mirrors/poky
1
0
Fork 0
mirror of https://git.yoctoproject.org/poky synced 2026-05-30 12:29:55 +00:00
Code Issues Projects Releases Wiki Activity

documentation: Rename of poky-ref-manual folder to ref-manual.

Browse Source 
Changing the folder that holds the YP Reference Manual to be
"ref-manual".  This will help with confustion over the manual's
intended purpose.

(From yocto-docs rev: 1106442964b5080cb0b6b3bd3af32e9407c0f7c1)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
This commit is contained in:
Scott Rifenbark
2012-12-11 12:07:58 -06:00
committed by Richard Purdie
parent af19d889ef
commit ed0a240e16
214 changed files with 26016 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files
documentation/ref-manual/usingpoky.xml
+651
View File
@@ -0,0 +1,651 @@
<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
[<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] >
<chapter id='usingpoky'>
<title>Using the Yocto Project</title>
<para>
This chapter describes common usage for the Yocto Project.
The information is introductory in nature as other manuals in the Yocto Project
documentation set provide more details on how to use the Yocto Project.
</para>
<section id='usingpoky-build'>
<title>Running a Build</title>
<para>
This section provides a summary of the build process and provides information
for less obvious aspects of the build process.
For general information on how to build an image using the OpenEmbedded build
system, see the
"<ulink url='&YOCTO_DOCS_QS_URL;#building-image'>Building an Image</ulink>"
section of the Yocto Project Quick Start.
</para>
<section id='build-overview'>
<title>Build Overview</title>
<para>
The first thing you need to do is set up the OpenEmbedded build environment by sourcing
the <link linkend='structure-core-script'>environment setup script</link> as follows:
<literallayout class='monospaced'>
$ source &OE_INIT_FILE; [build_dir]
</literallayout>
</para>
<para>
The <filename>build_dir</filename> is optional and specifies the directory the
OpenEmbedded build system uses for the build -
the <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>.
If you do not specify a Build Directory it defaults to <filename>build</filename>
in your current working directory.
A common practice is to use a different Build Directory for different targets.
For example, <filename>~/build/x86</filename> for a <filename>qemux86</filename>
target, and <filename>~/build/arm</filename> for a <filename>qemuarm</filename> target.
See <link linkend="structure-core-script">&OE_INIT_FILE;</link>
for more information on this script.
</para>
<para>
Once the build environment is set up, you can build a target using:
<literallayout class='monospaced'>
$ bitbake &lt;target&gt;
</literallayout>
</para>
<para>
The <filename>target</filename> is the name of the recipe you want to build.
Common targets are the images in <filename>meta/recipes-core/images</filename>,
<filename>/meta/recipes-sato/images</filename>, etc. all found in the
<ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>.
Or, the target can be the name of a recipe for a specific piece of software such as
<application>busybox</application>.
For more details about the images the OpenEmbedded build system supports, see the
"<link linkend="ref-images">Images</link>" chapter.
</para>
<note>
Building an image without GNU General Public License Version 3 (GPLv3) components
is only supported for minimal and base images.
See the "<link linkend='ref-images'>Images</link>" chapter for more information.
</note>
</section>
<section id='building-an-image-using-gpl-components'>
<title>Building an Image Using GPL Components</title>
<para>
When building an image using GPL components, you need to maintain your original
settings and not switch back and forth applying different versions of the GNU
General Public License.
If you rebuild using different versions of GPL, dependency errors might occur
due to some components not being rebuilt.
</para>
</section>
</section>
<section id='usingpoky-install'>
<title>Installing and Using the Result</title>
<para>
Once an image has been built, it often needs to be installed.
The images and kernels built by the OpenEmbedded build system are placed in the
<ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink> in
<filename class="directory">tmp/deploy/images</filename>.
For information on how to run pre-built images such as <filename>qemux86</filename>
and <filename>qemuarm</filename>, see the
"<ulink url='&YOCTO_DOCS_QS_URL;#using-pre-built'>Using Pre-Built Binaries and QEMU</ulink>"
section in the Yocto Project Quick Start.
For information about how to install these images, see the documentation for your
particular board/machine.
</para>
</section>
<section id='usingpoky-debugging'>
<title>Debugging Build Failures</title>
<para>
The exact method for debugging build failures depends on the nature of the
problem and on the system's area from which the bug originates.
Standard debugging practices such as comparison against the last
known working version with examination of the changes and the re-application of steps
to identify the one causing the problem are
valid for the Yocto Project just as they are for any other system.
Even though it is impossible to detail every possible potential failure,
this section provides some general tips to aid in debugging.
