From 8914519565567d0f31bc60f6b16b61e5be95ba74 Mon Sep 17 00:00:00 2001 From: Scott Rifenbark Date: Thu, 11 Nov 2010 13:40:30 -0800 Subject: Poky Reference Manual: General edits for English. Signed-off-by: Scott Rifenbark --- documentation/poky-ref-manual/extendpoky.xml | 190 +++++++++++++-------------- 1 file changed, 95 insertions(+), 95 deletions(-) (limited to 'documentation') diff --git a/documentation/poky-ref-manual/extendpoky.xml b/documentation/poky-ref-manual/extendpoky.xml index ad8918dcb8..03546e6d3f 100644 --- a/documentation/poky-ref-manual/extendpoky.xml +++ b/documentation/poky-ref-manual/extendpoky.xml @@ -5,13 +5,12 @@ Extending Poky - This section provides information about how to extend the functionality + This chapter provides information about how to extend the functionality already present in Poky. - The section also documents standard tasks such as adding new + The chapter also documents standard tasks such as adding new software packages, extending or customizing images or porting Poky to new hardware (adding a new machine). - Finally, the section contains advice about how - to make changes to Poky to achieve the best results. + Finally, the chapter contains advice about how to make changes to Poky to achieve the best results.
@@ -21,7 +20,7 @@ Writing a recipe means creating a .bb file that sets some variables. For information on variables that are useful for recipes and for information about recipe naming - issues, see Recipe Variables - Required + issues, see the Recipe Variables - Required appendix. @@ -29,7 +28,7 @@ whether someone else has written one already. OpenEmbedded is a good place to look as it has a wider scope and range of packages. Because Poky aims to be compatible with OpenEmbedded, most recipes should - just work in Poky. + simply work in Poky. For new packages, the simplest way to add a recipe is to base it on a similar @@ -43,11 +42,11 @@ Building an application from a single file that is stored locally (e.g. under files/) requires a recipe that has the file listed in the SRC_URI variable. - Additionally, you need to manually write the do_compile and - do_install tasks. + Additionally, you need to manually write the "do_compile" and + "do_install" tasks. The S variable defines the directory containing the source code, which is set to - WORKDIR in this case - the directory BitBake uses for the build. + WORKDIR in this case - the directory Bitbake uses for the build. DESCRIPTION = "Simple helloworld application" @@ -82,13 +81,13 @@ do_install() { Applications that use autotools such as autoconf and automake require a recipe that has a source archive listed in SRC_URI and - also inherits autotools, which instructs BitBake to use the - autotools.bbclass containing the definitions of all the steps + also inherits autotools, which instructs Bitbake to use the + autotools.bbclass file, which contains the definitions of all the steps needed to build an autotooled application. The result of the build is automatically packaged. And, if the application uses NLS for localization, packages with local information are generated (one package per language). - Following is one example (hello_2.2.bb) + Following is one example: (hello_2.2.bb) DESCRIPTION = "GNU Helloworld application" @@ -102,9 +101,9 @@ SRC_URI = "${GNU_MIRROR}/hello/hello-${PV}.tar.gz" inherit autotools gettext - LIC_FILES_CHKSUM + The variable LIC_FILES_CHKSUM is used to - track source license change. + track source license changes. You can quickly create autotool-based recipes in a manner similar to the previous example. @@ -115,13 +114,13 @@ inherit autotools gettext Applications that use GNU make also require a recipe that has the source archive listed in SRC_URI. - You do not need to add a do_compile step since by default BitBake + You do not need to add a do_compile step since by default Bitbake starts the make command to compile the application. If you need additional make options you should store them in the EXTRA_OEMAKE variable. Bitbake passes these options into the make GNU invocation. - Note that a do_install task is still required. - Otherwise BitBake runs an empty do_install task by default. + Note that a "do_install" task is still required. + Otherwise Bitbake runs an empty "do_install" task by default. Some applications might require extra parameters to be passed to the compiler. @@ -134,7 +133,7 @@ inherit autotools gettext CFLAGS_prepend = "-I ${S}/include " - In the following example mtd-utils is a Makefile-based package: + In the following example mtd-utils is a makefile-based package: DESCRIPTION = "Tools for managing memory technology devices." @@ -171,7 +170,7 @@ do_install () { Following is an example that uses the "libXpm" recipe (libxpm_3.5.7.bb). - By default, the "libXpm" recipe generates a single package containing the library, along + By default, the "libXpm" recipe generates a single package that contains the library along with a few binaries. You can modify the recipe to split the binaries into separate packages: @@ -198,8 +197,8 @@ FILES_sxpm = "${bindir}/sxpm" package by default, we prepend the PACKAGES variable so additional package names are added to the start of list. This results in the extra FILES_* - variables then containing information defining which files and - directories go into which package. + variables then containing information that define which files and + directories go into which packages. Files included by earlier packages are skipped by latter packages. Thus, the main PN package does not include the above listed files. @@ -234,7 +233,7 @@ pkg_postinst_PACKAGENAME () { Sometimes it is necessary for the execution of a post-installation script to be delayed until the first boot. For example, the script might need to be executed on the device itself. - To delay script execution until boot time, use the following structure for the + To delay script execution until boot time, use the following structure in the post-installation script: @@ -259,8 +258,8 @@ fi
Customizing Images - You can customize Poky images to satisfy particular requirements. - This section describes several methods and provides guidelines for each. + You can customize Poky images to satisfy particular requirements. + This section describes several methods and provides guidelines for each.
