+static int action_to_runlevel(void) {
+
+ static const char table[_ACTION_MAX] = {
+ [ACTION_HALT] = '0',
+ [ACTION_POWEROFF] = '0',
+ [ACTION_REBOOT] = '6',
+ [ACTION_RUNLEVEL2] = '2',
+ [ACTION_RUNLEVEL3] = '3',
+ [ACTION_RUNLEVEL4] = '4',
+ [ACTION_RUNLEVEL5] = '5',
+ [ACTION_RESCUE] = '1'
+ };
+
+ assert(arg_action < _ACTION_MAX);
+
+ return table[arg_action];
+}
+
+static int talk_upstart(void) {
+ DBusMessage *m = NULL, *reply = NULL;
+ DBusError error;
+ int previous, rl, r;
+ char
+ env1_buf[] = "RUNLEVEL=X",
+ env2_buf[] = "PREVLEVEL=X";
+ char *env1 = env1_buf, *env2 = env2_buf;
+ const char *emit = "runlevel";
+ dbus_bool_t b_false = FALSE;
+ DBusMessageIter iter, sub;
+ DBusConnection *bus;
+
+ dbus_error_init(&error);
+
+ if (!(rl = action_to_runlevel()))
+ return 0;
+
+ if (utmp_get_runlevel(&previous, NULL) < 0)
+ previous = 'N';
+
+ if (!(bus = dbus_connection_open("unix:abstract=/com/ubuntu/upstart", &error))) {
+ if (dbus_error_has_name(&error, DBUS_ERROR_NO_SERVER)) {
+ r = 0;
+ goto finish;
+ }
+
+ log_error("Failed to connect to Upstart bus: %s", error.message);
+ r = -EIO;
+ goto finish;
+ }
+
+ if ((r = bus_check_peercred(bus)) < 0) {
+ log_error("Failed to verify owner of bus.");
+ goto finish;
+ }
+
+ if (!(m = dbus_message_new_method_call(
+ "com.ubuntu.Upstart",
+ "/com/ubuntu/Upstart",
+ "com.ubuntu.Upstart0_6",
+ "EmitEvent"))) {
+
+ log_error("Could not allocate message.");
+ r = -ENOMEM;
+ goto finish;
+ }
+
+ dbus_message_iter_init_append(m, &iter);
+
+ env1_buf[sizeof(env1_buf)-2] = rl;
+ env2_buf[sizeof(env2_buf)-2] = previous;
+
+ if (!dbus_message_iter_append_basic(&iter, DBUS_TYPE_STRING, &emit) ||
+ !dbus_message_iter_open_container(&iter, DBUS_TYPE_ARRAY, "s", &sub) ||
+ !dbus_message_iter_append_basic(&sub, DBUS_TYPE_STRING, &env1) ||
+ !dbus_message_iter_append_basic(&sub, DBUS_TYPE_STRING, &env2) ||
+ !dbus_message_iter_close_container(&iter, &sub) ||
+ !dbus_message_iter_append_basic(&iter, DBUS_TYPE_BOOLEAN, &b_false)) {
+ log_error("Could not append arguments to message.");
+ r = -ENOMEM;
+ goto finish;
+ }
+
+ if (!(reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error))) {
+
+ if (error_is_no_service(&error)) {
+ r = 0;
+ goto finish;
+ }
+
+ log_error("Failed to issue method call: %s", error.message);
+ r = -EIO;
+ goto finish;
+ }
+
+ r = 1;
+
+finish:
+ if (m)
+ dbus_message_unref(m);
+
+ if (reply)
+ dbus_message_unref(reply);
+
+ if (bus)
+ dbus_connection_unref(bus);
+
+ dbus_error_free(&error);
+
+ return r;