lfs-book/chapter06/udev.xml

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  <!ENTITY % general-entities SYSTEM "../general.ent">
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<sect1 id="ch-system-udev" role="wrap">
  <?dbhtml filename="udev.html"?>

  <sect1info condition="script">
    <productname>udev</productname>
    <productnumber>&udev-version;</productnumber>
    <address>&udev-url;</address>
  </sect1info>

  <title>Udev-&udev-version;</title>

  <indexterm zone="ch-system-udev">
    <primary sortas="a-Udev">Udev</primary>
  </indexterm>

  <sect2 role="package">
    <title/>

    <para>The Udev package contains programs for dynamic creation of device
    nodes.</para>

    <segmentedlist>
      <segtitle>&buildtime;</segtitle>
      <segtitle>&diskspace;</segtitle>

      <seglistitem>
        <seg>&udev-ch6-sbu;</seg>
        <seg>&udev-ch6-du; plus &udev-testfiles-du; for testfiles</seg>
      </seglistitem>
    </segmentedlist>

  </sect2>

  <sect2 role="installation">
    <title>Installation of Udev</title>

    <para>Fix a bug in the Makefile that prevents some tools from being built
    and installed:</para>

<screen><userinput remap="pre">sed -i -e '228d' -e '317d' Makefile.am</userinput></screen>

    <para>The udev-config tarball contains LFS-specific files used to configure
    Udev. Unpack it into the Udev source directory:</para>

<screen><userinput remap="pre">tar -xvf ../&udev-config;.tar.bz2</userinput></screen>

    <para>The udev-testfiles tarball contains files needed to test udev. The 
    file expands to an apparent size of about 37MB but the actual disk usage
    is less than 7MB.</para>

<screen><userinput remap="pre">tar -xvf ../udev-&udev-version;-testfiles.tar.bz2 --strip-components=1</userinput></screen>

    <para>Create some devices and directories that Udev cannot handle due to
    them being required very early in the boot process, or by Udev itself:</para>

<screen><userinput remap="install">install -dv /lib/{firmware,udev/devices/{pts,shm}}
mknod -m0666 /lib/udev/devices/null c 1 3</userinput></screen>

    <para>Prepare the package for compilation:</para>

<!-- Note that "libdir=/usr/lib64" would be required for multilib. -->
<screen><userinput remap="configure">./configure --prefix=/usr \
    --sysconfdir=/etc --sbindir=/sbin \
    --with-rootlibdir=/lib --libexecdir=/lib/udev \
    --disable-extras --disable-introspection</userinput></screen>

    <variablelist>
      <title>The meaning of the new configure options</title>

      <varlistentry>
        <term><parameter>--with-rootlibdir=/lib</parameter></term>
        <listitem>
          <para>This controls where the <filename
          class="libraryfile">libudev</filename> library is installed.  The
          library needs to be in <filename class="directory">/lib</filename>
          because it's used by Udev at boot time, before <filename
          class="directory">/usr</filename> might be available, and the default
          --rootlibdir is <filename class="directory">/usr/lib</filename>.</para>
        </listitem>
      </varlistentry>

      <!-- Note that libexecdir *MUST* stay /lib/udev, even on a 64-bit
           / multilib system where udev is compiled for 64-bit.  Other
           packages require this exact path; the udev maintainers have
           said this is part of the udev API. -->
      <varlistentry>
        <term><parameter>--libexecdir=/lib/udev</parameter></term>
        <listitem>
          <para>This controls where Udev-internal rules and helper programs
          are installed.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><parameter>--disable-extras</parameter></term>
        <listitem>
          <para>This option prevents Udev from installing helper programs and
          other extras which require more external libraries.  These libraries
          are not part of the base LFS system.  See the Udev
          <filename>README</filename> file for more information.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><parameter>--disable-introspection</parameter></term>
        <listitem>
          <para>This option prevents Udev's instrospection feature, which
          requires packages not installed as part of the base LFS system.  See
          the Udev <filename>README</filename> file for more information.</para>
        </listitem>
      </varlistentry>
    </variablelist>

    <para>Compile the package:</para>

<screen><userinput remap="make">make</userinput></screen>

    <para>Test the package.</para>

<screen><userinput remap="test">make check</userinput></screen>

    <para>Install the package:</para>

<screen><userinput remap="install">make install</userinput></screen>

    <para>Remove an empty documentation directory:</para>

<screen><userinput remap="install">rmdir -v /usr/share/doc/udev</userinput></screen>

    <para>Now install the LFS-specific custom rules files:</para>

<screen><userinput remap="install">cd &udev-config;
make install</userinput></screen>

    <para>Install the documentation that explains the LFS-specific rules
    files:</para>

<screen><userinput remap="install">make install-doc</userinput></screen>

  </sect2>

  <sect2 id="contents-udev" role="content">
    <title>Contents of Udev</title>

    <segmentedlist>
      <segtitle>Installed programs</segtitle>
      <segtitle>Installed libraries</segtitle>
      <segtitle>Installed directories</segtitle>

