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<chapter id='ref-tasks'>
<title>Tasks</title>

<para>
    Tasks are units of execution for BitBake.
    Recipes (<filename>.bb</filename> files) use tasks to complete
    configuring, compiling, and packaging software.
    This chapter provides a reference of the tasks defined in the
    OpenEmbedded build system.
</para>

<section id='normal-recipe-build-tasks'>
    <title>Normal Recipe Build Tasks</title>

    <para>
        The following sections describe normal tasks associated with building
        a recipe.
    </para>

    <section id='ref-tasks-build'>
        <title><filename>do_build</filename></title>

        <para>
            The default task for all recipes.
            This task depends on all other normal tasks
            required to build a recipe.
        </para>
    </section>

    <section id='ref-tasks-compile'>
        <title><filename>do_compile</filename></title>

        <para>
            Compiles the source in the compilation directory, which is pointed
            to by the
            <link linkend='var-B'><filename>B</filename></link> variable.
        </para>
    </section>

    <section id='ref-tasks-compile_ptest_base'>
        <title><filename>do_compile_ptest_base</filename></title>

        <para>
            Compiles the runtime test suite included in the software being
            built.
        </para>
    </section>

    <section id='ref-tasks-configure'>
        <title><filename>do_configure</filename></title>

        <para>
            Configures the source by enabling and disabling any build-time and
            configuration options for the software being built.
        </para>
    </section>

    <section id='ref-tasks-configure_ptest_base'>
        <title><filename>do_configure_ptest_base</filename></title>

        <para>
            Configures the runtime test suite included in the software being
            built.
        </para>
    </section>

    <section id='ref-tasks-deploy'>
        <title><filename>do_deploy</filename></title>

        <para>
            Writes output files that are to be deployed to the deploy
            directory, which is defined by the
            <link linkend='var-DEPLOYDIR'><filename>DEPLOYDIR</filename></link>
            variable.
        </para>

        <para>
            The <filename>do_deploy</filename> task is a
            shared state (sstate) task, which means that the task can
            be accelerated through sstate use.
            Realize also that if the task is re-executed, any previous output
            is removed (i.e. "cleaned").
        </para>
    </section>

    <section id='ref-tasks-fetch'>
        <title><filename>do_fetch</filename></title>

        <para>
            Fetches the source code.
            This task uses the
            <link linkend='var-SRC_URI'><filename>SRC_URI</filename></link>
            variable and the argument's prefix to determine the correct
            fetcher module.
        </para>
    </section>

    <section id='ref-tasks-install'>
        <title><filename>do_install</filename></title>

        <para>
            Copies files from the compilation directory, which is defined by
            the
            <link linkend='var-B'><filename>B</filename></link> variable,
            to a holding area defined by the
            <link linkend='var-D'><filename>D</filename></link> variable.
        </para>
    </section>

    <section id='ref-tasks-install_ptest_base'>
        <title><filename>do_install_ptest_base</filename></title>

        <para>
            Copies the runtime test suite files from the compilation directory
            to a holding area.
        </para>
    </section>

    <section id='ref-tasks-package'>
        <title><filename>do_package</filename></title>

        <para>
            Analyzes the content of the holding area and splits it into subsets
            based on available packages and files.
        </para>
    </section>

    <section id='ref-tasks-package_write_deb'>
        <title><filename>do_package_write_deb</filename></title>

        <para>
            Creates the actual DEB packages and places them in the
            <link linkend='package-feeds-dev-environment'>Package Feeds</link>
            area.
        </para>
    </section>

    <section id='ref-tasks-package_write_ipk'>
        <title><filename>do_package_write_ipk</filename></title>

        <para>
            Creates the actual IPK packages and places them in the
            <link linkend='package-feeds-dev-environment'>Package Feeds</link>
            area.
        </para>
    </section>

    <section id='ref-tasks-package_write_rpm'>
        <title><filename>do_package_write_rpm</filename></title>

