Merge branch 'x-gdm-sessionregisters' into 'master'

Allow sessions to register with GDM

Closes #483

See merge request GNOME/gdm!67

12 files changed, 292 insertions, 107 deletions

diff --git a/common/gdm-common.h b/common/gdm-common.h
index 07812b10..58814aa2 100644
--- a/common/gdm-common.h
+++ b/common/gdm-common.h
@@ -27,6 +27,8 @@
 #include <pwd.h>
 #include <errno.h>
 
+#define REGISTER_SESSION_TIMEOUT 10
+
 #define        VE_IGNORE_EINTR(expr) \
         do {                         \
                 errno = 0;           \
diff --git a/configure.ac b/configure.ac
index e54017f2..0a1c6c19 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1416,12 +1416,12 @@ AC_ARG_WITH(initial-vt,
         AS_HELP_STRING([--with-initial-vt=<nr>],
                 [Initial virtual terminal to use]))
 if ! test -z "$with_initial_vt"; then
-        GDM_INITIAL_VT="$with_initial_vt"
+        GDM_INITIAL_VT=$with_initial_vt
 else
-        GDM_INITIAL_VT="1"
+        GDM_INITIAL_VT=1
 fi
 AC_SUBST(GDM_INITIAL_VT)
-AC_DEFINE_UNQUOTED(GDM_INITIAL_VT, "$GDM_INITIAL_VT", [Initial Virtual Terminal])
+AC_DEFINE_UNQUOTED(GDM_INITIAL_VT, $GDM_INITIAL_VT, [Initial Virtual Terminal])
 
 # Set configuration choices.
 #
diff --git a/daemon/gdm-display.c b/daemon/gdm-display.c
index a8747785..8f4fbc71 100644
--- a/daemon/gdm-display.c
+++ b/daemon/gdm-display.c
@@ -66,7 +66,6 @@ typedef struct _GdmDisplayPrivate
         char                 *x11_display_name;
         int                   status;
         time_t                creation_time;
-        GTimer               *server_timer;
 
         char                 *x11_cookie;
         gsize                 x11_cookie_size;
@@ -93,6 +92,7 @@ typedef struct _GdmDisplayPrivate
         guint                 allow_timed_login : 1;
         guint                 have_existing_user_accounts : 1;
         guint                 doing_initial_setup : 1;
+        guint                 session_registered : 1;
 } GdmDisplayPrivate;
 
 enum {
@@ -115,6 +115,7 @@ enum {
         PROP_ALLOW_TIMED_LOGIN,
         PROP_HAVE_EXISTING_USER_ACCOUNTS,
         PROP_DOING_INITIAL_SETUP,
+        PROP_SESSION_REGISTERED,
 };
 
 static void     gdm_display_class_init  (GdmDisplayClass *klass);
@@ -598,8 +599,6 @@ gdm_display_manage (GdmDisplay *self)
                 }
         }
 
-        g_timer_start (priv->server_timer);
-
         if (g_strcmp0 (priv->session_class, "greeter") == 0) {
                 if (GDM_DISPLAY_GET_CLASS (self)->manage != NULL) {
                         GDM_DISPLAY_GET_CLASS (self)->manage (self);
@@ -671,7 +670,6 @@ gboolean
 gdm_display_unmanage (GdmDisplay *self)
 {
         GdmDisplayPrivate *priv;
-        gdouble elapsed;
 
         g_return_val_if_fail (GDM_IS_DISPLAY (self), FALSE);
 
@@ -681,8 +679,6 @@ gdm_display_unmanage (GdmDisplay *self)
 
         gdm_display_disconnect (self);
 
-        g_timer_stop (priv->server_timer);
-
         if (priv->user_access_file != NULL) {
                 gdm_display_access_file_close (priv->user_access_file);
                 g_object_unref (priv->user_access_file);
@@ -695,9 +691,8 @@ gdm_display_unmanage (GdmDisplay *self)
                 priv->access_file = NULL;
         }
 