      <seglistitem>
        <seg>ata_id, cdrom_id, collect, create_floppy_devices, edd_id,
        firmware.sh, fstab_import, path_id, scsi_id, udevadm, udevd,
        usb_id, write_cd_rules, and write_net_rules</seg>
        <seg>libudev.{a,so}</seg>
        <seg>/etc/udev, /lib/udev, /lib/firmware</seg>
      </seglistitem>
    </segmentedlist>

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

      <varlistentry id="ata_id">
        <term><command>ata_id</command></term>
        <listitem>
          <para>Provides Udev with a unique string and
          additional information (uuid, label) for an ATA drive</para>
          <indexterm zone="ch-system-udev ata_id">
            <primary sortas="b-ata_id">ata_id</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="cdrom_id">
        <term><command>cdrom_id</command></term>
        <listitem>
          <para>Provides Udev with the capabilities of a
          CD-ROM or DVD-ROM drive</para>
          <indexterm zone="ch-system-udev cdrom_id">
            <primary sortas="b-cdrom_id">cdrom_id</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="collect">
        <term><command>collect</command></term>
        <listitem>
          <para>Given an ID for the current uevent and a list of
          IDs (for all target uevents), registers the current ID
          and indicates whether all target IDs have been registered</para>
          <indexterm zone="ch-system-udev collect">
            <primary sortas="b-collect">collect</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="create_floppy_devices">
        <term><command>create_floppy_devices</command></term>
        <listitem>
          <para>Creates all possible floppy devices based on the CMOS type</para>
          <indexterm zone="ch-system-udev create_floppy_devices">
            <primary sortas="b-create_floppy_devices">create_floppy_devices</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="edd_id">
        <term><command>edd_id</command></term>
        <listitem>
          <para>Provides Udev with the EDD ID for a BIOS disk drive</para>
          <indexterm zone="ch-system-udev edd_id">
            <primary sortas="b-edd_id">edd_id</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="firmware.sh">
        <term><command>firmware.sh</command></term>
        <listitem>
          <para>Uploads firmware to devices</para>
          <indexterm zone="ch-system-udev firmware.sh">
            <primary sortas="b-firmware.sh">firmware.sh</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="fstab_import">
        <term><command>fstab_import</command></term>
        <listitem>
          <para>Finds an entry in <filename>/etc/fstab</filename> that
          matches the current device, and provides its information to
          Udev</para>
          <indexterm zone="ch-system-udev fstab_import">
            <primary sortas="b-fstab_import">fstab_import</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="path_id">
        <term><command>path_id</command></term>
        <listitem>
          <para>Provides the shortest possible unique hardware path to a
          device</para>
          <indexterm zone="ch-system-udev path_id">
            <primary sortas="b-path_id">path_id</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="scsi_id">
        <term><command>scsi_id</command></term>
        <listitem>
          <para>Provides Udev with a unique SCSI identifier
          based on the data returned from sending a SCSI INQUIRY command to
          the specified device</para>
          <indexterm zone="ch-system-udev scsi_id">
            <primary sortas="b-scsi_id">scsi_id</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="udevadm">
        <term><command>udevadm</command></term>
        <listitem>
          <para>Generic udev administration tool: controls the udevd daemon,
          provides info from the Udev database, monitors uevents, waits for
          uevents to finish, tests Udev configuration, and triggers uevents
          for a given device</para>
          <indexterm zone="ch-system-udev udevadm">
            <primary sortas="b-udevadm">udevadm</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="udevd">
        <term><command>udevd</command></term>
        <listitem>
          <para>A daemon that listens for uevents on the netlink socket,
          creates devices and runs the configured external programs in
          response to these uevents</para>
          <indexterm zone="ch-system-udev udevd">
            <primary sortas="b-udevd">udevd</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="usb_id">
        <term><command>usb_id</command></term>
        <listitem>
          <para>Provides Udev with information about USB
          devices</para>
          <indexterm zone="ch-system-udev usb_id">
            <primary sortas="b-usb_id">usb_id</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="write_cd_rules">
        <term><command>write_cd_rules</command></term>
        <listitem>
          <para>A script which generates Udev rules to provide stable names for
          optical drives (see also <xref linkend="ch-scripts-symlinks"/>)</para>
          <indexterm zone="ch-system-udev write_cd_rules">
            <primary sortas="b-write_cd_rules">write_cd_rules</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="write_net_rules">
        <term><command>write_net_rules</command></term>
        <listitem>
          <para>A script which generates rules to provide stable names for
          network interfaces (see also <xref linkend="ch-scripts-network"/>)
          </para>
          <indexterm zone="ch-system-udev write_net_rules">
            <primary sortas="b-write_net_rules">write_net_rules</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="libudev">
        <term><filename class="libraryfile">libudev</filename></term>
        <listitem>
          <para>A library interface to udev device information</para>
          <indexterm zone="ch-system-udev libudev">
            <primary sortas="c-libudev">libudev</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="etc-udev">
        <term><filename class="directory">/etc/udev</filename></term>
        <listitem>
          <para>Contains Udev configuration files,
          device permissions, and rules for device naming</para>
          <indexterm zone="ch-system-udev etc-udev">
            <primary sortas="e-/etc/udev">/etc/udev</primary>
          </indexterm>
        </listitem>
      </varlistentry>

    </variablelist>

  </sect2>

</sect1>