session/logind: check for XDG_SESSION_ID first
In order to support compositors running as systemd user units without display manager,
a mechanism for specifying session ID exactly must exist.
Checking for `XDG_SESSION_ID` mimics loginctl behaviour
@@ -538,15 +538,26 @@ static bool get_display_session(char **session_id) {
assert(session_id != NULL);
int ret;
+ char *type = NULL;
+ char *state = NULL;
+ char *xdg_session_id = getenv("XDG_SESSION_ID");
+
+ if (xdg_session_id) {
+ // This just checks whether the supplied session ID is valid
+ if (sd_session_is_active(xdg_session_id) < 0) {
+ wlr_log(WLR_ERROR, "Invalid XDG_SESSION_ID: '%s'", xdg_session_id);
+ goto error;
+ }
+ *session_id = strdup(xdg_session_id);
+ return true;
+ }
+
// If there's a session active for the current process then just use that
ret = sd_pid_get_session(getpid(), session_id);
if (ret == 0) {
return true;
}
- char *type = NULL;
- char *state = NULL;
-
// Find any active sessions for the user if the process isn't part of an
// active session itself
ret = sd_uid_get_display(getuid(), session_id);
