From d0c89b6d59840f900d1aa9bdde32197eef7cdbb1 Mon Sep 17 00:00:00 2001 From: Scott Rifenbark Date: Mon, 7 Aug 2017 15:30:38 -0700 Subject: [PATCH] dev-manual: Updates to "Using .bbappend Files in Your Layer" I did some rewriting for clarity in the "Using .bbappend Files in Your Layer" section. The section needed to be retitled so focus on the layer aspect of .bbappend files. Also, while I was in there, I did more work on the prose in general. Also had to fix some links in the bsp, kernel, and ref manuals that linked into the section whose name I changes. (From yocto-docs rev: 27003c525a05ffa2f810a038c7c8f96bb7535986) Signed-off-by: Scott Rifenbark Signed-off-by: Richard Purdie --- documentation/bsp-guide/bsp.xml | 2 +- .../dev-manual/dev-manual-common-tasks.xml | 71 +-- documentation/kernel-dev/kernel-dev-faq.xml | 2 +- documentation/ref-manual/introduction.xml | 407 ++++++++++++++++++ 4 files changed, 445 insertions(+), 37 deletions(-) diff --git a/documentation/bsp-guide/bsp.xml b/documentation/bsp-guide/bsp.xml index cb9940c77a..a92e6115b1 100644 --- a/documentation/bsp-guide/bsp.xml +++ b/documentation/bsp-guide/bsp.xml @@ -936,7 +936,7 @@ Create a .bbappend file for the modified recipe. For information on using append files, see the - "Using .bbappend Files" + "Using .bbappend Files in Your Layer" section in the Yocto Project Development Manual. diff --git a/documentation/dev-manual/dev-manual-common-tasks.xml b/documentation/dev-manual/dev-manual-common-tasks.xml index 76a2c654dd..6e6577220d 100644 --- a/documentation/dev-manual/dev-manual-common-tasks.xml +++ b/documentation/dev-manual/dev-manual-common-tasks.xml @@ -685,37 +685,46 @@
- Using .bbappend Files + Using .bbappend Files in Your Layer - Recipes used to append Metadata to other recipes are called - BitBake append files. - BitBake append files use the .bbappend file - type suffix, while the corresponding recipes to which Metadata - is being appended use the .bb file type - suffix. + A recipe that appends Metadata to another recipe is called a + BitBake append file. + A BitBake append file uses the .bbappend + file type suffix, while the corresponding recipe to which + Metadata is being appended uses the .bb + file type suffix. - A .bbappend file allows your layer to make - additions or changes to the content of another layer's recipe - without having to copy the other recipe into your layer. + You can use a .bbappend file in your + layer to make additions or changes to the content of another + layer's recipe without having to copy the other layer's + recipe into your layer. Your .bbappend file resides in your layer, while the main .bb recipe file to which you are appending Metadata resides in a different layer. - Append files must have the same root names as their corresponding - recipes. + Being able to append information to an existing recipe not only + avoids duplication, but also automatically applies recipe + changes from a different layer into your layer. + If you were copying recipes, you would have to manually merge + changes as they occur. + + + + When you create an append file, you must use the same root + name as the corresponding recipe file. For example, the append file someapp_&DISTRO;.bbappend must apply to someapp_&DISTRO;.bb. - This means the original recipe and append file names are version - number-specific. + This means the original recipe and append file names are + version number-specific. If the corresponding recipe is renamed to update to a newer - version, the corresponding .bbappend file must - be renamed (and possibly updated) as well. + version, you must also rename and possibly update + the corresponding .bbappend as well. During the build process, BitBake displays an error on starting if it detects a .bbappend file that does not have a corresponding recipe with a matching name. @@ -724,14 +733,6 @@ variable for information on how to handle this error. - - Being able to append information to an existing recipe not only - avoids duplication, but also automatically applies recipe - changes in a different layer to your layer. - If you were copying recipes, you would have to manually merge - changes as they occur. - - As an example, consider the main formfactor recipe and a corresponding formfactor append file both from the @@ -744,8 +745,7 @@ SUMMARY = "Device formfactor information" SECTION = "base" LICENSE = "MIT" - LIC_FILES_CHKSUM = "file://${COREBASE}/LICENSE;md5=4d92cd373abda3937c2bc47fbc49d690 \ - file://${COREBASE}/meta/COPYING.MIT;md5=3da9cfbcb788c80a0384361b4de20420" + LIC_FILES_CHKSUM = "file://${COREBASE}/meta/COPYING.MIT;md5=3da9cfbcb788c80a0384361b4de20420" PR = "r45" SRC_URI = "file://config file://machconfig" @@ -761,8 +761,7 @@ if [ -s "${S}/machconfig" ]; then install -m 0644 ${S}/machconfig ${D}${sysconfdir}/formfactor/ fi - } - + } In the main recipe, note the SRC_URI variable, which tells the OpenEmbedded build system where to @@ -774,7 +773,8 @@ formfactor_0.0.bbappend and is from the Raspberry Pi BSP