source: gnome/platform/gdm.xml@ b747635

<?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;

  <!ENTITY gdm-download-http "&gnome-download-http;/gdm/&gnome-40;/gdm-&gdm-version;.tar.xz">
  <!ENTITY gdm-download-ftp  "&gnome-download-ftp;/gdm/&gnome-40;/gdm-&gdm-version;.tar.xz">
  <!ENTITY gdm-md5sum        "85e6a306f1d0c88c276938a0519d8332">
  <!ENTITY gdm-size          "784 KB">
  <!ENTITY gdm-buildsize     "35 MB">
  <!ENTITY gdm-time          "0.1 SBU">
]>

<sect1 id="gdm" xreflabel="GDM-&gdm-version;">
  <?dbhtml filename="gdm.html"?>

  <sect1info>
    <date>$Date$</date>
  </sect1info>

  <title>GDM-&gdm-version;</title>

  <indexterm zone="gdm">
    <primary sortas="a-GDM">GDM</primary>
  </indexterm>

  <sect2 role="package">
    <title>Introduction to GDM</title>

    <para>
      <application>GDM</application> is a system service that is
      responsible for providing graphical logins and managing local
      and remote displays.
    </para>

    &lfs101_checked;

    <bridgehead renderas="sect3">Package Information</bridgehead>
    <itemizedlist spacing="compact">
      <listitem>
        <para>
          Download (HTTP): <ulink url="&gdm-download-http;"/>
        </para>
      </listitem>
      <listitem>
        <para>
          Download (FTP): <ulink url="&gdm-download-ftp;"/>
        </para>
      </listitem>
      <listitem>
        <para>
          Download MD5 sum: &gdm-md5sum;
        </para>
      </listitem>
      <listitem>
        <para>
          Download size: &gdm-size;
        </para>
      </listitem>
      <listitem>
        <para>
          Estimated disk space required: &gdm-buildsize;
        </para>
      </listitem>
      <listitem>
        <para>
          Estimated build time: &gdm-time;
        </para>
      </listitem>
    </itemizedlist>
    <!--
    <bridgehead renderas="sect3">Additional Downloads</bridgehead>
    <itemizedlist spacing="compact">
      <listitem>
        <para>
          Required patch:
          <ulink url="&patch-root;/gdm-&gdm-version;-security_fix-1.patch"/>
        </para>
      </listitem>
    </itemizedlist>
    -->
    <bridgehead renderas="sect3">GDM Dependencies</bridgehead>

    <bridgehead renderas="sect4">Required</bridgehead>
    <para role="required">
      <xref linkend="accountsservice"/>,
      <xref linkend="gtk3"/>,
      <xref linkend="iso-codes"/>,
      <xref linkend="itstool"/>,
      <xref linkend="libcanberra"/>, 
      <xref linkend="libdaemon"/>, and
      <xref linkend="linux-pam"/>
    </para>

    <bridgehead renderas="sect4">Optional</bridgehead>
    <para role="optional">
      <xref linkend="keyutils"/>
    </para>

    <bridgehead renderas="sect4">Runtime Dependencies</bridgehead>
    <para role="required">
      <xref role="runtime" linkend="gnome-session"/>,
      <xref role="runtime" linkend="gnome-shell"/>, and
      <phrase revision="sysv"><xref role="runtime" linkend="elogind"/></phrase>
      <phrase revision="systemd"><xref role="runtime" linkend="systemd"/></phrase>
    </para>

    <para condition="html" role="usernotes">User Notes:
      <ulink url="&blfs-wiki;/gdm"/>
    </para>
  </sect2>

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

    <para>
      It is recommended to have a dedicated user and group to take
      control of the <command>gdm</command> daemon after it is
      started. Issue the following commands as the
      <systemitem class="username">root</systemitem> user:
    </para>

<screen role="root"><userinput>groupadd -g 21 gdm &amp;&amp;
useradd -c "GDM Daemon Owner" -d /var/lib/gdm -u 21 \
        -g gdm -s /bin/false gdm &amp;&amp;
passwd -ql gdm</userinput></screen>

    <para revision="sysv">
      First, adapt GDM to build without systemd present:
    </para>

<screen revision="sysv"><userinput remap="pre">sed -i -r '/(^| )systemd_dep/d' meson.build</userinput></screen>

    <para>
      Install <application>GDM</application> by running the following
      commands:
    </para>

<screen revision="sysv"><userinput>sed 's@systemd@elogind@' -i data/pam-lfs/gdm-launch-environment.pam &amp;&amp;

mkdir build &amp;&amp;
cd    build &amp;&amp;

meson --prefix=/usr               \
      -Dplymouth=disabled         \
      -Dgdm-xsession=true         \
      -Dsystemd-journal=false     \
      -Dsystemdsystemunitdir=/tmp \
      -Dsystemduserunitdir=/tmp   .. &amp;&amp;
ninja</userinput></screen>

<screen revision="systemd"><userinput>mkdir build &amp;&amp;
cd    build &amp;&amp;

meson --prefix=/usr               \
      -Dplymouth=disabled         \
      -Dgdm-xsession=true ..      &amp;&amp;
ninja</userinput></screen>

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

    <para>
      Now, as the <systemitem class="username">root</systemitem> user:
    </para>

