utils: reintroduce gdmflexiserver

Partial revert of 920b38e2aac1f79100ed86a0296bbcaf4fecabd9 to
reinstroduce gdmflexiserver since gnome-screensaver depends on it.

https://bugzilla.gnome.org/show_bug.cgi?id=685622

2 files changed, 791 insertions, 0 deletions

diff --git a/utils/Makefile.am b/utils/Makefile.am
index eaf98696..1cda413d 100644
--- a/utils/Makefile.am
+++ b/utils/Makefile.am
@@ -21,9 +21,20 @@ edit = sed \
 	-e 's|@GDM_PID_FILE[@]|$(GDM_PID_FILE)|g'
 
 bin_PROGRAMS = \
+	gdmflexiserver		\
 	gdm-screenshot		\
 	$(NULL)
 
+gdmflexiserver_SOURCES =	\
+	gdmflexiserver.c	\
+	$(NULL)
+
+gdmflexiserver_LDADD =		\
+	$(GTK_LIBS)		\
+	$(COMMON_LIBS)		\
+	$(SYSTEMD_LIBS)         \
+	$(NULL)
+
 gdm_screenshot_SOURCES =	\
 	gdm-screenshot.c	\
 	$(NULL)
diff --git a/utils/gdmflexiserver.c b/utils/gdmflexiserver.c
new file mode 100644
index 00000000..d1b72fe6
--- /dev/null
+++ b/utils/gdmflexiserver.c
@@ -0,0 +1,780 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*-
+ *
+ * Copyright (C) 2008 William Jon McCann <jmccann@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+
+#include "config.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <locale.h>
+
+#include <glib/gi18n.h>
+#include <gtk/gtk.h>
+
+#ifdef WITH_SYSTEMD
+#include <systemd/sd-daemon.h>
+#include <systemd/sd-login.h>
+#endif
+
+#define GDM_DBUS_NAME                            "org.gnome.DisplayManager"
+#define GDM_DBUS_LOCAL_DISPLAY_FACTORY_PATH      "/org/gnome/DisplayManager/LocalDisplayFactory"
+#define GDM_DBUS_LOCAL_DISPLAY_FACTORY_INTERFACE "org.gnome.DisplayManager.LocalDisplayFactory"
+
+#ifdef WITH_CONSOLE_KIT
+#define CK_NAME      "org.freedesktop.ConsoleKit"
+#define CK_PATH      "/org/freedesktop/ConsoleKit"
+#define CK_INTERFACE "org.freedesktop.ConsoleKit"
+
+#define CK_MANAGER_PATH      "/org/freedesktop/ConsoleKit/Manager"
+#define CK_MANAGER_INTERFACE "org.freedesktop.ConsoleKit.Manager"
+#define CK_SEAT_INTERFACE    "org.freedesktop.ConsoleKit.Seat"
+#define CK_SESSION_INTERFACE "org.freedesktop.ConsoleKit.Session"
+#endif
+
+static const char *send_command     = NULL;
+static gboolean    use_xnest        = FALSE;
+static gboolean    no_lock          = FALSE;
+static gboolean    debug_in         = FALSE;
+static gboolean    authenticate     = FALSE;
+static gboolean    startnew         = FALSE;
+static gboolean    monte_carlo_pi   = FALSE;
+static gboolean    show_version     = FALSE;
+static char      **args_remaining   = NULL;
+
+/* Keep all config options for compatibility even if they are noops */
+GOptionEntry options [] = {
+        { "command", 'c', 0, G_OPTION_ARG_STRING, &send_command, N_("Only the VERSION command is supported"), N_("COMMAND") },
+        { "xnest", 'n', 0, G_OPTION_ARG_NONE, &use_xnest, N_("Ignored — retained for compatibility"), NULL },
+        { "no-lock", 'l', 0, G_OPTION_ARG_NONE, &no_lock, N_("Ignored — retained for compatibility"), NULL },
+        { "debug", 'd', 0, G_OPTION_ARG_NONE, &debug_in, N_("Debugging output"), NULL },
+        { "authenticate", 'a', 0, G_OPTION_ARG_NONE, &authenticate, N_("Ignored — retained for compatibility"), NULL },
+        { "startnew", 's', 0, G_OPTION_ARG_NONE, &startnew, N_("Ignored — retained for compatibility"), NULL },
+        { "monte-carlo-pi", 0, 0, G_OPTION_ARG_NONE, &monte_carlo_pi, NULL, NULL },
+        { "version", 0, 0, G_OPTION_ARG_NONE, &show_version, N_("Version of this application"), NULL },
+        { G_OPTION_REMAINING, 0, 0, G_OPTION_ARG_STRING_ARRAY, &args_remaining, NULL, NULL },
+        { NULL }
+};
+
+#define GDM_FLEXISERVER_ERROR gdm_flexiserver_error_quark ()
+static GQuark
+gdm_flexiserver_error_quark (void)
+{
+        static GQuark ret = 0;
+        if (ret == 0) {
+                ret = g_quark_from_static_string ("gdm_flexiserver_error");
+        }
+
+        return ret;
+}
+
+static gboolean
+is_program_in_path (const char *program)
+{
+        char *tmp = g_find_program_in_path (program);
+        if (tmp != NULL) {
+                g_free (tmp);
+                return TRUE;
+        } else {
+                return FALSE;
+        }
+}
+
+static void
+maybe_lock_screen (void)
+{
+        gboolean   use_gscreensaver = FALSE;
+        GError    *error            = NULL;
+        char      *command;
+
+        if (is_program_in_path ("gnome-screensaver-command")) {
+                use_gscreensaver = TRUE;
+        } else if (! is_program_in_path ("xscreensaver-command")) {
+                return;
+        }
+
+        if (use_gscreensaver) {
+                command = g_strdup ("gnome-screensaver-command --lock");