-        elapsed = g_timer_elapsed (priv->server_timer, NULL);
-        if (elapsed < 3) {
-                g_warning ("GdmDisplay: display lasted %lf seconds", elapsed);
+        if (!priv->session_registered) {
+                g_warning ("GdmDisplay: Session never registered, failing");
                 _gdm_display_set_status (self, GDM_DISPLAY_FAILED);
         } else {
                 _gdm_display_set_status (self, GDM_DISPLAY_UNMANAGED);
@@ -872,6 +867,17 @@ _gdm_display_set_is_local (GdmDisplay     *self,
 }
 
 static void
+_gdm_display_set_session_registered (GdmDisplay     *self,
+                                     gboolean        registered)
+{
+        GdmDisplayPrivate *priv;
+
+        priv = gdm_display_get_instance_private (self);
+        g_debug ("GdmDisplay: session registered: %s", registered? "yes" : "no");
+        priv->session_registered = registered;
+}
+
+static void
 _gdm_display_set_launch_environment (GdmDisplay           *self,
                                      GdmLaunchEnvironment *launch_environment)
 {
@@ -959,6 +965,9 @@ gdm_display_set_property (GObject        *object,
         case PROP_IS_INITIAL:
                 _gdm_display_set_is_initial (self, g_value_get_boolean (value));
                 break;
+        case PROP_SESSION_REGISTERED:
+                _gdm_display_set_session_registered (self, g_value_get_boolean (value));
+                break;
         default:
                 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
                 break;
@@ -1031,6 +1040,9 @@ gdm_display_get_property (GObject        *object,
         case PROP_DOING_INITIAL_SETUP:
                 g_value_set_boolean (value, priv->doing_initial_setup);
                 break;
+        case PROP_SESSION_REGISTERED:
+                g_value_set_boolean (value, priv->session_registered);
+                break;
         case PROP_ALLOW_TIMED_LOGIN:
                 g_value_set_boolean (value, priv->allow_timed_login);
                 break;
@@ -1356,6 +1368,14 @@ gdm_display_class_init (GdmDisplayClass *klass)
                                                                FALSE,
                                                                G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
         g_object_class_install_property (object_class,
+                                         PROP_SESSION_REGISTERED,
+                                         g_param_spec_boolean ("session-registered",
+                                                               NULL,
+                                                               NULL,
+                                                               FALSE,
+                                                               G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+
+        g_object_class_install_property (object_class,
                                          PROP_LAUNCH_ENVIRONMENT,
                                          g_param_spec_object ("launch-environment",
                                                               NULL,
@@ -1381,7 +1401,6 @@ gdm_display_init (GdmDisplay *self)
         priv = gdm_display_get_instance_private (self);
 
         priv->creation_time = time (NULL);
-        priv->server_timer = g_timer_new ();
 }
 
 static void
@@ -1419,10 +1438,6 @@ gdm_display_finalize (GObject *object)
                 g_object_unref (priv->user_access_file);
         }
 
-        if (priv->server_timer != NULL) {
-                g_timer_destroy (priv->server_timer);
-        }
-
         G_OBJECT_CLASS (gdm_display_parent_class)->finalize (object);
 }
 
@@ -1720,7 +1735,6 @@ void
 gdm_display_stop_greeter_session (GdmDisplay *self)
 {
         GdmDisplayPrivate *priv;
-        GError *error = NULL;
 
         priv = gdm_display_get_instance_private (self);
 
diff --git a/daemon/gdm-local-display-factory.c b/daemon/gdm-local-display-factory.c
index 98daca48..ee41308b 100644
--- a/daemon/gdm-local-display-factory.c
+++ b/daemon/gdm-local-display-factory.c
@@ -64,9 +64,8 @@ struct _GdmLocalDisplayFactory
         guint            seat_removed_id;
 
 #if defined(ENABLE_WAYLAND_SUPPORT) && defined(ENABLE_USER_DISPLAY_SERVER)
-        char            *tty_of_active_vt;
+        unsigned int     active_vt;
         guint            active_vt_watch_id;
-        guint            wait_to_finish_timeout_id;
 #endif
 };
 
@@ -299,6 +298,25 @@ finish_waiting_displays_on_seat (GdmLocalDisplayFactory *factory,
 }
 
 static void
+on_session_registered_cb (GObject *gobject,
+                          GParamSpec *pspec,
+                          gpointer user_data)
+{
+        GdmDisplay *display = GDM_DISPLAY (gobject);
+        GdmLocalDisplayFactory *factory = GDM_LOCAL_DISPLAY_FACTORY (user_data);
+        gboolean registered;
+
+        g_object_get (display, "session-registered", &registered, NULL);
+
+        if (!registered)
+                return;
+
+        g_debug ("GdmLocalDisplayFactory: session registered on display, looking for any background displays to kill");
+
+        finish_waiting_displays_on_seat (factory, "seat0");
+}
+
+static void
 on_display_status_changed (GdmDisplay             *display,
                            GParamSpec             *arg1,
                            GdmLocalDisplayFactory *factory)
@@ -376,6 +394,13 @@ on_display_status_changed (GdmDisplay             *display,
         case GDM_DISPLAY_PREPARED:
                 break;
         case GDM_DISPLAY_MANAGED:
+#if defined(ENABLE_WAYLAND_SUPPORT) && defined(ENABLE_USER_DISPLAY_SERVER)
+                g_signal_connect_object (display,
+                                         "notify::session-registered",
+                                         G_CALLBACK (on_session_registered_cb),
+                                         factory,
+                                         0);
+#endif
                 break;
         case GDM_DISPLAY_WAITING_TO_FINISH:
                 break;
@@ -604,14 +629,6 @@ lookup_by_session_id (const char *id,
 }
 
