systemd/man/pam_systemd.xml
Jan Engelhardt fbce11397f man: wording and grammar updates
This includes regularly-submitted corrections to comma setting and
orthographical mishaps that appeared in man/ in recent commits.
2013-07-21 11:23:58 -04:00

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<?xml version='1.0'?> <!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<refentry id="pam_systemd" conditional='HAVE_PAM'>
<refentryinfo>
<title>pam_systemd</title>
<productname>systemd</productname>
<authorgroup>
<author>
<contrib>Developer</contrib>
<firstname>Lennart</firstname>
<surname>Poettering</surname>
<email>lennart@poettering.net</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>pam_systemd</refentrytitle>
<manvolnum>8</manvolnum>
</refmeta>
<refnamediv>
<refname>pam_systemd</refname>
<refpurpose>Register user sessions in the systemd login manager</refpurpose>
</refnamediv>
<refsynopsisdiv>
<para><filename>pam_systemd.so</filename></para>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><command>pam_systemd</command> registers user
sessions in the systemd login manager
<citerefentry><refentrytitle>systemd-logind.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
and hence the systemd control group hierarchy.</para>
<para>On login, this module ensures the following:</para>
<orderedlist>
<listitem><para>If it does not exist yet, the
user runtime directory
<filename>/run/user/$USER</filename> is
created and its ownership changed to the user
that is logging in.</para></listitem>
<listitem><para>The
<varname>$XDG_SESSION_ID</varname> environment
variable is initialized. If auditing is
available and
<command>pam_loginuid.so</command> run before
this module (which is highly recommended), the
variable is initialized from the auditing
session id
(<filename>/proc/self/sessionid</filename>). Otherwise
an independent session counter is
used.</para></listitem>
<listitem><para>A new systemd scope unit is
created for the session. If this is the first
concurrent session of the user, an implicit
slice below <filename>user.slice</filename> is
automatically created and the scope placed in
it. In instance of the system service
<filename>user@.service</filename> which runs
the systemd user manager
instance.</para></listitem>
</orderedlist>
<para>On logout, this module ensures the following:</para>
<orderedlist>
<listitem><para>If this is enabled, all
processes of the session are terminated. If
the last concurrent session of a user ends, his
user systemd instance will be terminated too,
and so will the user's slice
unit.</para></listitem>
<listitem><para>If the last concurrent session
of a user ends, the
<varname>$XDG_RUNTIME_DIR</varname> directory
and all its contents are removed,
too.</para></listitem>
</orderedlist>
<para>If the system was not booted up with systemd as
init system, this module does nothing and immediately
returns PAM_SUCCESS.</para>
</refsect1>
<refsect1>
<title>Options</title>
<para>The following options are understood:</para>
<variablelist class='pam-directives'>
<varlistentry>
<term><option>class=</option></term>
<listitem><para>Takes a string
argument which sets the session class.
The XDG_SESSION_CLASS environmental variable
takes precedence.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>debug=</option></term>
<listitem><para>Takes a boolean
argument. If yes, the module will log
debugging information as it
operates.</para></listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Module Types Provided</title>
<para>Only <option>session</option> is provided.</para>
</refsect1>
<refsect1>
<title>Environment</title>
<para>The following environment variables are set for the processes of the user's session:</para>
<variablelist class='environment-variables'>
<varlistentry>
<term><varname>$XDG_SESSION_ID</varname></term>
<listitem><para>A session identifier,
suitable to be used in filenames. The
string itself should be considered
opaque, although often it is just the
audit session ID as reported by
<filename>/proc/self/sessionid</filename>. Each
ID will be assigned only once during
machine uptime. It may hence be used
to uniquely label files or other
resources of this
session.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>$XDG_RUNTIME_DIR</varname></term>
<listitem><para>Path to a user-private
user-writable directory that is bound
to the user login time on the
machine. It is automatically created
the first time a user logs in and
removed on his final logout. If a user
logs in twice at the same time, both
sessions will see the same
<varname>$XDG_RUNTIME_DIR</varname>
and the same contents. If a user logs
in once, then logs out again, and logs
in again, the directory contents will
have been lost in between, but
applications should not rely on this
behavior and must be able to deal with
stale files. To store session-private
data in this directory, the user should
include the value of <varname>$XDG_SESSION_ID</varname>
in the filename. This directory shall
be used for runtime file system
objects such as <constant>AF_UNIX</constant> sockets,
FIFOs, PID files and similar. It is
guaranteed that this directory is
local and offers the greatest possible
file system feature set the
operating system
provides.</para></listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Example</title>
<programlisting>#%PAM-1.0
auth required pam_unix.so
auth required pam_nologin.so
account required pam_unix.so
password required pam_unix.so
session required pam_unix.so
session required pam_loginuid.so
session required pam_systemd.so</programlisting>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-logind.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>logind.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>loginctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>pam.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>pam.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>pam</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>pam_loginuid</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>