do masquerade-behind-proxy checking with better control over locks

git-svn-id: http://svn.digium.com/svn/asterisk/branches/1.2@37361 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 28 insertions, 8 deletions

diff --git a/channel.c b/channel.c
index 1f5f59605..dc33e8a57 100644
--- a/channel.c
+++ b/channel.c
@@ -2748,25 +2748,43 @@ int ast_channel_masquerade(struct ast_channel *original, struct ast_channel *clo
 {
 	struct ast_frame null = { AST_FRAME_NULL, };
 	int res = -1;
+	struct ast_channel *final_orig = original, *final_clone = clone;
+
+	ast_mutex_lock(&original->lock);
+	while(ast_mutex_trylock(&clone->lock)) {
+		ast_mutex_unlock(&original->lock);
+		usleep(1);
+		ast_mutex_lock(&original->lock);
+	}
 
 	/* each of these channels may be sitting behind a channel proxy (i.e. chan_agent)
 	   and if so, we don't really want to masquerade it, but its proxy */
 	if (original->_bridge && (original->_bridge != ast_bridged_channel(original)))
-		original = original->_bridge;
+		final_orig = original->_bridge;
 
 	if (clone->_bridge && (clone->_bridge != ast_bridged_channel(clone)))
-		clone = clone->_bridge;
+		final_clone = clone->_bridge;
+
+	if ((final_orig != original) || (final_clone != clone)) {
+		ast_mutex_lock(&final_orig->lock);
+		while(ast_mutex_trylock(&final_clone->lock)) {
+			ast_mutex_unlock(&final_orig->lock);
+			usleep(1);
+			ast_mutex_lock(&final_orig->lock);
+		}
+		ast_mutex_unlock(&clone->lock);
+		ast_mutex_unlock(&original->lock);
+		original = final_orig;
+		clone = final_clone;
+	}
 
 	if (original == clone) {
 		ast_log(LOG_WARNING, "Can't masquerade channel '%s' into itself!\n", original->name);
-		return -1;
-	}
-	ast_mutex_lock(&original->lock);
-	while(ast_mutex_trylock(&clone->lock)) {
+		ast_mutex_unlock(&clone->lock);
 		ast_mutex_unlock(&original->lock);
-		usleep(1);
-		ast_mutex_lock(&original->lock);
+		return -1;
 	}
+
 	ast_log(LOG_DEBUG, "Planning to masquerade channel %s into the structure of %s\n",
 		clone->name, original->name);
 	if (original->masq) {
@@ -2783,8 +2801,10 @@ int ast_channel_masquerade(struct ast_channel *original, struct ast_channel *clo
 		ast_log(LOG_DEBUG, "Done planning to masquerade channel %s into the structure of %s\n", clone->name, original->name);
 		res = 0;
 	}
+
 	ast_mutex_unlock(&clone->lock);
 	ast_mutex_unlock(&original->lock);
+
 	return res;
 }