Mike at 15:43, 18 January 2023

2023-01-18T15:43:32Z

← Older revision		Revision as of 15:43, 18 January 2023
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	https://wiki.yoctoproject.org/wiki/TipsAndTricks/Patching_the_source_for_a_recipe		https://wiki.yoctoproject.org/wiki/TipsAndTricks/Patching_the_source_for_a_recipe

	Patching the source for a recipe		Patching the source for a recipe
	One of the useful things about OpenEmbedded building everything from source is that it's fairly easy to make changes to anything that gets built, but doing so for the first time can be a bit daunting.		One of the useful things about OpenEmbedded building everything from source is that it's fairly easy to make changes to anything that gets built, but doing so for the first time can be a bit daunting.
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	Luckily if you're using the fido (1.8) or later release, there's a much better method using the devtool command:		Luckily if you're using the fido (1.8) or later release, there's a much better method using the devtool command:

	# Run devtool modify <recipename>. This will fetch the sources for the recipe and unpack them to a workspace/sources/<recipename> directory and initialise it as a git repository if it isn't already one. If you prefer you can specify your own path, or if you already have your own existing source tree you can specify the path along with the -n option to use that instead of unpacking a new one.		# Run devtool modify <recipename>. This will fetch the sources for the recipe and unpack them to a workspace/sources/<recipename> directory and initialise it as a git repository if it isn't already one. If you prefer you can specify your own path, or if you already have your own existing source tree you can specify the path along with the -n option to use that instead of unpacking a new one
	Make the changes you want to make to the source		# Make the changes you want to make to the source
	Run a build to test your changes - you can just bitbake <recipename> or even build an entire image incorporating the changes assuming a package produced by the recipe is part of an image. There's no need to force anything - the build system will detect changes to the source and recompile as necessary.		# Run a build to test your changes - you can just bitbake <recipename> or even build an entire image incorporating the changes assuming a package produced by the recipe is part of an image. There's no need to force anything - the build system will detect changes to the source and recompile as necessary.
	If you wish, test your changes on the target. There's a "devtool deploy-target" command which will copy the files installed at do_install over to the target machine assuming it has network access, and any dependencies are already present in the image.		#* If you wish, test your changes on the target. There's a "devtool deploy-target" command which will copy the files installed at do_install over to the target machine assuming it has network access, and any dependencies are already present in the image
	Repeat from step 2 as needed until you're happy with the results.		# Repeat from step 2 as needed until you're happy with the results.
	At this point you will almost certainly want to place your changes in the form of a patch to be applied from the metadata - devtool provides help with this as well. Commit your changes using "git commit" (as many or as few commits as you'd like) and then run either:		#* At this point you will almost certainly want to place your changes in the form of a patch to be applied from the metadata - devtool provides help with this as well. Commit your changes using "git commit" (as many or as few commits as you'd like) and then run either:
	devtool update-recipe <recipename> to update the original recipe - usually appropriate if it's your own recipe or you're submitting the changes back to the upstream layer		# devtool update-recipe <recipename> to update the original recipe - usually appropriate if it's your own recipe or you're submitting the changes back to the upstream layer devtool update-recipe -a <layerpath> <recipename> to put your changes in the form of a bbappend to be applied by a different layer. This is usually the desired method if your changes are customisations rather than bugfixes.
	devtool update-recipe -a <layerpath> <recipename> to put your changes in the form of a bbappend to be applied by a different layer. This is usually the desired method if your changes are customisations rather than bugfixes.		#* If you're finished working on the recipe, run devtool reset <recipename>.
	If you're finished working on the recipe, run devtool reset <recipename>.
	This is just one of the things that devtool can do - it provides some powerful tools to help you maintain recipes and make changes to source code.		This is just one of the things that devtool can do - it provides some powerful tools to help you maintain recipes and make changes to source code.


			https://wiki.koansoftware.com/index.php/Using_devtool_to_modify_recipes_in_Yocto

			== Example ==
			devtool modify linux-yocto-custom --no-extract tmp-glibc/work-shared/sm800a/kernel-source/

			== Create patches from first principles ==
			Do the changes and commit the files to the git repository and then generate a patch. eg.<pre>
			git format-patch -1 head
			</pre>Generates a patch file, that can be added to the .bbappend file by<pre>
			SRC_URI += "
			file://mypatch.patch
			"
			</pre>build again form a clean system, and the patch will be applied.

