From 02429cabcddd3a12e0cddd975820b37e8440f1c7 Mon Sep 17 00:00:00 2001

From: Ray Strode <rstrode@redhat.com>

Date: Wed, 22 May 2019 10:53:12 -0400

Subject: [PATCH] local-display-factory: don't spawn login screen if background

 session dies

At the moment gdm conjures up a login screen any time a user session

exits.

This is the right behavior if the user explicitly logs out, but if an

admin is killing a session on a background VT, then going to the login

screen is wrong.

This commit changes the code to detect when the killed session is in

the foreground, and only then bring up a login screen.

---

 daemon/gdm-local-display-factory.c | 24 +++++++++++++++++++++++-

 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/daemon/gdm-local-display-factory.c b/daemon/gdm-local-display-factory.c

index cf4f5095c..6856d30d0 100644

--- a/daemon/gdm-local-display-factory.c

+++ b/daemon/gdm-local-display-factory.c

@@ -227,137 +227,159 @@ gdm_local_display_factory_create_transient_display (GdmLocalDisplayFactory *fact

         store_display (factory, display);

         if (! gdm_display_manage (display)) {

                 display = NULL;

                 goto out;

         }

         if (! gdm_display_get_id (display, id, NULL)) {

                 display = NULL;

                 goto out;

         }

         ret = TRUE;

  out:

         /* ref either held by store or not at all */

         g_object_unref (display);

         return ret;

 }

 static void

 on_display_status_changed (GdmDisplay             *display,

                            GParamSpec             *arg1,

                            GdmLocalDisplayFactory *factory)

 {

         int              status;

         GdmDisplayStore *store;

         int              num;

         char            *seat_id = NULL;

+        char            *session_id = NULL;

         char            *session_type = NULL;

         char            *session_class = NULL;

         gboolean         is_initial = TRUE;

         gboolean         is_local = TRUE;

+        int              ret;

         num = -1;

         gdm_display_get_x11_display_number (display, &num, NULL);

         store = gdm_display_factory_get_display_store (GDM_DISPLAY_FACTORY (factory));

         g_object_get (display,

                       "seat-id", &seat_id,

+                      "session-id", &session_id,

                       "is-initial", &is_initial,

                       "is-local", &is_local,

                       "session-type", &session_type,

                       "session-class", &session_class,

                       NULL);

         status = gdm_display_get_status (display);

         g_debug ("GdmLocalDisplayFactory: display status changed: %d", status);

         switch (status) {

         case GDM_DISPLAY_FINISHED:

                 /* remove the display number from factory->priv->used_display_numbers

                    so that it may be reused */

                 if (num != -1) {

                         g_hash_table_remove (factory->priv->used_display_numbers, GUINT_TO_POINTER (num));

                 }

                 gdm_display_store_remove (store, display);

                 /* if this is a local display, recreate the display so

                  * a new login screen comes up if one is missing.

                  */

                 if (is_local && g_strcmp0 (session_class, "greeter") != 0) {

+                        g_autofree char *active_session = NULL;

+

                         /* reset num failures */

                         factory->priv->num_failures = 0;

-                        create_display (factory, seat_id, session_type, is_initial);

+                        ret = sd_seat_get_active (seat_id, &active_session, NULL);

+

+                        if (ret == 0) {

+                                g_autofree char *state = NULL;

+                                ret = sd_session_get_state (active_session, &state);

+                                if (ret != 0 ||

+                                    g_strcmp0 (state, "closing") == 0 ||

+                                    g_strcmp0 (active_session, session_id) == 0) {

+                                        g_clear_pointer (&active_session, free);

+                                }

+                        }

+

+                        /* If this died in the foreground leaving us on a blank vt,

+                           start a new login screen */

+                        if (!sd_seat_can_multi_session (seat_id) || active_session == NULL) {

+                                create_display (factory, seat_id, session_type, is_initial);

+                        }

                 }

                 break;

         case GDM_DISPLAY_FAILED:

                 /* leave the display number in factory->priv->used_display_numbers

                    so that it doesn't get reused */

                 gdm_display_store_remove (store, display);

                 /* Create a new equivalent display if it was static */

                 if (is_local) {

                         factory->priv->num_failures++;

                         if (factory->priv->num_failures > MAX_DISPLAY_FAILURES) {

                                 /* oh shit */

                                 g_warning ("GdmLocalDisplayFactory: maximum number of X display failures reached: check X server log for errors");

                         } else {

 #ifdef ENABLE_WAYLAND_SUPPORT

                                 if (g_strcmp0 (session_type, "wayland") == 0) {

                                         g_free (session_type);

                                         session_type = NULL;

                                 }

 #endif

                                 create_display (factory, seat_id, session_type, is_initial);

                         }

                 }

                 break;

         case GDM_DISPLAY_UNMANAGED:

                 break;

         case GDM_DISPLAY_PREPARED:

                 break;

         case GDM_DISPLAY_MANAGED:

                 break;

         default:

                 g_assert_not_reached ();

                 break;

         }

         g_free (seat_id);

+        g_free (session_id);

         g_free (session_type);

         g_free (session_class);

 }

 static gboolean

 lookup_by_seat_id (const char *id,

                    GdmDisplay *display,

                    gpointer    user_data)

 {

         const char *looking_for = user_data;

         char *current;

         gboolean res;

         g_object_get (G_OBJECT (display), "seat-id", &current, NULL);

         res = g_strcmp0 (current, looking_for) == 0;

         g_free(current);

         return res;

 }

 static gboolean

 activate_session_id (GdmLocalDisplayFactory *self,

                      const char             *seat_id,

                      const char             *session_id)

 {

         GError *error = NULL;

         GVariant *reply;

-- 

2.21.0