source: general/sysutils/dbus.xml@ aa0b625

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
  <!ENTITY % general-entities SYSTEM "../../general.ent">
  %general-entities;

  <!ENTITY dbus-download-http "https://dbus.freedesktop.org/releases/dbus/dbus-&dbus-version;.tar.xz">
  <!ENTITY dbus-download-ftp  " ">
  <!ENTITY dbus-md5sum        "ddd5570aff05191dbee8e42d751f1b7d">
  <!ENTITY dbus-size          "1.3 MB">
  <!ENTITY dbus-buildsize     "21 MB (add 18 MB for the tests)">
  <!ENTITY dbus-time          "0.3 SBU (add 8.0 SBU for the tests)">
  <!-- The former value was 0.8 SBU, which was far more sensible. -->
]>

<sect1 id="dbus" xreflabel="dbus-&dbus-version;">
  <?dbhtml filename="dbus.html"?>

  <sect1info>
    <date>$Date$</date>
  </sect1info>

  <title>dbus-&dbus-version;</title>

  <indexterm zone="dbus">
    <primary sortas="a-D-Bus">D-Bus</primary>
  </indexterm>

  <sect2 role="package">
    <title>Introduction to D-Bus</title>

    <para revision="sysv">
      <application>D-Bus</application> is a message bus system, a simple way
      for applications to talk to one another.
      <application>D-Bus</application> supplies both a system daemon (for
      events such as <quote>new hardware device added</quote> or <quote>printer
      queue changed</quote>) and a per-user-login-session daemon (for general
      IPC needs among user applications). Also, the message bus is built on top
      of a general one-to-one message passing framework, which can be used by
      any two applications to communicate directly (without going through the
      message bus daemon).
    </para>

    <para revision="systemd">
      Even though <application>D-Bus</application> was built in LFS, there are
      some features provided by the package that other BLFS packages need, but
      their dependencies didn't fit into LFS.
    </para>

    &lfs112_checked;

    <bridgehead renderas="sect3">Package Information</bridgehead>
    <itemizedlist spacing="compact">
      <listitem>
        <para>
          Download (HTTP): <ulink url="&dbus-download-http;"/>
        </para>
      </listitem>
      <listitem>
        <para>
          Download (FTP): <ulink url="&dbus-download-ftp;"/>
        </para>
      </listitem>
      <listitem>
        <para>
          Download MD5 sum: &dbus-md5sum;
        </para>
      </listitem>
      <listitem>
        <para>
          Download size: &dbus-size;
        </para>
      </listitem>
      <listitem>
        <para>
          Estimated disk space required: &dbus-buildsize;
        </para>
      </listitem>
      <listitem>
        <para>
          Estimated build time: &dbus-time;
        </para>
      </listitem>
    </itemizedlist>

    <bridgehead renderas="sect3">D-Bus Dependencies</bridgehead>

    <bridgehead renderas="sect4" revision="systemd">Required</bridgehead>
    <para role="required" revision="systemd">
      <xref linkend="systemd"/>
    </para>


    <bridgehead renderas="sect4">Recommended</bridgehead>
    <para role="recommended">
      <xref linkend="xorg7-lib"/> (for <command>dbus-launch</command> program)
      <phrase revision="sysv">and <xref linkend="elogind"/> (These are
      circular dependencies. First build without them, and then again after
      both packages are installed.)</phrase>
    </para>

    <bridgehead renderas="sect4">Optional</bridgehead>
    <para role="optional">
      For the tests:
      <xref linkend="dbus-glib"/>,
      <xref linkend="dbus-python"/>,
      <xref linkend="pygobject3"/>,
      and <xref linkend="valgrind"/>;

      for documentation:
      <xref linkend="doxygen"/>,
      <xref linkend="xmlto"/>,
      <ulink url="https://pypi.python.org/pypi/mallard-ducktype">Ducktype</ulink>,
      and
      <ulink url="&gnome-download-http;/yelp-tools/">Yelp Tools</ulink>
    </para>

    <para condition="html" role="usernotes">User Notes:
      <ulink url="&blfs-wiki;/dbus"/>
    </para>
  </sect2>

  <sect2 role="installation">
    <title>Installation of D-Bus</title>
    <!--
    <para revision="sysv">
      If they do not already exist,
      as the <systemitem class="username">root</systemitem> user, create a
      system user and group to handle the system message bus activity:
    </para>

