<corpauthor>BitBake Team</corpauthor>
</authorgroup>
<copyright>
- <year>2004</year>
+ <year>2004, 2005, 2006</year>
<holder>Chris Larson</holder>
<holder>Phil Blundell</holder>
</copyright>
<legalnotice>
- <para>This work is licensed under the Creative Commons Attribution License. To view a copy of this license, visit <ulink url="http://creativecommons.org/licenses/by/2.0/">http://creativecommons.org/licenses/by/2.0/</ulink> or send a letter to Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.</para>
+ <para>This work is licensed under the Creative Commons Attribution License. To view a copy of this license, visit <ulink url="http://creativecommons.org/licenses/by/2.5/">http://creativecommons.org/licenses/by/2.5/</ulink> or send a letter to Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.</para>
</legalnotice>
</bookinfo>
<chapter>
<para>In this example, <varname>B</varname> is now <literal>bval additionaldata</literal> and <varname>C</varname> is <literal>test cval</literal>.</para>
</section>
<section>
+ <title>Appending (.=) and prepending (=.) without spaces</title>
+ <para><screen><varname>B</varname> = "bval"
+<varname>B</varname> .= "additionaldata"
+<varname>C</varname> = "cval"
+<varname>C</varname> =. "test"</screen></para>
+ <para>In this example, <varname>B</varname> is now <literal>bvaladditionaldata</literal> and <varname>C</varname> is <literal>testcval</literal>. In contrast to the above Appending and Prepending operators no additional space
+will be introduced.</para>
+ </section>
+ <section>
<title>Conditional metadata set</title>
<para>OVERRIDES is a <quote>:</quote> seperated variable containing each item you want to satisfy conditions. So, if you have a variable which is conditional on <quote>arm</quote>, and <quote>arm</quote> is in OVERRIDES, then the <quote>arm</quote> specific version of the variable is used rather than the non-conditional version. Example:</para>
<para><screen><varname>OVERRIDES</varname> = "architecture:os:machine"
<para>Next, there is the <literal>include</literal> directive, which causes BitBake to parse in whatever file you specify, and insert it at that location, which is not unlike <command>make</command>. However, if the path specified on the <literal>include</literal> line is a relative path, BitBake will locate the first one it can find within <envar>BBPATH</envar>.</para>
</section>
<section>
+ <title>Requiring Inclusion</title>
+ <para>In contrast to the <literal>include</literal> directive, <literal>require</literal> will
+raise an ParseError if the to be included file can not be found. Otherwise it will behave just like the <literal>
+include</literal> directive.</para>
+ </section>
+ <section>
<title>Python variable expansion</title>
<para><screen><varname>DATE</varname> = "${@time.strftime('%Y%m%d',time.gmtime())}"</screen></para>
<para>This would result in the <varname>DATE</varname> variable containing today's date.</para>
<title>Defining python functions into the global python namespace</title>
<para><emphasis>NOTE:</emphasis> This is only supported in .bb and .bbclass files.</para>
<para><screen>def get_depends(bb, d):
- if bb.data.getVar('SOMECONDITION', d, 1):
+ if bb.data.getVar('SOMECONDITION', d, True):
return "dependencywithcond"
else:
return "dependency"
<section>
<title>Events</title>
<para><emphasis>NOTE:</emphasis> This is only supported in .bb and .bbclass files.</para>
- <para>BitBake also implements a means of registering event handlers. Events are triggered at certain points during operation, such as, the beginning of operation against a given .bb, the start of a given task, task failure, task success, et cetera. The intent was to make it easy to do things like email notifications on build failure.</para>
- <para><emphasis>[Insert instructions on how to add event handlers here]</emphasis></para>
+ <para>BitBake allows to install event handlers. Events are triggered at certain points during operation, such as, the beginning of operation against a given .bb, the start of a given task, task failure, task success, et cetera. The intent was to make it easy to do things like email notifications on build failure.</para>
+ <para><screen>addhandler myclass_eventhandler
+python myclass_eventhandler() {
+ from bb.event import NotHandled, getName
+ from bb import data
+
+ print "The name of the Event is %s" % getName(e)
+ print "The file we run for is %s" % data.getVar('FILE', e.data, True)
+
+ return NotHandled
+}
+</screen></para><para>
+This event handler gets called every time an event is triggered. A global variable <varname>e</varname> is defined. <varname>e</varname>.data contains an instance of bb.data. With the getName(<varname>e</varname>)
+method one can get the name of the triggered event.</para><para>The above event handler prints the name
+of the event and the content of the <varname>FILE</varname> variable.</para>
</section>
</section>
<section>
</section>
</section>
</chapter>
+
<chapter>
- <title>Commands</title>
+ <title>File Download support</title>
<section>
- <title>bbread</title>
- <para>test</para>
+ <title>Overview</title>
+ <para>BitBake provides support to download files this procedure is called fetching. The SRC_URI is normally used to indicate BitBake which files to fetch. The next sections will describe th available fetchers and the options they have. Each Fetcher honors a set of Variables and
+a per URI parameters separated by a <quote>;</quote> consisting of a key and a value. The semantic of the Variables and Parameters are defined by the Fetcher. BitBakes tries to have a consistent semantic between the different Fetchers.
