[gdm] local-display-factory: disconnect signal handlers when factory is disposed

[Ray Strode <halfline src gnome org>]

commit e980b9101bfb1387df3cab4bf0c5ebdb4c6badbb
Author: Ray Strode <rstrode redhat com>
Date:   Wed Jun 22 10:13:07 2016 -0400

    local-display-factory: disconnect signal handlers when factory is disposed
    
    There's the potential for a crash in the shutdown path after the
    factory is disposed, since we fail to disconnect signal handlers to
    the displays / display store at factory dispose time.
    
    This commit changes the g_signal_connect to g_signal_connect_object, to
    avoid any potential for crash.
    
    (this is a fix noticed when reading through the source.  It's tangentially
    related to a discussion on irc for a different bug)

 daemon/gdm-local-display-factory.c |   26 +++++++++++++++-----------
 1 files changed, 15 insertions(+), 11 deletions(-)
---
diff --git a/daemon/gdm-local-display-factory.c b/daemon/gdm-local-display-factory.c
index d06f378..cf84439 100644
--- a/daemon/gdm-local-display-factory.c
+++ b/daemon/gdm-local-display-factory.c
@@ -536,8 +536,10 @@ on_display_added (GdmDisplayStore        *display_store,
         display = gdm_display_store_lookup (display_store, id);
 
         if (display != NULL) {
-                g_signal_connect (display, "notify::status",
-                                  G_CALLBACK (on_display_status_changed), factory);
+                g_signal_connect_object (display, "notify::status",
+                                         G_CALLBACK (on_display_status_changed),
+                                         factory,
+                                         0);
 
                 g_object_weak_ref (G_OBJECT (display), (GWeakNotify)on_display_disposed, factory);
         }
@@ -569,15 +571,17 @@ gdm_local_display_factory_start (GdmDisplayFactory *base_factory)
 
         store = gdm_display_factory_get_display_store (GDM_DISPLAY_FACTORY (factory));
 
-        g_signal_connect (G_OBJECT (store),
-                          "display-added",
-                          G_CALLBACK (on_display_added),
-                          factory);
-
-        g_signal_connect (G_OBJECT (store),
-                          "display-removed",
-                          G_CALLBACK (on_display_removed),
-                          factory);
+        g_signal_connect_object (G_OBJECT (store),
+                                 "display-added",
+                                 G_CALLBACK (on_display_added),
+                                 factory,
+                                 0);
+
+        g_signal_connect_object (G_OBJECT (store),
+                                 "display-removed",
+                                 G_CALLBACK (on_display_removed),
+                                 factory,
+                                 0);
 
         gdm_local_display_factory_start_monitor (factory);
         return gdm_local_display_factory_sync_seats (factory);