1 files changed, 334 insertions, 0 deletions

diff --git a/bitbake/doc/bitbake-user-manual/bitbake-user-manual-hello.xml b/bitbake/doc/bitbake-user-manual/bitbake-user-manual-hello.xml
new file mode 100644
index 0000000000..3215e49a28
--- /dev/null
+++ b/bitbake/doc/bitbake-user-manual/bitbake-user-manual-hello.xml
@@ -0,0 +1,334 @@
+<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+
+<appendix id='hello-world-example'>
+    <title>Hello World Example</title>
+
+    <section id='bitbake-hello-world'>
+        <title>BitBake Hello World</title>
+
+        <para>
+            The simplest example commonly used to demonstrate any new
+            programming language or tool is the
+            <ulink url="http://en.wikipedia.org/wiki/Hello_world_program">Hello World</ulink>
+            example.
+            This appendix demonstrates, in tutorial form, Hello
+            World within the context of BitBake.
+            The tutorial describes how to create a new Project
+            and the applicable metadata files necessary to allow
+            BitBake to build it.
+        </para>
+    </section>
+
+    <section id='example-obtaining-bitbake'>
+        <title>Obtaining BitBake</title>
+
+        <para>
+            See the
+            "<link linkend='obtaining-bitbake'>Obtaining BitBake</link>"
+            section for information on how to obtain BitBake.
+            Once you have the source code on your machine, the BitBake directory
+            appears as follows:
+            <literallayout class='monospaced'>
+     $ ls -al
+     total 100
+     drwxrwxr-x. 9 wmat wmat  4096 Jan 31 13:44 .
+     drwxrwxr-x. 3 wmat wmat  4096 Feb  4 10:45 ..
+     -rw-rw-r--. 1 wmat wmat   365 Nov 26 04:55 AUTHORS
+     drwxrwxr-x. 2 wmat wmat  4096 Nov 26 04:55 bin
+     drwxrwxr-x. 4 wmat wmat  4096 Jan 31 13:44 build
+     -rw-rw-r--. 1 wmat wmat 16501 Nov 26 04:55 ChangeLog
+     drwxrwxr-x. 2 wmat wmat  4096 Nov 26 04:55 classes
+     drwxrwxr-x. 2 wmat wmat  4096 Nov 26 04:55 conf
+     drwxrwxr-x. 3 wmat wmat  4096 Nov 26 04:55 contrib
+     -rw-rw-r--. 1 wmat wmat 17987 Nov 26 04:55 COPYING
+     drwxrwxr-x. 3 wmat wmat  4096 Nov 26 04:55 doc
+     -rw-rw-r--. 1 wmat wmat    69 Nov 26 04:55 .gitignore
+     -rw-rw-r--. 1 wmat wmat   849 Nov 26 04:55 HEADER
+     drwxrwxr-x. 5 wmat wmat  4096 Jan 31 13:44 lib
+     -rw-rw-r--. 1 wmat wmat   195 Nov 26 04:55 MANIFEST.in
+     -rwxrwxr-x. 1 wmat wmat  3195 Jan 31 11:57 setup.py
+     -rw-rw-r--. 1 wmat wmat  2887 Nov 26 04:55 TODO
+            </literallayout>
+        </para>
+
+        <para>
+            At this point, you should have BitBake cloned to
+            a directory that matches the previous listing except for
+            dates and user names.
+        </para>
+    </section>
+
+    <section id='setting-up-the-bitbake-environment'>
+        <title>Setting Up the BitBake Environment</title>
+
+        <para>
+            The recommended method to run BitBake is from a directory of your
+            choice.
+            The directory can be within your home directory or in
+            <filename>/usr/local</filename>,
+            depending on your preference.
+        </para>
+
+        <para>
+            First, run BitBake to make sure it's working.
+            From the BitBake source code directory, issue the following command:
+            <literallayout class='monospaced'>
+     $ ./bin/bitbake --version
+     BitBake Build Tool Core version 1.19.0, bitbake version
+     1.19.0
+            </literallayout>
+            You are now ready to use BitBake.
+        </para>
+
+        <para>
+            A final step to make development easier is to add the executable
+            binary to your environment <filename>PATH</filename>.
+            First, look at your current <filename>PATH</filename> variable
+            by entering the following:
+            <literallayout class='monospaced'>
+     $ echo $PATH
+            </literallayout>
+            Next, add the directory location for the BitBake binary to the
+            <filename>PATH</filename> using this form:
+            <literallayout class='monospaced'>
+     $ export PATH=&lt;path-to-bitbake-executable&gt;:$PATH
+            </literallayout>
+            This will add the directory to the beginning of your
+            <filename>PATH</filename> environment variable.
+            You should now be able to enter the <filename>bitbake</filename>
+            command at the command line to run BitBake.
