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[<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] >

<chapter id='adt-prepare'>

<title>Preparing for Application Development</title>

<para>
    In order to develop applications, you need set up your host development system.
    Several ways exist that allow you to install cross-development tools, QEMU, the
    Eclipse Yocto Plug-in, and other tools.
    This chapter describes how to prepare for application development.
</para>

<section id='installing-the-adt'>
    <title>Installing the ADT and Toolchains</title>

    <para>
        The following list describes installation methods that set up varying degrees of tool
        availability on your system.
        Regardless of the installation method you choose,
        you must <filename>source</filename> the cross-toolchain
        environment setup script before you use a toolchain.
        See the "<link linkend='setting-up-the-cross-development-environment'>Setting Up the
        Cross-Development Environment</link>" section for more information.
    </para>

    <note>
        <para>Avoid mixing installation methods when installing toolchains for different architectures.
        For example, avoid using the ADT Installer to install some toolchains and then hand-installing
        cross-development toolchains by running the toolchain installer for different architectures.
        Mixing installation methods can result in situations where the ADT Installer becomes
        unreliable and might not install the toolchain.</para>
        <para>If you must mix installation methods, you might avoid problems by deleting
        <filename>/var/lib/opkg</filename>, thus purging the <filename>opkg</filename> package
        metadata</para>
    </note>

    <para>
        <itemizedlist>
            <listitem><para><emphasis>Use the ADT Installer Script:</emphasis>
                This method is the recommended way to install the ADT because it
                automates much of the process for you.
                For example, you can configure the installation to install the QEMU emulator
                and the user-space NFS, specify which root filesystem profiles to download,
                and define the target sysroot location.</para></listitem>
            <listitem><para><emphasis>Use an Existing Toolchain:</emphasis>
                Using this method, you select and download an architecture-specific
                toolchain installer and then run the script to hand-install the toolchain.
                If you use this method, you just get the cross-toolchain and QEMU - you do not
                get any of the other mentioned benefits had you run the ADT Installer script.</para></listitem>
            <listitem><para><emphasis>Use the Toolchain from within the Build Directory:</emphasis>
                If you already have a
                <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>,
                you can build the cross-toolchain within the directory.
                However, like the previous method mentioned, you only get the cross-toolchain and QEMU - you
                do not get any of the other benefits without taking separate steps.</para></listitem>
        </itemizedlist>
    </para>

    <section id='using-the-adt-installer'>
        <title>Using the ADT Installer</title>

        <para>
            To run the ADT Installer, you need to get the ADT Installer tarball, be sure
            you have the necessary host development packages that support the ADT Installer,
            and then run the ADT Installer Script.
        </para>

        <para>
            For a list of the host packages needed to support ADT installation and use, see the
            "ADT Installer Extras" lists in the
            "<ulink url='&YOCTO_DOCS_REF_URL;#required-packages-for-the-host-development-system'>Required Packages for the Host Development System</ulink>" section
            of the Yocto Project Reference Manual.
        </para>

        <section id='getting-the-adt-installer-tarball'>
            <title>Getting the ADT Installer Tarball</title>

            <para>
                The ADT Installer is contained in the ADT Installer tarball.
                You can download the tarball into any directory from the
                <ulink url='&YOCTO_DL_URL;/releases'>Index of Releases</ulink>, specifically
                at
                <ulink url='&YOCTO_ADTINSTALLER_DL_URL;'></ulink>.
                Or, you can use BitBake to generate the tarball inside the existing
                <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>.
            </para>

            <para>
                If you use BitBake to generate the ADT Installer tarball, you must
                <filename>source</filename> the environment setup script
                (<filename>&OE_INIT_FILE;</filename>) located
                in the Source Directory before running the <filename>bitbake</filename>
                command that creates the tarball.
            </para>

