PAM_SYSTEMD(8)                   pam_systemd                  PAM_SYSTEMD(8)

NAME         top

       pam_systemd - Register user sessions in the systemd login manager

SYNOPSIS         top

DESCRIPTION         top

       pam_systemd registers user sessions with the systemd login manager
       systemd-logind.service(8), and hence the systemd control group

       On login, this module — in conjunction with systemd-logind.service —
       ensures the following:

        1. If it does not exist yet, the user runtime directory
           /run/user/$UID is either created or mounted as new "tmpfs" file
           system with quota applied, and its ownership changed to the user
           that is logging in.

        2. The $XDG_SESSION_ID environment variable is initialized. If
           auditing is available and was run before this
           module (which is highly recommended), the variable is initialized
           from the auditing session id (/proc/self/sessionid). Otherwise,
           an independent session counter is used.

        3. 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 user.slice is automatically created and the
           scope placed into it. An instance of the system service
           user@.service, which runs the systemd user manager instance, is

       On logout, this module ensures the following:

        1. If enabled in logind.conf(5) (KillUserProcesses=), 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.

        2. If the last concurrent session of a user ends, the user runtime
           directory /run/user/$UID and all its contents are removed, too.

       If the system was not booted up with systemd as init system, this
       module does nothing and immediately returns PAM_SUCCESS.

OPTIONS         top

       The following options are understood:

           Takes a string argument which sets the session class. The
           XDG_SESSION_CLASS environmental variable takes precedence. One of
           "user", "greeter", "lock-screen" or "background". See
           sd_session_get_class(3) for details about the session class.

           Takes a string argument which sets the session type. The
           XDG_SESSION_TYPE environmental variable takes precedence. One of
           "unspecified", "tty", "x11", "wayland" or "mir". See
           sd_session_get_type(3) for details about the session type.

           Takes an optional boolean argument. If yes or without the
           argument, the module will log debugging information as it


       Only session is provided.

ENVIRONMENT         top

       The following environment variables are set for the processes of the
       user's session:

           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 /proc/self/sessionid.
           Each ID will be assigned only once during machine uptime. It may
           hence be used to uniquely label files or other resources of this

           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 the user's final
           logout. If a user logs in twice at the same time, both sessions
           will see the same $XDG_RUNTIME_DIR 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 $XDG_SESSION_ID
           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. For further details, see the XDG Base Directory
           Specification[1].  $XDG_RUNTIME_DIR is not set if the current
           user is not the original user of the session.

       The following environment variables are read by the module and may be
       used by the PAM service to pass metadata to the module:

           The session type. This may be used instead of session= on the
           module parameter line, and is usually preferred.

           The session class. This may be used instead of class= on the
           module parameter line, and is usually preferred.

           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:
           "GNOME", or "KDE". It is recommended to use the same identifiers
           and capitalization as for $XDG_CURRENT_DESKTOP, as defined by the
           Desktop Entry Specification[2]. (However, note that
           $XDG_SESSION_DESKTOP only takes a single item, and not a
           colon-separated list like $XDG_CURRENT_DESKTOP.) See
           sd_session_get_desktop(3) for more details.

           The seat name the session shall be registered for, if any.

           The VT number the session shall be registered for, if any. (Only
           applies to seats with a VT available, such as "seat0")

EXAMPLE         top

           auth       required
           auth       required
           account    required
           password   required
           session    required
           session    required
           session    required

SEE ALSO         top

       systemd(1), systemd-logind.service(8), logind.conf(5), loginctl(1),
       pam.conf(5), pam.d(5), pam(8), pam_loginuid(8), systemd.scope(5),
       systemd.slice(5), systemd.service(5)

NOTES         top

        1. XDG Base Directory Specification

        2. Desktop Entry Specification

COLOPHON         top

       This page is part of the systemd (systemd system and service manager)
       project.  Information about the project can be found at 
       ⟨⟩.  If you have a bug
       report for this manual page, see
       ⟨⟩.  This
       page was obtained from the project's upstream Git repository
       ⟨⟩ on 2019-05-09.  (At that
       time, the date of the most recent commit that was found in the repos‐
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       of the original manual page), send a mail to

systemd 234                                                   PAM_SYSTEMD(8)

Pages that refer to this page: systemd.exec(5)systemd.directives(7)systemd.index(7)systemd-logind.service(8)