 #if defined(ENABLE_WAYLAND_SUPPORT) && defined(ENABLE_USER_DISPLAY_SERVER)
-static gboolean
-wait_to_finish_timeout (GdmLocalDisplayFactory *factory)
-{
-        finish_waiting_displays_on_seat (factory, "seat0");
-        factory->wait_to_finish_timeout_id = 0;
-        return G_SOURCE_REMOVE;
-}
-
 static void
 maybe_stop_greeter_in_background (GdmLocalDisplayFactory *factory,
                                   GdmDisplay             *display)
@@ -643,16 +660,8 @@ maybe_stop_greeter_in_background (GdmLocalDisplayFactory *factory,
         }
 
         g_debug ("GdmLocalDisplayFactory: killing login window once its unused");
-        g_object_set (G_OBJECT (display), "status", GDM_DISPLAY_WAITING_TO_FINISH, NULL);
 
-        /* We stop the greeter after a timeout to avoid flicker */
-        if (factory->wait_to_finish_timeout_id != 0)
-                g_source_remove (factory->wait_to_finish_timeout_id);
-
-        factory->wait_to_finish_timeout_id =
-                g_timeout_add_seconds (WAIT_TO_FINISH_TIMEOUT,
-                                       (GSourceFunc)wait_to_finish_timeout,
-                                       factory);
+        g_object_set (G_OBJECT (display), "status", GDM_DISPLAY_WAITING_TO_FINISH, NULL);
 }
 
 static gboolean
@@ -661,13 +670,12 @@ on_vt_changed (GIOChannel    *source,
                GdmLocalDisplayFactory *factory)
 {
         GIOStatus status;
-        static const char *tty_of_initial_vt = "tty" GDM_INITIAL_VT;
-        g_autofree char *tty_of_previous_vt = NULL;
         g_autofree char *tty_of_active_vt = NULL;
         g_autofree char *login_session_id = NULL;
         g_autofree char *active_session_id = NULL;
+        unsigned int previous_vt, new_vt;
         const char *session_type = NULL;
-        int ret;
+        int ret, n_returned;
 
         g_debug ("GdmLocalDisplayFactory: received VT change event");
         g_io_channel_seek_position (source, 0, G_SEEK_SET, NULL);
@@ -703,38 +711,43 @@ on_vt_changed (GIOChannel    *source,
 
         g_strchomp (tty_of_active_vt);
 
+        errno = 0;
+        n_returned = sscanf (tty_of_active_vt, "tty%u", &new_vt);
+
+        if (n_returned != 1 || errno != 0) {
+                g_critical ("GdmLocalDisplayFactory: Couldn't read active VT (got '%s')",
+                            tty_of_active_vt);
+                return G_SOURCE_CONTINUE;
+        }
+
         /* don't do anything if we're on the same VT we were before */
-        if (g_strcmp0 (tty_of_active_vt, factory->tty_of_active_vt) == 0) {
+        if (new_vt == factory->active_vt) {
                 g_debug ("GdmLocalDisplayFactory: VT changed to the same VT, ignoring");
                 return G_SOURCE_CONTINUE;
         }
 
-        tty_of_previous_vt = g_steal_pointer (&factory->tty_of_active_vt);
-        factory->tty_of_active_vt = g_steal_pointer (&tty_of_active_vt);
+        previous_vt = factory->active_vt;
+        factory->active_vt = new_vt;
 
         /* don't do anything at start up */
-        if (tty_of_previous_vt == NULL) {
-                g_debug ("GdmLocalDisplayFactory: VT is %s at startup",
-                         factory->tty_of_active_vt);
+        if (previous_vt == 0) {
+                g_debug ("GdmLocalDisplayFactory: VT is %u at startup",
+                         factory->active_vt);
                 return G_SOURCE_CONTINUE;
         }
 
-        g_debug ("GdmLocalDisplayFactory: VT changed from %s to %s",
-                 tty_of_previous_vt, factory->tty_of_active_vt);
+        g_debug ("GdmLocalDisplayFactory: VT changed from %u to %u",
+                 previous_vt, factory->active_vt);
 
