systemdlogindservice

systemd-logind, or logind, is a system daemon that is part of the systemd initiative for Linux system management. It provides centralized handling of user logins, user sessions, and seats on systems that run systemd. logind exposes a D-Bus API and coordinates with PAM, udev, and other system components to track active users and their processes, and to manage access to devices and power-related events. It is commonly accessed through the loginctl command-line utility.

The primary responsibilities of systemd-logind include maintaining a registry of current user logins, creating and tracking user sessions, and organizing those sessions into seats (for example, seat0). It also manages device access permissions for logged-in users, handles power-related actions such as suspend or shutdown in response to user input, and provides an inhibit interface that applications can use to block those actions when necessary. logind supports idle and inactivity handling, including actions like suspend or screen blanks, which can be configured by the system administrator.

Configuration and behavior are largely governed by the /etc/systemd/logind.conf file. Administrators can tailor responses to events such as power key presses, lid switches, and idle timeouts, as well as whether user processes should be killed upon logout. Settings commonly adjusted include HandlePowerKey, HandleSuspendKey, IdleAction, and IdleActionSec, among others. The service also supports various policies for device access and session management.

ystemd-logind interacts with the rest of the desktop and server ecosystem via the D-Bus API at org.freedesktop.login1 and is typically used by login managers and session controllers. It replaced ConsoleKit as the de facto login manager in many distributions and is frequently utilized indirectly through loginctl for session inspection and control.