</para>
<section id='usingpoky-debugging-taskfailures'>
<title>Task Failures</title>
<para>The log file for shell tasks is available in
<filename>${WORKDIR}/temp/log.do_taskname.pid</filename>.
For example, the <filename>compile</filename> task for the QEMU minimal image for the x86
machine (<filename>qemux86</filename>) might be
<filename>tmp/work/qemux86-poky-linux/core-image-minimal/1.0-r0/temp/log.do_compile.20830</filename>.
To see what BitBake runs to generate that log, look at the corresponding
<filename>run.do_taskname.pid</filename> file located in the same directory.
</para>
<para>
Presently, the output from Python tasks is sent directly to the console.
</para>
</section>
<section id='usingpoky-debugging-taskrunning'>
<title>Running Specific Tasks</title>
<para>
Any given package consists of a set of tasks.
The standard BitBake behavior in most cases is: <filename>fetch</filename>,
<filename>unpack</filename>,
<filename>patch</filename>, <filename>configure</filename>,
<filename>compile</filename>, <filename>install</filename>, <filename>package</filename>,
<filename>package_write</filename>, and <filename>build</filename>.
The default task is <filename>build</filename> and any tasks on which it depends
build first.
Some tasks exist, such as <filename>devshell</filename>, that are not part of the
default build chain.
If you wish to run a task that is not part of the default build chain, you can use the
<filename>-c</filename> option in BitBake as follows:
<literallayout class='monospaced'>
$ bitbake matchbox-desktop -c devshell
</literallayout>
</para>
<para>
If you wish to rerun a task, use the <filename>-f</filename> force option.
For example, the following sequence forces recompilation after changing files in the
working directory.
<literallayout class='monospaced'>
$ bitbake matchbox-desktop
.
.
[make some changes to the source code in the working directory]
.
.
$ bitbake matchbox-desktop -c compile -f
$ bitbake matchbox-desktop
</literallayout>
</para>
<para>
This sequence first builds <filename>matchbox-desktop</filename> and then recompiles it.
The last command reruns all tasks (basically the packaging tasks) after the compile.
BitBake recognizes that the <filename>compile</filename> task was rerun and therefore
understands that the other tasks also need to be run again.
</para>
<para>
You can view a list of tasks in a given package by running the
<filename>listtasks</filename> task as follows:
<literallayout class='monospaced'>
$ bitbake matchbox-desktop -c listtasks
</literallayout>
The results are in the file <filename>${WORKDIR}/temp/log.do_listtasks</filename>.
</para>
</section>
<section id='usingpoky-debugging-dependencies'>
<title>Dependency Graphs</title>
<para>
Sometimes it can be hard to see why BitBake wants to build some other packages before a given
package you have specified.
The <filename>bitbake -g targetname</filename> command creates the
<filename>depends.dot</filename>, <filename>package-depends.dot</filename>,
and <filename>task-depends.dot</filename> files in the current directory.
These files show the package and task dependencies and are useful for debugging problems.
You can use the <filename>bitbake -g -u depexp targetname</filename> command to
display the results in a more human-readable form.
</para>
</section>
<section id='usingpoky-debugging-bitbake'>
<title>General BitBake Problems</title>
<para>
You can see debug output from BitBake by using the <filename>-D</filename> option.
The debug output gives more information about what BitBake
is doing and the reason behind it.
Each <filename>-D</filename> option you use increases the logging level.
The most common usage is <filename>-DDD</filename>.
</para>
<para>
The output from <filename>bitbake -DDD -v targetname</filename> can reveal why
BitBake chose a certain version of a package or why BitBake
picked a certain provider.
This command could also help you in a situation where you think BitBake did something
unexpected.
</para>
</section>
<section id='usingpoky-debugging-buildfile'>
<title>Building with No Dependencies</title>
<para>
If you really want to build a specific <filename>.bb</filename> file, you can use
the command form <filename>bitbake -b &lt;somepath/somefile.bb&gt;</filename>.
This command form does not check for dependencies so you should use it
only when you know its dependencies already exist.
You can also specify fragments of the filename.
In this case, BitBake checks for a unique match.
</para>
</section>
<section id='usingpoky-debugging-variables'>
<title>Variables</title>
<para>
The <filename>-e</filename> option dumps the resulting environment for
either the configuration (no package specified) or for a
specific package when specified; or <filename>-b recipename</filename>
to show the environment from parsing a single recipe file only.
</para>
</section>
<section id='recipe-logging-mechanisms'>
<title>Recipe Logging Mechanisms</title>
<para>
Best practices exist while writing recipes that both log build progress and
act on build conditions such as warnings and errors.