        <para>
            Creates the actual RPM packages and places them in the
            <link linkend='package-feeds-dev-environment'>Package Feeds</link>
            area.
        </para>
    </section>

    <section id='ref-tasks-package_write_tar'>
        <title><filename>do_package_write_tar</filename></title>

        <para>
            Creates tar archives for packages and places them in the
            <link linkend='package-feeds-dev-environment'>Package Feeds</link>
            area.
        </para>
    </section>

    <section id='ref-tasks-packagedata'>
        <title><filename>do_packagedata</filename></title>

        <para>
            Creates package metadata used by the build system to generate the
            final packages.
        </para>
    </section>

    <section id='ref-tasks-patch'>
        <title><filename>do_patch</filename></title>

        <para>
            Locates patch files and applies them to the source code.
            See the
            "<link linkend='patching-dev-environment'>Patching</link>"
            section for more information.
        </para>
    </section>

    <section id='ref-tasks-populate_lic'>
        <title><filename>do_populate_lic</filename></title>

        <para>
            Writes license information for the recipe that is collected later
            when the image is constructed.
        </para>
    </section>

    <section id='ref-tasks-populate_sdk'>
        <title><filename>do_populate_sdk</filename></title>

        <para>
            Creates the file and directory structure for an installable SDK.
            See the
            "<link linkend='sdk-generation-dev-environment'>SDK Generation</link>"
            section for more information.
        </para>
    </section>

    <section id='ref-tasks-populate_sysroot'>
        <title><filename>do_populate_sysroot</filename></title>

        <para>
            Copies a subset of files installed by the
            <link linkend='ref-tasks-install'><filename>do_install</filename></link>
            task into the sysroot in order to make them available to other
            recipes.
        </para>

        <para>
            The <filename>do_populate_sysroot</filename> task is a
            shared state (sstate) task, which means that the task can
            be accelerated through sstate use.
            Realize also that if the task is re-executed, any previous output
            is removed (i.e. "cleaned").
        </para>
    </section>

    <section id='ref-tasks-rm_work'>
        <title><filename>do_rm_work</filename></title>

        <para>
            Removes work files after the OpenEmbedded build system has
            finished with them.
            You can learn more by looking at the
            "<link linkend='ref-classes-rm-work'><filename>rm_work.bbclass</filename></link>"
            section.
        </para>
    </section>

    <section id='ref-tasks-rm_work_all'>
        <title><filename>do_rm_work_all</filename></title>

        <para>
            Top-level task for removing work files after the build system has
            finished with them.
        </para>
    </section>

    <section id='ref-tasks-unpack'>
        <title><filename>do_unpack</filename></title>

        <para>
            Unpacks the source code into a working directory pointed to
            by
            <filename>${</filename><link linkend='var-WORKDIR'><filename>WORKDIR</filename></link><filename>}</filename>.
            The
            <link linkend='var-S'><filename>S</filename></link> variable also
            plays a role in where unpacked source files ultimately reside.
            For more information on how source files are unpacked, see the
            "<link linkend='source-fetching-dev-environment'>Source Fetching</link>"
            section and the <filename>WORKDIR</filename> and
            <filename>S</filename> variable descriptions.
        </para>
    </section>
</section>

<section id='manually-called-tasks'>
    <title>Manually Called Tasks</title>

    <para>
        These tasks are typically manually triggered (e.g. by using the
        <filename>bitbake -c</filename> command-line option):
    </para>

    <section id='ref-tasks-checkuri'>
        <title><filename>do_checkuri</filename></title>

        <para>
            Validates the
            <link linkend='var-SRC_URI'><filename>SRC_URI</filename></link>
            value.
        </para>
    </section>

    <section id='ref-tasks-checkuriall'>
        <title><filename>do_checkuriall</filename></title>

        <para>
            Validates the
            <link linkend='var-SRC_URI'><filename>SRC_URI</filename></link>
            value for all recipes required to build a target.
        </para>
    </section>