Mike: Created page with "https://wiki.yoctoproject.org/wiki/TipsAndTricks/Patching_the_source_for_a_recipe Patching the source for a recipe One of the useful things about OpenEmbedded building everything from source is that it's fairly easy to make changes to anything that gets built, but doing so for the first time can be a bit daunting. As part of building a recipe, OE creates a tmp/work/// directory, known as the "work directory". This is where all of the work..."

2023-01-17T11:22:44Z

Created page with "https://wiki.yoctoproject.org/wiki/TipsAndTricks/Patching_the_source_for_a_recipe Patching the source for a recipe One of the useful things about OpenEmbedded building everything from source is that it's fairly easy to make changes to anything that gets built, but doing so for the first time can be a bit daunting. As part of building a recipe, OE creates a tmp/work/<architecture>/<recipe>/<version> directory, known as the "work directory". This is where all of the work..."

New page

https://wiki.yoctoproject.org/wiki/TipsAndTricks/Patching_the_source_for_a_recipe
Patching the source for a recipe
One of the useful things about OpenEmbedded building everything from source is that it's fairly easy to make changes to anything that gets built, but doing so for the first time can be a bit daunting.

As part of building a recipe, OE creates a tmp/work/<architecture>/<recipe>/<version> directory, known as the "work directory". This is where all of the work done to build a recipe takes place. One of the things you'll find in this directory is the source, usually under a subdirectory named <recipename>-<version> or "git" (depending on how the fetched source is provided). The temptation (and what people used to do in the past) is to simply make changes here and then recompile, but there are several reasons why that's not a good idea:

It's awkward - you have to use bitbake -c compile -f or bitbake -C compile to force recompilation, since the build system doesn't know that you've made any changes
You can easily lose your changes if you're not careful e.g. running bitbake -c clean will wipe the directory out
Luckily if you're using the fido (1.8) or later release, there's a much better method using the devtool command:

# Run devtool modify <recipename>. This will fetch the sources for the recipe and unpack them to a workspace/sources/<recipename> directory and initialise it as a git repository if it isn't already one. If you prefer you can specify your own path, or if you already have your own existing source tree you can specify the path along with the -n option to use that instead of unpacking a new one.
Make the changes you want to make to the source
Run a build to test your changes - you can just bitbake <recipename> or even build an entire image incorporating the changes assuming a package produced by the recipe is part of an image. There's no need to force anything - the build system will detect changes to the source and recompile as necessary.
If you wish, test your changes on the target. There's a "devtool deploy-target" command which will copy the files installed at do_install over to the target machine assuming it has network access, and any dependencies are already present in the image.
Repeat from step 2 as needed until you're happy with the results.
At this point you will almost certainly want to place your changes in the form of a patch to be applied from the metadata - devtool provides help with this as well. Commit your changes using "git commit" (as many or as few commits as you'd like) and then run either:
devtool update-recipe <recipename> to update the original recipe - usually appropriate if it's your own recipe or you're submitting the changes back to the upstream layer
devtool update-recipe -a <layerpath> <recipename> to put your changes in the form of a bbappend to be applied by a different layer. This is usually the desired method if your changes are customisations rather than bugfixes.
If you're finished working on the recipe, run devtool reset <recipename>.
This is just one of the things that devtool can do - it provides some powerful tools to help you maintain recipes and make changes to source code.

Create patches - Revision history

Mike at 15:43, 18 January 2023