org.freedesktop.login1 — The D-Bus interface of systemd-logind
systemd-logind.service(8) is a system service that keeps track of user logins and seats.
The daemon provides both a C library interface as well as a D-Bus interface. The library interface may be used to introspect and watch the state of user logins and seats. The bus interface provides the same functionality but in addition may also be used to make changes to the system state. For more information please consult sd-login(3).
The service exposes the following interfaces on the Manager object on the bus:
node /org/freedesktop/login1 {
  interface org.freedesktop.login1.Manager {
    methods:
      GetSession(in  s session_id,
                 out o object_path);
      GetSessionByPID(in  u pid,
                      out o object_path);
      GetUser(in  u uid,
              out o object_path);
      GetUserByPID(in  u pid,
                   out o object_path);
      GetSeat(in  s seat_id,
              out o object_path);
      ListSessions(out a(susso) sessions);
      ListSessionsEx(out a(sussussbto) sessions);
      ListUsers(out a(uso) users);
      ListSeats(out a(so) seats);
      ListInhibitors(out a(ssssuu) inhibitors);
      @org.freedesktop.systemd1.Privileged("true")
      CreateSession(in  u uid,
                    in  u pid,
                    in  s service,
                    in  s type,
                    in  s class,
                    in  s desktop,
                    in  s seat_id,
                    in  u vtnr,
                    in  s tty,
                    in  s display,
                    in  b remote,
                    in  s remote_user,
                    in  s remote_host,
                    in  a(sv) properties,
                    out s session_id,
                    out o object_path,
                    out s runtime_path,
                    out h fifo_fd,
                    out u uid,
                    out s seat_id,
                    out u vtnr,
                    out b existing);
      @org.freedesktop.systemd1.Privileged("true")
      CreateSessionWithPIDFD(in  u uid,
                             in  h pidfd,
                             in  s service,
                             in  s type,
                             in  s class,
                             in  s desktop,
                             in  s seat_id,
                             in  u vtnr,
                             in  s tty,
                             in  s display,
                             in  b remote,
                             in  s remote_user,
                             in  s remote_host,
                             in  t flags,
                             in  a(sv) properties,
                             out s session_id,
                             out o object_path,
                             out s runtime_path,
                             out h fifo_fd,
                             out u uid,
                             out s seat_id,
                             out u vtnr,
                             out b existing);
      ReleaseSession(in  s session_id);
      ActivateSession(in  s session_id);
      ActivateSessionOnSeat(in  s session_id,
                            in  s seat_id);
      LockSession(in  s session_id);
      UnlockSession(in  s session_id);
      LockSessions();
      UnlockSessions();
      KillSession(in  s session_id,
                  in  s whom,
                  in  i signal_number);
      KillUser(in  u uid,
               in  i signal_number);
      TerminateSession(in  s session_id);
      TerminateUser(in  u uid);
      TerminateSeat(in  s seat_id);
      SetUserLinger(in  u uid,
                    in  b enable,
                    in  b interactive);
      AttachDevice(in  s seat_id,
                   in  s sysfs_path,
                   in  b interactive);
      FlushDevices(in  b interactive);
      PowerOff(in  b interactive);
      PowerOffWithFlags(in  t flags);
      Reboot(in  b interactive);
      RebootWithFlags(in  t flags);
      Halt(in  b interactive);
      HaltWithFlags(in  t flags);
      Suspend(in  b interactive);
      SuspendWithFlags(in  t flags);
      Hibernate(in  b interactive);
      HibernateWithFlags(in  t flags);
      HybridSleep(in  b interactive);
      HybridSleepWithFlags(in  t flags);
      SuspendThenHibernate(in  b interactive);
      SuspendThenHibernateWithFlags(in  t flags);
      Sleep(in  t flags);
      CanPowerOff(out s result);
      CanReboot(out s result);
      CanHalt(out s result);
      CanSuspend(out s result);
      CanHibernate(out s result);
      CanHybridSleep(out s result);
      CanSuspendThenHibernate(out s result);
      CanSleep(out s result);
      ScheduleShutdown(in  s type,
                       in  t usec);
      CancelScheduledShutdown(out b cancelled);
      Inhibit(in  s what,
              in  s who,
              in  s why,
              in  s mode,
              out h pipe_fd);
      CanRebootParameter(out s result);
      SetRebootParameter(in  s parameter);
      CanRebootToFirmwareSetup(out s result);
      SetRebootToFirmwareSetup(in  b enable);
      CanRebootToBootLoaderMenu(out s result);
      SetRebootToBootLoaderMenu(in  t timeout);
      CanRebootToBootLoaderEntry(out s result);
      SetRebootToBootLoaderEntry(in  s boot_loader_entry);
      SetWallMessage(in  s wall_message,
                     in  b enable);
    signals:
      SecureAttentionKey(s seat_id,
                         o object_path);
      SessionNew(s session_id,
                 o object_path);
      SessionRemoved(s session_id,
                     o object_path);
      UserNew(u uid,
              o object_path);
      UserRemoved(u uid,
                  o object_path);
      SeatNew(s seat_id,
              o object_path);
      SeatRemoved(s seat_id,
                  o object_path);
      PrepareForShutdown(b start);
      PrepareForShutdownWithMetadata(b start,
                                     a{sv} metadata);
      PrepareForSleep(b start);
    properties:
      @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
      @org.freedesktop.systemd1.Privileged("true")
      readwrite b EnableWallMessages = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
      @org.freedesktop.systemd1.Privileged("true")
      readwrite s WallMessage = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly u NAutoVTs = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly as KillOnlyUsers = ['...', ...];
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly as KillExcludeUsers = ['...', ...];
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly b KillUserProcesses = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