            <para>
                The following example commands download the Poky tarball, set up the
                <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>,
                set up the environment while also creating the default Build Directory,
                and run the <filename>bitbake</filename> command that results in the tarball
                <filename>~/yocto-project/build/tmp/deploy/sdk/adt_installer.tar.bz2</filename>:
                <literallayout class='monospaced'>
     $ cd ~
     $ mkdir yocto-project
     $ cd yocto-project
     $ wget &YOCTO_RELEASE_DL_URL;/&YOCTO_POKY_TARBALL;
     $ tar xjf &YOCTO_POKY_TARBALL;
     $ source &OE_INIT_PATH;
     $ bitbake adt-installer
                </literallayout>
            </para>
        </section>

        <section id='configuring-and-running-the-adt-installer-script'>
            <title>Configuring and Running the ADT Installer Script</title>

            <para>
                Before running the ADT Installer script, you need to unpack the tarball.
                You can unpack the tarball in any directory you wish.
                For example, this command copies the ADT Installer tarball from where
                it was built into the home directory and then unpacks the tarball into
                a top-level directory named <filename>adt-installer</filename>:
                <literallayout class='monospaced'>
     $ cd ~
     $ cp ~/poky/build/tmp/deploy/sdk/adt_installer.tar.bz2 $HOME
     $ tar -xjf adt_installer.tar.bz2
                </literallayout>
                Unpacking it creates the directory <filename>adt-installer</filename>,
                which contains the ADT Installer script (<filename>adt_installer</filename>)
                and its configuration file (<filename>adt_installer.conf</filename>).
            </para>

            <para>
                Before you run the script, however, you should examine the ADT Installer configuration
                file and be sure you are going to get what you want.
                Your configurations determine which kernel and filesystem image are downloaded.
            </para>

            <para>
                The following list describes the configurations you can define for the ADT Installer.
                For configuration values and restrictions, see the comments in
                the <filename>adt-installer.conf</filename> file:

                <itemizedlist>
                    <listitem><para><filename>YOCTOADT_REPO</filename>: This area
                        includes the IPKG-based packages and the root filesystem upon which
                        the installation is based.
                        If you want to set up your own IPKG repository pointed to by
                        <filename>YOCTOADT_REPO</filename>, you need to be sure that the
                        directory structure follows the same layout as the reference directory
                        set up at <ulink url='http://adtrepo.yoctoproject.org'></ulink>.
                        Also, your repository needs to be accessible through HTTP.</para></listitem>
                    <listitem><para><filename>YOCTOADT_TARGETS</filename>: The machine
                        target architectures for which you want to set up cross-development
                        environments.</para></listitem>
                    <listitem><para><filename>YOCTOADT_QEMU</filename>: Indicates whether
                        or not to install the emulator QEMU.</para></listitem>
                    <listitem><para><filename>YOCTOADT_NFS_UTIL</filename>: Indicates whether
                        or not to install user-mode NFS.
                        If you plan to use the Eclipse IDE Yocto plug-in against QEMU,
                        you should install NFS.
                        <note>To boot QEMU images using our userspace NFS server, you need
                            to be running <filename>portmap</filename> or <filename>rpcbind</filename>.
                            If you are running <filename>rpcbind</filename>, you will also need to add the
                            <filename>-i</filename> option when <filename>rpcbind</filename> starts up.
                            Please make sure you understand the security implications of doing this.
                            You might also have to modify your firewall settings to allow
                            NFS booting to work.</note></para></listitem>
                    <listitem><para><filename>YOCTOADT_ROOTFS_&lt;arch&gt;</filename>: The root
                        filesystem images you want to download from the
                        <filename>YOCTOADT_IPKG_REPO</filename> repository.</para></listitem>
                    <listitem><para><filename>YOCTOADT_TARGET_SYSROOT_IMAGE_&lt;arch&gt;</filename>: The
                        particular root filesystem used to extract and create the target sysroot.
                        The value of this variable must have been specified with
                        <filename>YOCTOADT_ROOTFS_&lt;arch&gt;</filename>.
                        For example, if you downloaded both <filename>minimal</filename> and
                        <filename>sato-sdk</filename> images by setting
                        <filename>YOCTOADT_ROOTFS_&lt;arch&gt;</filename>
                        to "minimal sato-sdk", then <filename>YOCTOADT_ROOTFS_&lt;arch&gt;</filename>
                        must be set to either <filename>minimal</filename> or
                        <filename>sato-sdk</filename>.</para></listitem>
                    <listitem><para><filename>YOCTOADT_TARGET_SYSROOT_LOC_&lt;arch&gt;</filename>: The
                        location on the development host where the target sysroot is created.
                        </para></listitem>
                </itemizedlist>
            </para>