+ </para>
+ </section>
+
+ <section>
+ <title>Local File Fetcher</title>
+ <para>The URN for the Local File Fetcher is <emphasis>file</emphasis>. The filename can be either absolute or relative. If the filename is relative <varname>FILESPATH</varname> and <varname>FILESDIR</varname> will be used to find the appropriate relative file depending on the <varname>OVERRIDES</varname>. Single files and complete directories can be specified.
+<screen><varname>SRC_URI</varname>= "file://relativefile.patch"
+<varname>SRC_URI</varname>= "file://relativefile.patch;this=ignored"
+<varname>SRC_URI</varname>= "file:///Users/ich/very_important_software"
+</screen>
+ </para>
+ </section>
+
+ <section>
+ <title>CVS File Fetcher</title>
+ <para>The URN for the CVS Fetcher is <emphasis>cvs</emphasis>. This Fetcher honors the variables <varname>DL_DIR</varname>, <varname>SRCDATE</varname>, <varname>FETCHCOMMAND_cvs</varname>, <varname>UPDATECOMMAND_cvs</varname>. <varname>DL_DIRS</varname> specifies where a temporary checkout is saved, <varname>SRCDATE</varname> specifies which date to use when doing the fetching, <varname>FETCHCOMMAND</varname> and <varname>UPDATECOMMAND</varname> specify which executables should be used when doing the CVS checkout or update.
+ </para>
+ <para>The supported Parameters are <varname>module</varname>, <varname>tag</varname>, <varname>date</varname>, <varname>method</varname>, <varname>localdir</varname>, <varname>rsh</varname>. The <varname>module</varname> specifies which module to check out, the <varname>tag</varname> describes which CVS TAG should be used for the checkout by default the TAG is empty. A <varname>date</varname> can be specified to override the SRCDATE of the configuration to checkout a specific date. <varname>method</varname> is by default <emphasis>pserver</emphasis>, if <emphasis>ext</emphasis> is used the <varname>rsh</varname> parameter will be evaluated and <varname>CVS_RSH</varname> will be set. Finally <varname>localdir</varname> is used to checkout into a special directory relative to <varname>CVSDIR></varname>.
+<screen><varname>SRC_URI</varname> = "cvs://CVSROOT;module=mymodule;tag=some-version;method=ext"
+<varname>SRC_URI</varname> = "cvs://CVSROOT;module=mymodule;date=20060126;localdir=usethat"
+</screen>
+ </para>
+ </section>
+
+ <section>
+ <title>HTTP/FTP Fetcher</title>
+ <para>The URNs for the HTTP/FTP are <emphasis>http</emphasis>, <emphasis>https</emphasis> and <emphasis>ftp</emphasis>. This Fetcher honors the variables <varname>DL_DIR</varname>, <varname>FETCHCOMMAND_wget</varname>, <varname>PREMIRRORS</varname>, <varname>MIRRORS</varname>. The <varname>DL_DIR</varname> defines where to store the fetched file, <varname>FETCHCOMMAND</varname> contains the command used for fetching. <quote>${URI}</quote> and <quote>${FILES}</quote> will be replaced by the uri and basename of the to be fetched file. <varname>PREMIRRORS</varname>
+will be tried first when fetching a file if that fails the actual file will be tried and finally all <varname>MIRRORS</varname> will be tried.
