+static int check_inhibitors(DBusConnection *bus, enum action a) {
+#ifdef HAVE_LOGIND
+ _cleanup_dbus_message_unref_ DBusMessage *reply = NULL;
+ DBusMessageIter iter, sub, sub2;
+ int r;
+ unsigned c = 0;
+ _cleanup_strv_free_ char **sessions = NULL;
+ char **s;
+
+ if (!bus)
+ return 0;
+
+ if (arg_ignore_inhibitors || arg_force > 0)
+ return 0;
+
+ if (arg_when > 0)
+ return 0;
+
+ if (geteuid() == 0)
+ return 0;
+
+ if (!on_tty())
+ return 0;
+
+ r = bus_method_call_with_reply(
+ bus,
+ "org.freedesktop.login1",
+ "/org/freedesktop/login1",
+ "org.freedesktop.login1.Manager",
+ "ListInhibitors",
+ &reply,
+ NULL,
+ DBUS_TYPE_INVALID);
+ if (r < 0)
+ /* If logind is not around, then there are no inhibitors... */
+ return 0;
+
+ if (!dbus_message_iter_init(reply, &iter) ||
+ dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_ARRAY ||
+ dbus_message_iter_get_element_type(&iter) != DBUS_TYPE_STRUCT) {
+ log_error("Failed to parse reply.");
+ return -EIO;
+ }
+
+ dbus_message_iter_recurse(&iter, &sub);
+ while (dbus_message_iter_get_arg_type(&sub) != DBUS_TYPE_INVALID) {
+ const char *what, *who, *why, *mode;
+ uint32_t uid, pid;
+ _cleanup_strv_free_ char **sv = NULL;
+ _cleanup_free_ char *comm = NULL, *user = NULL;
+
+ if (dbus_message_iter_get_arg_type(&sub) != DBUS_TYPE_STRUCT) {
+ log_error("Failed to parse reply.");
+ return -EIO;
+ }
+
+ dbus_message_iter_recurse(&sub, &sub2);
+
+ if (bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_STRING, &what, true) < 0 ||
+ bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_STRING, &who, true) < 0 ||
+ bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_STRING, &why, true) < 0 ||
+ bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_STRING, &mode, true) < 0 ||
+ bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_UINT32, &uid, true) < 0 ||
+ bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_UINT32, &pid, false) < 0) {
+ log_error("Failed to parse reply.");
+ return -EIO;
+ }
+
+ if (!streq(mode, "block"))
+ goto next;
+
+ sv = strv_split(what, ":");
+ if (!sv)
+ return log_oom();
+
+ if (!strv_contains(sv,
+ a == ACTION_HALT ||
+ a == ACTION_POWEROFF ||
+ a == ACTION_REBOOT ||
+ a == ACTION_KEXEC ? "shutdown" : "sleep"))
+ goto next;
+
+ get_process_comm(pid, &comm);
+ user = uid_to_name(uid);
+ log_warning("Operation inhibited by \"%s\" (PID %lu \"%s\", user %s), reason is \"%s\".",
+ who, (unsigned long) pid, strna(comm), strna(user), why);
+ c++;
+
+ next:
+ dbus_message_iter_next(&sub);
+ }
+
+ dbus_message_iter_recurse(&iter, &sub);
+
+ /* Check for current sessions */
+ sd_get_sessions(&sessions);
+ STRV_FOREACH(s, sessions) {
+ uid_t uid;
+ _cleanup_free_ char *type = NULL, *tty = NULL, *seat = NULL, *user = NULL, *service = NULL, *class = NULL;
+
+ if (sd_session_get_uid(*s, &uid) < 0 || uid == getuid())
+ continue;
+
+ if (sd_session_get_class(*s, &class) < 0 || !streq(class, "user"))
+ continue;
+
+ if (sd_session_get_type(*s, &type) < 0 || (!streq(type, "x11") && !streq(type, "tty")))
+ continue;
+
+ sd_session_get_tty(*s, &tty);
+ sd_session_get_seat(*s, &seat);
+ sd_session_get_service(*s, &service);
+ user = uid_to_name(uid);
+
+ log_warning("User %s is logged in on %s.", strna(user), isempty(tty) ? (isempty(seat) ? strna(service) : seat) : tty);
+ c++;
+ }
+
+ if (c <= 0)
+ return 0;
+
+ log_error("Please retry operation after closing inhibitors and logging out other users.\nAlternatively, ignore inhibitors and users with 'systemctl %s -i'.",
+ action_table[a].verb);
+
+ return -EPERM;
+#else
+ return 0;
+#endif
+}
+