Layer named meta-raspberrypi. - The file is in recipes-bsp/formfactor: + The file is in the layer at + recipes-bsp/formfactor: FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:" @@ -794,12 +794,13 @@ - The statement in this example extends the directories to include + The statement in this example extends the directories to + include ${THISDIR}/${PN}, which resolves to a directory named formfactor in the same directory in which the append file resides (i.e. - meta-raspberrypi/recipes-bsp/formfactor/formfactor. + meta-raspberrypi/recipes-bsp/formfactor. This implies that you must have the supporting directory structure set up that will contain any files or patches you will be including from the layer. @@ -807,8 +808,8 @@ Using the immediate expansion assignment operator - := is important because of the reference to - THISDIR. + := is important because of the reference + to THISDIR. The trailing colon character is important as it ensures that items in the list remain colon-separated. @@ -6571,7 +6572,7 @@ and SRC_URI statements enable the OpenEmbedded build system to find the patch file. For more information on using append files, see the - "Using .bbappend Files" + "Using .bbappend Files in Your Layer" section. Put the patch file in your layer: @@ -7050,7 +7051,7 @@ Add a psplash append file for a branded splash screen. For information on append files, see the - "Using .bbappend Files" + "Using .bbappend Files in Your Layer" section. Add any other append files to make custom changes that are specific to individual diff --git a/documentation/kernel-dev/kernel-dev-faq.xml b/documentation/kernel-dev/kernel-dev-faq.xml index 2b99ad2dde..9e0517d4af 100644 --- a/documentation/kernel-dev/kernel-dev-faq.xml +++ b/documentation/kernel-dev/kernel-dev-faq.xml @@ -72,7 +72,7 @@ RDEPENDS_kernel-base to include or not include "kernel-image". See the - "Using .bbappend Files" + "Using .bbappend Files in Your Layer" section in the Yocto Project Development Manual for information on how to use an append file to override metadata. diff --git a/documentation/ref-manual/introduction.xml b/documentation/ref-manual/introduction.xml index cec23b6039..e3b4df3a91 100644 --- a/documentation/ref-manual/introduction.xml +++ b/documentation/ref-manual/introduction.xml @@ -621,6 +621,413 @@
+
+ Yocto Project Terms + + + Following is a list of terms and definitions users new to the Yocto + Project development environment might find helpful. + While some of these terms are universal, the list includes them + just in case: + + + Append Files: + Files that append build information to a recipe file. + Append files are known as BitBake append files and + .bbappend files. + The OpenEmbedded build system expects every append file to have + a corresponding recipe (.bb) file. + Furthermore, the append file and corresponding recipe file + must use the same root filename. + The filenames can differ only in the file type suffix used + (e.g. + formfactor_0.0.bb and + formfactor_0.0.bbappend). + + Information in append files extends or overrides the + information in the similarly-named recipe file. + For an example of an append file in use, see the + "Using .bbappend Files in Your Layer" + section in the Yocto Project Development Manual. + + Append files can also use wildcard patterns in their + version numbers so they can be applied to more than one + version of the underlying recipe file. + + + + BitBake: + The task executor and scheduler used by the OpenEmbedded build + system to build images. + For more information on BitBake, see the + BitBake User Manual. + + + + Build Directory: + This term refers to the area used by the OpenEmbedded build + system for builds. + The area is created when you source the + setup environment script that is found in the Source Directory + (i.e. &OE_INIT_FILE; + or + oe-init-build-env-memres). + The + TOPDIR + variable points to the Build Directory. + + You have a lot of flexibility when creating the Build + Directory. + Following are some examples that show how to create the + directory. + The examples assume your + Source Directory is + named poky: + + Create the Build Directory inside your + Source Directory and let the name of the Build + Directory default to build: + + $ cd $HOME/poky + $ source &OE_INIT_FILE; + + + Create the Build Directory inside your + home directory and specifically name it + test-builds: + + $ cd $HOME + $ source poky/&OE_INIT_FILE; test-builds + + + + Provide a directory path and specifically name the + Build Directory. + Any intermediate folders in the pathname must exist. + This next example creates a Build Directory named + YP-&POKYVERSION; + in your home directory within the existing + directory mybuilds: + + $cd $HOME + $ source $HOME/poky/&OE_INIT_FILE; $HOME/mybuilds/YP-&POKYVERSION; + + + + + By default, the Build Directory contains + TMPDIR, + which is a temporary directory the build system uses for + its work. + TMPDIR cannot be under NFS. + Thus, by default, the Build Directory cannot