man/pam_systemd.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4
   5 <!--
   6   This file is part of systemd.
   7
   8   Copyright 2010 Lennart Poettering
   9
  10   systemd is free software; you can redistribute it and/or modify it
  11   under the terms of the GNU Lesser General Public License as published by
  12   the Free Software Foundation; either version 2.1 of the License, or
  13   (at your option) any later version.
  14
  15   systemd is distributed in the hope that it will be useful, but
  16   WITHOUT ANY WARRANTY; without even the implied warranty of
  17   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  18   Lesser General Public License for more details.
  19
  20   You should have received a copy of the GNU Lesser General Public License
  21   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  22 -->
  23
  24 <refentry id="pam_systemd" conditional='HAVE_PAM'>
  25
  26         <refentryinfo>
  27                 <title>pam_systemd</title>
  28                 <productname>systemd</productname>
  29
  30                 <authorgroup>
  31                         <author>
  32                                 <contrib>Developer</contrib>
  33                                 <firstname>Lennart</firstname>
  34                                 <surname>Poettering</surname>
  35                                 <email>lennart@poettering.net</email>
  36                         </author>
  37                 </authorgroup>
  38         </refentryinfo>
  39
  40         <refmeta>
  41                 <refentrytitle>pam_systemd</refentrytitle>
  42                 <manvolnum>8</manvolnum>
  43         </refmeta>
  44
  45         <refnamediv>
  46                 <refname>pam_systemd</refname>
  47                 <refpurpose>Register user sessions in the systemd login manager</refpurpose>
  48         </refnamediv>
  49
  50         <refsynopsisdiv>
  51                 <para><filename>pam_systemd.so</filename></para>
  52         </refsynopsisdiv>
  53
  54         <refsect1>
  55                 <title>Description</title>
  56
  57                 <para><command>pam_systemd</command> registers user
  58                 sessions with the systemd login manager
  59                 <citerefentry><refentrytitle>systemd-logind.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
  60                 and hence the systemd control group hierarchy.</para>
  61
  62                 <para>On login, this module ensures the following:</para>
  63
  64                 <orderedlist>
  65                         <listitem><para>If it does not exist yet, the
  66                         user runtime directory
  67                         <filename>/run/user/$USER</filename> is
  68                         created and its ownership changed to the user
  69                         that is logging in.</para></listitem>
  70
  71                         <listitem><para>The
  72                         <varname>$XDG_SESSION_ID</varname> environment
  73                         variable is initialized. If auditing is
  74                         available and
  75                         <command>pam_loginuid.so</command> run before
  76                         this module (which is highly recommended), the
  77                         variable is initialized from the auditing
  78                         session id
  79                         (<filename>/proc/self/sessionid</filename>). Otherwise
  80                         an independent session counter is
  81                         used.</para></listitem>
  82
  83                         <listitem><para>A new systemd scope unit is
  84                         created for the session. If this is the first
  85                         concurrent session of the user, an implicit
  86                         slice below <filename>user.slice</filename> is
  87                         automatically created and the scope placed in
  88                         it. In instance of the system service
  89                         <filename>user@.service</filename> which runs
  90                         the systemd user manager
  91                         instance.</para></listitem>
  92                 </orderedlist>
  93
  94                 <para>On logout, this module ensures the following:</para>
  95
  96                 <orderedlist>
  97                         <listitem><para>If this is enabled, all
  98                         processes of the session are terminated. If
  99                         the last concurrent session of a user ends, his
 100                         user systemd instance will be terminated too,
 101                         and so will the user's slice
 102                         unit.</para></listitem>
 103
 104                         <listitem><para>If the last concurrent session
 105                         of a user ends, the
 106                         <varname>$XDG_RUNTIME_DIR</varname> directory
 107                         and all its contents are removed,
 108                         too.</para></listitem>
 109                 </orderedlist>
 110
 111                 <para>If the system was not booted up with systemd as
 112                 init system, this module does nothing and immediately
 113                 returns PAM_SUCCESS.</para>
 114
 115         </refsect1>
 116
 117         <refsect1>
 118                 <title>Options</title>
 119
 120                 <para>The following options are understood:</para>
 121
 122                 <variablelist class='pam-directives'>
 123
 124                         <varlistentry>
 125                                 <term><option>class=</option></term>
 126
 127                                 <listitem><para>Takes a string
 128                                 argument which sets the session class.
 129                                 The XDG_SESSION_CLASS environmental variable
 130                                 takes precedence. One of
 131                                 <literal>user</literal>,
 132                                 <literal>greeter</literal>,
 133                                 <literal>lock-screen</literal> or
 134                                 <literal>background</literal>. See
 135                                 <citerefentry><refentrytitle>sd_session_get_class</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 136                                 for details about the session class.</para></listitem>
 137                         </varlistentry>
 138
 139                         <varlistentry>
 140                                 <term><option>type=</option></term>
 141
 142                                 <listitem><para>Takes a string
 143                                 argument which sets the session type.
