lfs-book/chapter06/sysvinit.xml

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<!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">
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<sect1 id="ch-system-sysvinit" role="wrap">
  <?dbhtml filename="sysvinit.html"?>

  <title>Sysvinit-&sysvinit-version;</title>

  <indexterm zone="ch-system-sysvinit">
    <primary sortas="a-Sysvinit">Sysvinit</primary>
  </indexterm>

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

    <para>The Sysvinit package contains programs for controlling the startup,
    running, and shutdown of the system.</para>

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

      <seglistitem>
        <seg>&sysvinit-ch6-sbu;</seg>
        <seg>&sysvinit-ch6-du;</seg>
      </seglistitem>
    </segmentedlist>

  </sect2>

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

    <para>When run-levels are changed (for example, when halting the
    system), <command>init</command> sends termination signals to those
    processes that <command>init</command> itself started and that should
    not be running in the new run-level.  While doing this,
    <command>init</command> outputs messages like <quote>Sending processes
    the TERM signal</quote> which seem to imply that it is sending these
    signals to all currently running processes. To avoid this
    misinterpretation, modify the source so that these messages read like
    <quote>Sending processes configured via /etc/inittab the TERM signal</quote>
    instead:</para>

<screen><userinput>sed -i 's@Sending processes@&amp; configured via /etc/inittab@g' \
    src/init.c</userinput></screen>

    <para>Compile the package:</para>

<screen><userinput>make -C src</userinput></screen>

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

    <para>Install the package:</para>

<screen><userinput>make -C src install</userinput></screen>

  </sect2>

  <sect2 id="conf-sysvinit" role="configuration">
    <title>Configuring Sysvinit</title>

    <indexterm zone="conf-sysvinit">
      <primary sortas="a-Sysvinit">Sysvinit</primary>
      <secondary>configuring</secondary>
    </indexterm>

    <indexterm zone="conf-sysvinit">
      <primary sortas="e-/etc/inittab">/etc/inittab</primary>
    </indexterm>

    <para>Create a new file <filename>/etc/inittab</filename> by running the
    following:</para>

<screen><userinput>cat &gt; /etc/inittab &lt;&lt; "EOF"
<literal># Begin /etc/inittab

id:3:initdefault:

si::sysinit:/etc/rc.d/init.d/rc sysinit

l0:0:wait:/etc/rc.d/init.d/rc 0
l1:S1:wait:/etc/rc.d/init.d/rc 1
l2:2:wait:/etc/rc.d/init.d/rc 2
l3:3:wait:/etc/rc.d/init.d/rc 3
l4:4:wait:/etc/rc.d/init.d/rc 4
l5:5:wait:/etc/rc.d/init.d/rc 5
l6:6:wait:/etc/rc.d/init.d/rc 6

ca:12345:ctrlaltdel:/sbin/shutdown -t1 -a -r now

su:S016:once:/sbin/sulogin

1:2345:respawn:/sbin/agetty tty1 9600
2:2345:respawn:/sbin/agetty tty2 9600
3:2345:respawn:/sbin/agetty tty3 9600
4:2345:respawn:/sbin/agetty tty4 9600
5:2345:respawn:/sbin/agetty tty5 9600
6:2345:respawn:/sbin/agetty tty6 9600

# End /etc/inittab</literal>
EOF</userinput></screen>

  </sect2>

  <sect2 id="contents-sysvinit" role="content">
    <title>Contents of Sysvinit</title>

    <segmentedlist>
      <segtitle>Installed programs</segtitle>

      <seglistitem>
        <seg>bootlogd, halt, init, killall5, last, lastb (link to last), mesg,
        mountpoint, pidof (link to killall5), poweroff (link to halt),
        reboot (link to halt), runlevel, shutdown, sulogin,
        telinit (link to init), utmpdump, and wall</seg>
      </seglistitem>
    </segmentedlist>