+        } else {
+                command = g_strdup ("xscreensaver-command -lock");
+        }
+
+        if (! g_spawn_command_line_async (command, &error)) {
+                g_warning ("Cannot lock screen: %s", error->message);
+                g_error_free (error);
+        }
+
+        g_free (command);
+
+        if (! use_gscreensaver) {
+                command = g_strdup ("xscreensaver-command -throttle");
+                if (! g_spawn_command_line_async (command, &error)) {
+                        g_warning ("Cannot disable screensaver engines: %s", error->message);
+                        g_error_free (error);
+                }
+
+                g_free (command);
+        }
+}
+
+static void
+calc_pi (void)
+{
+        unsigned long n = 0, h = 0;
+        double x, y;
+        printf ("\n");
+        for (;;) {
+                x = g_random_double ();
+                y = g_random_double ();
+                if (x*x + y*y <= 1)
+                        h++;
+                n++;
+                if ( ! (n & 0xfff))
+                        printf ("pi ~~ %1.10f\t(%lu/%lu * 4) iteration: %lu \r",
+                                ((double)h)/(double)n * 4.0, h, n, n);
+        }
+}
+
+static gboolean
+create_transient_display (GDBusConnection *connection,
+                          GError         **error)
+{
+        GError *local_error = NULL;
+        GVariant *reply;
+        const char     *value;
+
+        reply = g_dbus_connection_call_sync (connection,
+                                             GDM_DBUS_NAME,
+                                             GDM_DBUS_LOCAL_DISPLAY_FACTORY_PATH,
+                                             GDM_DBUS_LOCAL_DISPLAY_FACTORY_INTERFACE,
+                                             "CreateTransientDisplay",
+                                             NULL, /* parameters */
+                                             G_VARIANT_TYPE ("(o)"),
+                                             G_DBUS_CALL_FLAGS_NONE,
+                                             -1,
+                                             NULL, &local_error);
+        if (reply == NULL) {
+                g_warning ("Unable to create transient display: %s", local_error->message);
+                g_propagate_error (error, local_error);
+                return FALSE;
+        }
+
+        g_variant_get (reply, "(&o)", &value);
+        g_debug ("Started %s", value);
+
+        g_variant_unref (reply);
+        return TRUE;
+}
+
+#ifdef WITH_CONSOLE_KIT
+
+static gboolean
+get_current_session_id (GDBusConnection  *connection,
+                        char            **session_id)
+{
+        GError *local_error = NULL;
+        GVariant *reply;
+
+        reply = g_dbus_connection_call_sync (connection,
+                                             CK_NAME,
+                                             CK_MANAGER_PATH,
+                                             CK_MANAGER_INTERFACE,
+                                             "GetCurrentSession",
+                                             NULL, /* parameters */
+                                             G_VARIANT_TYPE ("(o)"),
+                                             G_DBUS_CALL_FLAGS_NONE,
+                                             -1,
+                                             NULL, &local_error);
+        if (reply == NULL) {
+                g_warning ("Unable to determine session: %s", local_error->message);
+                g_error_free (local_error);
+                return FALSE;
+        }
+
+        g_variant_get (reply, "(o)", session_id);
+        g_variant_unref (reply);
+
+        return TRUE;
+}
+
+static gboolean
+get_seat_id_for_session (GDBusConnection  *connection,
+                         const char       *session_id,
+                         char            **seat_id)
+{
+        GError *local_error = NULL;
+        GVariant *reply;
+
+        reply = g_dbus_connection_call_sync (connection,
+                                             CK_NAME,
+                                             session_id,
+                                             CK_SESSION_INTERFACE,
+                                             "GetSeatId",
+                                             NULL, /* parameters */
+                                             G_VARIANT_TYPE ("(o)"),
+                                             G_DBUS_CALL_FLAGS_NONE,
+                                             -1,
+                                             NULL, &local_error);
+        if (reply == NULL) {