+ </para>
+ <para>The only supported Parameter is <varname>md5sum</varname>. After a fetch the <varname>md5sum</varname> of the file will be calculated and the two sums will be compared.
+ </para>
+ <para><screen><varname>SRC_URI</varname> = "http://oe.handhelds.org/not_there.aac;md5sum=12343"
+<varname>SRC_URI</varname> = "ftp://oe.handhelds.org/not_there_as_well.aac;md5sum=1234"
+<varname>SRC_URI</varname> = "ftp://you@oe.handheld.sorg/home/you/secret.plan;md5sum=1234"
+</screen></para>
+ </section>
+
+ <section>
+ <title>SVK Fetcher</title>
+ <para>
+ <emphasis>Currently NOT suppoered</emphasis>
+ </para>
+ </section>
+
+ <section>
+ <title>SVN Fetcher</title>
+ <para>The URN for the SVN Fetcher is <emphasis>svn</emphasis>.
+ </para>
+ <para>The Variables <varname>FETCHCOMMAND_svn</varname>, <varname>DL_DIR</varname> are used by the SVN Fetcher. <varname>FETCHCOMMAND</varname> contains the subversion command, <varname>DL_DIR</varname> is the directory where tarballs will be saved.
+ </para>
+ <para>The supported Parameters are <varname>proto</varname>, <varname>rev</varname>. <varname>proto</varname> is the subversion prototype, <varname>rev</varname> is the subversions revision.
+ </para>
+ <para><screen><varname>SRC_URI</varname> = "svn://svn.oe.handhelds.org/svn;module=vip;proto=http;rev=667"
+<varname>SRC_URI</varname> = "svn://svn.oe.handhelds.org/svn/;module=opie;proto=svn+ssh;date=20060126"
+</screen></para>
</section>
+
<section>
- <title>bbmake</title>
- <para>test</para>
+ <title>GIT Fetcher</title>
+ <para>The URN for the GIT Fetcher is <emphasis>git</emphasis>.
+ </para>
+ <para>The Variables <varname>DL_DIR</varname>, <varname>GITDIR</varname> are used. <varname>DL_DIR</varname> will be used to store the checkedout version. <varname>GITDIR</varname> will be used as the base directory where the git tree is cloned to.
+ </para>
+ <para>The Parameters are <emphasis>tag</emphasis>, <emphasis>protocol</emphasis>. <emphasis>tag</emphasis> is a git tag, the default is <quote>master</quote>. <emphasis>protocol</emphasis> is the git protocol to use and defaults to <quote>rsync</quote>.
+ </para>
+ <para><screen><varname>SRC_URI</varname> = "git://git.oe.handhelds.org/git/vip.git;tag=version-1"
+<varname>SRC_URI</varname> = "git://git.oe.handhelds.org/git/vip.git;protocol=http"
+ </screen></para>
</section>
+
</chapter>
- <appendix>
- <title>Reference</title>
+
+
+ <chapter>
+ <title>Commands</title>
<section>
- <title>Required Metadata</title>
- <para>test</para>
+ <title>bbread</title>
+ <para>bbread is a command for displaying BitBake metadata. When run with no arguments, it has the core parse 'conf/bitbake.conf', as located in BBPATH, and displays that. If you supply a file on the commandline, such as a .bb, then it parses that afterwards, using the aforementioned configuration metadata.</para>
+ <para><emphasis>NOTE: the stand a lone bbread command was removed. Instead of bbread use bitbake -e.
+ </emphasis></para>
</section>
- </appendix>
+ <section>
+ <title>bitbake</title>
+ <section>
+ <title>Introduction</title>
+ <para>bitbake is the primary command in the system. It facilitates executing tasks in a single .bb file, or executing a given task on a set of multiple .bb files, accounting for interdependencies amongst them.</para>
+ </section>
+ <section>
+ <title>Usage and Syntax</title>
+ <para>
+ <screen><prompt>$ </prompt>bitbake --help
+usage: bitbake [options] [package ...]
+
+Executes the specified task (default is 'build') for a given set of BitBake files.
