daemon: add switch-on-finish property to display

When a display exits, sometimes it's desirable to
jump to a login screen.

This depends if the display is transient or not, and
also whether the display is hosting an already logged
in session or not.

This commit adds a property to the display object that
says whether a switch should happen or not.

Note the code to actually perform the switch will get
added in a follow up commit.

Based on work by Josselin Mouette <joss@debian.org>

https://bugzilla.gnome.org/show_bug.cgi?id=618047

5 files changed, 86 insertions, 0 deletions

diff --git a/daemon/gdm-display.c b/daemon/gdm-display.c
index abedc0b8..84b49255 100644
--- a/daemon/gdm-display.c
+++ b/daemon/gdm-display.c
@@ -66,6 +66,7 @@ struct GdmDisplayPrivate
         GdmDisplayAccessFile *access_file;
 
         gboolean              is_local;
+        gboolean              switch_on_finish;
         guint                 finish_idle_id;
 
         GdmSlaveProxy        *slave_proxy;
@@ -84,6 +85,7 @@ enum {
         PROP_X11_COOKIE,
         PROP_X11_AUTHORITY_FILE,
         PROP_IS_LOCAL,
+        PROP_SWITCH_ON_FINISH,
         PROP_SLAVE_COMMAND,
 };
 
@@ -134,6 +136,14 @@ gdm_display_get_status (GdmDisplay *display)
         return display->priv->status;
 }
 
+gboolean
+gdm_display_get_switch_on_finish (GdmDisplay *display)
+{
+        g_return_val_if_fail (GDM_IS_DISPLAY (display), 0);
+
+        return display->priv->switch_on_finish;
+}
+
 static GdmDisplayAccessFile *
 _create_access_file_for_user (GdmDisplay  *display,
                               const char  *username,
@@ -824,6 +834,30 @@ _gdm_display_set_is_local (GdmDisplay     *display,
 }
 
 static void
+_gdm_display_set_switch_on_finish (GdmDisplay     *display,
+                                   gboolean        switch_on_finish)
+{
+        display->priv->switch_on_finish = switch_on_finish;
+}
+
+gboolean
+gdm_display_set_switch_on_finish (GdmDisplay *display,
+                                  gboolean    switch_display,
+                                  GError    **error)
+{
+        gboolean ret = TRUE;
+
+        g_return_val_if_fail (GDM_IS_DISPLAY (display), FALSE);
+
+        g_debug ("GdmDisplay: Setting display to %sswitch to login screen on finish",
+                 switch_display? "" : "not ");
+
+        _gdm_display_set_switch_on_finish (display, switch_display);
+
+        return ret;
+}
+
+static void
 _gdm_display_set_slave_command (GdmDisplay     *display,
                                 const char     *command)
 {
@@ -866,6 +900,9 @@ gdm_display_set_property (GObject        *object,
         case PROP_IS_LOCAL:
                 _gdm_display_set_is_local (self, g_value_get_boolean (value));
                 break;
+        case PROP_SWITCH_ON_FINISH:
+                _gdm_display_set_switch_on_finish (self, g_value_get_boolean (value));
+                break;
         case PROP_SLAVE_COMMAND:
                 _gdm_display_set_slave_command (self, g_value_get_string (value));
                 break;
@@ -914,6 +951,9 @@ gdm_display_get_property (GObject        *object,
         case PROP_IS_LOCAL:
                 g_value_set_boolean (value, self->priv->is_local);
                 break;
+        case PROP_SWITCH_ON_FINISH:
+                g_value_set_boolean (value, self->priv->switch_on_finish);
+                break;
         case PROP_SLAVE_COMMAND:
                 g_value_set_string (value, self->priv->slave_command);
                 break;
@@ -1086,6 +1126,14 @@ gdm_display_class_init (GdmDisplayClass *klass)
                                                                G_PARAM_READWRITE | G_PARAM_CONSTRUCT));
 