<screen role="root" revision="sysv"><userinput>groupadd -g 18 messagebus &amp;&amp;
useradd -c "D-Bus Message Daemon User" -d /var/run/dbus \
        -u 18 -g messagebus -s /bin/false messagebus</userinput></screen>
    -->

    <para>
      Install <application>D-Bus</application> by running the following
      commands (you may wish to review the output from <command>./configure
      --help</command> first and add any desired parameters to the
      <command>configure</command> command shown below):
    </para>

<screen revision="sysv"><userinput>./configure --prefix=/usr                        \
            --sysconfdir=/etc                    \
            --localstatedir=/var                 \
            --runstatedir=/run                   \
            --enable-user-session                \
            --disable-doxygen-docs               \
            --disable-xml-docs                   \
            --disable-static                     \
            --with-systemduserunitdir=no         \
            --with-systemdsystemunitdir=no       \
            --docdir=/usr/share/doc/dbus-&dbus-version;  \
            --with-system-socket=/run/dbus/system_bus_socket &amp;&amp;
make</userinput></screen>

<screen revision="systemd"><userinput>./configure --prefix=/usr                        \
            --sysconfdir=/etc                    \
            --localstatedir=/var                 \
            --runstatedir=/run                   \
            --enable-user-session                \
            --disable-doxygen-docs               \
            --disable-xml-docs                   \
            --disable-static                     \
            --docdir=/usr/share/doc/dbus-&dbus-version;  \
            --with-system-socket=/run/dbus/system_bus_socket &amp;&amp;
make</userinput></screen>

    <para>
      See below for test instructions.
    </para>

<!--
    <warning revision="systemd">
      <para>
        Installing the package will override all files installed by
        <application>D-Bus</application> in LFS. It is critical that
        nothing uses <application>D-Bus</application> libraries or
        programs during the installation. The best way to ensure that these
        libraries are not being used is to run the installation in rescue mode.
        To switch to rescue mode, run the following command as the
        <systemitem class="username">root</systemitem> user (from a TTY):
      </para>

<screen role="root"><userinput>systemctl start rescue.target</userinput></screen>

    </warning>
-->

    <para>
      Now, as the <systemitem class="username">root</systemitem> user:
    </para>

<screen role="root"><userinput>make install</userinput></screen>

<!-- FIXME: No longer needed with usr merge
    <para>
      The shared library needs to be moved to
      <filename class="directory">/lib</filename>, and as a result the
      <filename class="extension">.so</filename> file in
      <filename class="directory">/usr/lib</filename> will need to be
      recreated. Run the following command as the
      <systemitem class="username">root</systemitem> user:
    </para>

<screen role="root"><userinput>mv -v /usr/lib/libdbus-1.so.* /lib &amp;&amp;
ln -sfv ../../lib/$(readlink /usr/lib/libdbus-1.so) /usr/lib/libdbus-1.so</userinput></screen>
-->

    <para>
      If you are using a DESTDIR install,
      <command>dbus-daemon-launch-helper</command> needs to be fixed
      afterwards. Issue, as <systemitem class="username">root</systemitem>
      user:
    </para>

<screen role="root"><userinput>chown -v root:messagebus /usr/libexec/dbus-daemon-launch-helper &amp;&amp;
chmod -v      4750       /usr/libexec/dbus-daemon-launch-helper</userinput></screen>

    <para revision="sysv">
      If you are still building your system in chroot or you did not start the
      daemon yet, but you want to compile some packages that require
      <application>D-Bus</application>, generate the
      <application>D-Bus</application> UUID to avoid warnings when compiling
      some packages with the following command as the
      <systemitem class="username">root</systemitem> user:
    </para>

<screen role="root" revision="sysv"><userinput>dbus-uuidgen --ensure</userinput></screen>

    <para revision="sysv">
      If using <xref linkend="elogind"/>, create a symlink to the
      <filename>/var/lib/dbus/machine-id</filename> file:
    </para>

<screen role="root" revision="sysv"><userinput>ln -sv /var/lib/dbus/machine-id /etc</userinput></screen>

<!--
    <para revision="systemd">
      If not in chroot, at this point, you should reload the systemd daemon,
      and reenter multi-user mode with the following commands (as the
      <systemitem class="username">root</systemitem> user):
    </para>

<screen role="root" revision="systemd"><userinput>systemctl daemon-reload
systemctl start multi-user.target</userinput></screen>
-->

    <para>
      The dbus tests cannot be run until after <xref linkend="dbus-glib"/> has
      been installed.  They must be run as an unprivileged user from a local
      session with bus address. To run the standard tests issue
      <command>make check</command>.
    </para>

