source: chapter08/eudev.xml@ f7cdb10

<?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;
]>

<sect1 id="ch-system-eudev" role="wrap" revision="sysv">
  <?dbhtml filename="eudev.html"?>

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

  <title>Eudev-&eudev-version;</title>

  <indexterm zone="ch-system-eudev">
    <primary sortas="a-Eudev">Eudev</primary>
  </indexterm>

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

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

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

      <seglistitem>
        <seg>&eudev-fin-sbu;</seg>
        <seg>&eudev-fin-du;</seg>
      </seglistitem>
    </segmentedlist>
  </sect2>

  <sect2 role="installation">
    <title>Installation of Eudev</title>
    <!-- No longer seems needed. bdubbs 5/18/23
    <para>First fix the location of udev rules in the .pc file:</para>

<screen><userinput remap="pre">sed -i '/udevdir/a udev_dir=${udevdir}' src/udev/udev.pc.in</userinput></screen>
-->
    <!-- different from systemd: we do not have a render group and file is
    named differently -->
    <para>Remove an unneeded group
    <systemitem class="groupname">sgx</systemitem>, from the default udev
    rules:</para>

<screen><userinput remap="pre">sed -i -e 's/GROUP="sgx", //' rules/50-udev-default.rules</userinput></screen>

    <para>Prepare Eudev for compilation:</para>

<screen><userinput remap="configure">./configure --prefix=/usr           \
            --bindir=/usr/sbin      \
            --sysconfdir=/etc       \
            --enable-manpages       \
            --disable-static</userinput></screen>

    <para>Compile the package:</para>

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

    <para>Create some directories now that are needed for tests, but
    will also be used as a part of installation:</para>

<screen><userinput remap="test">mkdir -pv /usr/lib/udev/rules.d
mkdir -pv /etc/udev/rules.d</userinput></screen>

    <para>To test the results, issue:</para>

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

    <para>Install the package:</para>

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

    <para>Install some custom rules and support files useful in an LFS
    environment:</para>

<screen><userinput remap="install">tar -xvf ../&udev-lfs-version;.tar.xz
make -f &udev-lfs-version;/Makefile.lfs install</userinput></screen>

  </sect2>

  <sect2 id="conf-eudev" role="configuration">
    <title>Configuring Eudev</title>

    <indexterm zone="conf-eudev">
      <primary sortas="a-Eudev">Eudev</primary>
      <secondary>configuring</secondary>
    </indexterm>

    <indexterm zone="conf-eudev">
      <primary sortas="e-/etc/udev/rules.d/65-kvm.rules">/etc/udev/rules.d/65-kvm.rules</primary>
    </indexterm>

    <para>
      The default udev rule installed by Eudev would allow all users to
      access <filename class='devicefile'>/dev/kvm</filename>.  The editors
      consider it dangerous.  Create a configuration file to override it:
    </para>

<screen><userinput>cat > /etc/udev/rules.d/65-kvm.rules &lt;&lt; "EOF"
<literal>KERNEL=="kvm", GROUP="kvm", MODE="0660", TAG+="uaccess"</literal>
EOF</userinput></screen>

    <indexterm zone="conf-eudev">
      <primary sortas="e-/etc/udev/hwdb.bin">/etc/udev/hwdb.bin</primary>
    </indexterm>

    <para>Information about hardware devices is maintained in the
    <filename class="directory">/etc/udev/hwdb.d</filename> and
    <filename class="directory">/usr/lib/udev/hwdb.d</filename> directories.
    <application>Eudev</application> needs that information to be compiled
    into a binary database <filename>/etc/udev/hwdb.bin</filename>. Create the
    initial database:</para>

<screen><userinput>udevadm hwdb --update</userinput></screen>

    <para>This command needs to be run each time the hardware information is
    updated.</para>

  </sect2>

  <sect2 id="contents-eudev" role="content">
    <title>Contents of Eudev</title>

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

      <seglistitem>
        <seg><!-- These are in /usr/lib/udev and not to be called by the user:
         accelerometer, ata_id, cdrom_id, collect, mtd_probe,
         scsi_id, v4l_id,--> udevadm and udevd</seg>

        <seg>libudev.so</seg>

        <seg>/etc/udev, /usr/lib/udev, and /usr/share/doc/udev-&udev-lfs-version;</seg>
      </seglistitem>
    </segmentedlist>

    <variablelist>
      <bridgehead renderas="sect3">Short Descriptions</bridgehead>
      <?dbfo list-presentation="list"?>
      <?dbhtml list-presentation="table"?>
      <varlistentry id="udevadm" revision="sysv">
        <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-eudev 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-eudev udevd">
            <primary sortas="b-udevd">udevd</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-eudev 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-eudev etc-udev">
            <primary sortas="e-/etc/udev">/etc/udev</primary>
          </indexterm>
        </listitem>
      </varlistentry>

    </variablelist>

  </sect2>

</sect1>