[gdm/wip/try-harder-to-get-a-login-screen: 5/5] daemon: try harder to get to a login screen at logout

[Ray Strode <halfline src gnome org>]

commit 5e737a57402fa626af7f037b9485bd172c8a3dff
Author: Ray Strode <rstrode redhat com>
Date:   Mon Jul 30 16:21:29 2018 -0400

    daemon: try harder to get to a login screen at logout
    
    commit 22c332ba and some follow up commits try to ensure the
    user never stays on a blank VT by jumping to a login screen in
    the event they'd end up on one.
    
    Unfortunately, that part of the code can't start a login screen
    if there's not one running at all.
    
    This commit moves the code to GdmLocalDisplyFactory where the
    login screens are created, so users won't end up on a blank
    VT even if no login screen is yet running.

 daemon/gdm-local-display-factory.c | 36 ++++++++++++++++++++++++----
 daemon/gdm-manager.c               | 48 --------------------------------------
 2 files changed, 31 insertions(+), 53 deletions(-)
---
diff --git a/daemon/gdm-local-display-factory.c b/daemon/gdm-local-display-factory.c
index f68eda8d..f214185f 100644
--- a/daemon/gdm-local-display-factory.c
+++ b/daemon/gdm-local-display-factory.c
@@ -28,6 +28,8 @@
 #include <glib-object.h>
 #include <gio/gio.h>
 
+#include <systemd/sd-login.h>
+
 #include "gdm-common.h"
 #include "gdm-manager.h"
 #include "gdm-display-factory.h"
@@ -267,6 +269,7 @@ on_display_status_changed (GdmDisplay             *display,
         int              num;
         char            *seat_id = NULL;
         char            *session_type = NULL;
+        char            *session_class = NULL;
         gboolean         is_initial = TRUE;
         gboolean         is_local = TRUE;
 
@@ -278,6 +281,7 @@ on_display_status_changed (GdmDisplay             *display,
                       "is-initial", &is_initial,
                       "is-local", &is_local,
                       "session-type", &session_type,
+                      "session-class", &session_class,
                       NULL);
 
         status = gdm_display_get_status (display);
@@ -297,7 +301,7 @@ on_display_status_changed (GdmDisplay             *display,
                  * ensures we get a new login screen when the user logs out,
                  * if there isn't one.
                  */
-                if (is_local) {
+                if (is_local && g_strcmp0 (session_class, "greeter") != 0) {
                         /* reset num failures */
                         factory->priv->num_failures = 0;
 
@@ -342,6 +346,7 @@ on_display_status_changed (GdmDisplay             *display,
 
         g_free (seat_id);
         g_free (session_type);
+        g_free (session_class);
 }
 
 static gboolean
@@ -370,12 +375,33 @@ create_display (GdmLocalDisplayFactory *factory,
 {
         GdmDisplayStore *store;
         GdmDisplay      *display = NULL;
+        char            *active_session_id = NULL;
+        int              ret;
 
-        /* Ensure we don't create the same display more than once */
         store = gdm_display_factory_get_display_store (GDM_DISPLAY_FACTORY (factory));
-        display = gdm_display_store_find (store, lookup_by_seat_id, (gpointer) seat_id);
-        if (display != NULL) {
-                return NULL;
+
+        ret = sd_seat_get_active (seat_id, &active_session_id, NULL);
+
+        if (ret == 0) {
+                char *login_session_id = NULL;
+
+                /* If we already have a login window, switch to it */
+                if (gdm_get_login_window_session_id (seat_id, &login_session_id)) {
+                        if (g_strcmp0 (active_session_id, login_session_id) != 0) {
+                                gdm_activate_session_by_id (factory->priv->connection, seat_id, 
login_session_id);
+                        }
+                        g_clear_pointer (&login_session_id, g_free);
+                        g_clear_pointer (&active_session_id, g_free);
+                        return NULL;
+                }
+                g_clear_pointer (&active_session_id, g_free);
+        } else {
+                /* Ensure we don't create the same display more than once */
+                display = gdm_display_store_find (store, lookup_by_seat_id, (gpointer) seat_id);
+
+                if (display != NULL) {
+                        return NULL;
+                }
         }
 
         g_debug ("GdmLocalDisplayFactory: Adding display on seat %s", seat_id);
diff --git a/daemon/gdm-manager.c b/daemon/gdm-manager.c
index 11945522..f17bd1a5 100644
--- a/daemon/gdm-manager.c
+++ b/daemon/gdm-manager.c
@@ -1287,53 +1287,6 @@ maybe_start_pending_initial_login (GdmManager *manager,
         g_free (user_session_seat_id);
 }
 
-static void
-activate_login_window_session_on_seat (GdmManager *self,
-                                       const char *seat_id)
-{
-        char *session_id;
-
-        if (!gdm_get_login_window_session_id (seat_id, &session_id)) {
-                return;
-        }
-
-        if (session_id) {
-                gdm_activate_session_by_id (self, seat_id, session_id);
-                g_free (session_id);
-        }
-}
-
-static void
-maybe_activate_other_session (GdmManager *self,
-                              GdmDisplay *old_display)
-{
-        char *seat_id = NULL;
-        char *session_id = NULL;
-        int ret;
-
-        g_object_get (G_OBJECT (old_display),
-                      "seat-id", &seat_id,
-                      NULL);
-
-        ret = sd_seat_get_active (seat_id, &session_id, NULL);
-
-        if (ret == 0) {
-                GdmDisplay *display;
-
-                display = gdm_display_store_find (self->priv->display_store,
-                                                  lookup_by_session_id,
-                                                  (gpointer) session_id);
-
-                if (display == NULL || gdm_display_get_status (display) == GDM_DISPLAY_FINISHED) {
-                        activate_login_window_session_on_seat (self, seat_id);
-                }
-
-                g_free (session_id);
-        }
-
-        g_free (seat_id);
-}
-
 static const char *
 get_username_for_greeter_display (GdmManager *manager,
                                   GdmDisplay *display)
@@ -1579,7 +1532,6 @@ on_display_status_changed (GdmDisplay *display,
                                 manager->priv->ran_once = TRUE;
                         }
                         maybe_start_pending_initial_login (manager, display);
-                        maybe_activate_other_session (manager, display);
                         break;
                 default:
                         break;