      readonly s RebootParameter = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
      readonly b RebootToFirmwareSetup = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
      readonly t RebootToBootLoaderMenu = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
      readonly s RebootToBootLoaderEntry = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly as BootLoaderEntries = ['...', ...];
      readonly b IdleHint = ...;
      readonly t IdleSinceHint = ...;
      readonly t IdleSinceHintMonotonic = ...;
      readonly s BlockInhibited = '...';
      readonly s BlockWeakInhibited = '...';
      readonly s DelayInhibited = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly t InhibitDelayMaxUSec = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly t UserStopDelayUSec = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly as SleepOperation = ['...', ...];
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s HandlePowerKey = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s HandlePowerKeyLongPress = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s HandleRebootKey = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s HandleRebootKeyLongPress = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s HandleSuspendKey = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s HandleSuspendKeyLongPress = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s HandleHibernateKey = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s HandleHibernateKeyLongPress = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s HandleLidSwitch = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s HandleLidSwitchExternalPower = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s HandleLidSwitchDocked = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s HandleSecureAttentionKey = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly t HoldoffTimeoutUSec = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s IdleAction = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly t IdleActionUSec = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
      readonly b PreparingForShutdown = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
      readonly a{sv} PreparingForShutdownWithMetadata = [...];
      @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
      readonly b PreparingForSleep = ...;
      readonly (st) ScheduledShutdown = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s DesignatedMaintenanceTime = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
      readonly b Docked = ...;
      readonly b LidClosed = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
      readonly b OnExternalPower = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly b RemoveIPC = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly t RuntimeDirectorySize = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly t RuntimeDirectoryInodesMax = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly t InhibitorsMax = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
      readonly t NCurrentInhibitors = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly t SessionsMax = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
      readonly t NCurrentSessions = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly t StopIdleSessionUSec = ...;
  };
  interface org.freedesktop.DBus.Peer { ... };
  interface org.freedesktop.DBus.Introspectable { ... };
  interface org.freedesktop.DBus.Properties { ... };
};
GetSession() may be used to get the session object path for the session with
      the specified ID. Similarly, GetUser() and GetSeat() get the
      user and seat objects, respectively. GetSessionByPID() and
      GetUserByPID() get the session/user object the specified PID belongs to if there
      is any.
ListSessions() returns an array of all current sessions. The structures in
      the array consist of the following fields: session id, user id,
      user name, seat id, and session object path.
      If a session does not have a seat attached, the seat id field will be an empty string.
ListSessionsEx() returns an array of all current sessions with more metadata
      than ListSessions(). The structures in the array consist of the following fields:
      session id, user id, user name,
      seat id, leader pid, session class,
      tty name, idle hint, idle hint monotonic timestamp,
      and session object path. tty and seat id fields
      could be empty, if the session has no associated tty or session has no seat attached, respectively.
ListUsers() returns an array of all currently logged in users. The
      structures in the array consist of the following fields: user id, user name, user object path.
ListSeats() returns an array of all currently available seats. The
      structure in the array consists of the following fields: seat id, seat object path.
ListInhibitors() lists all currently active inhibitors. It returns an array of
      structures consisting of what, who, why,
      mode, uid (user ID), and pid (process ID).
CreateSession(), CreateSessionWithPIDFD(), and
      ReleaseSession() may be used to open or close login sessions. These calls should
      never be invoked directly by clients. Creating/closing sessions is exclusively the job
      of PAM and its pam_systemd(8)
      module.
ActivateSession() brings the session with the specified ID into the
      foreground. ActivateSessionOnSeat() does the same, but only if the seat id
      matches.
LockSession() asks the session with the specified ID to activate the screen
      lock. UnlockSession() asks the session with the specified ID to remove an active
      screen lock, if there is any. This is implemented by sending out the Lock() and Unlock() signals from
      the respective session object which session managers are supposed to listen on.
LockSessions() asks all sessions to activate their screen locks. This may be
      used to lock access to the entire machine in one action. Similarly, UnlockSessions()
      asks all sessions to deactivate their screen locks.
KillSession() may be used to send a Unix signal to one or all processes of a
      session. As arguments it takes the session id, either the string "leader" or
      "all" and a signal number. If "leader" is passed only the session
      "leader" is killed. If "all" is passed all processes of the session
      are killed.
KillUser() may be used to send a Unix signal to all processes of a user. As
      arguments it takes the user id and a signal number.
TerminateSession(), TerminateUser(),
      TerminateSeat() may be used to forcibly terminate one specific session, all
      processes of a user, and all sessions attached to a specific seat, respectively. The session, user,
      and seat are identified by their respective IDs.