+                g_warning ("Unable to determine seat: %s", local_error->message);
+                g_error_free (local_error);
+                return FALSE;
+        }
+
+        g_variant_get (reply, "(o)", seat_id);
+        g_variant_unref (reply);
+
+        return TRUE;
+}
+
+static char *
+get_current_seat_id (GDBusConnection *connection)
+{
+        gboolean res;
+        char    *session_id;
+        char    *seat_id;
+
+        session_id = NULL;
+        seat_id = NULL;
+
+        res = get_current_session_id (connection, &session_id);
+        if (res) {
+                res = get_seat_id_for_session (connection, session_id, &seat_id);
+        }
+        g_free (session_id);
+
+        return seat_id;
+}
+
+static gboolean
+activate_session_id_for_ck (GDBusConnection *connection,
+                            const char      *seat_id,
+                            const char      *session_id)
+{
+        GError *local_error = NULL;
+        GVariant *reply;
+
+        reply = g_dbus_connection_call_sync (connection,
+                                             CK_NAME,
+                                             seat_id,
+                                             CK_SEAT_INTERFACE,
+                                             "ActivateSession",
+                                             g_variant_new ("(o)", session_id),
+                                             NULL,
+                                             G_DBUS_CALL_FLAGS_NONE,
+                                             -1,
+                                             NULL, &local_error);
+        if (reply == NULL) {
+                g_warning ("Unable to activate session: %s", local_error->message);
+                g_error_free (local_error);
+                return FALSE;
+        }
+
+        g_variant_unref (reply);
+
+        return TRUE;
+}
+
+static gboolean
+session_is_login_window (GDBusConnection *connection,
+                         const char      *session_id)
+{
+        GError *local_error = NULL;
+        GVariant *reply;
+        const char *value;
+        gboolean ret;
+
+        reply = g_dbus_connection_call_sync (connection,
+                                             CK_NAME,
+                                             session_id,
+                                             CK_SESSION_INTERFACE,
+                                             "GetSessionType",
+                                             NULL,
+                                             G_VARIANT_TYPE ("(s)"),
+                                             G_DBUS_CALL_FLAGS_NONE,
+                                             -1,
+                                             NULL, &local_error);
+        if (reply == NULL) {
+                g_warning ("Unable to determine session type: %s", local_error->message);
+                g_error_free (local_error);
+                return FALSE;
+        }
+
+        g_variant_get (reply, "(&s)", &value);
+
+        if (value == NULL || value[0] == '\0' || strcmp (value, "LoginWindow") != 0) {
+                ret = FALSE;
+        } else {
+                ret = TRUE;
+        }
+
+        g_variant_unref (reply);
+
+        return ret;
+}
+
+static gboolean
+seat_can_activate_sessions (GDBusConnection *connection,
+                            const char      *seat_id)
+{
+        GError *local_error = NULL;
+        GVariant *reply;
+        gboolean ret;
+
+        reply = g_dbus_connection_call_sync (connection,
+                                             CK_NAME,
+                                             seat_id,
+                                             CK_SEAT_INTERFACE,
+                                             "CanActivateSessions",
+                                             NULL,
+                                             G_VARIANT_TYPE ("(b)"),
+                                             G_DBUS_CALL_FLAGS_NONE,
+                                             -1,
+                                             NULL, &local_error);
+        if (reply == NULL) {
+                g_warning ("Unable to determine if can activate sessions: %s", local_error->message);
+                g_error_free (local_error);
+                return FALSE;
+        }
+
+        g_variant_get (reply, "(b)", &ret);
+        g_variant_unref (reply);
+
+        return ret;
+}
+
+static const char **
+seat_get_sessions (GDBusConnection *connection,
+                   const char      *seat_id)
+{
+        GError *local_error = NULL;
+        GVariant *reply;
+        const char **value;
+