    <para>
      If you want to run the unit regression tests, configure requires
      additional parameters which expose additional functionality in the
      binaries that are not intended to be used in a production build of
      <application>D-Bus</application>.  If you would like to run the tests,
      issue the following commands (for the tests, you don't need to build the
      docs):
    </para>

<screen remap="test"><userinput>make distclean                                    &amp;&amp;
PYTHON=python3 ./configure --enable-tests         \
                           --enable-asserts       \
                           --disable-doxygen-docs \
                           --disable-xml-docs     &amp;&amp;
make                                              &amp;&amp;
make check</userinput></screen>

    <para>
      There have been reports that the tests may fail if running inside a
      Midnight Commander shell. You may get out-of-memory error messages when
      running the tests. These are normal and can be safely ignored.
    </para>

  </sect2>

  <sect2 role="commands">
    <title>Command Explanations</title>

    <para>
      <parameter>--disable-doxygen-docs</parameter>: This switch disables
      doxygen documentation build and install, if you have
      <application>doxygen</application> installed. If
      <application>doxygen</application> is installed, and you wish to build
      them, remove this parameter.
    </para>

    <para>
      <parameter>--disable-xml-docs</parameter>: This switch disables html
      documentation build and install, if you have
      <application>xmlto</application> installed. If
      <application>xmlto</application> is installed, and you wish to build
      them, remove this parameter.
    </para>

    <xi:include xmlns:xi="http://www.w3.org/2001/XInclude"
      href="../../xincludes/static-libraries.xml"/>

    <para>
      <parameter>--enable-user-session</parameter>: This parameter enables
      per-user DBus sessions with
      <phrase revision="sysv"><application>elogind</application>.</phrase>
      <phrase revision="systemd"><application>systemd</application>.</phrase>
    </para>

    <para revision="sysv">
      <parameter>--with-systemd{user,system}unitdir=no</parameter>: These
      switches disable installation of systemd units on elogind based systems.
    </para>

    <para>
      <parameter>--with-system-pid-file=/run/dbus/pid</parameter>: This
      parameter specifies the location of the PID file.
    </para>

    <para>
      <parameter>--with-system-socket=/run/dbus/system_bus_socket</parameter>:
      This parameter specifies the location of the system bus socket.
    </para>

    <para>
      <parameter>--enable-tests</parameter>: Builds extra parts of the code to
      support all tests. Do not use on a production build.
    </para>

    <para>
      <option>--enable-embedded-tests</option>: Builds extra parts of the
      code to support only unit tests. Do not use on a production build.
    </para>

    <para>
      <parameter>--enable-asserts</parameter>: Enables debugging code to run
      assertions for statements normally assumed to be true. This prevents a
      warning that '<parameter>--enable-tests</parameter>' on its own is only
      useful for profiling and might not give true results for all tests, but
      adds its own NOTE that this should not be used in a production build.
    </para>

  </sect2>

  <sect2 role="configuration">
    <title>Configuring D-Bus</title>

    <sect3 id="dbus-config">
      <title>Config Files</title>

      <para>
        <filename>/etc/dbus-1/session.conf</filename>,
        <filename>/etc/dbus-1/system.conf</filename> and
        <filename>/etc/dbus-1/system.d/*</filename>
      </para>

      <indexterm zone="dbus dbus-config">
        <primary sortas="e-etc-dbus-1-session.conf">/etc/dbus-1/session.conf</primary>
      </indexterm>

      <indexterm zone="dbus dbus-config">
        <primary sortas="e-etc-dbus-1/system.conf">/etc/dbus-1/system.conf</primary>
      </indexterm>

      <indexterm zone="dbus dbus-config">
        <primary sortas="e-etc-dbus-1-system.d-star">/etc/dbus-1/system.d/*</primary>
      </indexterm>

    </sect3>

    <sect3 id="dbus-session-config" xreflabel="D-Bus custom services directory">
      <title>Configuration Information</title>

      <para>
        The configuration files listed above should probably not be
        modified. If changes are required, you should create
        <filename>/etc/dbus-1/session-local.conf</filename> and/or
        <filename>/etc/dbus-1/system-local.conf</filename> and make any
        desired changes to these files.
     </para>

      <para>
        If any packages install a
        <application>D-Bus</application> <filename>.service</filename>
        file outside of the standard <filename
        class="directory">/usr/share/dbus-1/services</filename> directory,
        that directory should be added to the local session configuration.
        For instance, <filename
        class="directory">/usr/local/share/dbus-1/services</filename> can
        be added by performing the following commands as the
        <systemitem class="username">root</systemitem> user:
      </para>

