cfd497d4c3
Also export BUILD_DIR for post-{build,images} hooks, so they do have
a place to store generated files.
Note: this will be more einteresting for the instrumentation of steps,
to come in a later patch.
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Thomas De Schampheleire <patrickdepinguin@gmail.com>
Reviewed-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Reviewed-by: Samuel Martin <s.martin49@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
90 lines
4.8 KiB
Plaintext
90 lines
4.8 KiB
Plaintext
// -*- mode:doc; -*-
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// vim: set syntax=asciidoc:
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[[rootfs-custom]]
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Customizing the generated target filesystem
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Besides changing one or another configuration through +make *config+,
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there are a few ways to customize the resulting target filesystem.
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* Customize the target filesystem directly and rebuild the image. The
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target filesystem is available under +output/target/+. You can
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simply make your changes here and run make afterwards - this will
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rebuild the target filesystem image. This method allows you to do
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anything to the target filesystem, but if you decide to completely
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rebuild your toolchain and tools, these changes will be lost. This
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solution is therefore only useful for quick tests only: _changes do
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not survive the +make clean+ command_. Once you have validated your
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changes, you should make sure that they will persist after a +make
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clean+ by using one of the following methods.
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* Create a filesystem overlay: a tree of files that are copied directly
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over the target filesystem after it has been built. Set
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+BR2_ROOTFS_OVERLAY+ to the top of the tree. +.git+, +.svn+, +.hg+
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directories, +.empty+ files and files ending with +~+ are excluded.
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_Among these first 3 methods, this one should be preferred_.
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* In the Buildroot configuration, you can specify the paths to one or
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more *post-build scripts*. These scripts are called in the given order,
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'after' Buildroot builds all the selected software, but 'before' the
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rootfs images are assembled. The +BR2_ROOTFS_POST_BUILD_SCRIPT+ allows
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you to specify the location of your post-build scripts. This option can be
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found in the +System configuration+ menu. The destination root
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filesystem folder is given as the first argument to these scripts,
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and these scripts can then be used to remove or modify any file in your
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target filesystem. You should, however, use this feature with care.
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Whenever you find that a certain package generates wrong or unneeded
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files, you should fix that package rather than work around it with some
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post-build cleanup scripts.
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You may also use these variables in your post-build script:
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- +BUILDROOT_CONFIG+: the path to the Buildroot .config file
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- +HOST_DIR+, +STAGING_DIR+, +TARGET_DIR+: see
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xref:generic-package-reference[]
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- +BUILD_DIR+: the directory where packages are extracted and built
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- +BINARIES_DIR+: the place where all binary files (aka images) are
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stored
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- +BASE_DIR+: the base output directory
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* Create your own 'target skeleton'. You can start with the default
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skeleton available under +system/skeleton+ and then customize it to
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suit your needs. The +BR2_ROOTFS_SKELETON_CUSTOM+ and
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+BR2_ROOTFS_SKELETON_CUSTOM_PATH+ will allow you to specify the
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location of your custom skeleton. These options can be found in the
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+System configuration+ menu. At build time, the contents of the
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skeleton are copied to output/target before any package
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installation. Note that this method is *not recommended*, as it
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duplicates the entire skeleton, which prevents from taking advantage
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of the fixes or improvements brought to the default Buildroot
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skeleton. The recommended method is to use the _post-build scripts_
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mechanism described in the previous item.
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Note also that you can use the *post-image scripts*
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if you want to perform some specific actions 'after' all
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filesystem images have been created (for example to automatically
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extract your root filesystem tarball in a location exported by your
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NFS server, or to create a special firmware image that bundles your
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root filesystem and kernel image, or any other custom action), you can
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specify a space-separated list of scripts in the
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+BR2_ROOTFS_POST_IMAGE_SCRIPT+ configuration option. This option can be
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found in the +System configuration+ menu as well.
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Each of those scripts will be called with the path to the +images+
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output directory as first argument, and will be executed with the main
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Buildroot source directory as the current directory. Those scripts will
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be executed as the user that executes Buildroot, which should normally
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not be the root user. Therefore, any action requiring root permissions
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in one of these _post-image scripts_ will require special handling
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(usage of fakeroot or sudo), which is left to the script developer.
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Just like for the _post-build scripts_ mentioned above, you also have
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access to the following environment variables from your _post-image
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scripts_: +BUILDROOT_CONFIG+, +BUILD_DIR+, +HOST_DIR+, +STAGING_DIR+,
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+TARGET_DIR+, +BINARIES_DIR+ and +BASE_DIR+.
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Additionally, each of the +BR2_ROOTFS_POST_BUILD_SCRIPT+ and
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+BR2_ROOTFS_POST_IMAGE_SCRIPT+ scripts will be passed the arguments
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specified in +BR2_ROOTFS_POST_SCRIPT_ARGS+ (if that is not empty).
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All the scripts will be passed the exact same set of arguments, it
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is not possible to pass different sets of arguments to each script.
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