            <para>
                After you have configured the <filename>adt_installer.conf</filename> file,
                run the installer using the following command.
                Be sure that you are not trying to use cross-compilation tools.
                When you run the installer, the environment must use a
                host <filename>gcc</filename>:
                <literallayout class='monospaced'>
     $ cd ~/adt-installer
     $ ./adt_installer
                </literallayout>
                Once the installer begins to run, you are asked to enter the
                location for cross-toolchain installation.
                The default location is
                <filename>/opt/poky/&lt;release&gt;</filename>.
                After either accepting the default location or selecting your
                own location, you are prompted to run the installation script
                interactively or in silent mode.
                If you want to closely monitor the installation,
                choose “I” for interactive mode rather than “S” for silent mode.
                Follow the prompts from the script to complete the installation.
            </para>

            <para>
                Once the installation completes, the ADT, which includes the
                cross-toolchain, is installed in the selected installation
                directory.
                You will notice environment setup files for the cross-toolchain
                in the installation directory, and image tarballs in the
                <filename>adt-installer</filename> directory according to your
                installer configurations, and the target sysroot located
                according to the
                <filename>YOCTOADT_TARGET_SYSROOT_LOC_&lt;arch&gt;</filename>
                variable also in your configuration file.
            </para>
         </section>
    </section>

    <section id='using-an-existing-toolchain-tarball'>
        <title>Using a Cross-Toolchain Tarball</title>

        <para>
            If you want to simply install the cross-toolchain by hand, you can
            do so by running the toolchain installer.
            If you use this method to install the cross-toolchain and you
            might still need to install the target sysroot by installing and
            extracting it separately.
            For information on how to install the sysroot, see the
            "<link linkend='extracting-the-root-filesystem'>Extracting the Root Filesystem</link>" section.
        </para>