<screen role="root"><userinput>cat &gt; /etc/dbus-1/session-local.conf &lt;&lt; "EOF"
<literal>&lt;!DOCTYPE busconfig PUBLIC
 "-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN"
 "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd"&gt;
&lt;busconfig&gt;

  &lt;!-- Search for .service files in /usr/local --&gt;
  &lt;servicedir&gt;/usr/local/share/dbus-1/services&lt;/servicedir&gt;

&lt;/busconfig&gt;</literal>
EOF</userinput></screen>

    </sect3>

    <sect3  id="dbus-session">
      <title>D-Bus Session Daemon</title>

      <para revision="sysv">
        To automatically start <command>dbus-daemon</command> when the
        system is rebooted, install the
        <filename>/etc/rc.d/init.d/dbus</filename> bootscript from the
        <xref linkend="bootscripts"/> package.
      </para>

      <indexterm zone="dbus dbus-session" revision="sysv">
        <primary sortas="f-dbus">dbus</primary>
      </indexterm>

<screen role="root" revision="sysv"><userinput>make install-dbus</userinput></screen>

      <para revision="sysv">
        Note that this boot script only starts the system-wide
        <application>D-Bus</application> daemon. Each user requiring access to
        <application>D-Bus</application> services will also need to run a
        session daemon as well. There are many methods you can use to start a
        session daemon using the <command>dbus-launch</command> command. Review
        the <command>dbus-launch</command> man page for details about the
        available parameters and options. Here are some suggestions and
        examples:
      </para>

      <para revision="systemd">
        There are many methods you can use to start a session daemon
        using the <command>dbus-launch</command> command. Review the
        <command>dbus-launch</command> man page for details about the
        available parameters and options. Here are some suggestions and
        examples:
      </para>


      <itemizedlist spacing="compact">
        <listitem>
          <para>
            Add <command>dbus-launch</command> to the line in the
            <filename>~/.xinitrc</filename> file that starts your graphical
            desktop environment.
          </para>
        </listitem>
        <listitem>
          <para>
            If you use <command>gdm</command> or some other display manager
            that calls the <filename>~/.xsession</filename> file, you can add
            <command>dbus-launch</command> to the line in your
            <filename>~/.xsession</filename> file that starts your graphical
            desktop environment. The syntax would be similar to the example in
            the <filename>~/.xinitrc</filename> file.
          </para>
        </listitem>
        <listitem>
          <para>
            The examples shown previously use
            <command>dbus-launch</command> to specify a program to be run. This
            has the benefit (when also using the
            <parameter>--exit-with-session</parameter> parameter) of stopping the
            session daemon when the specified program is stopped. You can also
            start the session daemon in your system or personal startup scripts
            by adding the following lines:
          </para>

<screen role="nodump"><userinput><literal># Start the D-Bus session daemon
eval `dbus-launch`
export DBUS_SESSION_BUS_ADDRESS</literal></userinput></screen>

          <para>
            This method will not stop the session daemon when you exit
            your shell, therefore you should add the following line to your
            <filename>~/.bash_logout</filename> file:
          </para>

<screen role="nodump"><userinput><literal># Kill the D-Bus session daemon
kill $DBUS_SESSION_BUS_PID</literal></userinput></screen>
        </listitem>

        <!-- KDM is no longer usable, SDDM is it's replacement
        <listitem>
          <para>
            A hint has been written that provides ways to start scripts
            using the KDM session manager of KDE. The concepts in this hint could
            possibly be used with other session managers as well. The hint is
            located at <ulink
            url="&hints-root;/downloads/files/execute-session-scripts-using-kdm.txt"/>.
          </para>
        </listitem>
        -->

      </itemizedlist>

    </sect3>

  </sect2>

  <sect2 role="content" revision="sysv">
    <title>Contents</title>

    <segmentedlist>
      <segtitle>Installed Programs</segtitle>
      <segtitle>Installed Library</segtitle>
      <segtitle>Installed Directories</segtitle>

