daemon: support launching sessions on separate VTwip/wayland

If an xsession file sets X-GDM-NeedsVT to true, then GDM will
now automatically allocate a new VT for that session and jump to
it before starting the session.  Once the session completes, the
worker will automatically jump back to the VT it started on.

This will be useful for getting mutter-launch to be able to launch
a gnome-shell wayland sesssion.  Longer term, I think mutter-launch
will go away and its functionality will get moved into logind.

1 files changed, 58 insertions, 0 deletions

diff --git a/daemon/gdm-session.c b/daemon/gdm-session.c
index f8f09670..41ed3f90 100644
--- a/daemon/gdm-session.c
+++ b/daemon/gdm-session.c
@@ -2689,6 +2689,10 @@ gdm_session_bypasses_xsession (GdmSession *self)
         g_return_val_if_fail (self != NULL, FALSE);
         g_return_val_if_fail (GDM_IS_SESSION (self), FALSE);
 
+        if (gdm_session_needs_vt (self)) {
+                return TRUE;
+        }
+
         filename = g_strdup_printf ("%s.desktop", get_session_name (self));
 
         key_file = g_key_file_new ();
@@ -2725,6 +2729,54 @@ out:
         return bypasses_xsession;
 }
 
+gboolean
+gdm_session_needs_vt (GdmSession *self)
+{
+        GError     *error;
+        GKeyFile   *key_file;
+        gboolean    res;
+        gboolean    needs_vt = FALSE;
+        char       *filename;
+
+        g_return_val_if_fail (self != NULL, FALSE);
+        g_return_val_if_fail (GDM_IS_SESSION (self), FALSE);
+
+        filename = g_strdup_printf ("%s.desktop", get_session_name (self));
+
+        key_file = g_key_file_new ();
+        error = NULL;
+        res = g_key_file_load_from_dirs (key_file,
+                                         filename,
+                                         get_system_session_dirs (),
+                                         NULL,
+                                         G_KEY_FILE_NONE,
+                                         &error);
+        if (! res) {
+                g_debug ("GdmSession: File '%s' not found: %s", filename, error->message);
+                goto out;
+        }
+
+        error = NULL;
+        res = g_key_file_has_key (key_file, G_KEY_FILE_DESKTOP_GROUP, "X-GDM-NeedsVT", NULL);
+        if (!res) {
+                goto out;
+        } else {
+                needs_vt = g_key_file_get_boolean (key_file, G_KEY_FILE_DESKTOP_GROUP, "X-GDM-NeedsVT", &error);
+                if (error) {
+                        needs_vt = FALSE;
+                        g_error_free (error);
+                        goto out;
+                }
+                if (needs_vt) {
+                        g_debug ("GdmSession: Session %s runs on its own VT", filename);
+                }
+        }
+
+out:
+        g_free (filename);
+        return needs_vt;
+}
+
 void
 gdm_session_select_program (GdmSession *self,
                             const char *text)
@@ -2760,6 +2812,7 @@ gdm_session_select_session (GdmSession *self,
 {
         GHashTableIter iter;
         gpointer key, value;
+        gboolean needs_vt;
 
         g_free (self->priv->selected_session);
 
@@ -2769,6 +2822,8 @@ gdm_session_select_session (GdmSession *self,
                 self->priv->selected_session = g_strdup (text);
         }
 
+        needs_vt = gdm_session_needs_vt (self);
+
         g_hash_table_iter_init (&iter, self->priv->conversations);
         while (g_hash_table_iter_next (&iter, &key, &value)) {
                 GdmSessionConversation *conversation;
@@ -2778,6 +2833,9 @@ gdm_session_select_session (GdmSession *self,
                 gdm_dbus_worker_call_set_session_name (conversation->worker_proxy,
                                                        get_session_name (self),
                                                        NULL, NULL, NULL);
+                gdm_dbus_worker_call_set_session_needs_vt (conversation->worker_proxy,
+                                                           needs_vt,
+                                                           NULL, NULL, NULL);
         }
 }