rtsp-stream: Have one copy of the transports cache for RTP and RTCP each

Fixes crash when two threads access handle_new_sample() at the same
time, one for RTP, one for RTCP.

Otherwise, when iterating over the transports cache, it might be modified by
another thread at the same time if the transports cookie has changed.

https://bugzilla.gnome.org/show_bug.cgi?id=742954

diff --git a/gst/rtsp-server/rtsp-stream.c b/gst/rtsp-server/rtsp-stream.c
index 33ee7d4..d64fed4 100644 (file)
--- a/gst/rtsp-server/rtsp-stream.c
+++ b/gst/rtsp-server/rtsp-stream.c
@@ -139,7 +139,8 @@ struct _GstRTSPStreamPrivate
   guint n_active;
   GList *transports;
   guint transports_cookie;
-  GList *tr_cache;
+  GList *tr_cache_rtp;
+  GList *tr_cache_rtcp;
   guint tr_cache_cookie;
 
   /* UDP sources for UDP multicast transports */
@@ -1575,11 +1576,17 @@ on_timeout (GObject * session, GObject * source, GstRTSPStream * stream)
 }
 
 static void
-clear_tr_cache (GstRTSPStreamPrivate * priv)
+clear_tr_cache (GstRTSPStreamPrivate * priv, gboolean is_rtp)
 {
-  g_list_foreach (priv->tr_cache, (GFunc) g_object_unref, NULL);
-  g_list_free (priv->tr_cache);
-  priv->tr_cache = NULL;
+  if (is_rtp) {
+    g_list_foreach (priv->tr_cache_rtp, (GFunc) g_object_unref, NULL);
+    g_list_free (priv->tr_cache_rtp);
+    priv->tr_cache_rtp = NULL;
+  } else {
+    g_list_foreach (priv->tr_cache_rtcp, (GFunc) g_object_unref, NULL);
+    g_list_free (priv->tr_cache_rtcp);
+    priv->tr_cache_rtcp = NULL;
+  }
 }
 
 static GstFlowReturn
@@ -1604,21 +1611,29 @@ handle_new_sample (GstAppSink * sink, gpointer user_data)
 
   g_mutex_lock (&priv->lock);
   if (priv->tr_cache_cookie != priv->transports_cookie) {
-    clear_tr_cache (priv);
+    clear_tr_cache (priv, is_rtp);
     for (walk = priv->transports; walk; walk = g_list_next (walk)) {
       GstRTSPStreamTransport *tr = (GstRTSPStreamTransport *) walk->data;
-      priv->tr_cache = g_list_prepend (priv->tr_cache, g_object_ref (tr));
+      if (is_rtp) {
+        priv->tr_cache_rtp =
+            g_list_prepend (priv->tr_cache_rtp, g_object_ref (tr));
+      } else {
+        priv->tr_cache_rtcp =
+            g_list_prepend (priv->tr_cache_rtcp, g_object_ref (tr));
+      }
     }
     priv->tr_cache_cookie = priv->transports_cookie;
   }
   g_mutex_unlock (&priv->lock);
 
-  for (walk = priv->tr_cache; walk; walk = g_list_next (walk)) {
-    GstRTSPStreamTransport *tr = (GstRTSPStreamTransport *) walk->data;
-
-    if (is_rtp) {
+  if (is_rtp) {
+    for (walk = priv->tr_cache_rtp; walk; walk = g_list_next (walk)) {
+      GstRTSPStreamTransport *tr = (GstRTSPStreamTransport *) walk->data;
       gst_rtsp_stream_transport_send_rtp (tr, buffer);
-    } else {
+    }
+  } else {
+    for (walk = priv->tr_cache_rtcp; walk; walk = g_list_next (walk)) {
+      GstRTSPStreamTransport *tr = (GstRTSPStreamTransport *) walk->data;
       gst_rtsp_stream_transport_send_rtcp (tr, buffer);
     }
   }
@@ -2099,7 +2114,8 @@ gst_rtsp_stream_leave_bin (GstRTSPStream * stream, GstBin * bin,
   if (priv->transports != NULL)
     goto transports_not_removed;
 
-  clear_tr_cache (priv);
+  clear_tr_cache (priv, TRUE);
+  clear_tr_cache (priv, FALSE);
 
   GST_INFO ("stream %p leaving bin", stream);