable identifies the tcmode-* files used in the meta/conf/distro/include directory, which is found in the Source Directory. By default, TCMODE is set to "default", which chooses the tcmode-default.inc file. The variable is similar to TCLIBC, which controls the variant of the GNU standard C library (libc) used during the build process: eglibc or uclibc. TEST_IMAGE Automatically runs the series of automated tests for images when an image is successfully built. Currently, there is only support for running these tests under QEMU. These tests are written in Python making use of the unittest module, and the majority of them run commands on the target system over ssh. You can set this variable to "1" in your local.conf file in the Build Directory to have the OpenEmbedded build system automatically run these tests after an image successfully builds: TEST_IMAGE = "1" For more information on enabling, running, and writing these tests, see the "Performing Automated Runtime Testing" section in the Yocto Project Development Manual and the "testimage.bbclass" section. TEST_QEMUBOOT_TIMEOUT The time in seconds allowed for an image to boot before automated runtime tests begin to run against an image. The default timeout period to allow the boot process to reach the login prompt is 500 seconds. You can specify a different value in the local.conf file. For more information on testing images, see the "Performing Automated Runtime Testing" section in the Yocto Project Development Manual. TEST_SUITES An ordered list of tests (modules) to run against an image when performing automated runtime testing. The OpenEmbedded build system provides a core set of tests that can be used against images. Currently, there is only support for running these tests under QEMU. Tests include ping, ssh, df among others. You can add your own tests to the list of tests by appending TEST_SUITES as follows: TEST_SUITES_append = " mytest" Alternatively, you can provide the "auto" option to have all applicable tests run against the image. TEST_SUITES_append = " auto" Using this option causes the build system to automatically run tests that are applicable to the image. Tests that are not applicable are skipped. The order in which tests are run is important. Tests that depend on another test must appear later in the list than the test on which they depend. For example, if you append the list of tests with two tests (test_A and test_B) where test_B is dependent on test_A, then you must order the tests as follows: TEST_SUITES = " test_A test_B" For more information on testing images, see the "Performing Automated Runtime Testing" section in the Yocto Project Development Manual. THISDIR The directory in which the file BitBake is currently parsing is located. Do not manually set this variable. TMPDIR This variable is the base directory the OpenEmbedded build system uses for all build output and intermediate files (other than the shared state cache). By default, the TMPDIR variable points to tmp within the Build Directory. If you want to establish this directory in a location other than the default, you can uncomment and edit the following statement in the conf/local.conf file in the Source Directory: #TMPDIR = "${TOPDIR}/tmp" TOOLCHAIN_HOST_TASK This variable lists packages the OpenEmbedded build system uses when building an SDK, which contains a cross-development environment. The packages specified by this variable are part of the toolchain set that runs on the SDKMACHINE, and each package should usually have the prefix "nativesdk-". When building an SDK using bitbake -c populate_sdk <imagename>, a default list of packages is set in this variable, but you can add additional packages to the list. 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 "Installing the ADT and Toolchains" section in the Yocto Project Application Developer's Guide. TOOLCHAIN_TARGET_TASK This variable lists packages the OpenEmbedded build system uses when it creates the target part of an SDK (i.e. the part built for the target hardware), which includes libraries and headers. 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 "Installing the ADT and Toolchains" section in the Yocto Project Application Developer's Guide. TOPDIR This variable points to the Build Directory. BitBake automatically sets this variable. TRANSLATED_TARGET_ARCH A sanitized version of TARGET_ARCH. This variable is used where the architecture is needed in a value where underscores are not allowed, for example within package filenames. In this case, dash characters replace any underscore characters used in TARGET_ARCH. Do not edit this variable. TUNE_PKGARCH The package architecture understood by the packaging system to define the architecture, ABI, and tuning of output packages. UBOOT_CONFIG Configures the UBOOT_MACHINE and can also define IMAGE_FSTYPES for individual cases. Following is an example from the meta-fsl-arm layer. UBOOT_CONFIG ??