be under NFS. + However, if you need the Build Directory to be under NFS, + you can set this up by setting TMPDIR + in your local.conf file + to use a local drive. + Doing so effectively separates TMPDIR + from TOPDIR, which is the Build + Directory. + + + + Classes: + Files that provide for logic encapsulation and inheritance so + that commonly used patterns can be defined once and then + easily used in multiple recipes. + For reference information on the Yocto Project classes, see the + "Classes" chapter. + Class files end with the .bbclass + filename extension. + + + Configuration File: + Configuration information in various .conf + files provides global definitions of variables. + The conf/local.conf configuration file in + the + Build Directory + contains user-defined variables that affect every build. + The meta-poky/conf/distro/poky.conf + configuration file defines Yocto "distro" configuration + variables used only when building with this policy. + Machine configuration files, which + are located throughout the + Source Directory, define + variables for specific hardware and are only used when building + for that target (e.g. the + machine/beaglebone.conf configuration + file defines variables for the Texas Instruments ARM Cortex-A8 + development board). + Configuration files end with a .conf + filename extension. + + + Cross-Development Toolchain: + In general, a cross-development toolchain is a collection of + software development tools and utilities that run on one + architecture and allow you to develop software for a + different, or targeted, architecture. + These toolchains contain cross-compilers, linkers, and + debuggers that are specific to the target architecture. + + The Yocto Project supports two different cross-development + toolchains: + + + A toolchain only used by and within + BitBake when building an image for a target + architecture. + + A relocatable toolchain used outside of + BitBake by developers when developing applications + that will run on a targeted device. + + + + Creation of these toolchains is simple and automated. + For information on toolchain concepts as they apply to the + Yocto Project, see the + "Cross-Development Toolchain Generation" + section. + You can also find more information on using the + relocatable toolchain in the + Yocto Project Software Development Kit (SDK) Developer's Guide. + + + Image: + An image is an artifact of the BitBake build process given + a collection of recipes and related Metadata. + Images are the binary output that run on specific hardware or + QEMU and are used for specific use-cases. + For a list of the supported image types that the Yocto Project + provides, see the + "Images" + chapter. + + + Layer: + A collection of recipes representing the core, + a BSP, or an application stack. + For a discussion specifically on BSP Layers, see the + "BSP Layers" + section in the Yocto Project Board Support Packages (BSP) + Developer's Guide. + + + Metadata: + The files that BitBake parses when building an image. + In general, Metadata includes recipes, classes, and + configuration files. + In the context of the kernel ("kernel Metadata"), + it refers to Metadata in the meta + branches of the kernel source Git repositories. + + + OE-Core: + A core set of Metadata originating with OpenEmbedded (OE) + that is shared between OE and the Yocto Project. + This Metadata is found in the meta + directory of the + Source Directory. + + + OpenEmbedded Build System: + The build system specific to the Yocto Project. + The OpenEmbedded build system is based on another project known + as "Poky", which uses + BitBake as the task + executor. + Throughout the Yocto Project documentation set, the + OpenEmbedded build system is sometimes referred to simply + as "the build system". + If other build systems, such as a host or target build system + are referenced, the documentation clearly states the + difference. + + For some historical information about Poky, see the + Poky term. + + + + Package: + In the context of the Yocto Project, this term refers to a + recipe's packaged output produced by BitBake (i.e. a + "baked recipe"). + A package is generally the compiled binaries produced from the + recipe's sources. + You "bake" something by running it through BitBake. + + It is worth noting that the term "package" can, + in general, have subtle meanings. + For example, the packages referred to in the + "The Build Host Packages" + section in the Yocto Project Quick Start are compiled binaries + that, when installed, add functionality to your Linux + distribution. + + Another point worth noting is that historically within + the Yocto Project, recipes were referred to as packages - thus, + the existence of several BitBake variables that are seemingly + mis-named, + (e.g. PR, + PV, and + PE). + + + Package Groups: + Arbitrary groups of software Recipes. + You use package groups to hold recipes that, when built, + usually accomplish a single task. + For example, a package group