 144                                 The XDG_SESSION_TYPE environmental
 145                                 variable takes precedence. One of
 146                                 <literal>unspecified</literal>,
 147                                 <literal>tty</literal>,
 148                                 <literal>x11</literal> or
 149                                 <literal>wayland</literal>. See
 150                                 <citerefentry><refentrytitle>sd_session_get_type</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 151                                 for details about the session type.</para></listitem>
 152                         </varlistentry>
 153
 154                         <varlistentry>
 155                                 <term><option>debug<optional>=</optional></option></term>
 156
 157                                 <listitem><para>Takes an optional
 158                                 boolean argument. If yes or without
 159                                 the argument, the module will log
 160                                 debugging information as it
 161                                 operates.</para></listitem>
 162                         </varlistentry>
 163                 </variablelist>
 164         </refsect1>
 165
 166         <refsect1>
 167                 <title>Module Types Provided</title>
 168
 169                 <para>Only <option>session</option> is provided.</para>
 170         </refsect1>
 171
 172         <refsect1>
 173                 <title>Environment</title>
 174
 175                 <para>The following environment variables are set for the processes of the user's session:</para>
 176
 177                 <variablelist class='environment-variables'>
 178                         <varlistentry>
 179                                 <term><varname>$XDG_SESSION_ID</varname></term>
 180
 181                                 <listitem><para>A session identifier,
 182                                 suitable to be used in filenames. The
 183                                 string itself should be considered
 184                                 opaque, although often it is just the
 185                                 audit session ID as reported by
 186                                 <filename>/proc/self/sessionid</filename>. Each
 187                                 ID will be assigned only once during
 188                                 machine uptime. It may hence be used
 189                                 to uniquely label files or other
 190                                 resources of this
 191                                 session.</para></listitem>
 192                         </varlistentry>
 193
 194                         <varlistentry>
 195                                 <term><varname>$XDG_RUNTIME_DIR</varname></term>
 196
 197                                 <listitem><para>Path to a user-private
 198                                 user-writable directory that is bound
 199                                 to the user login time on the
 200                                 machine. It is automatically created
 201                                 the first time a user logs in and
 202                                 removed on his final logout. If a user
 203                                 logs in twice at the same time, both
 204                                 sessions will see the same
 205                                 <varname>$XDG_RUNTIME_DIR</varname>
 206                                 and the same contents. If a user logs
 207                                 in once, then logs out again, and logs
 208                                 in again, the directory contents will
 209                                 have been lost in between, but
 210                                 applications should not rely on this
 211                                 behavior and must be able to deal with
 212                                 stale files. To store session-private
 213                                 data in this directory, the user should
 214                                 include the value of <varname>$XDG_SESSION_ID</varname>
 215                                 in the filename. This directory shall
 216                                 be used for runtime file system
 217                                 objects such as <constant>AF_UNIX</constant> sockets,
 218                                 FIFOs, PID files and similar. It is
 219                                 guaranteed that this directory is
 220                                 local and offers the greatest possible
 221                                 file system feature set the
 222                                 operating system
 223                                 provides.</para></listitem>
 224                         </varlistentry>
 225
 226                 </variablelist>
 227
 228                 <para>The following environment variables are read by
 229                 the module and may be used by the PAM service to pass
 230                 metadata to the module:</para>
 231
 232                 <variablelist class='environment-variables'>
 233                         <varlistentry>
 234                                 <term><varname>$XDG_SESSION_TYPE</varname></term>
 235
 236                                 <listitem><para>The session type. This
 237                                 may be used instead of
 238                                 <option>session=</option> on the
 239                                 module parameter line, and is usually
 240                                 preferred.</para></listitem>
 241                         </varlistentry>
 242
 243                         <varlistentry>
 244                                 <term><varname>$XDG_SESSION_CLASS</varname></term>
 245
 246                                 <listitem><para>The session class. This
 247                                 may be used instead of
 248                                 <option>class=</option> on the
 249                                 module parameter line, and is usually
 250                                 preferred.</para></listitem>
 251                         </varlistentry>
 252
 253                         <varlistentry>
 254                                 <term><varname>$XDG_SESSION_DESKTOP</varname></term>
 255
 256                                 <listitem><para>The session
 257                                 deskop. This may be used to indicate
 258                                 the session desktop used, where this
 259                                 applies. This should be a short,
 260                                 lowercase string identifying the
 261                                 desktop environment used if this
 262                                 information is available. For example:
 263                                 <literal>gnome</literal>, or
 264                                 <literal>kde</literal>.</para></listitem>
 265                         </varlistentry>
 266
 267                         <varlistentry>
 268                                 <term><varname>$XDG_SEAT</varname></term>
 269
 270                                 <listitem><para>The seat name the session
 271                                 shall be registered for, if
 272                                 any.</para></listitem>
 273                         </varlistentry>
 274
 275                         <varlistentry>
 276                                 <term><varname>$XDG_VTNR</varname></term>
 277
 278                                 <listitem><para>The VT number the
 279                                 session shall be registered for, if
 280                                 any. (Only applies to seats with a VT
 281                                 available, such as
 282                                 <literal>seat0</literal>)</para></listitem>
 283                         </varlistentry>
 284
 285                 </variablelist>
 286         </refsect1>
 287
 288         <refsect1>
 289                 <title>Example</title>
 290
 291                 <programlisting>#%PAM-1.0
 292 auth       required     pam_unix.so
 293 auth       required     pam_nologin.so
 294 account    required     pam_unix.so
 295 password   required     pam_unix.so
 296 session    required     pam_unix.so
 297 session    required     pam_loginuid.so
 298 session    required     pam_systemd.so</programlisting>
 299         </refsect1>
 300
 301         <refsect1>
 302                 <title>See Also</title>
 303                 <para>
 304                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 305                         <citerefentry><refentrytitle>systemd-logind.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 306                         <citerefentry><refentrytitle>logind.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 307                         <citerefentry><refentrytitle>loginctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 308                         <citerefentry><refentrytitle>pam.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 309                         <citerefentry><refentrytitle>pam.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 310                         <citerefentry><refentrytitle>pam</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 311                         <citerefentry><refentrytitle>pam_loginuid</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 312                         <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 313                         <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 314                         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 315                 </para>
 316         </refsect1>
 317
 318 </refentry>