systemd Developer Lennart Poettering lennart@poettering.net pam_systemd 8 pam_systemd Register user sessions in the systemd control group hierarchy pam_systemd.so pam_systemd registers user sessions in the systemd control group hierarchy. On login, this module ensures the following: If it does not exist yet, the user runtime directory /var/run/user/$USER is created and its ownership changed to the user that is logging in. If create-session=1 is set, the $XDG_SESSION_ID environment variable is initialized. If auditing is available and pam_loginuid.so run before this module (which is highly recommended), the variable is initialized from the auditing session id (/proc/self/sessionid). Otherwise an independent session counter is used. If create-session=1 is set, a new control group /user/$USER/$XDG_SESSION_ID is created and the login process moved into it. If create-session=0 is set, a new control group /user/$USER/user is created and the login process moved into it. On logout, this module ensures the following: If $XDG_SESSION_ID is set and kill-session=1 specified, all remaining processes in the /user/$USER/$XDG_SESSION_ID control group are killed and the control group is removed. If $XDG_SESSION_ID is set and kill-session=0 specified, all remaining processes in the /user/$USER/$XDG_SESSION_ID control group are migrated to /user/$USER/user and the original control group is removed. If kill-user=1 is specified, and no other user session control group remains, except /user/$USER/user, all remaining processes in the /user/$USER hierarchy are killed and the control group is removed. If kill-user=0 is specified, and no process remains in the /user/$USER hierarchy the control group is removed. If the /user/$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. The following options are understood: create-session= Takes a boolean argument. If true, a new session is created: the $XDG_SESSION_ID environment variable is set and the login process moved to the /user/$USER/$XDG_SESSION_ID control group. It is recommended that all services which are directly created on the user's behalf set this option. Only for services that shall automatically be terminated when the user logs out completely, otherwise create-session=0 should be set. kill-session= 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-user= Takes a boolean argument. If true, all processes created by the user during his session and from his session will be terminated after he logged out completely. This is a weaker version of kill-session=1 and is more friendly for users logged in more than once, as their processes are terminated only on their complete logout. keep-root= Takes a boolean argument. If true, all processes created by the root user (UID 0) during his session and from his session will be kept around after he logged out. This option allows cancelling the effect of kill-session=1 and kill-user=1 for the root user. controllers= Takes a comma separated list of cgroup controllers in which hierarchies a user/session cgroup will be created by default for each user logging in. If ommited, defaults to 'cpu', meaning that in addition to creating per-user and per-session cgroups in systemd's own hierarchy, groups are created in the 'cpu' hierarchy, on order to ensure that every use and every sessions gets an equal amount of CPU time, regardless how many processes a user or session might own. Note that setting kill-user=1 or even kill-session=1 will break tools like screen1. If the options are omitted they default to create-session=1, kill-session=0, kill-user=0, keep-root=1. Only session is provided. 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. #%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-user=1 pam.conf5, pam.d5, pam8, pam_loginuid8, systemd1