@@ -344,8 +343,8 @@ RRECOMMENDS_task-custom-tools = "\ task-custom-tools. To build an image using these task packages, you need to add "task-custom-apps" and/or "task-custom-tools" to IMAGE_INSTALL or other forms - of image dependencies as described in other areas of this section. + linkend='var-IMAGE_INSTALL'>IMAGE_INSTALL. + For other forms of image dependencies see the other areas of this section.
@@ -359,7 +358,7 @@ RRECOMMENDS_task-custom-tools = "\ meta/classes/poky-image.bbclass, which shows how poky achieves this. In summary, the file looks at the contents of the IMAGE_FEATURES - variable and then maps them into a set of tasks or packages. + variable and then maps that into a set of tasks or packages. Based on this information the IMAGE_INSTALL variable is generated automatically. Users can add extra features by extending the class or creating a custom class for use @@ -370,12 +369,12 @@ RRECOMMENDS_task-custom-tools = "\
Customizing Images Using local.conf - It is possible to customize image contents by abusing variables used by distribution - maintainers in local.conf. + It is possible to customize image contents by using variables used by distribution + maintainers in the local.conf. This method only allows the addition of packages and is not recommended. - For example, to add the "strace" package into the image the you would add this to the + For example, to add the "strace" package into the image you would add this package to the local.conf file: @@ -387,18 +386,18 @@ DISTRO_EXTRA_RDEPENDS += "strace" distribution maintainers, adding packages using this method is not as simple as adding them using a custom .bb file. Using the local.conf file method could result in some packages - requiring recreation. + needing to be recreated. For example, if packages were previously created and the image was rebuilt then the packages would need to be recreated. - Cleaning task-* packages is required because they use the + Cleaning task-* packages are required because they use the DISTRO_EXTRA_RDEPENDS variable. You do not have to build them by hand because Poky images depend on the packages they contain. This means dependencies are automatically built when the image builds. For this reason we don't use the "rebuild" task. - In this case the "rebuild" task does does not care about + In this case the "rebuild" task does not care about dependencies - it only rebuilds the specified package. @@ -416,24 +415,23 @@ $ bitbake poky-image-sato This section provides information that gives you an idea of the changes you must make. The information covers adding machines similar to those Poky already supports. Although well within the capabilities of Poky, adding a totally new architecture might require - changes to gcc/glibc and to the site information. - Consequently, the information is beyond the scope of this manual. + changes to gcc/glibc and to the site information, which is + beyond the scope of this manual.
Adding the Machine Configuration File To add a machine configuration you need to add a .conf file - with details of the device being added to conf/machine/. + with details of the device being added to the conf/machine/ file. The name of the file determines the name Poky uses to reference the new machine. The most important variables to set in this file are - TARGET_ARCH - (e.g. "arm"), - PREFERRED_PROVIDER_virtual/kernel (see below) and - MACHINE_FEATURES - (e.g. "kernel26 apm screen wifi"). + TARGET_ARCH (e.g. "arm"), + PREFERRED_PROVIDER_virtual/kernel + (see below) and MACHINE_FEATURES + (e.g. "kernel26 apm screen wifi"). You might also need other variables like SERIAL_CONSOLE (e.g. "115200 ttyS0"), KERNEL_IMAGETYPE @@ -461,7 +459,7 @@ $ bitbake poky-image-sato S to point at the source code. You need to create a "configure" task that configures the unpacked kernel with a defconfig. You can do this by using a make defconfig command or - more commonly by copying in a suitable defconfig and and then running + more commonly by copying in a suitable defconfig file and and then running make oldconfig. By making use of "inherit kernel" and potentially some of the linux-*.inc files, most other functionality is @@ -486,12 +484,12 @@ COMPATIBLE_MACHINE = '(qemux86|qemumips)' Adding a Formfactor Configuration File A formfactor configuration file provides information about the - target hardware on which Poky is running, and that Poky cannot + target hardware on which Poky is running, and information that Poky cannot obtain from other sources such as the kernel. Some examples of information contained in a formfactor configuration file include framebuffer orientation, whether or not the system has a keyboard, the positioning of the keyboard in relation to the screen, and - screen resolution. + the screen resolution. Reasonable defaults are used in most cases, but if customization is @@ -545,7 +543,7 @@ DISPLAY_SUBPIXEL_ORDER=vrgb The Poky tree includes several additional layers such as meta-emenlow and meta-extras that demonstrate this functionality. - The meta-emenlow layer is an example layer that by default is enabled. + The meta-emenlow layer is an example layer that, by default, is enabled. However, the meta-extras repository is not enabled by default. It is easy though to enable any layer. You simply add the layer's path to the @@ -554,16 +552,16 @@ DISPLAY_SUBPIXEL_ORDER=vrgb The following example shows how to enable meta-extras in the Poky build: - - LCONF_VERSION = "1" - - BBFILES ?