SetUserLinger() enables or disables user lingering. If enabled, the runtime
      directory of a user is kept around and they may continue to run processes while logged out. If
      disabled, the runtime directory goes away as soon as they log out. SetUserLinger()
      expects three arguments: the UID, a boolean whether to enable/disable and a boolean controlling the
      polkit
      authorization interactivity (see below). Note that the user linger state is persistently
      stored on disk.
AttachDevice() may be used to assign a specific device to a specific
      seat. The device is identified by its /sys/ path and must be eligible for seat
      assignments. AttachDevice() takes three arguments: the seat id, the sysfs path,
      and a boolean for controlling polkit interactivity (see below). Device assignments are persistently
      stored on disk. To create a new seat, simply specify a previously unused seat id. For more information
      about the seat assignment logic see
      sd-login(3).
FlushDevices() removes all explicit seat assignments for devices, resetting
      all assignments to the automatic defaults. The only argument it takes is the polkit interactivity
      boolean (see below).
PowerOff(), Reboot(), Halt(),
      Suspend(), and Hibernate() result in the system being powered
      off, rebooted, halted (shut down without turning off power), suspended (the system state is saved to
      RAM and the CPU is turned off), or hibernated (the system state is saved to disk and the machine is
      powered down). HybridSleep() results in the system entering a hybrid-sleep mode,
      i.e. the system is both hibernated and suspended. SuspendThenHibernate() results
      in the system being suspended, then later woken using an RTC timer and hibernated. The only argument is
      the polkit interactivity boolean interactive (see below). The main purpose of these
      calls is that they enforce polkit policy and hence allow powering off/rebooting/suspending/hibernating
      even by unprivileged users. They also enforce inhibition locks for non-privileged users.
      Sleep() automatically selects the most suitable sleep operation supported by the
      machine. The candidate sleep operations to check for support can be configured through SleepOperation=
      setting in logind.conf(5).
      UIs should expose these calls as the primary mechanism to poweroff/reboot/suspend/hibernate the machine. Methods
      PowerOffWithFlags(), RebootWithFlags(),
      HaltWithFlags(), SuspendWithFlags(),
      HibernateWithFlags(), HybridSleepWithFlags(),
      SuspendThenHibernateWithFlags(), and Sleep() take
      flags to allow for extendability, defined as follows:
#define SD_LOGIND_ROOT_CHECK_INHIBITORS (UINT64_C(1) << 0) #define SD_LOGIND_KEXEC_REBOOT (UINT64_C(1) << 1) #define SD_LOGIND_SOFT_REBOOT (UINT64_C(1) << 2) #define SD_LOGIND_SOFT_REBOOT_IF_NEXTROOT_SET_UP (UINT64_C(1) << 3) #define SD_LOGIND_SKIP_INHIBITORS (UINT64_C(1) << 4)
When the flags is 0 then these methods behave just like the versions without
      flags. Since systemd version 257 inhibitors of type "block" are enforced on operations
      requested by both privileged and unprivileged users. Previously they were honoured only by unprivileged
      users, excluding the user owning the inhibitor. The latter behaviour is now available through the
      "block-weak" inhibitor lock type. SD_LOGIND_ROOT_CHECK_INHIBITORS
      (0x01) makes "block-weak" locks behave like regular "block" locks,
      i.e. ensures they are honoured for any user. A flag SD_LOGIND_SKIP_INHIBITORS
      (0x10) can be specified to bypass both "block" and "block-weak"
      inhibitors (it has no effect on "delay" inhibitors). When
      SD_LOGIND_KEXEC_REBOOT (0x02) is set, then RebootWithFlags()
      performs a kexec reboot if kexec kernel is loaded. When SD_LOGIND_SOFT_REBOOT
      (0x04) is set, or SD_LOGIND_SOFT_REBOOT_IF_NEXTROOT_SET_UP (0x08) is set and a new
      root file system has been set up on "/run/nextroot/", then
      RebootWithFlags() performs a userspace reboot
      only. SD_LOGIND_SOFT_REBOOT_IF_NEXTROOT_SET_UP and
      SD_LOGIND_KEXEC_REBOOT can be combined, with soft-reboot having precedence.
      
SetRebootParameter() sets a parameter for a subsequent reboot operation.
      See the description of reboot in
      systemctl(1) and
      reboot(2)
      for more information.
SetRebootToFirmwareSetup(),
      SetRebootToBootLoaderMenu(), and SetRebootToBootLoaderEntry()
      configure the action to be taken from the boot loader after a reboot: respectively entering firmware
      setup mode, the boot loader menu, or a specific boot loader entry. See
      systemctl(1) for the
      corresponding command line interface.
CanPowerOff(), CanReboot(), CanHalt(),
      CanSuspend(), CanHibernate(), CanHybridSleep(),
      CanSuspendThenHibernate(), CanSleep(),
      CanRebootParameter(), CanRebootToFirmwareSetup(),
      CanRebootToBootLoaderMenu(), and CanRebootToBootLoaderEntry()
      test whether the system supports the respective operation and whether the calling user is allowed to
      execute it. Returns one of "na", "yes", "no", and
      "challenge". If "na" is returned, the operation is not available because
      hardware, kernel, or drivers do not support it. If "yes" is returned, the operation is
      supported and the user may execute the operation without further authentication. If "no"
      is returned, the operation is available but the user is not allowed to execute the operation. If
      "challenge" is returned, the operation is available but only after authorization.
