PAM_SYSTEMD(8)							    pam_systemd 						    PAM_SYSTEMD(8)

NAME

       pam_systemd - Register user sessions in the systemd control group hierarchy

SYNOPSIS

       pam_systemd.so

DESCRIPTION

       pam_systemd registers user sessions in the systemd control group hierarchy.

       On login, this module ensures the following:

	1. If it does not exist yet, the user runtime directory /run/user/$USER is created 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 pam_loginuid.so 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 control group /user/$USER/$XDG_SESSION_ID is created and the login process moved into it.

       On logout, this module ensures the following:

	1. If $XDG_SESSION_ID is set and kill-session-processes=1 specified, all remaining processes in the /user/$USER/$XDG_SESSION_ID control
	   group are killed and the control group is removed.

	2. If last subgroup of the /user/$USER control group was removed the $XDG_RUNTIME_DIR directory 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

       The following options are understood:

       kill-session-processes=
	   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.

       kill-only-users=
	   Takes a comma separated list of user names or numeric user ids as argument. If this option is used the effect of the
	   kill-session-processes= options will apply only to the listed users. If this option is not used the option applies to all local users.
	   Note that kill-exclude-users= takes precedence over this list and is hence subtracted from the list specified here.

       kill-exclude-users=
	   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 kill-session-processes=. Note that that this option takes precedence over kill-only-users=, and hence whatever is listed for
	   kill-exclude-users= is guaranteed to never be killed by this PAM module, independent of any other configuration setting.

       controllers=
	   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.

       reset-controllers=
	   Takes a comma separated list of control group controllers in which hierarchies the logged in processes will be reset to the root
	   control group.

       debug=
	   Takes a boolean argument. If yes, the module will log debugging information as it operates.

       Note that setting kill-session-processes=1 will break tools like screen(1).

       Note that kill-session-processes=1 is a stricter version of KillUserProcesses=1 which may be configured system-wide in systemd-
       logind.conf(5). 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.

       If the options are omitted they default to kill-session-processes=0, kill-only-users=, kill-exclude-users=, controllers=,
       reset-controllers=, debug=no.

MODULE TYPES PROVIDED

       Only session is provided.

ENVIRONMENT

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

       $XDG_SESSION_ID
	   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 /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 session.

       $XDG_RUNTIME_DIR
	   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
	   $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 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 $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.

EXAMPLE

	   #%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

SEE ALSO

       pam.conf(5), pam.d(5), pam(8), pam_loginuid(8), systemd-logind.conf(5), systemd(1)

AUTHOR

       Lennart Poettering <lennart@poettering.net>
	   Developer

systemd 							    10/07/2013							    PAM_SYSTEMD(8)