[glib] inotify: Don’t propagate unrecognised events to GLocalFileMonitor

[Philip Withnall <pwithnall src gnome org>]

commit 748bb24985419d54812f31f549e042dad8619084
Author: Philip Withnall <withnall endlessm com>
Date:   Fri Nov 24 20:02:43 2017 +0000

    inotify: Don’t propagate unrecognised events to GLocalFileMonitor
    
    If we can’t convert the inotify event mask into a GFileMonitorEvent enum
    value, don’t propagate it to GLocalFileMonitor, since it hits an
    assertion failure in that case.
    
    This should no longer be possible since the previous commit to ignore
    IN_Q_OVERFLOW events, but we might as well change this just in case
    other bugs crop up in event mask handling.
    
    Signed-off-by: Philip Withnall <withnall endlessm com>
    
    https://bugzilla.gnome.org/show_bug.cgi?id=776147

 gio/inotify/inotify-helper.c |   16 ++++++++++++----
 1 files changed, 12 insertions(+), 4 deletions(-)
---
diff --git a/gio/inotify/inotify-helper.c b/gio/inotify/inotify-helper.c
index dce57e5..a307a88 100644
--- a/gio/inotify/inotify-helper.c
+++ b/gio/inotify/inotify-helper.c
@@ -156,9 +156,12 @@ ih_event_callback (ik_event_t  *event,
                    gboolean     file_event)
 {
   gboolean interesting;
+  GFileMonitorEvent event_flags;
 
   g_assert (!file_event); /* XXX hardlink support */
 
+  event_flags = ih_mask_to_EventFlags (event->mask);
+
   if (event->mask & IN_MOVE)
     {
       /* We either have a rename (in the same directory) or a move
@@ -187,17 +190,22 @@ ih_event_callback (ik_event_t  *event,
           else
             other = NULL;
 
-          /* this is either an incoming or outgoing move */
-          interesting = g_file_monitor_source_handle_event (sub->user_data, ih_mask_to_EventFlags 
(event->mask),
+          /* This is either an incoming or outgoing move. Since we checked the
+           * event->mask above, it should have converted to a #GFileMonitorEvent
+           * properly. If not, the assumption we have made about event->mask
+           * only ever having a single bit set (apart from IN_ISDIR) is false.
+           * The kernel documentation is lacking here. */
+          g_assert (event_flags != -1);
+          interesting = g_file_monitor_source_handle_event (sub->user_data, event_flags
                                                             event->name, NULL, other, event->timestamp);
 
           if (other)
             g_object_unref (other);
         }
     }
-  else
+  else if (event_flags != -1)
     /* unpaired event -- no 'other' field */
-    interesting = g_file_monitor_source_handle_event (sub->user_data, ih_mask_to_EventFlags (event->mask),
+    interesting = g_file_monitor_source_handle_event (sub->user_data, event_flags
                                                       event->name, NULL, NULL, event->timestamp);
 
   if (event->mask & IN_CREATE)