ScheduleShutdown() schedules a shutdown operation type at
      time usec in microseconds since the UNIX epoch. Alternatively, if
      usec "UINT64_MAX" and a maintenance window is
      configured, systemd-logind will use the next time of the maintenance window
      instead. type can be one
      of "poweroff", "dry-poweroff", "reboot",
      "dry-reboot", "halt", and "dry-halt". (The
      "dry-" variants do not actually execute the shutdown action.)
      CancelScheduledShutdown() cancels a scheduled shutdown. The output parameter
      cancelled is true if a shutdown operation was scheduled.
SetWallMessage() sets the wall message (the message that will be sent out to
      all terminals and stored in a
      utmp(5) record) for a
      subsequent scheduled shutdown operation. The parameter wall_message specifies the
      shutdown reason (and may be empty) which will be included in the shutdown message. The parameter
      enable specifies whether to print a wall message on shutdown.
Inhibit() creates an inhibition lock. It takes four parameters:
      what, who, why, and
      mode. what is one or more of "shutdown",
      "sleep", "idle", "handle-power-key",
      "handle-suspend-key", "handle-hibernate-key",
      "handle-lid-switch", separated by colons, for inhibiting poweroff/reboot,
      suspend/hibernate, the automatic idle logic, or hardware key handling. who should be
      a short human-readable string identifying the application taking the lock. why
      should be a short human-readable string identifying the reason why the lock is taken. Finally,
      mode is either "block" or "delay" which encodes
      whether the inhibit shall be consider mandatory or whether it should just delay the operation to a
      certain maximum time, while the "block-weak" and variants will create an inhibitor
      that is automatically ignored in some circumstances. The method returns a file descriptor. The lock is
      released the moment this file descriptor and all its duplicates are closed. For more information on
      the inhibition logic see Inhibitor Locks.
      
Whenever the inhibition state or idle hint changes, PropertyChanged
      signals are sent out to clients which have subscribed.
The SecureAttentionKey() signal is sent when the user presses Ctrl+Alt+Shift+Esc to
      request the login manager to display the greeter, for instance in the case of a deadlocked compositor.
      
The SessionNew(), SessionRemoved(),
      UserNew(), UserRemoved(), SeatNew(), and
      SeatRemoved() signals are sent each time a session is created or removed, a user
      logs in or out, or a seat is added or removed. They each contain the ID of the object plus the object
      path.
The PrepareForShutdown(),
      PrepareForShutdownWithMetadata(), and PrepareForSleep()
      signals are sent right before (with the argument "true") or after (with the argument
      "false") the system goes down for reboot/poweroff and suspend/hibernate,
      respectively. This may be used by applications to save data on disk, release memory, or do other jobs
      that should be done shortly before shutdown/sleep, in conjunction with delay inhibitor locks. After
      completion of this work they should release their inhibition locks in order to not delay the operation
      any further. For more information see
      Inhibitor Locks. The
      PrepareForShutdownWithMetadata() signal additionally sends a list of key/value
      pair metadata fields. Currently it sends a type string which defines the type of
      shutdown. The type can be one of "power-off", "reboot",
      "halt", "kexec" or "soft-reboot". This signal is
      sent first, followed by PrepareForShutdown() (for backward compatibility).
Most properties simply reflect the configuration, see
      logind.conf(5). This
      includes: NAutoVTs, KillOnlyUsers,
      KillExcludeUsers, KillUserProcesses, IdleAction,
      InhibitDelayMaxUSec,
      InhibitorsMax,
      UserStopDelayUSec,
      HandlePowerKey, HandleSuspendKey,
      HandleHibernateKey, HandleLidSwitch,
      HandleLidSwitchExternalPower, HandleLidSwitchDocked,
      IdleActionUSec, HoldoffTimeoutUSec,
      RemoveIPC, RuntimeDirectorySize,
      RuntimeDirectoryInodesMax, InhibitorsMax, and
      SessionsMax.
      
The IdleHint property reflects the idle hint state of the system. If the
      system is idle it might get into automatic suspend or shutdown depending on the configuration.
IdleSinceHint and IdleSinceHintMonotonic encode the
      timestamps of the last change of the idle hint boolean, in CLOCK_REALTIME and
      CLOCK_MONOTONIC timestamps, respectively, in microseconds since the epoch.
The BlockInhibited, BlockWeakInhibited, and
      DelayInhibited properties encode the currently active locks of the respective
      modes. They are colon separated lists of "shutdown", "sleep", and
      "idle" (see above).
NCurrentSessions and NCurrentInhibitors contain the number
      of currently registered sessions and inhibitors.
The BootLoaderEntries property contains a list of boot loader entries.
      This includes boot loader entries defined in configuration and any additional loader entries
      reported by the boot loader. See
      systemd-boot(7)
      for more information.