+It expects that BBFILES is defined, which is a space seperated list of files to
+be executed. BBFILES does support wildcards.
+Default BBFILES are the .bb files in the current directory.
+
+options:
+ --version show program's version number and exit
+ -h, --help show this help message and exit
+ -b BUILDFILE, --buildfile=BUILDFILE
+ execute the task against this .bb file, rather than a
+ package from BBFILES.
+ -k, --continue continue as much as possible after an error. While the
+ target that failed, and those that depend on it,
+ cannot be remade, the other dependencies of these
+ targets can be processed all the same.
+ -f, --force force run of specified cmd, regardless of stamp status
+ -i, --interactive drop into the interactive mode also called the BitBake
+ shell.
+ -c CMD, --cmd=CMD Specify task to execute. Note that this only executes
+ the specified task for the providee and the packages
+ it depends on, i.e. 'compile' does not implicitly call
+ stage for the dependencies (IOW: use only if you know
+ what you are doing). Depending on the base.bbclass a
+ listtaks tasks is defined and will show available
+ tasks
+ -r FILE, --read=FILE read the specified file before bitbake.conf
+ -v, --verbose output more chit-chat to the terminal
+ -D, --debug Increase the debug level. You can specify this more
+ than once.
+ -n, --dry-run don't execute, just go through the motions
+ -p, --parse-only quit after parsing the BB files (developers only)
+ -d, --disable-psyco disable using the psyco just-in-time compiler (not
+ recommended)
+ -s, --show-versions show current and preferred versions of all packages
+ -e, --environment show the global or per-package environment (this is
+ what used to be bbread)
+ -g, --graphviz emit the dependency trees of the specified packages in
+ the dot syntax
+ -I IGNORED_DOT_DEPS, --ignore-deps=IGNORED_DOT_DEPS
+ Stop processing at the given list of dependencies when
+ generating dependency graphs. This can help to make
+ the graph more appealing
+
+</screen>
+ </para>
+ <para>
+ <example>
+ <title>Executing a task against a single .bb</title>
+ <para>Executing tasks for a single file is relatively simple. You specify the file in question, and bitbake parses it and executes the specified task (or <quote>build</quote> by default). It obeys intertask dependencies when doing so.</para>
+ <para><quote>clean</quote> task:</para>
+ <para><screen><prompt>$ </prompt>bitbake -b blah_1.0.bb -c clean</screen></para>
+ <para><quote>build</quote> task:</para>
+ <para><screen><prompt>$ </prompt>bitbake -b blah_1.0.bb</screen></para>
+ </example>
+ </para>
+ <para>
+ <example>
+ <title>Executing tasks against a set of .bb files</title>
+ <para>There are a number of additional complexities introduced when one wants to manage multiple .bb files. Clearly there needs to be a way to tell bitbake what files are available, and of those, which we want to execute at this time. There also needs to be a way for each .bb to express its dependencies, both for build time and runtime. There must be a way for the user to express their preferences when multiple .bb's provide the same functionality, or when there are multiple versions of a .bb.</para>
+ <para>The next section, Metadata, outlines how one goes about specifying such things.</para>
+ <para>Note that the bitbake command, when not using --buildfile, accepts a <varname>PROVIDER</varname>, not a filename or anything else. By default, a .bb generally PROVIDES its packagename, packagename-version, and packagename-version-revision.</para>
+ <screen><prompt>$ </prompt>bitbake blah</screen>
+ <screen><prompt>$ </prompt>bitbake blah-1.0</screen>
+ <screen><prompt>$ </prompt>bitbake blah-1.0-r0</screen>
+ <screen><prompt>$ </prompt>bitbake -c clean blah</screen>
+ <screen><prompt>$ </prompt>bitbake virtual/whatever</screen>
+ <screen><prompt>$ </prompt>bitbake -c clean virtual/whatever</screen>
+ </example>
+ <example>
+ <title>Generating dependency graphs</title>
+ <para>BitBake is able to generate dependency graphs using the dot syntax. These graphs can be converted
+to images using the <application>dot</application> application from <ulink url="http://www.graphviz.org">graphviz</ulink>.