+        </para>
+
+        <para>
+            For a more permanent solution assuming you are running the BASH
+            shell, edit <filename>~/.bashrc</filename> and add the following to the end
+            of that file:
+            <literallayout class='monospaced'>
+     PATH=&lt;path-to-bitbake-executable&gt;:$PATH
+            </literallayout>
+        </para>
+
+        <para>
+            If you're a Vim user, you will find useful
+            Vim configuration contributions in the
+            <filename>contrib/vim</filename> directory.
+            Copy the files from that directory to your
+            <filename>/home/yourusername/.vim</filename>
+            directory.
+            If that directory does not exist, create it, and then
+            restart Vim.
+        </para>
+    </section>
+
+    <section id='the-hello-world-example'>
+        <title>The Hello World Example</title>
+
+        <para>
+            The following example leaps directly into how BitBake
+            works.
+            While every attempt is made to explain what is happening,
+            not everything can be covered.
+            You can find further information in the
+            "<link linkend='bitbake-user-manual-metadata'>Syntax and Operators</link>"
+            chapter.
+        </para>
+
+        <para>
+            The overall goal of this exercise is to build a
+            complete "Hello World" example utilizing task and layer
+            concepts.
+            This is how modern projects such as OpenEmbedded and
+            the Yocto Project utilize BitBake, therefore it
+            provides an excellent starting point for understanding
+            BitBake.
+        </para>
+
+        <para>
+            It should be noted that this chapter was inspired by
+            and draws heavily from several sources:
+            <itemizedlist>
+                <listitem><para>
+                    <ulink href="http://www.mail-archive.com/yocto@yoctoproject.org/msg09379.html">Mailing List post - The BitBake equivalent of "Hello, World!"</ulink>
+                    </para></listitem>
+                <listitem><para>
+                    <ulink href="http://hambedded.org/blog/2012/11/24/from-bitbake-hello-world-to-an-image/">Hambedded Linux blog post - From Bitbake Hello World to an Image</ulink>
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+
+        <section id='a-reverse-walk-through'>
+            <title>A Reverse Walk-Through</title>
+
+            <para>
+                A good way to understand anything is to walk through the steps
+                that take you to where you want to be and observe first
+                principles.
+                BitBake allows us to do this through the
+                <filename>-D</filename> or <filename>Debug</filename>
+                command-line parameter.
+            </para>
+
+            <para>
+                The goal is to eventually compile a "Hello World" example.
+                However, it is unknown what is needed to achieve that goal.
+                Recall that BitBake utilizes three types of metadata files:
+                <link linkend='configuration-files'>Configuration Files</link>,
+                <link linkend='classes'>Classes</link>, and
+                <link linkend='recipes'>Recipes</link>.
+                But where do they go?
+                How does BitBake find them?
+                BitBake's error messaging helps you answer these types of questions
+                and helps you better understand exactly what is going on.
+            </para>
+
+            <para>
+                First, set up a directory for the "Hello World" project.
+                Here is how you can do so in your home directory:
+                <literallayout class='monospaced'>
+     $ mkdir ~/dev/hello &amp;&amp; cd ~/dev/hello
+                </literallayout>
+                Within this new, empty directory, run BitBake with
+                debugging output and see what happens:
+                <literallayout class='monospaced'>
+     $ bitbake -DDD
+     The BBPATH variable is not set
+     DEBUG: Removed the following variables from the environment:
+     GNOME_DESKTOP_SESSION_ID, LESSOPEN, WINDOWID,
+     GNOME_KEYRING_CONTROL, DISPLAY, SSH_AGENT_PID, LANG,
+     XDG_SESSION_PATH, XAUTHORITY, LANGUAGE, SESSION_MANAGER,
+     SHLVL, MANDATORY_PATH, COMPIZ_CONFIG_PROFILE, TEXTDOMAIN,
+     GPG_AGENT_INFO, SSH_AUTH_SOCK, XDG_RUNTIME_DIR,
+     COMPIZ_BIN_PATH, GDMSESSION, DEFAULTS_PATH, TEXTDOMAINDIR,
+     XDG_SEAT_PATH, XDG_CONFIG_DIRS, XDG_CURRENT_DESKTOP,
+     DBUS_SESSION_BUS_ADDRESS, _, XDG_SESSION_COOKIE,
+     DESKTOP_SESSION, LESSCLOSE, GNOME_KEYRING_PID,
+     UBUNTU_MENUPROXY, OLDPWD, GTK_MODULES, XDG_DATA_DIRS,
+     COLORTERM, LS_COLORS
+                </literallayout>
+                The majority of this output is specific to environment variables
+                that are not directly relevant to BitBake.
+                However, the very first message
+                "<filename>The BBPATH variable is not set</filename>"
+                is relevant and you need to rectify it by setting
+                <link linkend='var-BBPATH'><filename>BBPATH</filename></link>.
+            </para>
+
+            <para>
+                When you run BitBake, it begins looking for metadata files.
+                The <filename>BBPATH</filename> variable is what tells
+                BitBake where to look.
+                You could set <filename>BBPATH</filename> in the same manner
+                that you set <filename>PATH</filename> as shown earlier.