The PreparingForShutdown and PreparingForSleep boolean
      properties are true during the interval between the two PrepareForShutdown() and
      PrepareForSleep() signals respectively. The
      PreparingForShutdownWithMetadata property provides a list of key/value pair
      metadata fields. Currently it lists a preparing boolean that corresponds to the
      PreparingForShutdown property, and, if a shutdown is being prepared, it will also
      contain a type string which defines the type of shutdown. The type can be one of
      "power-off", "reboot", "halt",
      "kexec" or "soft-reboot". Note that these properties do not send out
      PropertyChanged signals.
The RebootParameter property shows the value set with the
      SetRebootParameter() method described above.
ScheduledShutdown shows the value pair set with the
      ScheduleShutdown() method described above.
RebootToFirmwareSetup, RebootToBootLoaderMenu, and
      RebootToBootLoaderEntry are true when the resprective post-reboot operation was
      selected with SetRebootToFirmwareSetup(),
      SetRebootToBootLoaderMenu(), or
      SetRebootToBootLoaderEntry().
The WallMessage and EnableWallMessages properties reflect the
      shutdown reason and wall message enablement switch which can be set with the
      SetWallMessage() method described above.
Docked is true if the machine is connected to a dock.
      LidClosed is true when the lid (of a laptop) is closed.
      OnExternalPower is true when the machine is connected to an external power supply.
      
A number of operations are protected via the polkit privilege
      system. SetUserLinger() requires the
      org.freedesktop.login1.set-user-linger
      privilege. AttachDevice() requires
      org.freedesktop.login1.attach-device and
      FlushDevices() requires
      org.freedesktop.login1.flush-devices. PowerOff(),
      Reboot(), Halt(), Suspend(),
      Hibernate() require
      org.freedesktop.login1.power-off,
      org.freedesktop.login1.power-off-multiple-sessions,
      org.freedesktop.login1.power-off-ignore-inhibit,
      org.freedesktop.login1.reboot,
      org.freedesktop.login1.reboot-multiple-sessions,
      org.freedesktop.login1.reboot-ignore-inhibit,
      org.freedesktop.login1.halt,
      org.freedesktop.login1.halt-multiple-sessions,
      org.freedesktop.login1.halt-ignore-inhibit,
      org.freedesktop.login1.suspend,
      org.freedesktop.login1.suspend-multiple-sessions,
      org.freedesktop.login1.suspend-ignore-inhibit,
      org.freedesktop.login1.hibernate,
      org.freedesktop.login1.hibernate-multiple-sessions,
      org.freedesktop.login1.hibernate-ignore-inhibit,
      respectively depending on whether there are other sessions around or active inhibits are present.
      HybridSleep() and SuspendThenHibernate()
      use the same privileges as Hibernate(). Sleep() uses
      the inhibits of the auto-selected sleep operation. SetRebootParameter() requires
      org.freedesktop.login1.set-reboot-parameter.
SetRebootToFirmwareSetup() requires
      org.freedesktop.login1.set-reboot-to-firmware-setup.
      SetRebootToBootLoaderMenu() requires
      org.freedesktop.login1.set-reboot-to-boot-loader-menu.
      SetRebootToBootLoaderEntry() requires
      org.freedesktop.login1.set-reboot-to-boot-loader-entry.
      
ScheduleShutdown() and CancelScheduledShutdown() require
      the same privileges (listed above) as the immediate poweroff/reboot/halt operations.
Inhibit() is protected via one of
      org.freedesktop.login1.inhibit-block-shutdown,
      org.freedesktop.login1.inhibit-delay-shutdown,
      org.freedesktop.login1.inhibit-block-sleep,
      org.freedesktop.login1.inhibit-delay-sleep,
      org.freedesktop.login1.inhibit-block-idle,
      org.freedesktop.login1.inhibit-handle-power-key,
      org.freedesktop.login1.inhibit-handle-suspend-key,
      org.freedesktop.login1.inhibit-handle-hibernate-key,
      org.freedesktop.login1.inhibit-handle-lid-switch depending on the lock
      type and mode taken.
The interactive boolean parameters can be used to control whether polkit
      should interactively ask the user for authentication credentials if required.
node /org/freedesktop/login1/seat/seat0 {
  interface org.freedesktop.login1.Seat {
    methods:
      Terminate();
      ActivateSession(in  s session_id);
      SwitchTo(in  u vtnr);
      SwitchToNext();
      SwitchToPrevious();
    properties:
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s Id = '...';
      readonly (so) ActiveSession = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly b CanTTY = ...;
      readonly b CanGraphical = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
      readonly a(so) Sessions = [...];
      readonly b IdleHint = ...;
      readonly t IdleSinceHint = ...;
      readonly t IdleSinceHintMonotonic = ...;
  };
  interface org.freedesktop.DBus.Peer { ... };
  interface org.freedesktop.DBus.Introspectable { ... };
  interface org.freedesktop.DBus.Properties { ... };
};
Terminate() and ActivateSession() work similarly to
      TerminateSeat() and ActivationSessionOnSeat() on the Manager
      object.
