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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">
<!--
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
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(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<refentry id="pam_systemd">
<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 control group hierarchy</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>pam_systemd.so</command>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><command>pam_systemd</command> registers user
sessions in 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 control group
<filename>/user/$USER/$XDG_SESSION_ID</filename>
is created and the login process moved into
it.</para></listitem>
</orderedlist>
<para>On logout, this module ensures the following:</para>
<orderedlist>
<listitem><para>If
<varname>$XDG_SESSION_ID</varname> is set and
<option>kill-session-processes=1</option> specified, all
remaining processes in the
<filename>/user/$USER/$XDG_SESSION_ID</filename>
control group are killed and the control group
is removed.</para></listitem>
<listitem><para>If last subgroup of the
<filename>/user/$USER</filename> control group
was removed 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>
<varlistentry>
<term><option>kill-session-processes=</option></term>
<listitem><para>Takes a boolean
argument. If true, all processes
created by the user during his session
and from his session will be
terminated when he logs out from his
session.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>kill-only-users=</option></term>
<listitem><para>Takes a comma
separated list of user names or
numeric user ids as argument. If this
option is used the effect of the
<option>kill-session-processes=</option> options
will apply only to the listed
users. If this option is not used the
option applies to all local
users. Note that
<option>kill-exclude-users=</option>
takes precedence over this list and is
hence subtracted from the list
specified here.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>kill-exclude-users=</option></term>
<listitem><para>Takes a comma
separated list of user names or
numeric user ids as argument. Users
listed in this argument will not be
subject to the effect of
<option>kill-session-processes=</option>. Note
that that this option takes precedence
over
<option>kill-only-users=</option>, and
hence whatever is listed for
<option>kill-exclude-users=</option>
is guaranteed to never be killed by
this PAM module, independent of any
other configuration
setting.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>controllers=</option></term>
<listitem><para>Takes a comma
separated list of control group
controllers in which hierarchies a
user/session control group will be
created by default for each user
logging in, in addition to the control
group in the named 'name=systemd'
hierarchy. If omitted, defaults to an
empty list.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>reset-controllers=</option></term>
<listitem><para>Takes a comma
separated list of control group
controllers in which hierarchies the
logged in processes will be reset to
the root control
group.</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>
<para>Note that setting
<varname>kill-session-processes=1</varname> will break tools
like
<citerefentry><refentrytitle>screen</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>
<para>Note that
<varname>kill-session-processes=1</varname> is a
stricter version of
<varname>KillUserProcesses=1</varname> which may be
configured system-wide in
<citerefentry><refentrytitle>systemd-logind.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
former kills processes of a session as soon as it
ends, the latter kills processes as soon as the last
session of the user ends.</para>
<para>If the options are omitted they default to
<option>kill-session-processes=0</option>,
<option>kill-only-users=</option>,
<option>kill-exclude-users=</option>,
<option>controllers=</option>,
<option>reset-controllers=</option>,
<option>debug=no</option>.</para>
</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>
<varlistentry>
<term><varname>$XDG_SESSION_ID</varname></term>
<listitem><para>A session identifier,
suitable to be used in file names. 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
behaviour 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 AF_UNIX 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 kill-session-processes=1</programlisting>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<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-logind.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>
|