+                However, it is much more flexible to set the
+                <link linkend='var-BBPATH'><filename>BBPATH</filename></link>
+                variable for each project.
+            </para>
+
+            <para>
+                Without <filename>BBPATH</filename>, Bitbake cannot
+                find any configuration files (<filename>.conf</filename>)
+                or recipe files (<filename>.bb</filename>) at all.
+                BitBake also cannot find the <filename>bitbake.conf</filename>
+                file.
+            </para>
+
+            <para>
+                It is standard practice to organize the project's directory tree
+                to include both a <filename>conf/</filename> and
+                <filename>classes/</filename> directory.
+                You need to add those directories to your project:
+                <literallayout class='monospaced'>
+     $ mkdir conf classes
+                </literallayout>
+                Once those directories are in place, you can copy the
+                sample configuration files provided in the
+                BitBake source tree to their appropriate directories.
+                First, change to the BitBake source tree directory and
+                then copy the directories:
+                <literallayout class='monospaced'>
+     cp conf/bitbake.conf ~/dev/hello/conf/
+     cp classes/base.bbclass ~/dev/hello/classes/
+                </literallayout>
+                At this point your project directory structure should look like
+                the following:
+               <literallayout class='monospaced'>
+     ~/dev/hello$ tree
+     .
+     |-- classes
+     |   +-- base.bbclass
+     +-- conf
+     +-- bitbake.conf
+                </literallayout>
+            </para>
+
+            <para>
+                Once you have copied these files into your project, you
+                can now get back to resolving the <filename>BBPATH</filename>
+                issue.
+            </para>
+
+            <para>
+                The first configuration file that BitBake looks for is always
+                <filename>bblayers.conf</filename>.
+                With this knowledge, you know that to resolve your
+                <filename>BBPATH</filename> error you can add a
+                <filename>conf/bblayers.conf</filename> file to the
+                project source tree and populate it with the
+                <filename>BBPATH</filename> variable declaration.
+            </para>
+
+            <para>
+                From your project source tree:
+                <literallayout class='monospaced'>
+     $ vim conf/bblayers.conf
+                </literallayout>
+                Now add the following to the empty
+                <filename>bblayers.conf</filename> file:
+                <literallayout class='monospaced'>
+     BBPATH := "${TOPDIR}"
+                </literallayout>
+            </para>
+
+            <para>
+                Now, from the root of your project directory, run BitBake
+                again and see what happens:
+                <literallayout class='monospaced'>
+     $ bitbake -DDD
+     Nothing to do.  Use 'bitbake world' to build everything, or run
+     'bitbake --help' for usage information.
+     DEBUG: Removed the following variables from the environment:
+     GNOME_DESKTOP_SESSION_ID, LESSOPEN, WINDOWID,
+     GNOME_KEYRING_CONTROL, DISPLAY, SSH_AGENT_PID, LANG,
+     XDG_SESSION_PATH, XAUTHORITY, LANGUAGE, SESSION_MANAGER,
+     SHLVL, MANDATORY_PATH, COMPIZ_CONFIG_PROFILE, TEXTDOMAIN,
+     GPG_AGENT_INFO, SSH_AUTH_SOCK, XDG_RUNTIME_DIR,
+     COMPIZ_BIN_PATH, GDMSESSION, DEFAULTS_PATH, TEXTDOMAINDIR,
+     XDG_SEAT_PATH, XDG_CONFIG_DIRS, XDG_CURRENT_DESKTOP,
+     DBUS_SESSION_BUS_ADDRESS, _, XDG_SESSION_COOKIE,
+     DESKTOP_SESSION, LESSCLOSE, GNOME_KEYRING_PID, UBUNTU_MENUPROXY,
+     OLDPWD, GTK_MODULES, XDG_DATA_DIRS, COLORTERM, LS_COLORS
+     DEBUG: Found bblayers.conf (/home/wmat/dev/hello/conf/
+     bblayers.conf)
+     DEBUG: LOAD /home/wmat/dev/hello/conf/bblayers.conf
+     DEBUG: LOAD /home/wmat/dev/hello/conf/bitbake.conf
+     DEBUG: BB configuration INHERITs:0: inheriting /home/wmat/dev/
+     hello/classes/base.bbclass
+     DEBUG: BB /home/wmat/dev/hello/classes/base.bbclass: handle
+     (data, include)
+     DEBUG: LOAD /home/wmat/dev/hello/classes/base.bbclass
+     DEBUG: Clearing SRCREV cache due to cache policy of: clear
+     DEBUG: Using cache in '/home/wmat/dev/hello/tmp/cache/
+     local_file_checksum_cache.dat'
+     DEBUG: Using cache in '/home/wmat/dev/hello/tmp/cache/
+     bb_codeparser.dat'
+                </literallayout>
+                <note>
+                    From this point forward in the example, the environment
+                    variable removal messages are ignored and omitted.
+                    Examine the relevant DEBUG messages:
+                </note>
+            </para>
+        </section>
+    </section>
+</appendix>