         /* if the old VT was running a wayland login screen kill it
          */
         if (gdm_get_login_window_session_id ("seat0", &login_session_id)) {
-                unsigned int vt;
-
-                ret = sd_session_get_vt (login_session_id, &vt);
-                if (ret == 0 && vt != 0) {
-                        g_autofree char *tty_of_login_window_vt = NULL;
-
-                        tty_of_login_window_vt = g_strdup_printf ("tty%u", vt);
+                unsigned int login_window_vt;
 
-                        g_debug ("GdmLocalDisplayFactory: tty of login window is %s", tty_of_login_window_vt);
-                        if (g_strcmp0 (tty_of_login_window_vt, tty_of_previous_vt) == 0) {
+                ret = sd_session_get_vt (login_session_id, &login_window_vt);
+                if (ret == 0 && login_window_vt != 0) {
+                        g_debug ("GdmLocalDisplayFactory: VT of login window is %u", login_window_vt);
+                        if (login_window_vt == previous_vt) {
                                 GdmDisplayStore *store;
                                 GdmDisplay *display;
 
@@ -744,7 +757,6 @@ on_vt_changed (GIOChannel    *source,
                                 display = gdm_display_store_find (store,
                                                                   lookup_by_session_id,
                                                                   (gpointer) login_session_id);
-
                                 if (display != NULL)
                                         maybe_stop_greeter_in_background (factory, display);
                         } else {
@@ -757,7 +769,7 @@ on_vt_changed (GIOChannel    *source,
          * on it (unless a login screen is already running elsewhere, then
          * jump to that login screen)
          */
-        if (strcmp (factory->tty_of_active_vt, tty_of_initial_vt) != 0) {
+        if (factory->active_vt != GDM_INITIAL_VT) {
                 g_debug ("GdmLocalDisplayFactory: active VT is not initial VT, so ignoring");
                 return G_SOURCE_CONTINUE;
         }
@@ -827,16 +839,10 @@ gdm_local_display_factory_stop_monitor (GdmLocalDisplayFactory *factory)
                 factory->seat_removed_id = 0;
         }
 #if defined(ENABLE_WAYLAND_SUPPORT) && defined(ENABLE_USER_DISPLAY_SERVER)
-        if (factory->wait_to_finish_timeout_id != 0) {
-                g_source_remove (factory->wait_to_finish_timeout_id);
-                factory->wait_to_finish_timeout_id = 0;
-        }
         if (factory->active_vt_watch_id) {
                 g_source_remove (factory->active_vt_watch_id);
                 factory->active_vt_watch_id = 0;
         }
-
-        g_clear_pointer (&factory->tty_of_active_vt, g_free);
 #endif
 }
 
diff --git a/daemon/gdm-manager.c b/daemon/gdm-manager.c
index 980aa62d..23e3b85d 100644
--- a/daemon/gdm-manager.c
+++ b/daemon/gdm-manager.c
@@ -804,6 +804,35 @@ gdm_manager_handle_register_display (GdmDBusManager        *manager,
 }
 
 static gboolean
+gdm_manager_handle_register_session (GdmDBusManager        *manager,
+                                     GDBusMethodInvocation *invocation,
+                                     GVariant              *details)
+{
+        GdmManager      *self = GDM_MANAGER (manager);
+        GdmDisplay      *display;
+        const char      *sender;
+        GDBusConnection *connection;
+
+        sender = g_dbus_method_invocation_get_sender (invocation);
+        connection = g_dbus_method_invocation_get_connection (invocation);
+
+        get_display_and_details_for_bus_sender (self, connection, sender, &display,
+                                                NULL, NULL, NULL, NULL, NULL, NULL, NULL);
+
+        g_debug ("GdmManager: trying to register new session on display %p", display);
+
+        if (display != NULL)
+                g_object_set (G_OBJECT (display), "session-registered", TRUE, NULL);
+        else
+                g_debug ("GdmManager: No display, not registering");
+
+        gdm_dbus_manager_complete_register_session (GDM_DBUS_MANAGER (manager),
+                                                    invocation);
+
+        return TRUE;
+}
+
+static gboolean
 gdm_manager_handle_open_session (GdmDBusManager        *manager,
                                  GDBusMethodInvocation *invocation)
 {
@@ -1159,6 +1188,7 @@ static void
 manager_interface_init (GdmDBusManagerIface *interface)
 {
         interface->handle_register_display = gdm_manager_handle_register_display;
+        interface->handle_register_session = gdm_manager_handle_register_session;
         interface->handle_open_session = gdm_manager_handle_open_session;
         interface->handle_open_reauthentication_channel = gdm_manager_handle_open_reauthentication_channel;
 }
diff --git a/daemon/gdm-manager.xml b/daemon/gdm-manager.xml
index f11f3fb7..92ef1d02 100644
--- a/daemon/gdm-manager.xml
+++ b/daemon/gdm-manager.xml
@@ -4,6 +4,9 @@
     <method name="RegisterDisplay">
       <arg name="details" direction="in" type="a{ss}"/>
     </method>
+    <method name="RegisterSession">
+      <arg name="details" direction="in" type="a{sv}"/>
+    </method>
     <method name="OpenSession">
       <arg name="address" direction="out" type="s"/>
     </method>
diff --git a/daemon/gdm-server.c b/daemon/gdm-server.c
index 7962de22..1ba00d45 100644
--- a/daemon/gdm-server.c
+++ b/daemon/gdm-server.c
@@ -753,7 +753,7 @@ gdm_server_start (GdmServer *server)
 