    <section id='ref-tasks-clean'>
        <title><filename>do_clean</filename></title>

        <para>
            Removes all output files for a target from the
            <link linkend='ref-tasks-unpack'><filename>do_unpack</filename></link>
            task forward (i.e.
            <link linkend='ref-tasks-patch'><filename>do_unpack</filename></link>,
            <link linkend='ref-tasks-configure'><filename>do_configure</filename></link>,
            <link linkend='ref-tasks-compile'><filename>do_compile</filename></link>,
            <link linkend='ref-tasks-install'><filename>do_install</filename></link>,
            and
            <link linkend='ref-tasks-package'><filename>do_package</filename></link>).
        </para>

        <para>
            You can run this task using BitBake as follows:
            <literallayout class='monospaced'>
     $ bitbake -c clean &lt;recipe&gt;
            </literallayout>
        </para>

        <para>
            Running this task does not remove the
            <link linkend='shared-state-cache'>sstate</link>) cache
            files.
            Consequently, if no changes have been made and the recipe is
            rebuilt after cleaning, output files are simply restored from the
            sstate cache.
            If you want to remove the sstate cache files for the recipe,
            you need to use the
            <link linkend='ref-tasks-cleansstate'><filename>do_cleansstate</filename></link>
            task instead (i.e. <filename>bitbake -c cleansstate &lt;recipe&gt;</filename>).
        </para>
    </section>

    <section id='ref-tasks-cleanall'>
        <title><filename>do_cleanall</filename></title>

        <para>
            Removes all output files, shared state
            (<link linkend='shared-state-cache'>sstate</link>) cache, and
            downloaded source files for a target (i.e. the contents of
            <link linkend='var-DL_DIR'><filename>DL_DIR</filename></link>).
            Essentially, the <filename>do_cleanall</filename> task is
            identical to the
            <link linkend='ref-tasks-cleansstate'><filename>do_cleansstate</filename></link>
            task with the added removal of downloaded source files.
        </para>

        <para>
            You can run this task using BitBake as follows:
            <literallayout class='monospaced'>
     $ bitbake -c cleanall &lt;recipe&gt;
            </literallayout>
        </para>

        <para>
            Typically, you would not normally use the
            <filename>cleanall</filename> task.
            Do so only if you want to start fresh with the
            <link linkend='ref-tasks-fetch'><filename>do_fetch</filename></link>
            task.
        </para>
    </section>

    <section id='ref-tasks-cleansstate'>
        <title><filename>do_cleansstate</filename></title>

        <para>
            Removes all output files and shared state
            (<link linkend='shared-state-cache'>sstate</link>)
            cache for a target.
            Essentially, the <filename>do_cleansstate</filename> task is
            identical to the
            <link linkend='ref-tasks-clean'><filename>do_clean</filename></link>
            task with the added removal of shared state
            (<link linkend='shared-state-cache'>sstate</link>) cache.
        </para>

        <para>
            You can run this task using BitBake as follows:
            <literallayout class='monospaced'>
     $ bitbake -c cleansstate &lt;recipe&gt;
            </literallayout>
        </para>

        <para>
            When you run the <filename>do_cleansstate</filename> task,
            the OpenEmbedded build system no longer uses any
            sstate.
            Consequently, building the recipe from scratch is guaranteed.
            <note>
                The <filename>do_cleansstate</filename> task cannot remove
                sstate from a remote sstate mirror.
                If you need to build a target from scratch using remote
                mirrors, use the "-f" option as follows:
                <literallayout class='monospaced'>
     $ bitbake -f -c do_cleansstate &lt;target&gt;
                </literallayout>
            </note>
        </para>
     </section>

    <section id='ref-tasks-devshell'>
        <title><filename>do_devshell</filename></title>

        <para>
            Starts a shell whose environment is set up for
            development, debugging, or both.
            See the
            "<ulink url='&YOCTO_DOCS_DEV_URL;#platdev-appdev-devshell'>Using a Development Shell</ulink>"
            section in the Yocto Project Development Manual for more
            information about using <filename>devshell</filename>.
        </para>
    </section>