+        reply = g_dbus_connection_call_sync (connection,
+                                             CK_NAME,
+                                             seat_id,
+                                             CK_SEAT_INTERFACE,
+                                             "GetSessions",
+                                             NULL,
+                                             G_VARIANT_TYPE ("(ao)"),
+                                             G_DBUS_CALL_FLAGS_NONE,
+                                             -1,
+                                             NULL, &local_error);
+        if (reply == NULL) {
+                g_warning ("Unable to list sessions: %s", local_error->message);
+                g_error_free (local_error);
+                return FALSE;
+        }
+
+        g_variant_get (reply, "(^ao)", &value);
+        g_variant_unref (reply);
+
+        return value;
+}
+
+static gboolean
+get_login_window_session_id_for_ck (GDBusConnection  *connection,
+                                    const char       *seat_id,
+                                    char            **session_id)
+{
+        gboolean     can_activate_sessions;
+        const char **sessions;
+        int          i;
+
+        *session_id = NULL;
+        sessions = NULL;
+
+        g_debug ("checking if seat can activate sessions");
+
+        can_activate_sessions = seat_can_activate_sessions (connection, seat_id);
+        if (! can_activate_sessions) {
+                g_debug ("seat is unable to activate sessions");
+                return FALSE;
+        }
+
+        sessions = seat_get_sessions (connection, seat_id);
+        for (i = 0; sessions [i] != NULL; i++) {
+                const char *ssid;
+
+                ssid = sessions [i];
+
+                if (session_is_login_window (connection, ssid)) {
+                        *session_id = g_strdup (ssid);
+                        break;
+                }
+        }
+        g_free (sessions);
+
+        return TRUE;
+}
+
+static gboolean
+goto_login_session_for_ck (GDBusConnection  *connection,
+                           GError          **error)
+{
+        gboolean        ret;
+        gboolean        res;
+        char           *session_id;
+        char           *seat_id;
+
+        ret = FALSE;
+
+        /* First look for any existing LoginWindow sessions on the seat.
+           If none are found, create a new one. */
+
+        seat_id = get_current_seat_id (connection);
+        if (seat_id == NULL || seat_id[0] == '\0') {
+                g_debug ("seat id is not set; can't switch sessions");
+                g_set_error (error, GDM_FLEXISERVER_ERROR, 0, _("Could not identify the current session."));
+
+                return FALSE;
+        }
+
+        res = get_login_window_session_id_for_ck (connection, seat_id, &session_id);
+        if (! res) {
+                g_set_error (error, GDM_FLEXISERVER_ERROR, 1, _("User unable to switch sessions."));
+                return FALSE;
+        }
+
+        if (session_id != NULL) {
+                res = activate_session_id_for_ck (connection, seat_id, session_id);
+                if (res) {
+                        ret = TRUE;
+                }
+        }
+
+        if (! ret && g_strcmp0 (seat_id, "/org/freedesktop/ConsoleKit/Seat1") == 0) {
+                res = create_transient_display (connection, error);
+                if (res) {
+                        ret = TRUE;
+                }
+        }
+
+        return ret;
+}
+#endif
+
+#ifdef WITH_SYSTEMD
+
+static gboolean
+activate_session_id_for_systemd (GDBusConnection *connection,
+                                 const char      *seat_id,
+                                 const char      *session_id)
+{
+        GError *local_error = NULL;
+        GVariant *reply;
+
+        reply = g_dbus_connection_call_sync (connection,
+                                             "org.freedesktop.login1",
+                                             "/org/freedesktop/login1",
+                                             "org.freedesktop.login1.Manager",
+                                             "ActivateSessionOnSeat",
+                                             g_variant_new ("(ss)", session_id, seat_id),
+                                             NULL,
+                                             G_DBUS_CALL_FLAGS_NONE,
+                                             -1,
+                                             NULL, &local_error);
+        if (reply == NULL) {
+                g_warning ("Unable to activate session: %s", local_error->message);