SwitchTo() switches to the session on the virtual terminal
      vtnr. SwitchToNext() and
      SwitchToPrevious() switch to, respectively, the next and previous sessions on the
      seat in the order of virtual terminals. If there is no active session, they switch to, respectively,
      the first and last session on the seat.
Whenever ActiveSession, Sessions,
      CanGraphical, CanTTY,
      or the idle state changes, PropertyChanged signals are sent out to clients which
      have subscribed.
Signals are only emitted on objects referencing a specific seat ID, not on the
      "/org/freedesktop/login1/seat/self" or
      "/org/freedesktop/login1/seat/auto" convenience objects, as they can only be
      dereferenced relative to a method caller.
The Id property encodes the ID of the seat.
ActiveSession encodes the currently active session if there is one. It is a
      structure consisting of the session id and the object path.
CanTTY encodes whether the session is suitable for text logins, and
      CanGraphical whether it is suitable for graphical sessions.
The Sessions property is an array of all current sessions of this seat, each
      encoded in a structure consisting of the ID and the object path.
The IdleHint, IdleSinceHint, and
      IdleSinceHintMonotonic properties encode the idle state, similarly to the ones
      exposed on the Manager object, but specific for this seat.
node /org/freedesktop/login1/user/_1000 {
  interface org.freedesktop.login1.User {
    methods:
      Terminate();
      Kill(in  i signal_number);
    properties:
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly u UID = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly u GID = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s Name = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly t Timestamp = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly t TimestampMonotonic = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s RuntimePath = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s Service = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s Slice = '...';
      readonly (so) Display = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
      readonly s State = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
      readonly a(so) Sessions = [...];
      readonly b IdleHint = ...;
      readonly t IdleSinceHint = ...;
      readonly t IdleSinceHintMonotonic = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
      readonly b Linger = ...;
  };
  interface org.freedesktop.DBus.Peer { ... };
  interface org.freedesktop.DBus.Introspectable { ... };
  interface org.freedesktop.DBus.Properties { ... };
};
Terminate() and Kill() work similarly to the
      TerminateUser() and KillUser() methods on the manager
      object.
Whenever Sessions or the idle state changes,
      PropertyChanged signals are sent out to clients which have subscribed.
Signals are only emitted on objects referencing a specific UID, not on the
      "/org/freedesktop/login1/user/self" convenience object, as self
      can only be dereferenced relative to a method caller.
The UID and GID properties encode the Unix UID and primary
      GID of the user.
The Name property encodes the user name.
Timestamp and TimestampMonotonic encode the login time of
      the user in microseconds since the epoch, in the CLOCK_REALTIME and
      CLOCK_MONOTONIC clocks, respectively.
RuntimePath encodes the runtime path of the user,
      i.e. $XDG_RUNTIME_DIR. For details see the
      
        XDG Basedir Specification
      .
Service contains the unit name of the user systemd service of this
      user. Each logged in user is assigned a user service that runs a user systemd instance. This is
      usually an instance of user@.service.
Slice contains the unit name of the user systemd slice of this user. Each
      logged in user gets a private slice.
Display encodes which graphical session should be used as the primary UI display
      for the user. It is a structure encoding the session ID and the object path of the session to use.
State encodes the user state and is one of "offline",
      "lingering", "online", "active", or
      "closing". See
      sd_uid_get_state(3)
      for more information about the states.
Sessions is an array of structures encoding all current sessions of the
      user. Each structure consists of the ID and object path.
The IdleHint, IdleSinceHint, and
      IdleSinceHintMonotonic properties encode the idle hint state of the user, similarly
      to the Manager's properties, but specific for this user.
The Linger property shows whether lingering is enabled for this user.
node /org/freedesktop/login1/session/1 {
  interface org.freedesktop.login1.Session {
    methods:
      Terminate();
      Activate();
      Lock();
      Unlock();
      SetIdleHint(in  b idle);
      SetLockedHint(in  b locked);
      Kill(in  s whom,
           in  i signal_number);
      TakeControl(in  b force);
      ReleaseControl();
      SetType(in  s type);
      SetClass(in  s class);
      SetDisplay(in  s display);
      SetTTY(in  h tty_fd);
      TakeDevice(in  u major,
                 in  u minor,
                 out h fd,
                 out b inactive);
      ReleaseDevice(in  u major,
                    in  u minor);
      PauseDeviceComplete(in  u major,
                          in  u minor);
      SetBrightness(in  s subsystem,
                    in  s name,
                    in  u brightness);
    signals:
      PauseDevice(u major,
                  u minor,
                  s type);
      ResumeDevice(u major,
                   u minor,
                   h fd);
      Lock();
      Unlock();
    properties:
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s Id = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly (uo) User = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s Name = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly t Timestamp = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly t TimestampMonotonic = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly u VTNr = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly (so) Seat = ...;
      readonly s TTY = '...';
      readonly s Display = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly b Remote = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s RemoteHost = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s RemoteUser = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s Service = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s Desktop = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly s Scope = '...';
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly u Leader = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly t LeaderPIDFDId = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly u Audit = ...;
      readonly s Type = '...';
      readonly s Class = '...';
      readonly b Active = ...;
      readonly s State = '...';
      readonly b IdleHint = ...;
      readonly t IdleSinceHint = ...;
      readonly t IdleSinceHintMonotonic = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly b CanIdle = ...;
      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
      readonly b CanLock = ...;
      readonly b LockedHint = ...;
  };
  interface org.freedesktop.DBus.Peer { ... };
  interface org.freedesktop.DBus.Introspectable { ... };
  interface org.freedesktop.DBus.Properties { ... };
};
Terminate(), Activate(), Lock(),
      Unlock(), and Kill() work similarly to the respective calls on
      the Manager object.