        <para>
            Follow these steps:
            <orderedlist>
                <listitem><para>Go to
                    <ulink url='&YOCTO_TOOLCHAIN_DL_URL;'></ulink>
                    and find the folder that matches your host development system
                    (i.e. <filename>i686</filename> for 32-bit machines or
                    <filename>x86-64</filename> for 64-bit machines).</para></listitem>
                <listitem><para>Go into that folder and download the toolchain installer whose name
                    includes the appropriate target architecture.
                    For example, if your host development system is an Intel-based 64-bit system and
                    you are going to use your cross-toolchain for an Intel-based 32-bit target, go into the
                    <filename>x86_64</filename> folder and download the following installer:
                    <literallayout class='monospaced'>
     poky-eglibc-x86_64-i586-toolchain-gmae-&DISTRO;.sh
                    </literallayout>
                    <note><para>As an alternative to steps one and two, you can
                        build the toolchain installer if you have a
                        <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>.
                        If you need GMAE, you should use the
                        <filename>bitbake meta-toolchain-gmae</filename>
                        command.
                        Running the resulting installation script will support
                        such development.
                        If you are not concerned with GMAE, you can generate
                        the toolchain installer using
                        <filename>bitbake meta-toolchain</filename>.
                        Either of these methods requires you to still
                        install the target sysroot by installing and
                        extracting it separately.
                        For information on how to install the sysroot, see the
                        "<link linkend='extracting-the-root-filesystem'>Extracting the Root Filesystem</link>" section.
                        </para>
                        <para>A final method of building the toolchain installer
                        exists that has significant advantages over the previous
                        two methods.
                        This method results in a toolchain installer that
                        contains the sysroot that matches your target root
                        filesystem.
                        To build this installer, use the
                        <filename>bitbake image -c populate_sdk</filename>
                        command.</para>
                        <para>Remember, before using any
                        <filename>bitbake</filename> command, you must source
                        the <filename>&OE_INIT_PATH;</filename> script
                        located in the Source Directory and you must make sure
                        your <filename>conf/local.conf</filename> variables are
                        correct.
                        In particular, you need to be sure the
                        <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE'><filename>MACHINE</filename></ulink>
                        variable matches the architecture for which you are
                        building and that the <filename>SDKMACHINE</filename>
                        variable is correctly set if you are building
                        a toolchain for an architecture that differs from your
                        current development host machine.</para>
                        <para>When the <filename>bitbake</filename> command
                        completes, the toolchain installer will be in
                        <filename>tmp/deploy/sdk</filename> in the Build
                        Directory.</para>
                    </note></para></listitem>
                <listitem><para>Once you have the installer, run it to install the toolchain.
                    You must change the permissions on the toolchain installer
                    script so that it is executable.</para>
                    <para>The following command shows how to run the installer given a toolchain tarball
                    for a 64-bit development host system and a 32-bit target architecture.
                    The example assumes the toolchain installer is located in <filename>~/Downloads/</filename>.
                    <literallayout class='monospaced'>
     $ ~/Downloads/poky-eglibc-x86_64-i586-toolchain-gmae-&DISTRO;.sh
                    </literallayout>
                    <note>
                        If you do not have write permissions for the directory into which you are installing
                        the toolchain, the toolchain installer notifies you and exits.
                        Be sure you have write permissions in the directory and run the installer again.
                    </note>
                    Once the tarball is expanded, the cross-toolchain is installed.
                    You will notice environment setup files for the cross-toolchain in the directory.
                    </para></listitem>
            </orderedlist>
        </para>
    </section>

    <section id='using-the-toolchain-from-within-the-build-tree'>
        <title>Using BitBake and the Build Directory</title>

        <para>
            A final way of making the cross-toolchain available is to use BitBake
            to generate the toolchain within an existing
            <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>.
            This method does not install the toolchain into the
            <filename>/opt</filename> directory.
            As with the previous method, if you need to install the target sysroot, you must
            do that separately as well.
        </para>

        <para>
            Follow these steps to generate the toolchain into the Build Directory:
            <orderedlist>
                <listitem><para>Source the environment setup script
                    <filename>&OE_INIT_FILE;</filename> located in the
                    <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>.
                    </para></listitem>
                <listitem><para>At this point, you should be sure that the
                    <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE'><filename>MACHINE</filename></ulink> variable
                    in the <filename>local.conf</filename> file found in the
                    <filename>conf</filename> directory of the Build Directory
                    is set for the target architecture.
                    Comments within the <filename>local.conf</filename> file list the values you
                    can use for the <filename>MACHINE</filename> variable.
                    <note>You can populate the Build Directory with the cross-toolchains for more
                        than a single architecture.
                        You just need to edit the <filename>MACHINE</filename> variable in the
                        <filename>local.conf</filename> file and re-run the BitBake
                        command.</note></para></listitem>
                <listitem><para>Run <filename>bitbake meta-ide-support</filename> to complete the
                    cross-toolchain generation.
                    <note>If you change out of your working directory after you
                        <filename>source</filename> the environment setup script and before you run
                        the <filename>bitbake</filename> command, the command might not work.
                        Be sure to run the <filename>bitbake</filename> command immediately
                        after checking or editing the <filename>local.conf</filename> but without
                        changing out of your working directory.</note>
                    Once the <filename>bitbake</filename> command finishes,
                    the cross-toolchain is generated and populated within the Build Directory.
                    You will notice environment setup files for the cross-toolchain in the
                    Build Directory in the <filename>tmp</filename> directory.
                    Setup script filenames contain the strings <filename>environment-setup</filename>.</para>
                    <para>Be aware that when you use this method to install the toolchain you still need
                    to separately extract and install the sysroot filesystem.
                    For information on how to do this, see the
                    "<link linkend='extracting-the-root-filesystem'>Extracting the Root Filesystem</link>" section.
                    </para></listitem>
            </orderedlist>
        </para>
    </section>
</section>