    <section id='ref-tasks-fetchall'>
        <title><filename>do_fetchall</filename></title>

        <para>
            Fetches all remote sources required to build a target.
        </para>
    </section>

    <section id='ref-tasks-listtasks'>
        <title><filename>do_listtasks</filename></title>

        <para>
            Lists all defined tasks for a target.
        </para>
    </section>

    <section id='ref-tasks-package_index'>
        <title><filename>do_package_index</filename></title>

        <para>
            Creates or updates the index in the
            <link linkend='package-feeds-dev-environment'>Package Feeds</link>
            area.
            <note>
                This task is not triggered with the
                <filename>bitbake -c</filename> command-line option as
                are the other tasks in this section.
                Because this task is specifically for the
                <filename>package-index</filename> recipe,
                you run it using
                <filename>bitbake package-index</filename>.
            </note>
        </para>
    </section>
</section>

<section id='image-related-tasks'>
    <title>Image-Related Tasks</title>

    <para>
        The following tasks are applicable to image recipes.
    </para>

    <section id='ref-tasks-bootimg'>
        <title><filename>do_bootimg</filename></title>

        <para>
            Creates a bootable live image.
            See the
            <link linkend='var-IMAGE_FSTYPES'><filename>IMAGE_FSTYPES</filename></link>
            variable for additional information on live image types.
        </para>
    </section>

    <section id='ref-tasks-bundle_initramfs'>
        <title><filename>do_bundle_initramfs</filename></title>

        <para>
            Combines an initial RAM disk (initramfs) image and kernel
            together to form a single image.
            The
            <link linkend='var-CONFIG_INITRAMFS_SOURCE'><filename>CONFIG_INITRAMFS_SOURCE</filename></link>
            variable has some more information about these types of images.
        </para>
    </section>

    <section id='ref-tasks-rootfs'>
        <title><filename>do_rootfs</filename></title>

        <para>
            Creates the root filesystem (file and directory structure) for an
            image.
            See the
            "<link linkend='image-generation-dev-environment'>Image Generation</link>"
            section for more information on how the root filesystem is created.
        </para>
    </section>

    <section id='ref-tasks-testimage'>
        <title><filename>do_testimage</filename></title>

        <para>
            Boots an image and performs runtime tests within the image.
            For information on automatically testing images, see the
            "<ulink url='&YOCTO_DOCS_DEV_URL;#performing-automated-runtime-testing'>Performing Automated Runtime Testing</ulink>"
            section in the Yocto Project Development Manual.
        </para>
    </section>

    <section id='ref-tasks-testimage_auto'>
        <title><filename>do_testimage_auto</filename></title>

        <para>
            Boots an image and performs runtime tests within the image
            immediately after it has been built.
            This task is enabled when you set
            <link linkend='var-TEST_IMAGE'><filename>TEST_IMAGE</filename></link>
            equal to "1".
        </para>

        <para>
            For information on automatically testing images, see the
            "<ulink url='&YOCTO_DOCS_DEV_URL;#performing-automated-runtime-testing'>Performing Automated Runtime Testing</ulink>"
            section in the Yocto Project Development Manual.
        </para>
    </section>

    <section id='ref-tasks-vmdkimg'>
        <title><filename>do_vmdkimg</filename></title>

        <para>
            Creates a <filename>.vmdk</filename> image for use with
            <ulink url='http://www.vmware.com/'>VMware</ulink>
            and compatible virtual machine hosts.
        </para>
    </section>
</section>

<section id='kernel-related-tasks'>
    <title>Kernel-Related Tasks</title>

    <para>
        The following tasks are applicable to kernel recipes.
        Some of these tasks (e.g. the
        <link linkend='ref-tasks-menuconfig'><filename>do_menuconfig</filename></link>
        task) are also applicable to recipes that use
        Linux kernel style configuration such as the BusyBox recipe.
    </para>