Both Python and Bash language bindings exist for the logging mechanism:
<itemizedlist>
<listitem><para><emphasis>Python:</emphasis> For Python functions, BitBake
supports several loglevels: <filename>bb.fatal</filename>,
<filename>bb.error</filename>, <filename>bb.warn</filename>,
<filename>bb.note</filename>, <filename>bb.plain</filename>,
and <filename>bb.debug</filename>.</para></listitem>
<listitem><para><emphasis>Bash:</emphasis> For Bash functions, the same set
of loglevels exist and are accessed with a similar syntax:
<filename>bbfatal</filename>, <filename>bberror</filename>,
<filename>bbwarn</filename>, <filename>bbnote</filename>,
<filename>bbplain</filename>, and <filename>bbdebug</filename>.</para></listitem>
</itemizedlist>
</para>
<para>
For guidance on how logging is handled in both Python and Bash recipes, see the
<filename>logging.bbclass</filename> file in the
<filename>meta/classes</filename> folder of the
<ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>.
</para>
<section id='logging-with-python'>
<title>Logging With Python</title>
<para>
When creating recipes using Python and inserting code that handles build logs
keep in mind the goal is to have informative logs while keeping the console as
"silent" as possible.
Also, if you want status messages in the log use the "debug" loglevel.
</para>
<para>
Following is an example written in Python.
The code handles logging for a function that determines the number of tasks
needed to be run:
<literallayout class='monospaced'>
python do_listtasks() {
bb.debug(2, "Starting to figure out the task list")
if noteworthy_condition:
bb.note("There are 47 tasks to run")
bb.debug(2, "Got to point xyz")
if warning_trigger:
bb.warn("Detected warning_trigger, this might be a problem later.")
if recoverable_error:
bb.error("Hit recoverable_error, you really need to fix this!")
if fatal_error:
bb.fatal("fatal_error detected, unable to print the task list")
bb.plain("The tasks present are abc")
bb.debug(2, "Finished figuring out the tasklist")
}
</literallayout>
</para>
</section>
<section id='logging-with-bash'>
<title>Logging With Bash</title>
<para>
When creating recipes using Bash and inserting code that handles build
logs you have the same goals - informative with minimal console output.
The syntax you use for recipes written in Bash is similar to that of
recipes written in Python described in the previous section.
</para>
<para>
Following is an example written in Bash.
The code logs the progress of the <filename>do_my_function</filename> function.
<literallayout class='monospaced'>
do_my_function() {
bbdebug 2 "Running do_my_function"
if [ exceptional_condition ]; then
bbnote "Hit exceptional_condition"
fi
bbdebug 2 "Got to point xyz"
if [ warning_trigger ]; then
bbwarn "Detected warning_trigger, this might cause a problem later."
fi
if [ recoverable_error ]; then
bberror "Hit recoverable_error, correcting"
fi
if [ fatal_error ]; then
bbfatal "fatal_error detected"
fi
bbdebug 2 "Completed do_my_function"
}
</literallayout>
</para>
</section>
</section>
<section id='usingpoky-debugging-others'>
<title>Other Tips</title>
<para>
Here are some other tips that you might find useful:
<itemizedlist>
<listitem><para>When adding new packages, it is worth watching for
undesirable items making their way into compiler command lines.
For example, you do not want references to local system files like
<filename>/usr/lib/</filename> or <filename>/usr/include/</filename>.
</para></listitem>
<listitem><para>If you want to remove the psplash boot splashscreen,
add <filename>psplash=false</filename> to the kernel command line.
Doing so prevents psplash from loading and thus allows you to see the console.
It is also possible to switch out of the splashscreen by
switching the virtual console (e.g. Fn+Left or Fn+Right on a Zaurus).
</para></listitem>
</itemizedlist>
</para>
</section>
</section>
<section id='maintaining-build-output-quality'>
<title>Maintaining Build Output Quality</title>
<para>
A build's quality can be influenced by many things.
For example, if you upgrade a recipe to use a new version of an upstream software
package or you experiment with some new configuration options, subtle changes
can occur that you might not detect until later.
Consider the case where your recipe is using a newer version of an upstream package.
In this case, a new version of a piece of software might introduce an optional
dependency on another library, which is auto-detected.
If that library has already been built when the software is building,
then the software will link to the built library and that library will be pulled
into your image along with the new software even if you did not want the
library.
</para>
<para>
The <filename>buildhistory</filename> class exists to help you maintain
the quality of your build output.
You can use the class to highlight unexpected and possibly unwanted
changes in the build output.
When you enable build history it records information about the contents of
each package and image and then commits that information to a local Git
repository where you can examine the information.