         /* Hardcode the VT for the initial X server, but nothing else */
         if (server->is_initial) {
-                vtarg = "vt" GDM_INITIAL_VT;
+                vtarg = "vt" G_STRINGIFY (GDM_INITIAL_VT);
         }
 
         /* fork X server process */
diff --git a/daemon/gdm-session-worker.c b/daemon/gdm-session-worker.c
index 640cdbb6..a5f90c4b 100644
--- a/daemon/gdm-session-worker.c
+++ b/daemon/gdm-session-worker.c
@@ -2224,7 +2224,7 @@ set_up_for_new_vt (GdmSessionWorker *worker)
         }
 
         if (worker->priv->display_is_initial) {
-                session_vt = atoi (GDM_INITIAL_VT);
+                session_vt = GDM_INITIAL_VT;
         } else {
                 if (ioctl(fd, VT_OPENQRY, &session_vt) < 0) {
                         g_debug ("GdmSessionWorker: couldn't open new VT: %m");
diff --git a/daemon/gdm-session.c b/daemon/gdm-session.c
index 6a116a85..d0e09b53 100644
--- a/daemon/gdm-session.c
+++ b/daemon/gdm-session.c
@@ -2837,6 +2837,7 @@ gdm_session_start_session (GdmSession *self,
         gboolean                allow_remote_connections = FALSE;
         char                   *command;
         char                   *program;
+        gboolean               register_session;
 
         g_return_if_fail (GDM_IS_SESSION (self));
         g_return_if_fail (self->session_conversation == NULL);
@@ -2862,6 +2863,8 @@ gdm_session_start_session (GdmSession *self,
                 run_launcher = TRUE;
         }
 
+        register_session = !gdm_session_session_registers (self);
+
         if (self->selected_program == NULL) {
                 gboolean run_xsession_script;
 
@@ -2879,12 +2882,14 @@ gdm_session_start_session (GdmSession *self,
 
                 if (run_launcher) {
                         if (is_x11) {
-                                program = g_strdup_printf (LIBEXECDIR "/gdm-x-session %s %s\"%s\"",
+                                program = g_strdup_printf (LIBEXECDIR "/gdm-x-session %s%s %s\"%s\"",
+                                                           register_session ? "--register-session " : "",
                                                            run_xsession_script? "--run-script " : "",
                                                            allow_remote_connections? "--allow-remote-connections " : "",
                                                            command);
                         } else {
-                                program = g_strdup_printf (LIBEXECDIR "/gdm-wayland-session \"%s\"",
+                                program = g_strdup_printf (LIBEXECDIR "/gdm-wayland-session %s\"%s\"",
+                                                           register_session ? "--register-session " : "",
                                                            command);
                         }
                 } else if (run_xsession_script) {
@@ -2897,10 +2902,12 @@ gdm_session_start_session (GdmSession *self,
         } else {
                 if (run_launcher) {
                         if (is_x11) {
-                                program = g_strdup_printf (LIBEXECDIR "/gdm-x-session \"%s\"",
+                                program = g_strdup_printf (LIBEXECDIR "/gdm-x-session %s\"%s\"",
+                                                           register_session ? "--register-session " : "",
                                                            self->selected_program);
                         } else {
-                                program = g_strdup_printf (LIBEXECDIR "/gdm-wayland-session \"%s\"",
+                                program = g_strdup_printf (LIBEXECDIR "/gdm-wayland-session %s\"%s\"",
+                                                           register_session ? "--register-session " : "",
                                                            self->selected_program);
                         }
                 } else {
@@ -3178,6 +3185,38 @@ update_session_type (GdmSession *self)
 }
 
