[tracker] tracker-extract: Blacklist vaapi/bmcdec gstreamer elements

[Carlos Garnacho <carlosg src gnome org>]

commit 8952c69051eaa2bbd5b50eb316422f0931e000ae
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sun Jun 4 17:37:18 2017 +0200

    tracker-extract: Blacklist vaapi/bmcdec gstreamer elements
    
    Remove these from the registry after initialization, the vaapi
    one could just cause undesired output/warnings after seccomp forbid
    it to do something. The bmcdec element is dumber and would just
    crash after shmget() despite trying to refuse it politely with an
    appropriate errno.
    
    Fixes SIGSYS on shmget() from gstreamer1-plugin-crystalhd if it
    happens to be installed and a video file is indexed. The blacklisting
    code has been lifted from totem-video-thumbnailer.

 src/tracker-extract/tracker-extract-gstreamer.c |   26 +++++++++++++++++++++++
 1 files changed, 26 insertions(+), 0 deletions(-)
---
diff --git a/src/tracker-extract/tracker-extract-gstreamer.c b/src/tracker-extract/tracker-extract-gstreamer.c
index 889ca60..4e6e8dd 100644
--- a/src/tracker-extract/tracker-extract-gstreamer.c
+++ b/src/tracker-extract/tracker-extract-gstreamer.c
@@ -1468,6 +1468,32 @@ tracker_extract_get_metadata (TrackerExtractInfo *info)
 G_MODULE_EXPORT gboolean
 tracker_extract_module_init (GError **error)
 {
+       /* Lifted from totem-video-thumbnailer */
+       const gchar *blacklisted[] = {
+               "vaapidecodebin",
+               "vaapidecode",
+               "vaapimpeg2dec",
+               "vaapih264dec",
+               "vaapivc1dec",
+               "vaapivp8dec",
+               "vaapivp9dec",
+               "vaapih265dec",
+               "bmcdec",
+       };
+       GstRegistry *registry;
+       guint i;
+
        gst_init (NULL, NULL);
+       registry = gst_registry_get ();
+
+       for (i = 0; i < G_N_ELEMENTS (blacklisted); i++) {
+               GstPluginFeature *feature =
+                       gst_registry_find_feature (registry,
+                                                  blacklisted[i],
+                                                  GST_TYPE_ELEMENT_FACTORY);
+               if (feature)
+                       gst_registry_remove_feature (registry, feature);
+       }
+
        return TRUE;
 }