</para>
<para>
The remainder of this section describes the following:
<itemizedlist>
<listitem><para>How you can enable and disable
build history</para></listitem>
<listitem><para>How to understand what the build history contains
</para></listitem>
<listitem><para>How to limit the information used for build history
</para></listitem>
<listitem><para>How to examine the build history from both a
command-line and web interface</para></listitem>
</itemizedlist>
</para>
<section id='enabling-and-disabling-build-history'>
<title>Enabling and Disabling Build History</title>
<para>
Build history is disabled by default.
To enable it, add the following statements to the end of your
<filename>conf/local.conf</filename> file found in the
<ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>:
<literallayout class='monospaced'>
INHERIT += "buildhistory"
BUILDHISTORY_COMMIT = "1"
</literallayout>
Enabling build history as previously described
causes the build process to collect build
output information and commit it to a local
<ulink url='&YOCTO_DOCS_DEV_URL;#git'>Git</ulink> repository.
<note>
Enabling build history increases your build times slightly,
particularly for images, and increases the amount of disk
space used during the build.
</note>
</para>
<para>
You can disable build history by removing the previous statements
from your <filename>conf/local.conf</filename> file.
However, you should realize that enabling and disabling
build history in this manner can change the
<filename>do_package</filename> task checksums, which if you
are using the OEBasicHash signature generator (the default
for many current distro configurations including
<filename>DISTRO = "poky"</filename> and
<filename>DISTRO = ""</filename>) will result in the packaging
tasks being re-run during the subsequent build.
</para>
<para>
To disable the build history functionality without causing the
packaging tasks to be re-run, add just this statement to your
<filename>conf/local.conf</filename> file:
<literallayout class='monospaced'>
BUILDHISTORY_FEATURES = ""
</literallayout>
</para>
</section>
<section id='understanding-what-the-build-history-contains'>
<title>Understanding What the Build History Contains</title>
<para>
Build history information is kept in
<link linkend='var-TMPDIR'><filename>$TMPDIR</filename></link><filename>/buildhistory</filename>
in the Build Directory.
The following is an example abbreviated listing:
<imagedata fileref="figures/buildhistory.png" align="center" width="6in" depth="4in" />
</para>
<section id='build-history-package-information'>
<title>Build History Package Information</title>
<para>
The history for each package contains a text file that has
name-value pairs with information about the package.
For example, <filename>buildhistory/packages/core2-poky-linux/busybox/busybox/latest</filename>
contains the following:
<literallayout class='monospaced'>
PV = 1.19.3
PR = r3
RDEPENDS = update-rc.d eglibc (>= 2.13)
RRECOMMENDS = busybox-syslog busybox-udhcpc
PKGSIZE = 564701
FILES = /usr/bin/* /usr/sbin/* /usr/libexec/* /usr/lib/lib*.so.* \
/etc /com /var /bin/* /sbin/* /lib/*.so.* /usr/share/busybox \
/usr/lib/busybox/* /usr/share/pixmaps /usr/share/applications \
/usr/share/idl /usr/share/omf /usr/share/sounds /usr/lib/bonobo/servers
FILELIST = /etc/busybox.links /etc/init.d/hwclock.sh /bin/busybox /bin/sh
</literallayout>
Most of these name-value pairs corresponds to variables used
to produce the package.
The exceptions are <filename>FILELIST</filename>, which is the
actual list of files in the package, and
<filename>PKGSIZE</filename>, which is the total size of files
in the package in bytes.
</para>
<para>
There is also a file corresponding to the recipe from which the
package came (e.g.
<filename>buildhistory/packages/core2-poky-linux/busybox/latest</filename>):
<literallayout class='monospaced'>
PV = 1.19.3
PR = r3
DEPENDS = virtual/i586-poky-linux-gcc virtual/i586-poky-linux-compilerlibs \
virtual/libc update-rc.d-native
PACKAGES = busybox-httpd busybox-udhcpd busybox-udhcpc busybox-syslog \
busybox-mdev busybox-dbg busybox busybox-doc busybox-dev \
busybox-staticdev busybox-locale
</literallayout>
</para>
</section>
<section id='build-history-image-information'>
<title>Build History Image Information</title>
<para>
The files produced for each image are as follows:
<itemizedlist>
<listitem><para><emphasis>build-id:</emphasis>
Human-readable information about the build configuration
and metadata source revisions.</para></listitem>
<listitem><para><emphasis>*.dot:</emphasis>
Dependency graphs for the image that are
compatible with <filename>graphviz</filename>.