 gboolean
+gdm_session_session_registers (GdmSession *self)
+{
+        g_autoptr(GError) error = NULL;
+        g_autoptr(GKeyFile) key_file = NULL;
+        gboolean session_registers = FALSE;
+        g_autofree char *filename = NULL;
+
+        g_return_val_if_fail (self != NULL, FALSE);
+        g_return_val_if_fail (GDM_IS_SESSION (self), FALSE);
+
+        filename = get_session_filename (self);
+
+        key_file = load_key_file_for_file (self, filename, NULL);
+
+        session_registers = g_key_file_get_boolean (key_file,
+                                                    G_KEY_FILE_DESKTOP_GROUP,
+                                                    "X-GDM-SessionRegisters",
+                                                    &error);
+        if (!session_registers &&
+            error != NULL &&
+            !g_error_matches (error, G_KEY_FILE_ERROR, G_KEY_FILE_ERROR_KEY_NOT_FOUND)) {
+                g_warning ("GdmSession: Couldn't read session file '%s'", filename);
+                return FALSE;
+        }
+
+        g_debug ("GdmSession: '%s' %s self", filename,
+                 session_registers ? "registers" : "does not register");
+
+        return session_registers;
+}
+
+gboolean
 gdm_session_bypasses_xsession (GdmSession *self)
 {
         GError     *error;
diff --git a/daemon/gdm-session.h b/daemon/gdm-session.h
index 98acb4f6..3b64ecd2 100644
--- a/daemon/gdm-session.h
+++ b/daemon/gdm-session.h
@@ -76,6 +76,7 @@ const char       *gdm_session_get_display_device          (GdmSession     *sessi
 const char       *gdm_session_get_display_seat_id         (GdmSession     *session);
 const char       *gdm_session_get_session_id              (GdmSession     *session);
 gboolean          gdm_session_bypasses_xsession           (GdmSession     *session);
+gboolean          gdm_session_session_registers           (GdmSession     *session);
 GdmSessionDisplayMode gdm_session_get_display_mode  (GdmSession     *session);
 
 #ifdef ENABLE_WAYLAND_SUPPORT
diff --git a/daemon/gdm-wayland-session.c b/daemon/gdm-wayland-session.c
index 94f49e19..35679b19 100644
--- a/daemon/gdm-wayland-session.c
+++ b/daemon/gdm-wayland-session.c
@@ -45,6 +45,7 @@ typedef struct
 
         GSubprocess     *bus_subprocess;
         GDBusConnection *bus_connection;
+        GdmDBusManager  *display_manager_proxy;
         char            *bus_address;
 
         char           **environment;
@@ -53,6 +54,8 @@ typedef struct
         char         *session_command;
         int           session_exit_status;
 
+        guint         register_session_id;
+
         GMainLoop    *main_loop;
 
         guint32       debug_enabled : 1;
@@ -385,29 +388,14 @@ static gboolean
 register_display (State        *state,
                   GCancellable *cancellable)
 {
-        GdmDBusManager  *manager = NULL;
         GError          *error = NULL;
         gboolean         registered = FALSE;
         GVariantBuilder  details;
 
-        manager = gdm_dbus_manager_proxy_new_for_bus_sync (G_BUS_TYPE_SYSTEM,
-                                                           G_DBUS_PROXY_FLAGS_DO_NOT_LOAD_PROPERTIES |
-                                                           G_DBUS_PROXY_FLAGS_DO_NOT_CONNECT_SIGNALS,
-                                                           "org.gnome.DisplayManager",
-                                                           "/org/gnome/DisplayManager/Manager",
-                                                           cancellable,
-                                                           &error);
-
-        if (!manager) {
-                g_debug ("could not contact display manager: %s", error->message);
-                g_error_free (error);
-                goto out;
-        }
-
         g_variant_builder_init (&details, G_VARIANT_TYPE ("a{ss}"));
         g_variant_builder_add (&details, "{ss}", "session-type", "wayland");
 
-        registered = gdm_dbus_manager_call_register_display_sync (manager,
+        registered = gdm_dbus_manager_call_register_display_sync (state->display_manager_proxy,
                                                                   g_variant_builder_end (&details),
                                                                   cancellable,
                                                                   &error);
@@ -416,8 +404,6 @@ register_display (State        *state,
                 g_error_free (error);
         }
 
