afc: Fix force unmount of devices

When unplugging an afc device without unmounting it first, the
corresponding gvfsd-afc process does not go away in spite of the
exit(1) workaround added for bgo#708288.

This happens because idevice_event_unsubscribe() in called from the
thread where the _idevice_event_cb() runs in. libimobiledevice (through
libusbmuxd) creates a thread to watch for device events, and calls the
idevice_event_cb_t from that thread. idevice_event_unsubscribe() then
forcfully kills that thread (see usbmuxd_unsubscribe() in libusbmuxd),
so exit(1) code after the call to idevice_event_unsubscribe() never gets
a chance to run.

Moving the call to idevice_event_unsubscribe() and the
g_vfs_backend_force_unmount() call to run in the main loop through
g_idle_add() avoids this issue, and allows the code handling force
unmounts to run as expected.

Fixes: https://bugzilla.gnome.org/show_bug.cgi?id=708288

1 files changed, 17 insertions, 7 deletions

diff --git a/daemon/gvfsbackendafc.c b/daemon/gvfsbackendafc.c
index bb9a38e5..22bab161 100644
--- a/daemon/gvfsbackendafc.c
+++ b/daemon/gvfsbackendafc.c
@@ -342,6 +342,20 @@ app_info_free (AppInfo *info)
   g_free (info);
 }
 
+static gboolean
+force_umount_idle (gpointer user_data)
+{
+  GVfsBackendAfc *afc_backend = G_VFS_BACKEND_AFC (user_data);
+
+  g_vfs_backend_afc_close_connection (afc_backend);
+
+  idevice_event_unsubscribe ();
+
+  g_vfs_backend_force_unmount (G_VFS_BACKEND(afc_backend));
+
+  return G_SOURCE_REMOVE;
+}
+
 static void
 _idevice_event_cb (const idevice_event_t *event, void *user_data)
 {
@@ -358,13 +372,9 @@ _idevice_event_cb (const idevice_event_t *event, void *user_data)
 
   g_print ("Shutting down AFC backend for device uuid %s\n", afc_backend->uuid);
 
-  g_vfs_backend_afc_close_connection (afc_backend);
-
-  idevice_event_unsubscribe ();
-
-  /* TODO: need a cleaner way to force unmount ourselves:
-   * https://bugzilla.gnome.org/show_bug.cgi?id=708288 */
-  exit (1);
+  /* idevice_event_unsubscribe() will terminate the thread _idevice_event_cb
+   * is running in, so we need to call back into our main loop */
+  g_idle_add(force_umount_idle, afc_backend);
 }
 
 static gboolean