source: BOOK/final-system/common/hotplug.xml@ 0f4dd37

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<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
  "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [
  <!ENTITY % general-entities SYSTEM "../../general.ent">
  %general-entities;
]>

<sect1 id="ch-system-hotplug" xreflabel="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 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>&dependencies;</segtitle>

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

  </sect2>

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

    <para os="a">Install the Hotplug package:</para>

<screen os="b"><userinput>make install</userinput></screen>

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

<screen os="d"><userinput>rm -rf /etc/init.d</userinput></screen>

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

<screen os="f"><userinput>rm -f /etc/hotplug/net.agent</userinput></screen>

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

<screen os="h"><userinput>mkdir /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 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>