SetIdleHint() is called by the session object to update the idle state
      of the session whenever it changes.
TakeControl() allows a process to take exclusive managed device
      access-control for that session. Only one D-Bus connection can be a controller for a given session at any
      time. If the force argument is set (root only), an existing controller is kicked
      out and replaced. Otherwise, this method fails if there is already a controller. Note that this method is
      limited to D-Bus users with the effective UID set to the user of the session or root.
ReleaseControl() drops control of a given session. Closing the D-Bus
      connection implicitly releases control as well. See TakeControl() for more
      information. This method also releases all devices for which the controller requested ownership via
      TakeDevice().
SetType() allows the type of the session to be changed dynamically.  It can
      only be called by session's current controller. If TakeControl() has not been
      called, this method will fail. In addition, the session type will be reset to its original value once
      control is released, either by calling ReleaseControl() or closing the D-Bus
      connection. This should help prevent a session from entering an inconsistent state, for example if the
      controller crashes. The only argument type is the new session type.
SetClass() allows the caller to change the class of the session dynamically.
      It may only be called by session's owning user. Currently, this call may be exclusively used to change
      the class from "user-incomplete" to "user". The call is synchronous,
      and will return only once the user's service manager has successfully been started, if necessary. The
      only argument type is the new session type.
SetDisplay() allows the display name of the graphical session to be changed. This is
      useful if the display server is started as part of the session. It can only be called by session's current
      controller. If TakeControl() has not been called, this method will fail. The only argument
      display is the new display name.
SetTTY() allows the device name of the session to be changed. This is
      useful if the tty device is only known after authentication. It can only be called by session's
      current controller. If TakeControl() has not been called, this method will fail.
      The only argument tty_fd is a file handle to the new tty device.
TakeDevice() allows a session controller to get a file descriptor for a
      specific device. Pass in the major and minor numbers of the character device and
      systemd-logind will return a file descriptor for the device. Only a limited set of
      device-types is currently supported (but may be extended). systemd-logind
      automatically mutes the file descriptor if the session is inactive and resumes it once the session is
      activated again. This guarantees that a session can only access session devices if the session is
      active. Note that this revoke/resume mechanism is asynchronous and may happen at any given time.  This
      only works on devices that are attached to the seat of the given session. A process is not required to
      have direct access to the device node. systemd-logind only requires you to be the
      active session controller (see TakeControl()). Also note that any device can only
      be requested once. As long as you do not release it, further TakeDevice() calls
      will fail.
ReleaseDevice() releases a device again (see
      TakeDevice()). This is also implicitly done by
      ReleaseControl() or when closing the D-Bus connection.
PauseDeviceComplete() allows a session controller to synchronously pause a
      device after receiving a PauseDevice(" signal. Forced
      signals (or after an internal timeout) are automatically completed by
      pause")systemd-logind asynchronously.
SetLockedHint() may be used to set the "locked hint" to
      locked, i.e. information whether the session is locked. This is intended to be used
      by the desktop environment to tell systemd-logind when the session is locked and
      unlocked.
SetBrightness() may be used to set the display brightness. This is intended
      to be used by the desktop environment and allows unprivileged programs to access hardware settings in
      a controlled way. The subsystem parameter specifies a kernel subsystem, either
      "backlight" or "leds". The name parameter
      specifies a device name under the specified subsystem. The brightness parameter
      specifies the brightness. The range is defined by individual drivers, see
      /sys/class/.
      subsystem/name/max_brightness
The active session controller exclusively gets PauseDevice() and
      ResumeDevice() events for any device it requested via
      TakeDevice(). They notify the controller whenever a device is paused or resumed. A
      device is never resumed if its session is inactive. Also note that PauseDevice()
      signals are sent before the PropertyChanged signal for the
      Active state. The inverse is true for ResumeDevice(). A device
      may remain paused for unknown reasons even though the Session is active.
      
A PauseDevice() signal carries the major and minor numbers and a string describing the
      type as arguments. force means the device was already paused by
      systemd-logind and the signal is only an asynchronous
      notification. pause means systemd-logind grants you a limited amount of time to pause the device. You must respond to this via
      PauseDeviceComplete(). This synchronous pausing mechanism is used for
      backwards-compatibility to VTs and systemd-logind is free to not make use of
      it. It is also free to send a forced PauseDevice() if you do not respond in a timely
      manner (or for any other reason). gone means the device was unplugged from the
      system and you will no longer get any notifications about it. There is no need to call
      ReleaseDevice(). You may call TakeDevice() again if a new
      device is assigned the major+minor combination.