+                g_error_free (local_error);
+                return FALSE;
+        }
+
+        g_variant_unref (reply);
+
+        return TRUE;
+}
+
+static gboolean
+get_login_window_session_id_for_systemd (const char  *seat_id,
+                                         char       **session_id)
+{
+        gboolean   ret;
+        int        res, i;
+        char     **sessions;
+        char      *service_id;
+        char      *service_class;
+        char      *state;
+
+        res = sd_seat_get_sessions (seat_id, &sessions, NULL, NULL);
+        if (res < 0) {
+                g_debug ("Failed to determine sessions: %s", strerror (-res));
+                return FALSE;
+        }
+
+        if (sessions == NULL || sessions[0] == NULL) {
+                *session_id = NULL;
+                ret = TRUE;
+                goto out;
+        }
+
+        for (i = 0; sessions[i]; i ++) {
+
+                res = sd_session_get_class (sessions[i], &service_class);
+                if (res < 0) {
+                        g_debug ("failed to determine class of session %s: %s", sessions[i], strerror (-res));
+                        ret = FALSE;
+                        goto out;
+                }
+
+                if (strcmp (service_class, "greeter") != 0) {
+                        free (service_class);
+                        continue;
+                }
+
+                free (service_class);
+
+                ret = sd_session_get_state (sessions[i], &state);
+                if (ret < 0) {
+                        g_debug ("failed to determine state of session %s: %s", sessions[i], strerror (-res));
+                        ret = FALSE;
+                        goto out;
+                }
+
+                if (g_strcmp0 (state, "closing") == 0) {
+                        free (state);
+                        continue;
+                }
+                free (state);
+
+                res = sd_session_get_service (sessions[i], &service_id);
+                if (res < 0) {
+                        g_debug ("failed to determine service of session %s: %s", sessions[i], strerror (-res));
+                        ret = FALSE;
+                        goto out;
+                }
+
+                if (strcmp (service_id, "gdm-welcome") == 0) {
+                        *session_id = g_strdup (sessions[i]);
+                        ret = TRUE;
+
+                        free (service_id);
+                        goto out;
+                }
+
+                free (service_id);
+        }
+
+        *session_id = NULL;
+        ret = TRUE;
+
+out:
+        for (i = 0; sessions[i]; i ++) {
+                free (sessions[i]);
+        }
+
+        free (sessions);
+
+        return ret;
+}
+
+static gboolean
+goto_login_session_for_systemd (GDBusConnection  *connection,
+                                GError          **error)
+{
+        gboolean        ret;
+        int             res;
+        char           *our_session;
+        char           *session_id;
+        char           *seat_id;
+
+        ret = FALSE;
+        session_id = NULL;
+        seat_id = NULL;
+
+        /* First look for any existing LoginWindow sessions on the seat.
+           If none are found, create a new one. */
+
+        /* Note that we mostly use free () here, instead of g_free ()
+         * since the data allocated is from libsystemd-logind, which
+         * does not use GLib's g_malloc (). */
+
+        res = sd_pid_get_session (0, &our_session);
+        if (res < 0) {
+                g_debug ("failed to determine own session: %s", strerror (-res));
+                g_set_error (error, GDM_FLEXISERVER_ERROR, 0, _("Could not identify the current session."));
+
+                return FALSE;
+        }
+
+        res = sd_session_get_seat (our_session, &seat_id);
+        free (our_session);
+        if (res < 0) {
+                g_debug ("failed to determine own seat: %s", strerror (-res));
+                g_set_error (error, GDM_FLEXISERVER_ERROR, 0, _("Could not identify the current seat."));
+
+                return FALSE;
+        }
+
+        res = sd_seat_can_multi_session (seat_id);
+        if (res < 0) {
+                free (seat_id);
+
+                g_debug ("failed to determine whether seat can do multi session: %s", strerror (-res));
+                g_set_error (error, GDM_FLEXISERVER_ERROR, 0, _("The system is unable to determine whether to switch to an existing login screen or start up a new login screen."));
+
+                return FALSE;
+        }
+