= "sd" UBOOT_CONFIG[sd] = "mx6qsabreauto_config,sdcard" UBOOT_CONFIG[eimnor] = "mx6qsabreauto_eimnor_config" UBOOT_CONFIG[nand] = "mx6qsabreauto_nand_config,ubifs" UBOOT_CONFIG[spinor] = "mx6qsabreauto_spinor_config" In this example, "sd" is selected as the configuration of the possible four for the UBOOT_MACHINE. The "sd" configuration defines "mx6qsabreauto_config" as the value for UBOOT_MACHINE, while the "sdcard" specifies the IMAGE_FSTYPES to use for the U-boot image. For more information on how the UBOOT_CONFIG is handled, see the uboot-config class. UBOOT_ENTRYPOINT Specifies the entry point for the U-Boot image. During U-Boot image creation, the UBOOT_ENTRYPOINT variable is passed as a command-line parameter to the uboot-mkimage utility. UBOOT_LOADADDRESS Specifies the load address for the U-Boot image. During U-Boot image creation, the UBOOT_LOADADDRESS variable is passed as a command-line parameter to the uboot-mkimage utility. UBOOT_LOCALVERSION Appends a string to the name of the local version of the U-Boot image. For example, assuming the version of the U-Boot image built was "2013.10, the full version string reported by U-Boot would be "2013.10-yocto" given the following statement: UBOOT_LOCALVERSION = "-yocto" UBOOT_MACHINE Specifies the value passed on the make command line when building a U-Boot image. The value indicates the target platform configuration. You typically set this variable from the machine configuration file (i.e. conf/machine/<machine_name>.conf). UBOOT_MAKE_TARGET Specifies the target called in the Makefile. The default target is "all". UBOOT_SUFFIX Points to the generated U-Boot extension. For example, u-boot.sb has a .sb extension. The default U-Boot extension is .bin UBOOT_TARGET Specifies the target used for building U-Boot. The target is passed directly as part of the "make" command (e.g. SPL and AIS). If you do not specifically set this variable, the OpenEmbedded build process passes and uses "all" for the target during the U-Boot building process. USER_CLASSES A list of classes to globally inherit. These classes are used by the OpenEmbedded build system to enable extra features (e.g. buildstats, image-mklibs, and so forth). The default list is set in your local.conf file: USER_CLASSES ?= "buildstats image-mklibs image-prelink" For more information, see meta-yocto/conf/local.conf.sample in the Source Directory. USERADD_PACKAGES When a recipe inherits the useradd class, this variable specifies the individual packages within the recipe that require users and/or groups to be added. You must set this variable if the recipe inherits the class. For example, the following enables adding a user for the main package in a recipe: USERADD_PACKAGES = "${PN}" If follows that if you are going to use the USERADD_PACKAGES variable, you need to set one or more of the USERADD_PARAM, GROUPADD_PARAM, or GROUPMEMS_PARAM variables. USERADD_PARAM When a recipe inherits the useradd class, this variable specifies for a package what parameters should be passed to the useradd command if you wish to add a user to the system when the package is installed. Here is an example from the dbus recipe: USERADD_PARAM_${PN} = "--system --home ${localstatedir}/lib/dbus \ --no-create-home --shell /bin/false \ --user-group messagebus" For information on the standard Linux shell command useradd, see . WARN_QA Specifies the quality assurance checks whose failures are reported as warnings by the OpenEmbedded build system. You set this variable in your distribution configuration file. For a list of the checks you can control with this variable, see the "insane.bbclass" section. WORKDIR The pathname of the work directory in which the OpenEmbedded build system builds a recipe. This directory is located within the TMPDIR directory structure and changes as different packages are built. The actual WORKDIR directory depends on several things: The temporary directory - TMPDIR The package architecture - PACKAGE_ARCH The target machine - MACHINE The target operating system - TARGET_OS The recipe name - PN The recipe version - PV The recipe revision - PR For packages that are not dependent on a particular machine, WORKDIR is defined as follows: ${TMPDIR}/work/${PACKAGE_ARCH}-poky-${TARGET_OS}/${PN}/${PV}-${PR} As an example, assume a Source Directory top-level folder name poky and a default Build Directory at poky/build. In this case, the work directory the build system uses to build the v86d package is the following: poky/build/tmp/work/qemux86-poky-linux/v86d/01.9-r0 For packages that are dependent on a particular machine, WORKDIR is defined slightly differently: ${TMPDIR}/work/${MACHINE}-poky-${TARGET_OS}/${PN}/${PV}-${PR} As an example, again assume a Source Directory top-level folder named poky and a default Build Directory at poky/build. In this case, the work directory the build system uses to build the acl recipe, which is being built for a MIPS-based device, is the following: poky/build/tmp/work/mips-poky-linux/acl/2.2.51-r2