<section id='setting-up-the-cross-development-environment'>
    <title>Setting Up the Cross-Development Environment</title>

    <para>
        Before you can develop using the cross-toolchain, you need to set up the
        cross-development environment by sourcing the toolchain's environment setup script.
        If you used the ADT Installer or hand-installed cross-toolchain,
        then you can find this script in the directory you chose for installation.
        The default installation directory is the <filename>&YOCTO_ADTPATH_DIR;</filename>
        directory.
        If you installed the toolchain in the
        <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>,
        you can find the environment setup
        script for the toolchain in the Build Directory's <filename>tmp</filename> directory.
    </para>

    <para>
        Be sure to run the environment setup script that matches the architecture for
        which you are developing.
        Environment setup scripts begin with the string “<filename>environment-setup</filename>”
        and include as part of their name the architecture.
        For example, the toolchain environment setup script for a 64-bit
        IA-based architecture installed in the default installation directory
        would be the following:
        <literallayout class='monospaced'>
     &YOCTO_ADTPATH_DIR;/environment-setup-x86_64-poky-linux
        </literallayout>
    </para>
</section>

<section id='securing-kernel-and-filesystem-images'>
    <title>Securing Kernel and Filesystem Images</title>

    <para>
        You will need to have a kernel and filesystem image to boot using your
        hardware or the QEMU emulator.
        Furthermore, if you plan on booting your image using NFS or you want to use the root filesystem
        as the target sysroot, you need to extract the root filesystem.
    </para>

    <section id='getting-the-images'>
        <title>Getting the Images</title>

        <para>
            To get the kernel and filesystem images, you either have to build them or download
            pre-built versions.
            You can find examples for both these situations in the
            "<ulink url='&YOCTO_DOCS_QS_URL;#test-run'>A Quick Test Run</ulink>" section of
            the Yocto Project Quick Start.
        </para>

        <para>
            The Yocto Project ships basic kernel and filesystem images for several
            architectures (<filename>x86</filename>, <filename>x86-64</filename>,
            <filename>mips</filename>, <filename>powerpc</filename>, and <filename>arm</filename>)
            that you can use unaltered in the QEMU emulator.
            These kernel images reside in the release
            area - <ulink url='&YOCTO_MACHINES_DL_URL;'></ulink>
            and are ideal for experimentation using Yocto Project.
            For information on the image types you can build using the OpenEmbedded build system,
            see the
            "<ulink url='&YOCTO_DOCS_REF_URL;#ref-images'>Images</ulink>" chapter in
            the Yocto Project Reference Manual.
        </para>

        <para>
            If you are planning on developing against your image and you are not
            building or using one of the Yocto Project development images
            (e.g. core-image-*-dev), you must be sure to include the development
            packages as part of your image recipe.
        </para>

        <para>
            Furthermore, if you plan on remotely deploying and debugging your
            application from within the
            Eclipse IDE, you must have an image that contains the Yocto Target Communication
            Framework (TCF) agent (<filename>tcf-agent</filename>).
            By default, the Yocto Project provides only one type pre-built image that contains the
            <filename>tcf-agent</filename>.
            And, those images are SDK (e.g.<filename>core-image-sato-sdk</filename>).
        </para>

