systemd-logind.service, systemd-logind-metrics.socket, systemd-logind — Login manager
systemd-logind.service
systemd-logind-metrics.socket
/usr/lib/systemd/systemd-logind
systemd-logind is a system service that manages user logins. It is responsible for:
Keeping track of users and sessions, their processes and their idle state. This is implemented by
allocating a systemd slice unit for each user below user.slice, and a scope unit below it
for each concurrent session of a user. Also, a per-user service manager is started as system service instance of
user@.service for each logged in user.
Generating and managing session IDs. If auditing is available and an audit session ID is already set for a session, then this ID is reused as the session ID. Otherwise, an independent session counter is used.
Providing polkit-based access for users for operations such as system shutdown or sleep
Implementing a shutdown/sleep inhibition logic for applications
Handling of power/sleep hardware keys
Multi-seat management
Session switch management
Device access management for users
Automatic spawning of text logins (gettys) on virtual console activation and user runtime directory management
Scheduled shutdown
Sending "wall" messages
User sessions are registered with logind via the pam_systemd(8) PAM module.
See logind.conf(5) for information about the configuration of this service.
See sd-login(3) for information about the basic concepts of logind such as users, sessions and seats.
See
org.freedesktop.login1(5)
and
org.freedesktop.LogControl1(5)
for information about the D-Bus APIs systemd-logind provides.
In addition to the D-Bus interface, systemd-logind also provides a Varlink
interface io.systemd.Shutdown for shutting down or rebooting the system. It
supports PowerOff, Reboot, Halt,
KExec, and SoftReboot methods. Each method accepts an
optional skipInhibitors boolean parameter to bypass active block inhibitors
(matching the SD_LOGIND_SKIP_INHIBITORS flag of the D-Bus interface). The
interface can be queried with
varlinkctl introspect /run/systemd/io.systemd.Login io.systemd.Shutdown.
For more information see Inhibitor Locks.
If you are interested in writing a display manager that makes use of logind, please have look at Writing Display Managers. If you are interested in writing a desktop environment that makes use of logind, please have look at Writing Desktop Environments.
systemd-logind is a metrics source for systemd-report(1) and reports the following metrics:
io.systemd.Login.CurrentSessions"¶A gauge metric with the number of current sessions. The metric field
class is set to the session class, see $XDG_SESSION_CLASS in
pam_systemd(8).
io.systemd.Login.SessionsStarted"¶A counter metric with the number of sessions started since boot, by session class.
Sessions are counted under the class they have been created with. The metric field
class is set as above. This counter is kept across restarts of the service, but
reset on reboot.
io.systemd.Login.SuspendCounter"¶A counter metric with the number of suspend cycles since boot. The metric field
result is set to "success" or "fail".