= "" - BBLAYERS = " \ - /path/to/poky/meta \ - /path/to/poky/meta-emenlow \ - /path/to/poky/meta-extras \ - " - + +LCONF_VERSION = "1" + +BBFILES ?= "" +BBLAYERS = " \ + /path/to/poky/meta \ + /path/to/poky/meta-emenlow \ + /path/to/poky/meta-extras \ + " + @@ -575,18 +573,18 @@ DISPLAY_SUBPIXEL_ORDER=vrgb The meta-emenlow/conf/layer.conf file demonstrates the required syntax: - - # We have a conf and classes directory, add to BBPATH - BBPATH := "${BBPATH}:${LAYERDIR}" + +# We have a conf and classes directory, add to BBPATH +BBPATH := "${BBPATH}:${LAYERDIR}" - # We have a recipes directory containing both .bb and .bbappend files, add to BBFILES - BBFILES := "${BBFILES} ${LAYERDIR}/recipes/*/*.bb \ +# We have a recipes directory containing both .bb and .bbappend files, add to BBFILES +BBFILES := "${BBFILES} ${LAYERDIR}/recipes/*/*.bb \ ${LAYERDIR}/recipes/*/*.bbappend" - BBFILE_COLLECTIONS += "emenlow" - BBFILE_PATTERN_emenlow := "^${LAYERDIR}/" - BBFILE_PRIORITY_emenlow = "6" - +BBFILE_COLLECTIONS += "emenlow" +BBFILE_PATTERN_emenlow := "^${LAYERDIR}/" +BBFILE_PRIORITY_emenlow = "6" + In the previous example, the recipes for the layers are added to @@ -598,7 +596,7 @@ DISPLAY_SUBPIXEL_ORDER=vrgb a particular layer, in this case by using the base pathname. The BBFILE_PRIORITY variable then assigns different priorities to the files in different layers. - This technique useful in situations where the same package might appear in multiple + Applying priorities is useful in situations where the same package might appear in multiple layers and allows you to choose what layer should take precedence. @@ -637,11 +635,14 @@ DISPLAY_SUBPIXEL_ORDER=vrgb revision control system. Because some simple practices can significantly improve usability, policy for committing changes is important. + It helps to use a consistent documentation style when committing changes. + We have found the following style works well. + + Following are suggestions for committing changes to the Poky core: + - It helps to use a consistent documentation style when committing changes. - We have found the following style works well. The first line of the commit summarizes the change and begins with the name of the affected package or packages. @@ -680,10 +681,10 @@ DISPLAY_SUBPIXEL_ORDER=vrgb If a committed change results in changing the package output then the value of the PR - variable needs to be increased ('bumped') as part of that commit. - This means that for new recipes you be sure to add the PR variable and set its initial value + variable needs to be increased (or 'bumped') as part of that commit. + This means that for new recipes you must be sure to add the PR variable and set its initial value equal to "r0". - Not initially defining PR makes makes it easy to miss when you bump a package. + Not initially defining PR makes it easy to miss when you bump a package. Note that you can only use integer values for the PR variable. @@ -691,7 +692,7 @@ DISPLAY_SUBPIXEL_ORDER=vrgb linkend='var-PV'>PV) and PR variables should be reset to "r0". - Usually a package version only increases. + Usually, version increases occur only to packages. However, if for some reason PV changes but does not increase, you can increase the PE variable (Package Epoch). The PE variable defaults to '0'. @@ -718,7 +719,7 @@ DISPLAY_SUBPIXEL_ORDER=vrgb
Using Poky in a Team Environment - It may not be immediately clear how you can use Poky in a team environment, + It might not be immediately clear how you can use Poky in a team environment, or scale it for a large team of developers. The specifics of any situation determine the best solution. Granted that Poky offers immense flexibility regarding this, practices do exist @@ -728,7 +729,7 @@ DISPLAY_SUBPIXEL_ORDER=vrgb The core component of any development effort with Poky is often an automated build testing framework and an image generation process. You can use these core components to check that the metadata is buildable, - highlight when commits break the builds, and provide up-to-date images that + highlight when commits break the build, and provide up-to-date images that allow people to test the end result and use it as a base platform for further development. Experience shows that buildbot is a good fit for this role. @@ -747,7 +748,7 @@ DISPLAY_SUBPIXEL_ORDER=vrgb Full builds build and test everything from the ground up. - They usually happen at preset times like during the night when the machine + They usually happen at predetermined times like during the night when the machine load is low. @@ -768,7 +769,7 @@ DISPLAY_SUBPIXEL_ORDER=vrgb Of course circumstances will be different in each case. However, this situation reveals one of Poky's advantages - the system itself does not force any particular policy on users, unlike a lot of build systems. - The system allows the best policy to be chosen for the given circumstances. + The system allows the best policies to be chosen for the given circumstances.