+Three files will be written into the current working directory, <emphasis>depends.dot</emphasis> containing <varname>DEPENDS</varname> variables, <emphasis>rdepends.dot</emphasis> containing <varname>RDEPENDS</varname> and <emphasis>alldepends.dot</emphasis> containing all depends. To stop depending on common depends one can use the <prompt>-I depend</prompt> to omit these from the graph. This can lead to more readable graphs.</para>
+ <screen><prompt>$ </prompt>bitbake -g blah</screen>
+ <screen><prompt>$ </prompt>bitbake -g -I virtual/whatever -I bloom blah</screen>
+ </example>
+ </para>
+ </section>
+ <section>
+ <title>Metadata</title>
+ <para>As you may have seen in the usage information, or in the information about .bb files, the BBFILES variable is how the bitbake tool locates its files. This variable is a space seperated list of files that are available, and supports wildcards.
+ <example>
+ <title>Setting BBFILES</title>
+ <programlisting><varname>BBFILES</varname> = "/path/to/bbfiles/*.bb"</programlisting>
+ </example></para>
+ <para>With regard to dependencies, it expects the .bb to define a <varname>DEPENDS</varname> variable, which contains a space seperated list of <quote>package names</quote>, which themselves are the <varname>PN</varname> variable. The <varname>PN</varname> variable is, in general, by default, set to a component of the .bb filename.</para>
+ <example>
+ <title>Depending on another .bb</title>
+ <para>a.bb:
+ <screen>PN = "package-a"
+DEPENDS += "package-b"</screen>
+ </para>
+ <para>b.bb:
+ <screen>PN = "package-b"</screen>
+ </para>
+ </example>
+ <example>
+ <title>Using PROVIDES</title>
+ <para>This example shows the usage of the PROVIDES variable, which allows a given .bb to specify what functionality it provides.</para>
+ <para>package1.bb:
+ <screen>PROVIDES += "virtual/package"</screen>
+ </para>
+ <para>package2.bb:
+ <screen>DEPENDS += "virtual/package"</screen>
+ </para>
+ <para>package3.bb:
+ <screen>PROVIDES += "virtual/package"</screen>
+ </para>
+ <para>As you can see, here there are two different .bb's that provide the same functionality (virtual/package). Clearly, there needs to be a way for the person running bitbake to control which of those providers gets used. There is, indeed, such a way.</para>
+ <para>The following would go into a .conf file, to select package1:
+ <screen>PREFERRED_PROVIDER_virtual/package = "package1"</screen>
+ </para>
+ </example>
+ <example>
+ <title>Specifying version preference</title>
+ <para>When there are multiple <quote>versions</quote> of a given package, bitbake defaults to selecting the most recent version, unless otherwise specified. If the .bb in question has a <varname>DEFAULT_PREFERENCE</varname> set lower than the other .bb's (default is 0), then it will not be selected. This allows the person or persons maintaining the repository of .bb files to specify their preferences for the default selected version. In addition, the user can specify their preferences with regard to version.</para>
+ <para>If the first .bb is named <filename>a_1.1.bb</filename>, then the <varname>PN</varname> variable will be set to <quote>a</quote>, and the <varname>PV</varname> variable will be set to 1.1.</para>
+ <para>If we then have an <filename>a_1.2.bb</filename>, bitbake will choose 1.2 by default. However, if we define the following variable in a .conf that bitbake parses, we can change that.
+ <screen>PREFERRED_VERSION_a = "1.1"</screen>
+ </para>
+ </example>
+ <example>
+ <title>Using <quote>bbfile collections</quote></title>
+ <para>bbfile collections exist to allow the user to have multiple repositories of bbfiles that contain the same exact package. For example, one could easily use them to make one's own local copy of an upstream repository, but with custom modifications that one does not want upstream. Usage:</para>
+ <screen>BBFILES = "/stuff/openembedded/*/*.bb /stuff/openembedded.modified/*/*.bb"
+BBFILE_COLLECTIONS = "upstream local"
+BBFILE_PATTERN_upstream = "^/stuff/openembedded/"
+BBFILE_PATTERN_local = "^/stuff/openembedded.modified/"
+BBFILE_PRIORITY_upstream = "5"
+BBFILE_PRIORITY_local = "10"</screen>
+ </example>
+ </section>
+ </section>
+ </chapter>
</book>
projects / vuplus_bitbake / blobdiff