        <para>
            If you want to use a different image type that contains the <filename>tcf-agent</filename>,
            you can do so one of two ways:
            <itemizedlist>
                <listitem><para>Modify the <filename>conf/local.conf</filename> configuration in
                    the <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>
                    and then rebuild the image.
                    With this method, you need to modify the
                    <ulink url='&YOCTO_DOCS_REF_URL;#var-EXTRA_IMAGE_FEATURES'><filename>EXTRA_IMAGE_FEATURES</filename></ulink>
                    variable to have the value of "tools-debug" before rebuilding the image.
                    Once the image is rebuilt, the <filename>tcf-agent</filename> will be included
                    in the image and is launched automatically after the boot.</para></listitem>
                <listitem><para>Manually build the <filename>tcf-agent</filename>.
                    To build the agent, follow these steps:
                    <orderedlist>
                        <listitem><para>Be sure the ADT is installed as described in the
                            "<link linkend='installing-the-adt'>Installing the ADT and Toolchains</link>" section.
                            </para></listitem>
                        <listitem><para>Set up the cross-development environment as described in the
                            "<link linkend='setting-up-the-cross-development-environment'>Setting
                            Up the Cross-Development Environment</link>" section.</para></listitem>
                        <listitem><para>Get the <filename>tcf-agent</filename> source code using
                            the following commands:
                            <literallayout class='monospaced'>
     $ git clone http://git.eclipse.org/gitroot/tcf/org.eclipse.tcf.agent.git
     $ cd agent
                            </literallayout></para></listitem>
                        <listitem><para>Modify the <filename>Makefile.inc</filename> file
                            for the cross-compilation environment by setting the
                            <filename>OPSYS</filename> and
                            <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE'><filename>MACHINE</filename></ulink>
                            variables according to your target.</para></listitem>
                        <listitem><para>Use the cross-development tools to build the
                            <filename>tcf-agent</filename>.
                            Before you "Make" the file, be sure your cross-tools are set up first.
                            See the "<link linkend='makefile-based-projects'>Makefile-Based Projects</link>"
                            section for information on how to make sure the cross-tools are set up
                            correctly.</para>
                            <para>If the build is successful, the <filename>tcf-agent</filename> output will
                            be <filename>obj/$(OPSYS)/$(MACHINE)/Debug/agent</filename>.</para></listitem>
                        <listitem><para>Deploy the agent into the image's root filesystem.</para></listitem>
                    </orderedlist>
                </para></listitem>
            </itemizedlist>
        </para>
    </section>

    <section id='extracting-the-root-filesystem'>
        <title>Extracting the Root Filesystem</title>

        <para>
            You must extract the root filesystem if you want to boot the image using NFS
            or you want to use the root filesystem as the target sysroot.
            For example, the Eclipse IDE environment with the Eclipse Yocto Plug-in installed allows you
            to use QEMU to boot under NFS.
            Another example is if you want to develop your target application using the
            root filesystem as the target sysroot.
        </para>

        <para>
            To extract the root filesystem, first <filename>source</filename>
            the cross-development environment setup script and then
            use the <filename>runqemu-extract-sdk</filename> command on the
            filesystem image.
            For example, the following commands set up the environment and then extract
            the root filesystem from a previously built filesystem image tarball named
            <filename>core-image-sato-sdk-qemux86-2011091411831.rootfs.tar.bz2</filename>.
            The example extracts the root filesystem into the <filename>$HOME/qemux86-sato</filename>
            directory:
            <literallayout class='monospaced'>
     $ source $HOME/toolchain_dir/environment-setup-i586-poky-linux
     $ runqemu-extract-sdk \
        ~Downloads/core-image-sato-sdk-qemux86-2011091411831.rootfs.tar.bz2 \
        $HOME/qemux86-sato
            </literallayout>
            In this case, you could now point to the target sysroot at
            <filename>$HOME/qemux86-sato</filename>.
        </para>
    </section>
</section>

</chapter>
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