@@ -797,7 +798,7 @@ DISPLAY_SUBPIXEL_ORDER=vrgb Although Poky is usually used to build software, you can use it to modify software. - During building, source is available in the + During a build, source is available in the WORKDIR directory. The actual location depends on the type of package and the architecture of the target device. For a standard recipe not related to @@ -811,7 +812,7 @@ DISPLAY_SUBPIXEL_ORDER=vrgb Be sure the package recipe sets the S variable to something - other than standard WORKDIR/PN-PV/ value. + other than the standard WORKDIR/PN-PV/ value. @@ -820,9 +821,9 @@ DISPLAY_SUBPIXEL_ORDER=vrgb following example: - -bitbake -c compile -f NAME_OF_PACKAGE - + + $ bitbake -c compile -f NAME_OF_PACKAGE + The "-f" or "--force" option forces re-execution of the specified task. @@ -836,28 +837,28 @@ bitbake -c compile -f NAME_OF_PACKAGE Modifying Package Source Code with quilt By default Poky uses quilt - to manage patches in the do_patch task. + to manage patches in the "do_patch" task. This is a powerful tool that you can use to track all modifications to package sources. Before modifying source code, it is important to notify quilt so it can track the changes into the new patch file: - + quilt new NAME-OF-PATCH.patch - + After notifying quilt, add all modified files into that patch: - + quilt add file1 file2 file3 - + You can now start editing. Once you are done editing, you need to use quilt to generate the final patch that will contain all your modifications. - + quilt refresh - + You can find the resulting patch file in the patches/ subdirectory of the source @@ -869,8 +870,8 @@ quilt refresh SRC_URI += "file://NAME-OF-PATCH.patch" Finally, don't forget to 'bump' the - PR value in the same recipe. - The resulting packages have changed. + PR value in the same recipe since + the resulting packages have changed.
@@ -880,8 +881,7 @@ SRC_URI += "file://NAME-OF-PATCH.patch" Track License Change The license of an upstream project might change in the future. - To address this situation, Poky uses the - LIC_FILES_CHKSUM variable + Poky uses the LIC_FILES_CHKSUM variable to track license changes. @@ -940,7 +940,7 @@ LIC_FILES_CHKSUM = "file://../license.html;md5=5c94767cedb5d6987c902ac850ded2c6" This mismatch triggers a build failure and notifies the developer. Notification allows the developer to review and address the license text changes. Also note that if a mis-match occurs during the build, the correct md5 - checksum is placed in the build log, which can be easily copied to a .bb file. + checksum is placed in the build log and can be easily copied to a .bb file. There is no limit to how many files you can specify using the LIC_FILES_CHKSUM variable. @@ -950,7 +950,7 @@ LIC_FILES_CHKSUM = "file://../license.html;md5=5c94767cedb5d6987c902ac850ded2c6" This practice allow you to just track the "COPYING" file as long as it is kept up to date. - If you specify an empty or invalid "md5" parameter, bitback returns an md5 mis-match + If you specify an empty or invalid "md5" parameter, Bitbake returns an md5 mis-match error and displays the correct "md5" parameter value during the build. The correct parameter is also captured in the build log. @@ -966,7 +966,7 @@ LIC_FILES_CHKSUM = "file://../license.html;md5=5c94767cedb5d6987c902ac850ded2c6" Sometimes a package name you are using might exist under an alias or as a similarly named package in a different distribution. - Poky implements a distro_check task that automatically connects to major distributions + Poky implements a "distro_check" task that automatically connects to major distributions and checks for these situations. If the package exists under a different name in a different distribution you get a distro_check mismatch. @@ -986,7 +986,7 @@ DISTRO_PN_ALIAS_pn-PACKAGENAME = "distro1=package_name_alias1 \ - If you have more than one distribution alias separate them with a space. + If you have more than one distribution alias, separate them with a space. Note that Poky currently automatically checks the Fedora, OpenSuSE, Debian, Ubuntu, and Mandriva distributions for source package recipes without having to specify them using the DISTRO_PN_ALIAS variable. -- cgit 1.2.3-korg