      <seglistitem>
        <seg>
          dbus-cleanup-sockets, dbus-daemon, dbus-launch, dbus-monitor,
          dbus-run-session, dbus-send, dbus-test-tool,
          dbus-update-activation-environment, and dbus-uuidgen
        </seg>
        <seg>
           libdbus-1.so
        </seg>
        <seg>
          /etc/dbus-1,
          /usr/{include,lib}/dbus-1.0,
          /usr/lib/cmake/DBus1,
          /usr/share/dbus-1,
          /usr/share/xml/dbus-1,
          /usr/share/doc/dbus-&dbus-version;, and
          /var/{lib,run}/dbus
        </seg>
      </seglistitem>
    </segmentedlist>

    <variablelist>
      <bridgehead renderas="sect3">Short Descriptions</bridgehead>
      <?dbfo list-presentation="list"?>
      <?dbhtml list-presentation="table"?>

      <varlistentry id="dbus-cleanup-sockets">
        <term><command>dbus-cleanup-sockets</command></term>
        <listitem>
          <para>
            is used to clean up leftover sockets in a directory
          </para>
          <indexterm zone="dbus dbus-cleanup-sockets">
            <primary sortas="b-dbus-cleanup-sockets">dbus-cleanup-sockets</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="dbus-daemon">
        <term><command>dbus-daemon</command></term>
        <listitem>
          <para>
            is the <application>D-Bus</application> message bus daemon
          </para>
          <indexterm zone="dbus dbus-daemon">
            <primary sortas="b-dbus-daemon">dbus-daemon</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="dbus-launch">
        <term><command>dbus-launch</command></term>
        <listitem>
          <para>
            is used to start <command>dbus-daemon</command> from a shell
            script. It  would  normally be called from a user's login
            scripts
          </para>
          <indexterm zone="dbus dbus-launch">
            <primary sortas="b-dbus-launch">dbus-launch</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="dbus-monitor">
        <term><command>dbus-monitor</command></term>
        <listitem>
          <para>
            is used to monitor messages going through a
            <application>D-Bus</application> message bus
          </para>
          <indexterm zone="dbus dbus-monitor">
            <primary sortas="b-dbus-monitor">dbus-monitor</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="dbus-run-session">
        <term><command>dbus-run-session</command></term>
        <listitem>
          <para>
            starts a process as a new <application>D-Bus</application> session
          </para>
          <indexterm zone="dbus dbus-run-session">
            <primary sortas="b-dbus-run-session">dbus-run-session</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="dbus-send">
        <term><command>dbus-send</command></term>
        <listitem>
          <para>
            is used to send a message to a <application>D-Bus</application>
            message bus
          </para>
          <indexterm zone="dbus dbus-send">
            <primary sortas="b-dbus-send">dbus-send</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="dbus-test-tool">
        <term><command>dbus-test-tool</command></term>
        <listitem>
          <para>
            is a <application>D-Bus</application> traffic generator and test
            tool; it is a multi-purpose tool for debugging and profiling
            <application>D-Bus</application>
          </para>
          <indexterm zone="dbus dbus-test-tool">
            <primary sortas="b-dbus-test-tool">dbus-test-tool</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="dbus-update-activation-environment">
        <term><command>dbus-update-activation-environment</command></term>
        <listitem>
          <para>
            is used to update the environment used for
            <application>D-Bus</application> session services;
            it updates the list of environment variables used by
            <command>dbus-daemon --session</command> when it activates session
            services without using systemd
          </para>
          <indexterm zone="dbus dbus-update-activation-environment">
            <primary sortas="b-dbus-update-activation-environment">
            dbus-update-activation-environment</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="dbus-uuidgen">
        <term><command>dbus-uuidgen</command></term>
        <listitem>
          <para>
            is used to generate a universally unique ID
          </para>
          <indexterm zone="dbus dbus-uuidgen">
            <primary sortas="b-dbus-uuidgen">dbus-uuidgen</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="libdbus-1">
        <term><filename class="libraryfile">libdbus-1.so</filename></term>
        <listitem>
          <para>
            contains the API functions used by the
            <application>D-Bus</application> message daemon.
            <application>D-Bus</application> is first a library that provides
            one-to-one communication between any two applications;
            <command>dbus-daemon</command> is an application that uses this
            library to implement a message bus daemon
          </para>
          <indexterm zone="dbus libdbus-1">
            <primary sortas="c-libdbus-1">libdbus-1.so</primary>
          </indexterm>
        </listitem>
      </varlistentry>

    </variablelist>

  </sect2>

  <sect2 role="content" revision="systemd">
    <title>Contents</title>

      <para>
        A list of the installed files, along with their short
        descriptions can be found at
        <ulink url="&lfs-root;/chapter08/dbus.html#contents-dbus"/>.
      </para>

  </sect2>

</sect1>