-out:
-        g_clear_object (&manager);
         return registered;
 }
 
@@ -439,6 +425,7 @@ clear_state (State **out_state)
         g_clear_object (&state->session_subprocess);
         g_clear_pointer (&state->environment, g_strfreev);
         g_clear_pointer (&state->main_loop, g_main_loop_unref);
+        g_clear_handle_id (&state->register_session_id, g_source_remove);
         *out_state = NULL;
 }
 
@@ -454,6 +441,49 @@ on_sigterm (State *state)
         return G_SOURCE_CONTINUE;
 }
 
+static gboolean
+register_session_timeout_cb (gpointer user_data)
+{
+        State *state;
+        GError *error = NULL;
+
+        state = (State *) user_data;
+
+        gdm_dbus_manager_call_register_session_sync (state->display_manager_proxy,
+                                                     g_variant_new ("a{sv}", NULL),
+                                                     state->cancellable,
+                                                     &error);
+
+        if (error != NULL) {
+                g_warning ("Could not register session: %s", error->message);
+                g_error_free (error);
+        }
+
+        return G_SOURCE_REMOVE;
+}
+
+static gboolean
+connect_to_display_manager (State *state)
+{
+        g_autoptr (GError) error = NULL;
+
+        state->display_manager_proxy = gdm_dbus_manager_proxy_new_for_bus_sync (
+                G_BUS_TYPE_SYSTEM,
+                G_DBUS_PROXY_FLAGS_DO_NOT_LOAD_PROPERTIES | G_DBUS_PROXY_FLAGS_DO_NOT_CONNECT_SIGNALS,
+                "org.gnome.DisplayManager",
+                "/org/gnome/DisplayManager/Manager",
+                state->cancellable,
+                &error);
+
+        if (state->display_manager_proxy == NULL) {
+                g_printerr ("gdm-wayland-session: could not contact display manager: %s\n",
+                            error->message);
+                return FALSE;
+        }
+
+        return TRUE;
+}
+
 int
 main (int    argc,
       char **argv)
@@ -464,7 +494,10 @@ main (int    argc,
         gboolean         debug = FALSE;
         gboolean         ret;
         int              exit_status = EX_OK;
+        static gboolean  register_session = FALSE;
+
         static GOptionEntry entries []   = {
+                { "register-session", 0, 0, G_OPTION_ARG_NONE, &register_session, "Register session after a delay", NULL },
                 { G_OPTION_REMAINING, 0, 0, G_OPTION_ARG_STRING_ARRAY, &args, "", "" },
                 { NULL }
         };
@@ -528,6 +561,9 @@ main (int    argc,
                 goto out;
         }
 
+        if (!connect_to_display_manager (state))
+                goto out;
+
         ret = register_display (state, state->cancellable);
 
         if (!ret) {
@@ -536,6 +572,15 @@ main (int    argc,
                 goto out;
         }
 
+        if (register_session) {
+                g_debug ("gdm-wayland-session: Will register session in %d seconds", REGISTER_SESSION_TIMEOUT);
+                state->register_session_id = g_timeout_add_seconds (REGISTER_SESSION_TIMEOUT,
+                                                                    register_session_timeout_cb,
+                                                                    state);
+        } else {
+                g_debug ("gdm-wayland-session: Session will register itself");
+        }
+
         g_main_loop_run (state->main_loop);
 
         /* Only use exit status of session if we're here because it exit */
diff --git a/daemon/gdm-x-session.c b/daemon/gdm-x-session.c
index 3b2fcef4..58865a6c 100644
--- a/daemon/gdm-x-session.c
+++ b/daemon/gdm-x-session.c
@@ -51,6 +51,7 @@ typedef struct
 
         GSubprocess     *bus_subprocess;
         GDBusConnection *bus_connection;
+        GdmDBusManager  *display_manager_proxy;
         char            *bus_address;
 
         char           **environment;
@@ -59,6 +60,8 @@ typedef struct
         char         *session_command;
         int           session_exit_status;
 
+        guint         register_session_id;
+
         GMainLoop    *main_loop;
 
         guint32       debug_enabled : 1;
@@ -737,30 +740,15 @@ static gboolean
 register_display (State        *state,
                   GCancellable *cancellable)
 {
-        GdmDBusManager  *manager = NULL;
         GError          *error = NULL;
         gboolean         registered = FALSE;
         GVariantBuilder  details;
 