</para></listitem>
<listitem><para><emphasis>files-in-image.txt:</emphasis>
A list of files in the image with permissions,
owner, group, size, and symlink information.
</para></listitem>
<listitem><para><emphasis>image-info.txt:</emphasis>
A text file containing name-value pairs with information
about the image.
See the following listing example for more information.
</para></listitem>
<listitem><para><emphasis>installed-package-names.txt:</emphasis>
A list of installed packages by name only.</para></listitem>
<listitem><para><emphasis>installed-package-sizes.txt:</emphasis>
A list of installed packages ordered by size.
</para></listitem>
<listitem><para><emphasis>installed-packages.txt:</emphasis>
A list of installed packages with fuill package
filenames.</para></listitem>
</itemizedlist>
<note>
Installed package information is able to be gathered and
produced even if package management is disabled for the final
image.
</note>
</para>
<para>
Here is an example of <filename>image-info.txt</filename>:
<literallayout class='monospaced'>
DISTRO = poky
DISTRO_VERSION = 1.1+snapshot-20120207
USER_CLASSES = image-mklibs image-prelink
IMAGE_CLASSES = image_types
IMAGE_FEATURES = debug-tweaks x11-base apps-x11-core \
package-management ssh-server-dropbear package-management
IMAGE_LINGUAS = en-us en-gb
IMAGE_INSTALL = task-core-boot task-base-extended
BAD_RECOMMENDATIONS =
ROOTFS_POSTPROCESS_COMMAND = buildhistory_get_image_installed ; rootfs_update_timestamp ;
IMAGE_POSTPROCESS_COMMAND = buildhistory_get_imageinfo ;
IMAGESIZE = 171816
</literallayout>
Other than <filename>IMAGESIZE</filename>, which is the
total size of the files in the image in Kbytes, the
name-value pairs are variables that may have influenced the
content of the image.
This information is often useful when you are trying to determine
why a change in the package or file listings has occurred.
</para>
</section>
<section id='using-build-history-to-gather-image-information-only'>
<title>Using Build History to Gather Image Information Only</title>
<para>
As you can see, build history produces image information,
including dependency graphs, so you can see why something
was pulled into the image.
If you are just interested in this information and not
interested in collecting history or any package information,
you can enable writing only image information without
any history by adding the following
to your <filename>conf/local.conf</filename> file found in the
<ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>:
<literallayout class='monospaced'>
INHERIT += "buildhistory"
BUILDHISTORY_COMMIT = "0"
BUILDHISTORY_FEATURES = "image"
</literallayout>
</para>
</section>
<section id='examining-build-history-information'>
<title>Examining Build History Information</title>
<para>
You can examine build history output from the command line or
from a web interface.
</para>
<para>
To see any changes that have occurred (assuming you have
<filename>BUILDHISTORY_COMMIT = "1"</filename>), you can simply
use any Git command that allows you to view the history of
a repository.
Here is one method:
<literallayout class='monospaced'>
$ git log -p
</literallayout>
You need to realize, however, that this method does show
changes that are not significant (e.g. a package's size
changing by a few bytes).
</para>
<para>
A command-line tool called <filename>buildhistory-diff</filename>
does exist though that queries the Git repository and prints just
the differences that might be significant in human-readable form.
Here is an example:
<literallayout class='monospaced'>
$ ~/poky/poky/scripts/buildhistory-diff . HEAD^
Changes to images/qemux86_64/eglibc/core-image-minimal (files-in-image.txt):
/etc/anotherpkg.conf was added
/sbin/anotherpkg was added
* (installed-package-names.txt):
* anotherpkg was added
Changes to images/qemux86_64/eglibc/core-image-minimal (installed-package-names.txt):
anotherpkg was added
packages/qemux86_64-poky-linux/v86d: PACKAGES: added "v86d-extras"
* PR changed from "r0" to "r1"
* PV changed from "0.1.10" to "0.1.12"
packages/qemux86_64-poky-linux/v86d/v86d: PKGSIZE changed from 110579 to 144381 (+30%)
* PR changed from "r0" to "r1"
* PV changed from "0.1.10" to "0.1.12"
</literallayout>
</para>
<para>
To see changes to the build history using a web interface, follow
the instruction in the <filename>README</filename> file here.
<ulink url='http://git.yoctoproject.org/cgit/cgit.cgi/buildhistory-web/'></ulink>.
</para>
<para>
Here is a sample screenshot of the interface:
<imagedata fileref="figures/buildhistory-web.png" align="center" scalefit="1" width="130%" contentdepth="130%" />
</para>
</section>
</section>
</section>
</chapter>
<!--
vim: expandtab tw=80 ts=4
-->