    <section id='ref-tasks-compile_kernelmodules'>
        <title><filename>do_compile_kernelmodules</filename></title>

        <para>
            Compiles loadable modules for the Linux kernel.
        </para>
    </section>

    <section id='ref-tasks-diffconfig'>
        <title><filename>do_diffconfig</filename></title>

        <para>
            Compares the old and new config files after running the
            <link linkend='ref-tasks-menuconfig'><filename>do_menuconfig</filename></link>
            task for the kernel.
        </para>
    </section>

    <section id='ref-tasks-kernel_checkout'>
        <title><filename>do_kernel_checkout</filename></title>

        <para>
            Checks out source/meta branches for a linux-yocto style kernel.
        </para>
    </section>

    <section id='ref-tasks-kernel_configcheck'>
        <title><filename>do_kernel_configcheck</filename></title>

        <para>
            Validates the kernel configuration for a linux-yocto style kernel.
        </para>
    </section>

    <section id='ref-tasks-kernel_configme'>
        <title><filename>do_kernel_configme</filename></title>

        <para>
            Assembles the kernel configuration for a linux-yocto style kernel.
        </para>
    </section>

    <section id='ref-tasks-kernel_link_vmlinux'>
        <title><filename>do_kernel_link_vmlinux</filename></title>

        <para>
            Creates a symbolic link in
            <filename>arch/$arch/boot</filename> for vmlinux kernel
            images.
        </para>
    </section>

    <section id='ref-tasks-menuconfig'>
        <title><filename>do_menuconfig</filename></title>

        <para>
            Runs <filename>make menuconfig</filename> for the kernel.
            For information on <filename>menuconfig</filename>, see the
            "<ulink url='&YOCTO_DOCS_DEV_URL;#using-menuconfig'>Using&nbsp;&nbsp;<filename>menuconfig</filename></ulink>"
            section in the Yocto Project Development Manual.
        </para>
    </section>

    <section id='ref-tasks-savedefconfig'>
        <title><filename>do_savedefconfig</filename></title>

        <para>
            Creates a minimal Linux kernel configuration file.
        </para>
    </section>

    <section id='ref-tasks-sizecheck'>
        <title><filename>do_sizecheck</filename></title>

        <para>
            Checks the size of the kernel image against
            <filename>KERNEL_IMAGE_MAXSIZE</filename> when set.
        </para>
    </section>

    <section id='ref-tasks-strip'>
        <title><filename>do_strip</filename></title>

        <para>
            Strips unneeded sections out of the Linux kernel image.
        </para>
    </section>

    <section id='ref-tasks-uboot_mkimage'>
        <title><filename>do_uboot_mkimage</filename></title>

        <para>
            Creates a uImage file from the kernel for the U-Boot bootloader.
        </para>
    </section>

    <section id='ref-tasks-validate_branches'>
        <title><filename>do_validate_branches</filename></title>

        <para>
            Ensures that the source, metadata (or both) branches are on the
            locations specified by their
            <link linkend='var-SRCREV'><filename>SRCREV</filename></link>
            values for a linux-yocto style kernel.
        </para>
    </section>
</section>

<section id='miscellaneous-tasks'>
    <title>Miscellaneous Tasks</title>

    <para>
        The following sections describe miscellaneous tasks.
    </para>

    <section id='ref-tasks-generate_qt_config_file'>
        <title><filename>do_generate_qt_config_file</filename></title>

        <para>
            Writes a <filename>qt.conf</filename> configuration
            file used for building a Qt-based application.
        </para>
    </section>

    <section id='ref-tasks-spdx'>
        <title><filename>do_spdx</filename></title>

        <para>
            A build stage that takes the source code and scans it on a remote
            FOSSOLOGY server in order to produce an SPDX document.
            This task applies only to the
            <link linkend='ref-classes-spdx'><filename>spdx</filename></link>
            class.
        </para>
    </section>
</section>

</chapter>
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