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- Copyright 2010 Lennart Poettering
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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>
<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>
+ <para>On login, this module — in conjunction with <filename>systemd-logind.service</filename> — 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> was run before this
- module (which is highly recommended), the variable is
- initialized from the auditing session id
- (<filename>/proc/self/sessionid</filename>). Otherwise, an
+ <listitem><para>If it does not exist yet, the user runtime directory <filename>/run/user/$UID</filename> is
+ either created or mounted as new <literal>tmpfs</literal> file system with quota applied, and its ownership
+ changed to the user that is logging in.</para></listitem>
+
+ <listitem><para>The <varname>$XDG_SESSION_ID</varname> environment variable is initialized. If auditing is
+ available and <command>pam_loginuid.so</command> was 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 into it. An instance
- of the system service <filename>user@.service</filename>, which
- runs the systemd user manager instance, is started.
- </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 per-user slice unit below <filename>user.slice</filename> is automatically created and the
+ scope placed into it. An instance of the system service <filename>user@.service</filename>, which runs the
+ systemd user manager instance, is started. </para></listitem>
</orderedlist>
<para>On logout, this module ensures the following:</para>
<orderedlist>
<listitem><para>If enabled in
<citerefentry><refentrytitle>logind.conf</refentrytitle>
- <manvolnum>5</manvolnum></citerefentry>, all processes of the
- session are terminated. If the last concurrent session of a user
- ends, the user's systemd instance will be terminated too, and so
- will the user's slice unit.</para></listitem>
+ <manvolnum>5</manvolnum></citerefentry> (<varname>KillUserProcesses=</varname>), all processes of the session are
+ terminated. If the last concurrent session of a user ends, the user's 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>$XDG_RUNTIME_DIR</varname> directory and all its
+ the user runtime directory <filename>/run/user/$UID</filename> and all its
contents are removed, too.</para></listitem>
</orderedlist>
<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. One of
- <literal>user</literal>,
- <literal>greeter</literal>,
- <literal>lock-screen</literal> or
- <literal>background</literal>. See
- <citerefentry><refentrytitle>sd_session_get_class</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- for details about the session class.</para></listitem>
+ <listitem><para>Takes a string argument which sets the session class. The <varname>XDG_SESSION_CLASS</varname>
+ environment variable (see below) takes precedence. One of <literal>user</literal>, <literal>greeter</literal>,
+ <literal>lock-screen</literal> or <literal>background</literal>. See
+ <citerefentry><refentrytitle>sd_session_get_class</refentrytitle><manvolnum>3</manvolnum></citerefentry> for
+ details about the session class.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>type=</option></term>
- <listitem><para>Takes a string argument which sets the session
- type. The XDG_SESSION_TYPE environmental variable takes
- precedence. One of
- <literal>unspecified</literal>,
- <literal>tty</literal>,
- <literal>x11</literal>,
- <literal>wayland</literal> or
- <literal>mir</literal>. See
- <citerefentry><refentrytitle>sd_session_get_type</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- for details about the session type.</para></listitem>
+ <listitem><para>Takes a string argument which sets the session type. The <varname>XDG_SESSION_TYPE</varname>
+ environment variable (see below) takes precedence. One of <literal>unspecified</literal>,
+ <literal>tty</literal>, <literal>x11</literal>, <literal>wayland</literal> or <literal>mir</literal>. See
+ <citerefentry><refentrytitle>sd_session_get_type</refentrytitle><manvolnum>3</manvolnum></citerefentry> for
+ details about the session type.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>desktop=</option></term>
+
+ <listitem><para>Takes a single, short identifier string for the desktop environment. The
+ <varname>XDG_SESSION_DESKTOP</varname> environment variable (see below) takes precedence. This may be used to
+ indicate the session desktop used, where this applies and if this information is available. For example:
+ <literal>GNOME</literal>, or <literal>KDE</literal>. It is recommended to use the same identifiers and
+ capitalization as for <varname>$XDG_CURRENT_DESKTOP</varname>, as defined by the <ulink
+ url="http://standards.freedesktop.org/desktop-entry-spec/latest/">Desktop Entry
+ Specification</ulink>. (However, note that the option only takes a single item, and not a colon-separated list
+ like <varname>$XDG_CURRENT_DESKTOP</varname>.) See
+ <citerefentry><refentrytitle>sd_session_get_desktop</refentrytitle><manvolnum>3</manvolnum></citerefentry> for
+ further details.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>debug<optional>=</optional></option></term>
- <listitem><para>Takes an optional
- boolean argument. If yes or without
- the argument, the module will log
- debugging information as it
- operates.</para></listitem>
+ <listitem><para>Takes an optional boolean argument. If yes or without the argument, the module will log
+ debugging information as it operates.</para></listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Environment</title>
- <para>The following environment variables are set for the
- processes of the user's session:</para>
+ <para>The following environment variables are initialized by the module and available to the processes of the
+ user's session:</para>
<variablelist class='environment-variables'>
<varlistentry>
<term><varname>$XDG_SESSION_ID</varname></term>
- <listitem><para>A session identifier, suitable to be used in
- filenames. The string itself should be considered opaque,
- although often it is just the audit session ID as reported by
- <filename>/proc/self/sessionid</filename>. Each ID will be
- assigned only once during machine uptime. It may hence be used
- to uniquely label files or other resources of this