+        if (res == 0) {
+                free (seat_id);
+
+                g_set_error (error, GDM_FLEXISERVER_ERROR, 0, _("The system is unable to start up a new login screen."));
+
+                return FALSE;
+        }
+
+        res = get_login_window_session_id_for_systemd (seat_id, &session_id);
+        if (res && session_id != NULL) {
+                res = activate_session_id_for_systemd (connection, seat_id, session_id);
+
+                if (res) {
+                        ret = TRUE;
+                }
+        }
+
+        if (! ret && g_strcmp0 (seat_id, "seat0") == 0) {
+                res = create_transient_display (connection, error);
+                if (res) {
+                        ret = TRUE;
+                }
+        }
+
+        free (seat_id);
+        g_free (session_id);
+
+        return ret;
+}
+#endif
+
+static gboolean
+goto_login_session (GError **error)
+{
+        GError *local_error;
+        GDBusConnection *connection;
+
+        local_error = NULL;
+        connection = g_bus_get_sync (G_BUS_TYPE_SYSTEM, NULL, &local_error);
+        if (connection == NULL) {
+                g_debug ("Failed to connect to the D-Bus daemon: %s", local_error->message);
+                g_propagate_error (error, local_error);
+                return FALSE;
+        }
+
+#ifdef WITH_SYSTEMD
+        if (sd_booted () > 0) {
+                return goto_login_session_for_systemd (connection, error);
+        }
+#endif
+
+#ifdef WITH_CONSOLE_KIT
+        return goto_login_session_for_ck (connection, error);
+#endif
+}
+
+int
+main (int argc, char *argv[])
+{
+        GOptionContext *ctx;
+        gboolean        res;
+        GError         *error;
+
+        bindtextdomain (GETTEXT_PACKAGE, GNOMELOCALEDIR);
+        bind_textdomain_codeset (GETTEXT_PACKAGE, "UTF-8");
+        textdomain (GETTEXT_PACKAGE);
+        setlocale (LC_ALL, "");
+
+        /* Option parsing */
+        ctx = g_option_context_new (_("- New GDM login"));
+        g_option_context_set_translation_domain (ctx, GETTEXT_PACKAGE);
+        g_option_context_add_main_entries (ctx, options, NULL);
+        g_option_context_parse (ctx, &argc, &argv, NULL);
+        g_option_context_free (ctx);
+
+
+        if (show_version) {
+                g_print ("%s %s\n", argv [0], VERSION);
+                exit (1);
+        }
+
+        /* don't support commands other than VERSION */
+        if (send_command != NULL) {
+                if (strcmp (send_command, "VERSION") == 0) {
+                        g_print ("GDM  %s \n", VERSION);
+                        return 0;
+                } else {
+                        g_warning ("No longer supported");
+                }
+                return 1;
+        }
+
+        gtk_init (&argc, &argv);
+
+        if (monte_carlo_pi) {
+                calc_pi ();
+                return 0;
+        }
+
+        if (args_remaining != NULL && args_remaining[0] != NULL) {
+
+        }
+
+        if (use_xnest) {
+                g_warning ("Not yet implemented");
+                return 1;
+        }
+
+        error = NULL;
+        res = goto_login_session (&error);
+        if (! res) {
+                GtkWidget *dialog;
+                char      *message;
+
+                if (error != NULL) {
+                        message = g_strdup_printf ("%s", error->message);
+                        g_error_free (error);
+                } else {
+                        message = g_strdup ("");
+                }
+
+                dialog = gtk_message_dialog_new (NULL,
+                                                 GTK_DIALOG_DESTROY_WITH_PARENT,
+                                                 GTK_MESSAGE_ERROR,
+                                                 GTK_BUTTONS_CLOSE,
+                                                 "%s", _("Unable to start new display"));
+
+                gtk_message_dialog_format_secondary_text (GTK_MESSAGE_DIALOG (dialog),
+                                                          "%s", message);
+                g_free (message);
+
+                gtk_window_set_title (GTK_WINDOW (dialog), "");
+                gtk_window_set_icon_name (GTK_WINDOW (dialog), "session-properties");
+                gtk_container_set_border_width (GTK_CONTAINER (dialog), 5);
+                gtk_box_set_spacing (GTK_BOX (gtk_dialog_get_content_area (GTK_DIALOG (dialog))), 14);
+
+                gtk_dialog_run (GTK_DIALOG (dialog));
+                gtk_widget_destroy (dialog);
+        } else {
+                maybe_lock_screen ();
+        }
+
+        return 1;
+}