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

      <varlistentry id="bootlogd">
        <term><command>bootlogd</command></term>
        <listitem>
          <para>Logs boot messages to a log file</para>
          <indexterm zone="ch-system-sysvinit bootlogd">
            <primary sortas="b-bootlogd">bootlogd</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="halt">
        <term><command>halt</command></term>
        <listitem>
          <para>Normally invokes <command>shutdown</command> with the
          <parameter>-h</parameter> option, except when already in run-level 0,
          then it tells the kernel to halt the system; it notes in the
          file <filename>/var/log/wtmp</filename> that the system is being
          brought down</para>
          <indexterm zone="ch-system-sysvinit halt">
            <primary sortas="b-halt">halt</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="init">
        <term><command>init</command></term>
        <listitem>
          <para>The first process to be started when the kernel has initialized
          the hardware which takes over the boot process and starts all the
          proceses it is instructed to</para>
          <indexterm zone="ch-system-sysvinit init">
            <primary sortas="b-init">init</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="killall5">
        <term><command>killall5</command></term>
        <listitem>
          <para>Sends a signal to all processes, except the processes in its own
          session so it will not kill the shell running the script that called
          it</para>
          <indexterm zone="ch-system-sysvinit killall5">
            <primary sortas="b-killall5">killall5</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="last">
        <term><command>last</command></term>
        <listitem>
          <para>Shows which users last logged in (and out), searching back
          through the <filename>/var/log/wtmp</filename> file; it also shows
          system boots, shutdowns, and run-level changes</para>
          <indexterm zone="ch-system-sysvinit last">
            <primary sortas="b-last">last</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="lastb">
        <term><command>lastb</command></term>
        <listitem>
          <para>Shows the failed login attempts, as logged in
          <filename>/var/log/btmp</filename></para>
          <indexterm zone="ch-system-sysvinit lastb">
            <primary sortas="b-lastb">lastb</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="mesg">
        <term><command>mesg</command></term>
        <listitem>
          <para>Controls whether other users can send messages to the current
          user's terminal</para>
          <indexterm zone="ch-system-sysvinit mesg">
            <primary sortas="b-mesg">mesg</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="mountpoint">
        <term><command>mountpoint</command></term>
        <listitem>
          <para>Checks if the directory is a mountpoint</para>
          <indexterm zone="ch-system-sysvinit mountpoint">
            <primary sortas="b-mountpoint">mountpoint</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="pidof">
        <term><command>pidof</command></term>
        <listitem>
          <para>Reports the PIDs of the given programs</para>
          <indexterm zone="ch-system-sysvinit pidof">
            <primary sortas="b-pidof">pidof</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="poweroff">
        <term><command>poweroff</command></term>
        <listitem>
          <para>Tells the kernel to halt the system and switch off the computer
          (see <command>halt</command>)</para>
          <indexterm zone="ch-system-sysvinit poweroff">
            <primary sortas="b-poweroff">poweroff</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="reboot">
        <term><command>reboot</command></term>
        <listitem>
          <para>Tells the kernel to reboot the system (see
          <command>halt</command>)</para>
          <indexterm zone="ch-system-sysvinit reboot">
            <primary sortas="b-reboot">reboot</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="runlevel">
        <term><command>runlevel</command></term>
        <listitem>
          <para>Reports the previous and the current run-level, as noted in the
          last run-level record in <filename>/var/run/utmp</filename></para>
          <indexterm zone="ch-system-sysvinit runlevel">
            <primary sortas="b-runlevel">runlevel</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="shutdown">
        <term><command>shutdown</command></term>
        <listitem>
          <para>Brings the system down in a secure way, signaling all processes
          and notifying all logged-in users</para>
          <indexterm zone="ch-system-sysvinit shutdown">
            <primary sortas="b-shutdown">shutdown</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="sulogin">
        <term><command>sulogin</command></term>
        <listitem>
          <para>Allows <systemitem class="username">root</systemitem> to log in;
          it is normally invoked by <command>init</command> when the system goes
          into single user mode</para>
          <indexterm zone="ch-system-sysvinit sulogin">
            <primary sortas="b-sulogin">sulogin</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="telinit">
        <term><command>telinit</command></term>
        <listitem>
          <para>Tells <command>init</command> which run-level to change to</para>
          <indexterm zone="ch-system-sysvinit telinit">
            <primary sortas="b-telinit">telinit</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="utmpdump">
        <term><command>utmpdump</command></term>
        <listitem>
          <para>Displays the content of the given login file in a more
          user-friendly format</para>
          <indexterm zone="ch-system-sysvinit utmpdump">
            <primary sortas="b-utmpdump">utmpdump</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="wall">
        <term><command>wall</command></term>
        <listitem>
          <para>Writes a message to all logged-in users</para>
          <indexterm zone="ch-system-sysvinit wall">
            <primary sortas="b-wall">wall</primary>
          </indexterm>
        </listitem>
      </varlistentry>

    </variablelist>

  </sect2>

</sect1>