lfs-book/chapter06/hotplug.xml

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

  <title>Hotplug-&hotplug-version;</title>

  <indexterm zone="ch-system-hotplug">
    <primary sortas="a-Hotplug">Hotplug</primary>
  </indexterm>

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

    <para>The Hotplug package contains scripts that react upon hotplug events
    generated by the kernel. Such events correspond to every change in the kernel
    state visible in the <systemitem class="filesystem">sysfs</systemitem>
    filesystem, e.g., the addition and removal of hardware. This package also
    detects existing hardware during boot and inserts the relevant modules into the
    running kernel.</para>

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

      <seglistitem>
        <seg>0.01 SBU</seg>
        <seg>460 KB</seg>
      </seglistitem>
    </segmentedlist>

    <segmentedlist>
      <segtitle>&dependencies;</segtitle>

      <seglistitem>
        <seg>Bash, Coreutils, Find, Gawk, and Make</seg>
      </seglistitem>
    </segmentedlist>

  </sect2>

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

    <para>This package does not come with a test suite.</para>

    <para>Install the Hotplug package:</para>

<screen><userinput>make install</userinput></screen>

    <para>Copy a file that the <quote>install</quote> target omits.</para>

<screen><userinput>cp -v etc/hotplug/pnp.distmap /etc/hotplug</userinput></screen>

    <para>Remove the init script that Hotplug installs since we are going to be
    using the script included in the LFS-Bootscripts package:</para>

<screen><userinput>rm -rfv /etc/init.d</userinput></screen>

    <para>Network device hotplugging is not yet supported by the LFS-Bootscripts
    package. For that reason, remove the network hotplug agent:</para>

<screen><userinput>rm -fv /etc/hotplug/net.agent</userinput></screen>

    <para>Create a directory for storing firmware that can be loaded by
    <command>hotplug</command>:</para>

<screen><userinput>mkdir -v /lib/firmware</userinput></screen>

  </sect2>


  <sect2 id="contents-hotplug" role="content">
    <title>Contents of Hotplug</title>

    <segmentedlist>
      <segtitle>Installed program</segtitle>
      <segtitle>Installed scripts</segtitle>
      <segtitle>Installed files</segtitle>

      <seglistitem>
        <seg>hotplug</seg>
        <seg>/etc/hotplug/*.rc, /etc/hotplug/*.agent</seg>
        <seg>/etc/hotplug/hotplug.functions, /etc/hotplug/blacklist,
        /etc/hotplug/{pci,usb}, /etc/hotplug/usb.usermap, /etc/hotplug.d,
        and /var/log/hotplug/events</seg>
      </seglistitem>
    </segmentedlist>

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

      <varlistentry id="hotplug">
        <term><command>hotplug</command></term>
        <listitem>
          <para>This script is called by default by the Linux kernel when
          something changes in its internal state (e.g., a new device is
          added or an existing device is removed)</para>
          <indexterm zone="ch-system-hotplug hotplug">
            <primary sortas="b-hotplug">hotplug</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="hotplug-rc">
        <term><command>/etc/hotplug/*.rc</command></term>
        <listitem>
          <para>These scripts are used for cold plugging, i.e., detecting and
          acting upon hardware already present during system startup. They are
          called by the <filename>hotplug</filename> initscript included in
          the LFS-Bootscripts package. The <command>*.rc</command> scripts try
          to recover hotplug events that were lost during system boot because,
          for example, the root filesystem was not mounted by the kernel</para>
          <indexterm zone="ch-system-hotplug hotplug-rc">
            <primary sortas="d-/etc/hotplug/*.rc">/etc/hotplug/*.rc</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="hotplug-agent">
        <term><command>/etc/hotplug/*.agent</command></term>
        <listitem>
          <para>These scripts are called by <command>hotplug</command> in response
          to different types of hotplug events generated by the kernel. Their
          action is to insert corresponding kernel modules and call any
          user-provided scripts</para>
          <indexterm zone="ch-system-hotplug hotplug-agent">
            <primary sortas="d-/etc/hotplug/*.agent">/etc/hotplug/*.agent</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="hotplug-blacklist">
        <term><filename>/etc/hotplug/blacklist</filename></term>
        <listitem>
          <para>This file contains the list of modules that should never be
          inserted into the kernel by the Hotplug scripts</para>
          <indexterm zone="ch-system-hotplug hotplug-blacklist">
            <primary sortas="e-/etc/hotplug/blacklist">/etc/hotplug/blacklist</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="hotplug-functions">
        <term><filename>/etc/hotplug/hotplug.functions</filename></term>
        <listitem>
          <para>This file contains common functions used by other scripts in the
          Hotplug package</para>
          <indexterm zone="ch-system-hotplug hotplug-functions">
            <primary sortas="e-/etc/hotplug/hotplug.functions">/etc/hotplug/hotplug.functions</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="hotplug-subdirs">
        <term><filename class="directory">/etc/hotplug/{pci,usb}</filename></term>
        <listitem>
          <para>These directories contain user-written handlers for hotplug
          events</para>
          <indexterm zone="ch-system-hotplug hotplug-subdirs">
            <primary sortas="e-/etc/hotplug/{pci,usb}">/etc/hotplug/{pci,usb}</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="hotplug-usb.usermap">
        <term><filename>/etc/hotplug/usb.usermap</filename></term>
        <listitem>
          <para>This file contains rules that determine which user-defined handlers to
          call for each USB device, based on its vendor ID and other
          attributes</para>
          <indexterm zone="ch-system-hotplug hotplug-usb.usermap">
            <primary sortas="e-/etc/hotplug/usb.usermap">/etc/hotplug/usb.usermap</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="hotplug-hotplug.d">
        <term><filename class="directory">/etc/hotplug.d</filename></term>
        <listitem>
          <para>This directory contains programs (or symlinks to them) that are
          interested in receiving hotplug events. For example, Udev puts its
          symlink here during installation</para>
          <indexterm zone="ch-system-hotplug hotplug-hotplug.d">
            <primary sortas="e-/etc/hotplug.d">/etc/hotplug.d</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="hotplug-firmware">
        <term><filename class="directory">/lib/firmware</filename></term>
        <listitem>
          <para>This directory contains the firmware for devices that need to
          have their firmware loaded before use</para>
          <indexterm zone="ch-system-hotplug hotplug-firmware">
            <primary sortas="e-/lib/firmware">/lib/firmware</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="hotplug-events">
        <term><filename>/var/log/hotplug/events</filename></term>
        <listitem>
          <para>This file contains all the events that <command>hotplug</command>
          has called since bootup</para>
          <indexterm zone="ch-system-hotplug hotplug-events">
            <primary sortas="e-/var/log/hotplug/events">/var/log/hotplug/events</primary>
          </indexterm>
        </listitem>
      </varlistentry>

    </variablelist>

  </sect2>

</sect1>