ResumeDevice() is sent whenever a session is active and a device is
      resumed. It carries the major/minor numbers as arguments and provides a new open file descriptor. You should
      switch to the new descriptor and close the old one. They are not guaranteed to have the same underlying
      open file descriptor in the kernel (except for a limited set of device types).
Whenever Active or the idle state changes,
      PropertyChanged signals are sent out to clients which have subscribed.
Lock()/Unlock() is sent when the session is asked to be
      screen-locked/unlocked. A session manager of the session should listen to this signal and act
      accordingly. This signal is sent out as a result of the Lock() and
      Unlock() methods, respectively.
Signals are only emitted on objects referencing a specific session ID, not on the
      "/org/freedesktop/login1/session/self" or
      "/org/freedesktop/login1/session/auto" convenience objects, as they can only be
      dereferenced relative to a method caller.
Id encodes the session ID.
User encodes the user ID of the user this session belongs to. This is a
      structure consisting of the Unix UID and the object path.
Name encodes the user name.
Timestamp and TimestampMonotonic encode the microseconds
      since the epoch when the session was created, in CLOCK_REALTIME or
      CLOCK_MONOTONIC, respectively.
VTNr encodes the virtual terminal number of the session if there is any, 0
      otherwise.
Seat encodes the seat this session belongs to if there is any. This is a
      structure consisting of the ID and the seat object path.
TTY encodes the kernel TTY path of the session if this is a text login. If not
      this is an empty string.
Display encodes the X11 display name if this is a graphical login. If not,
      this is an empty string.
Remote encodes whether the session is local or remote.
RemoteHost and RemoteUser encode the remote host and user
      if this is a remote session, or an empty string otherwise.
Service encodes the PAM service name that registered the session.
Desktop describes the desktop environment running in the session (if
      known).
Scope contains the systemd scope unit name of this session.
Leader encodes the PID of the process that registered the session.
LeaderPIDFDId encodes the Linux pidfd inode ID of the process that registered
      the session.
Audit encodes the Kernel Audit session ID of the session if auditing is
      available.
Type encodes the session type. It's one of "unspecified" (for
      cron PAM sessions and suchlike), "tty" (for text logins), "web" (for
      web-based logins), or "x11"/"mir"/"wayland" (for
      graphical logins).
Class encodes the session class. It's one of "user" (for
      normal user sessions), "greeter" (for display manager pseudo-sessions), or
      "lock-screen" (for display lock screens).
Active is a boolean that is true if the session is active, i.e. currently in the
      foreground. This field is semi-redundant due to State.
State encodes the session state and one of "online",
      "active", or "closing". See
      sd_session_get_state(3)
      for more information about the states.
IdleHint, IdleSinceHint, and
      IdleSinceHintMonotonic encapsulate the idle hint state of this session, similarly to
      how the respective properties on the manager object do it for the whole system.
LockedHint shows the locked hint state of this session, as set by the
      SetLockedHint() method described above.
CanIdle indicates whether the session supports the idle hint
      concept. Similarly, CanLock indicates whether the session supports the screen lock
      concept.
Example 1. Introspect the logind manager on the bus
$ gdbus introspect --system --dest org.freedesktop.login1 \ --object-path /org/freedesktop/login1
or
$ busctl introspect org.freedesktop.login1 /org/freedesktop/login1
Example 2. Introspect the default seat on the bus
$ gdbus introspect --system --dest org.freedesktop.login1 \ --object-path /org/freedesktop/login1/seat/seat0
or
$ busctl introspect org.freedesktop.login1 /org/freedesktop/login1/seat/seat0
Seat "seat0" is the default seat, so it'll be present unless local configuration
      is made to reassign all devices to a different seat. The list of seats and users can be acquired with
      loginctl list-sessions.
Example 3. Introspect a single user on the bus
$ gdbus introspect --system --dest org.freedesktop.login1 \ --object-path /org/freedesktop/login1/user/_1000
or
$ busctl introspect org.freedesktop.login1 /org/freedesktop/login1/user/_1000
Example 4. Introspect org.freedesktop.login1.Session on the bus
$ gdbus introspect --system --dest org.freedesktop.login1 \ --object-path /org/freedesktop/login1/session/45
or
$ busctl introspect org.freedesktop.login1 /org/freedesktop/login1/session/45
HandlePowerKeyLongPress,
      HandleRebootKey,
      HandleRebootKeyLongPress,
      HandleSuspendKeyLongPress, and
      HandleHibernateKeyLongPress were added in version 251.
StopIdleSessionUSec was added in version 252.
PrepareForShutdownWithMetadata() and
      CreateSessionWithPIDFD() were added in version 255.
Sleep(),
      CanSleep(),
      SleepOperation, and
      ListSessionsEx() were added in version 256.
HandleSecureAttentionKey, SecureAttentionKey(),
      PreparingForShutdownWithMetadata, DesignatedMaintenanceTime,
      CanIdle, CanLock,
      and BlockWeakInhibited were added in version 257.
SetDisplay() was added in version 252.
SetTTY() was added in version 254.
SetClass() was added in version 256.
LeaderPIDFDId was added in version 258.