-        manager = gdm_dbus_manager_proxy_new_for_bus_sync (G_BUS_TYPE_SYSTEM,
-                                                           G_DBUS_PROXY_FLAGS_DO_NOT_LOAD_PROPERTIES |
-                                                           G_DBUS_PROXY_FLAGS_DO_NOT_CONNECT_SIGNALS,
-                                                           "org.gnome.DisplayManager",
-                                                           "/org/gnome/DisplayManager/Manager",
-                                                           cancellable,
-                                                           &error);
-
-        if (!manager) {
-                g_debug ("could not contact display manager: %s", error->message);
-                g_error_free (error);
-                goto out;
-        }
-
         g_variant_builder_init (&details, G_VARIANT_TYPE ("a{ss}"));
         g_variant_builder_add (&details, "{ss}", "session-type", "x11");
         g_variant_builder_add (&details, "{ss}", "x11-display-name", state->display_name);
 
-        registered = gdm_dbus_manager_call_register_display_sync (manager,
+        registered = gdm_dbus_manager_call_register_display_sync (state->display_manager_proxy,
                                                                   g_variant_builder_end (&details),
                                                                   cancellable,
                                                                   &error);
@@ -769,8 +757,6 @@ register_display (State        *state,
                 g_error_free (error);
         }
 
-out:
-        g_clear_object (&manager);
         return registered;
 }
 
@@ -795,6 +781,7 @@ clear_state (State **out_state)
         g_clear_pointer (&state->auth_file, g_free);
         g_clear_pointer (&state->display_name, g_free);
         g_clear_pointer (&state->main_loop, g_main_loop_unref);
+        g_clear_handle_id (&state->register_session_id, g_source_remove);
         *out_state = NULL;
 }
 
@@ -810,6 +797,49 @@ on_sigterm (State *state)
         return G_SOURCE_CONTINUE;
 }
 
+static gboolean
+register_session_timeout_cb (gpointer user_data)
+{
+        State *state;
+        GError *error = NULL;
+
+        state = (State *) user_data;
+
+        gdm_dbus_manager_call_register_session_sync (state->display_manager_proxy,
+                                                     g_variant_new ("a{sv}", NULL),
+                                                     state->cancellable,
+                                                     &error);
+
+        if (error != NULL) {
+                g_warning ("Could not register session: %s", error->message);
+                g_error_free (error);
+        }
+
+        return G_SOURCE_REMOVE;
+}
+
+static gboolean
+connect_to_display_manager (State *state)
+{
+        g_autoptr (GError) error = NULL;
+
+        state->display_manager_proxy = gdm_dbus_manager_proxy_new_for_bus_sync (
+                G_BUS_TYPE_SYSTEM,
+                G_DBUS_PROXY_FLAGS_DO_NOT_LOAD_PROPERTIES | G_DBUS_PROXY_FLAGS_DO_NOT_CONNECT_SIGNALS,
+                "org.gnome.DisplayManager",
+                "/org/gnome/DisplayManager/Manager",
+                state->cancellable,
+                &error);
+
+        if (state->display_manager_proxy == NULL) {
+                g_printerr ("gdm-x-session: could not contact display manager: %s\n",
+                            error->message);
+                return FALSE;
+        }
+
+        return TRUE;
+}
+
 int
 main (int    argc,
       char **argv)
@@ -822,9 +852,12 @@ main (int    argc,
         gboolean         debug = FALSE;
         gboolean         ret;
         int              exit_status = EX_OK;
+        static gboolean  register_session = FALSE;
+
         static GOptionEntry entries []   = {
                 { "run-script", 'r', 0, G_OPTION_ARG_NONE, &run_script, N_("Run program through /etc/gdm/Xsession wrapper script"), NULL },
                 { "allow-remote-connections", 'a', 0, G_OPTION_ARG_NONE, &allow_remote_connections, N_("Listen on TCP socket"), NULL },
+                { "register-session", 0, 0, G_OPTION_ARG_NONE, &register_session, "Register session after a delay", NULL },
                 { G_OPTION_REMAINING, 0, 0, G_OPTION_ARG_STRING_ARRAY, &args, "", "" },
                 { NULL }
         };
@@ -896,6 +929,9 @@ main (int    argc,
                 goto out;
         }
 
+        if (!connect_to_display_manager (state))
+                goto out;
+
         ret = register_display (state, state->cancellable);
 
         if (!ret) {
@@ -912,6 +948,15 @@ main (int    argc,
                 goto out;
         }
 
+        if (register_session) {
+                g_debug ("gdm-x-session: Will register session in %d seconds", REGISTER_SESSION_TIMEOUT);
+                state->register_session_id = g_timeout_add_seconds (REGISTER_SESSION_TIMEOUT,
+                                                                    register_session_timeout_cb,
+                                                                    state);
+        } else {
+                g_debug ("gdm-x-session: Session will register itself");
+        }
+
         g_main_loop_run (state->main_loop);
 
         /* Only use exit status of session if we're here because it exit */