- session.</para></listitem>
+ <listitem><para>A short session identifier, suitable to be used in filenames. The string itself should be
+ considered opaque, although often it is just the audit session ID as reported by
+ <filename>/proc/self/sessionid</filename>. Each ID will be assigned only once during machine uptime. It may
+ hence be used to uniquely label files or other resources of this session. Combine this ID with the boot
+ identifier, as returned by
+ <citerefentry><refentrytitle>sd_id128_get_boot</refentrytitle><manvolnum>3</manvolnum></citerefentry>, for a
+ globally unique identifier for the current session.</para></listitem>
</varlistentry>
<varlistentry>
as <constant>AF_UNIX</constant> sockets, FIFOs, PID files and
similar. It is guaranteed that this directory is local and
offers the greatest possible file system feature set the
- operating system provides. For further details see the <ulink
+ operating system provides. For further details
, see the <ulink
url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG
- Base Directory Specification</ulink>.</para></listitem>
+ Base Directory Specification</ulink>. <varname>$XDG_RUNTIME_DIR</varname>
+ is not set if the current user is not the original user of the session.</para></listitem>
</varlistentry>
</variablelist>
- <para>The following environment variables are read by the module
- and may be used by the PAM service to pass metadata to the
- module:</para>
+ <para>The following environment variables are read by the module and may be used by the PAM service to pass
+ metadata to the module. If these variables are not set when the PAM module is invoked but can be determined
+ otherwise they are set by the module, so that these variables are initialized for the session and applications if
+ known at all.</para>
<variablelist class='environment-variables'>
<varlistentry>
<term><varname>$XDG_SESSION_TYPE</varname></term>
- <listitem><para>The session type. This may be used instead of
- <option>session=</option> on the module parameter line, and is
- usually preferred.</para></listitem>
+ <listitem><para>The session type. This may be used instead of <option>session=</option> on the module parameter
+ line, and is usually preferred.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>$XDG_SESSION_CLASS</varname></term>
- <listitem><para>The session class. This may be used instead of
- <option>class=</option> on the module parameter line, and is
- usually preferred.</para></listitem>
+ <listitem><para>The session class. This may be used instead of <option>class=</option> on the module parameter
+ line, and is usually preferred.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>$XDG_SESSION_DESKTOP</varname></term>
- <listitem><para>A single, short identifier string for the
- desktop environment. This may be used to indicate the session
- desktop used, where this applies and if this information is
- available. For example: <literal>GNOME</literal>, or
- <literal>KDE</literal>. It is recommended to use the same
- identifiers and capitalization as for
- <varname>$XDG_CURRENT_DESKTOP</varname>, as defined by the
- <ulink
- url="http://standards.freedesktop.org/desktop-entry-spec/latest/">Desktop
- Entry Specification</ulink>. (However, note that
- <varname>$XDG_SESSION_DESKTOP</varname> only takes a single
- item, and not a colon-separated list like
- <varname>$XDG_CURRENT_DESKTOP</varname>.) See
- <citerefentry><refentrytitle>sd_session_get_desktop</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- for more details.</para></listitem>
+ <listitem><para>The desktop identifier. This may be used instead of <option>desktop=</option> on the module
+ parameter line, and is usually preferred.</para></listitem>
</varlistentry>
<varlistentry>
for, if any. (Only applies to seats with a VT available, such
as <literal>seat0</literal>)</para></listitem>
</varlistentry>
+ </variablelist>
+
+ <para>If not set, <command>pam_systemd</command> will initialize
+ <varname>$XDG_SEAT</varname> and <varname>$XDG_VTNR</varname>
+ based on the <varname>$DISPLAY</varname> variable (if the latter is set).</para>
+ </refsect1>
+ <refsect1>
+ <title>Session limits</title>
+
+ <para>PAM modules earlier in the stack, that is those that come before <command>pam_systemd.so</command>,
+ can set session scope limits using the PAM context objects. The data for these objects is provided as NUL-terminated C strings
+ and maps directly to the respective unit resource control directives. Note that these limits apply to individual sessions of the user,
+ they do not apply to all user processes as a combined whole. In particular, the per-user <command>user@.service</command> unit instance,
+ which runs the <command>systemd --user</command> manager process and its children, and is tracked outside of any session, being shared
+ by all the user's sessions, is not covered by these limits.
+ </para>
+
+ <para> See
+ <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more information about the resources.
+ Also, see <citerefentry><refentrytitle>pam_set_data</refentrytitle><manvolnum>3</manvolnum></citerefentry> for additional information about how to set
+ the context objects.
+ </para>
+
+ <variablelist>
+ <varlistentry>
+ <term><varname>systemd.memory_max</varname></term>
+
+ <listitem><para>Sets unit <varname>MemoryMax=</varname>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>systemd.tasks_max</varname></term>
+
+ <listitem><para>Sets unit <varname>TasksMax=</varname>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>systemd.cpu_weight</varname></term>
+
+ <listitem><para>Sets unit <varname>CPUWeight=</varname>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>systemd.io_weight</varname></term>
+
+ <listitem><para>Sets unit <varname>IOWeight=</varname>.</para></listitem>
+ </varlistentry>
</variablelist>
+
+ <para>Example data as can be provided from an another PAM module:
+ <programlisting>
+pam_set_data(handle, "systemd.memory_max", (void *)"200M", cleanup);
+pam_set_data(handle, "systemd.tasks_max", (void *)"50", cleanup);
+pam_set_data(handle, "systemd.cpu_weight", (void *)"100", cleanup);
+pam_set_data(handle, "systemd.io_weight", (void *)"340", cleanup);
+ </programlisting>
+ </para>
+
</refsect1>
<refsect1>
projects / thirdparty / systemd.git / blobdiff