could contain the recipes for a + company’s proprietary or value-add software. + Or, the package group could contain the recipes that enable + graphics. + A package group is really just another recipe. + Because package group files are recipes, they end with the + .bb filename extension. + + + Poky: + The term "poky", which is pronounced + Pah-kee, can mean several things: + + + In its most general sense, poky is an open-source + project that was initially developed by OpenedHand. + OpenedHand developed poky off of the existing + OpenEmbedded build system to create a commercially + supportable build system for embedded Linux. + After Intel Corporation acquired OpenedHand, the + poky project became the basis for the Yocto Project's + build system. + + + Within the Yocto Project + Source Repositories, + "poky" exists as a separate Git + repository from which you can clone to yield a local + Git repository that is a copy on your host system. + Thus, "poky" can refer to the upstream or + local copy of the files used for development within + the Yocto Project. + + + Finally, "poky" can refer to the default + DISTRO + (i.e. distribution) created when you use the Yocto + Project in conjunction with the + poky repository to build an image. + + + + + Recipe: + A set of instructions for building packages. + A recipe describes where you get source code, which patches + to apply, how to configure the source, how to compile it and so on. + Recipes also describe dependencies for libraries or for other + recipes. + Recipes represent the logical unit of execution, the software + to build, the images to build, and use the + .bb file extension. + + + + Source Directory: + This term refers to the directory structure created as a result + of creating a local copy of the poky Git + repository git://git.yoctoproject.org/poky + or expanding a released poky tarball. + + Creating a local copy of the poky + Git repository is the recommended method for setting up + your Source Directory. + + Sometimes you might hear the term "poky directory" used to refer + to this directory structure. + + The OpenEmbedded build system does not support file or + directory names that contain spaces. + Be sure that the Source Directory you use does not contain + these types of names. + + + The Source Directory contains BitBake, Documentation, + Metadata and other files that all support the Yocto Project. + Consequently, you must have the Source Directory in place on + your development system in order to do any development using + the Yocto Project. + + When you create a local copy of the Git repository, you + can name the repository anything you like. + Throughout much of the documentation, "poky" + is used as the name of the top-level folder of the local copy of + the poky Git repository. + So, for example, cloning the poky Git + repository results in a local Git repository whose top-level + folder is also named "poky". + + While it is not recommended that you use tarball expansion + to set up the Source Directory, if you do, the top-level + directory name of the Source Directory is derived from the + Yocto Project release tarball. + For example, downloading and unpacking + &YOCTO_POKY_TARBALL; results in a + Source Directory whose root folder is named + &YOCTO_POKY;. + + It is important to understand the differences between the + Source Directory created by unpacking a released tarball as + compared to cloning + git://git.yoctoproject.org/poky. + When you unpack a tarball, you have an exact copy of the files + based on the time of release - a fixed release point. + Any changes you make to your local files in the Source Directory + are on top of the release and will remain local only. + On the other hand, when you clone the poky + Git repository, you have an active development repository with + access to the upstream repository's branches and tags. + In this case, any local changes you make to the local + Source Directory can be later applied to active development + branches of the upstream poky Git + repository. + + For more information on concepts related to Git + repositories, branches, and tags, see the + "Repositories, Tags, and Branches" + section. + + Task: + A unit of execution for BitBake (e.g. + do_compile, + do_fetch, + do_patch, + and so forth). + + Toaster: + A web interface to the Yocto Project's + OpenEmbedded Build System. + The interface enables you to configure and run your builds. + Information about builds is collected and stored in a database. + For information on Toaster, see the + Yocto Project Toaster Manual. + + + Upstream: + A reference to source code or repositories + that are not local to the development system but located in a + master area that is controlled by the maintainer of the source + code. + For example, in order for a developer to work on a particular + piece of code, they need to first get a copy of it from an + "upstream" source. + + + +
+ +>>>>>>> a82bcc9... dev-manual: Updates to "Using .bbappend Files in Your Layer"