         g_object_class_install_property (object_class,
+                                         PROP_SWITCH_ON_FINISH,
+                                         g_param_spec_boolean ("switch-on-finish",
+                                                               NULL,
+                                                               NULL,
+                                                               TRUE,
+                                                               G_PARAM_READWRITE | G_PARAM_CONSTRUCT));
+
+        g_object_class_install_property (object_class,
                                          PROP_SLAVE_COMMAND,
                                          g_param_spec_string ("slave-command",
                                                               "slave command",
diff --git a/daemon/gdm-display.h b/daemon/gdm-display.h
index 607ea1d4..e3aa8605 100644
--- a/daemon/gdm-display.h
+++ b/daemon/gdm-display.h
@@ -88,6 +88,7 @@ GQuark              gdm_display_error_quark                    (void);
 GType               gdm_display_get_type                       (void);
 
 int                 gdm_display_get_status                     (GdmDisplay *display);
+gboolean            gdm_display_get_switch_on_finish           (GdmDisplay *display);
 time_t              gdm_display_get_creation_time              (GdmDisplay *display);
 char *              gdm_display_get_user_auth                  (GdmDisplay *display);
 
@@ -140,6 +141,9 @@ gboolean            gdm_display_remove_user_authorization      (GdmDisplay *disp
 gboolean            gdm_display_set_slave_bus_name             (GdmDisplay *display,
                                                                 const char *name,
                                                                 GError    **error);
+gboolean            gdm_display_set_switch_on_finish           (GdmDisplay *display,
+                                                                gboolean    switch_display,
+                                                                GError    **error);
 
 
 G_END_DECLS
diff --git a/daemon/gdm-display.xml b/daemon/gdm-display.xml
index a92e37fc..d3ce4a4c 100644
--- a/daemon/gdm-display.xml
+++ b/daemon/gdm-display.xml
@@ -35,6 +35,9 @@
     <method name="SetSlaveBusName">
       <arg name="name" direction="in" type="s"/>
     </method>
+    <method name="SetSwitchOnFinish">
+      <arg name="switch_display" direction="in" type="b"/>
+    </method>
     <method name="GetTimedLoginDetails">
       <arg name="enabled" direction="out" type="b"/>
       <arg name="username" direction="out" type="s"/>
diff --git a/daemon/gdm-slave.c b/daemon/gdm-slave.c
index 2dc0323f..9fd65794 100644
--- a/daemon/gdm-slave.c
+++ b/daemon/gdm-slave.c
@@ -1438,6 +1438,31 @@ session_unlock (GdmSlave   *slave,
         return TRUE;
 }
 
+static void
+set_switch_display_on_finish (GdmSlave *slave,
+                              gboolean  switch_display)
+{
+        gboolean    res;
+        GError     *error;
+
+        error = NULL;
+        res = dbus_g_proxy_call (slave->priv->display_proxy,
+                                 "SetSwitchOnFinish",
+                                 &error,
+                                 G_TYPE_BOOLEAN, switch_display,
+                                 G_TYPE_INVALID,
+                                 G_TYPE_INVALID);
+
+        if (! res) {
+                if (error != NULL) {
+                        g_warning ("Failed to set respawn on parent display: %s", error->message);
+                        g_error_free (error);
+                } else {
+                        g_warning ("Failed to set respawn on parent display");
+                }
+        }
+}
+
 gboolean
 gdm_slave_switch_to_user_session (GdmSlave   *slave,
                                   const char *username)
@@ -1468,6 +1493,11 @@ gdm_slave_switch_to_user_session (GdmSlave   *slave,
                 g_debug ("GdmSlave: unable to unlock session: %s", ssid_to_activate);
         }
 
+        /* Since we're switching to a new display, make sure we don't switch again when
+         * this display finishes.
+         */
+        set_switch_display_on_finish (slave, FALSE);
+
         ret = TRUE;
 
  out:
diff --git a/daemon/gdm-transient-display.c b/daemon/gdm-transient-display.c
index dd33547c..01813f70 100644
--- a/daemon/gdm-transient-display.c
+++ b/daemon/gdm-transient-display.c
@@ -210,6 +210,7 @@ gdm_transient_display_new (int display_number)
         object = g_object_new (GDM_TYPE_TRANSIENT_DISPLAY,
                                "x11-display-number", display_number,
                                "x11-display-name", x11_display,
+                               "switch-on-finish", TRUE,
                                NULL);
         g_free (x11_display);