<screen role="root" revision="sysv"><userinput>ninja install &amp;&amp;
rm -rv /tmp/*.{service,target.d}</userinput></screen>

<screen role="root" revision="systemd"><userinput>ninja install</userinput></screen>

  </sect2>

  <sect2 role="commands">
    <title>Command Explanations</title>

    <para>
      <option>-Dinitial-vt=7</option>: Use this switch
      to make <application>GDM</application> start on VT7
      instead of the first free VT.
    </para>

    <para>
      <parameter>-Dplymouth=disabled</parameter>: GDM now explicitly requires 
      plymouth to be installed. Use this switch to disable this dependency.
    </para>

    <para>
      <option>-Ddefault-pam-config=lfs</option>: Use this
      switch if you did not create the
      <filename>/etc/lfs-release</filename> file or distribution
      auto detection will fail and you will be unable to use
      <application>GDM</application>.
    </para>

    <para>
      <parameter>-Dgdm-xsession=true</parameter>: This enables the
      installation of the <application>GDM</application> Xsession file.
    </para>

  </sect2>

  <sect2 role="configuration">
    <title>Configuring GDM</title>

    <sect3 id="gdm-config">
      <title>Config Files</title>

      <para>
        <filename>/etc/gdm/custom.conf</filename>
      </para>

      <indexterm zone="gdm gdm-config">
        <primary sortas="e-etc-gdm-custom.conf">/etc/gdm/custom.conf</primary>
      </indexterm>

    </sect3>

    <sect3>
      <title>Configuration Information</title>

      <para>
        The GDM daemon is configured using the
        <filename>/etc/gdm/custom.conf</filename> file. Default values
        are stored in GSettings in the <filename>gdm.schemas</filename>
        file. It is recommended that end-users modify the
        <filename>/etc/gdm/custom.conf</filename> file because the schemas
        file may be overwritten when the user updates their system to have
        a newer version of <application>GDM</application>.
      </para>

    </sect3>

    <sect3 id="gdm-init">
      <title><phrase revision="sysv">Boot Script</phrase>
             <phrase revision="systemd">Systemd Unit</phrase></title>

      <indexterm zone="gdm gdm-init">
        <primary sortas="f-gdm">gdm</primary>
      </indexterm>

      <para revision="sysv">
        To start <command>gdm</command> automatically when the system is
        switched to runlevel 5, install the
        <filename>/etc/rc.d/init.d/xdm</filename> script and the
        <filename>/etc/sysconfig/xdm</filename> configuration file
        included in the <xref linkend="bootscripts"/> package
        and adjust <filename>/etc/inittab</filename> by running
        as the <systemitem class="username">root</systemitem> user:
      </para>

<screen role="root" revision="sysv"><userinput>make install-gdm</userinput></screen>

      <para revision="sysv">
        In order to permanently set the default runlevel to 5, starting the
        <command>gdm</command> greeter screen automatically, you can modify
        <filename>/etc/inittab</filename>. As the  <systemitem
        class="username">root</systemitem> user:
      </para>

<screen role="root" revision="sysv"><userinput>sed /initdefault/s/3/5/ -i /etc/inittab</userinput></screen>

      <para revision="systemd">
        To start the <command>gdm</command> daemon at boot, enable
        the previously installed systemd unit by running the following command
        as the <systemitem class="username">root</systemitem> user:
      </para>

<screen role="root" revision="systemd"><userinput>systemctl enable gdm</userinput></screen>

<!-- [pierre October 2020] I don't understand why this is here: power
     management works perfectly well
      <para revision="sysv">
          You should also disable default elogind power management:
      </para>

<screen role="root" revision="sysv"><userinput>cat &gt;&gt; /etc/elogind/logind.conf &lt;&lt; "EOF"
<literal>AllowSuspend=no
AllowHibernation=no</literal>
EOF</userinput></screen>
-->

    </sect3>

  </sect2>

  <sect2 role="content">
    <title>Contents</title>

    <segmentedlist>
      <segtitle>Installed Programs</segtitle>
      <segtitle>Installed Libraries</segtitle>
      <segtitle>Installed Directories</segtitle>

      <seglistitem>
        <seg>
          gdm, gdmflexiserver, and gdm-screenshot
        </seg>
        <seg>
          libgdm.so and pam_gdm.so (PAM Module)
        </seg>
        <seg>
          /etc/gdm,
          /usr/include/gdm,
          /usr/share/gdm,
          /usr/share/help/*/gdm,
          /var/cache/gdm,
          /var/lib/gdm,
          /var/log/gdm, and
          /var/run/gdm
        </seg>
      </seglistitem>
    </segmentedlist>

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

      <varlistentry id="gdm-prog">
        <term><command>gdm</command></term>
        <listitem>
          <para>
            is a login prompt for <application>GNOME</application>
          </para>
          <indexterm zone="gdm gdm-prog">
            <primary sortas="b-gdm">gdm</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="gdm-screenshot">
        <term><command>gdm-screenshot</command></term>
        <listitem>
          <para>
            is a screenshot tool for <application>GDM</application>
          </para>
          <indexterm zone="gdm gdm-screenshot">
            <primary sortas="b-gdm-screenshot">gdm-screenshot</primary>
          </indexterm>
        </listitem>
      </varlistentry>

    </variablelist>

  </sect2>

</sect1>