Stasis: Fix StasisStart/End order and missing events

This corrects several bugs that currently exist in the stasis
application code.

* After a masquerade, the resulting channels have channel topics that
  do not match their uniqueids
** Masquerades now swap channel topics appropriately
* StasisStart and StasisEnd messages are leaked to observer
  applications due to being published on channel topics
** StasisStart and StasisEnd publishing is now properly restricted
   to controlling apps via app topics
* Race conditions exist where StasisStart and StasisEnd messages due to
  a masquerade may be received out of order due to being published on
  different topics
** These messages are now published directly on the app topic so this
   is now a non-issue
* StasisEnds are sometimes missing when sent due to masquerades and
  bridge swaps into and out of Stasis()
** This was due to StasisEnd processing adjusting message-sent flags
   after Stasis() had already exited and Stasis() had been re-entered
** This was corrected by adjusting these flags prior to sending the
   message while the initial Stasis() application was still shutting
   down

Review: https://reviewboard.asterisk.org/r/4213/
ASTERISK-24537 #close
Reported by: Matt DiMeo
........

Merged revisions 429061 from http://svn.asterisk.org/svn/asterisk/branches/12
........

Merged revisions 429062 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@429063 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 23 insertions, 43 deletions

diff --git a/res/res_stasis.c b/res/res_stasis.c
index 18d5963be..ad081d412 100644
--- a/res/res_stasis.c
+++ b/res/res_stasis.c
@@ -125,7 +125,7 @@ static struct ast_json *stasis_end_to_json(struct stasis_message *message,
 		"channel", ast_channel_snapshot_to_json(payload->snapshot, sanitize));
 }
 
-STASIS_MESSAGE_TYPE_DEFN(app_end_message_type,
+STASIS_MESSAGE_TYPE_DEFN_LOCAL(end_message_type,
 	.to_json = stasis_end_to_json);
 
 struct start_message_blob {
@@ -919,6 +919,12 @@ static int send_start_msg_snapshots(struct ast_channel *chan, struct stasis_app
 	struct stasis_message *msg;
 	int i;
 
+	if (app_subscribe_channel(app, chan)) {
+		ast_log(LOG_ERROR, "Error subscribing app '%s' to channel '%s'\n",
+			app_name(app), ast_channel_name(chan));
+		return -1;
+	}
+
 	payload = ao2_alloc(sizeof(*payload), start_message_blob_dtor);
 	if (!payload) {
 		ast_log(LOG_ERROR, "Error packing JSON for StasisStart message\n");
@@ -928,7 +934,8 @@ static int send_start_msg_snapshots(struct ast_channel *chan, struct stasis_app
 	payload->channel = ao2_bump(snapshot);
 	payload->replace_channel = ao2_bump(replace_channel_snapshot);
 
-	json_blob = ast_json_pack("{s: o, s: []}",
+	json_blob = ast_json_pack("{s: s, s: o, s: []}",
+		"app", app_name(app),
 		"timestamp", ast_json_timeval(ast_tvnow(), NULL),
 		"args");
 	if (!json_blob) {
@@ -956,7 +963,10 @@ static int send_start_msg_snapshots(struct ast_channel *chan, struct stasis_app
 		return -1;
 	}
 
-	stasis_publish(ast_channel_topic(chan), msg);
+	if (replace_channel_snapshot) {
+		app_unsubscribe_channel_id(app, replace_channel_snapshot->uniqueid);
+	}
+	stasis_publish(ast_app_get_topic(app), msg);
 	ao2_ref(msg, -1);
 	return 0;
 }
@@ -988,6 +998,7 @@ int app_send_end_msg(struct stasis_app *app, struct ast_channel *chan)
 {
 	struct stasis_message_sanitizer *sanitize = stasis_app_get_sanitizer();
 	struct ast_json *blob;
+	struct stasis_message *msg;
 
 	if (sanitize && sanitize->channel
 		&& sanitize->channel(chan)) {
@@ -1000,10 +1011,13 @@ int app_send_end_msg(struct stasis_app *app, struct ast_channel *chan)
 		return -1;
 	}
 
-	stasis_app_channel_set_stasis_end_published(chan);
 	remove_masquerade_store(chan);
-	ast_channel_publish_blob(chan, app_end_message_type(), blob);
-
+	app_unsubscribe_channel(app, chan);
+	msg = ast_channel_blob_create(chan, end_message_type(), blob);
+	if (msg) {
+		stasis_publish(ast_app_get_topic(app), msg);
+	}
+	ao2_cleanup(msg);
 	ast_json_unref(blob);
 
 	return 0;
@@ -1034,6 +1048,7 @@ static void channel_stolen_cb(void *data, struct ast_channel *old_chan, struct a
 	}
 
 	/* send the StasisEnd message to the app */
+	stasis_app_channel_set_stasis_end_published(new_chan);
 	app_send_end_msg(control_app(control), new_chan);
 
 	/* remove the datastore */
@@ -1083,11 +1098,6 @@ static void channel_replaced_cb(void *data, struct ast_channel *old_chan, struct
 	/* send the StasisEnd message to the app */
 	app_send_end_msg(control_app(control), old_chan);
 
-	/* fixup channel topic forwards */
-	if (app_replace_channel_forwards(control_app(control), old_snapshot->uniqueid, new_chan)) {
-		ast_log(LOG_ERROR, "Failed to fixup channel topic forwards for %s(%s) owned by %s\n",
-			old_snapshot->name, old_snapshot->uniqueid, app_name(control_app(control)));
-	}
 	ao2_cleanup(control);
 }
 
@@ -1251,14 +1261,6 @@ int stasis_app_exec(struct ast_channel *chan, const char *app_name, int argc,
 		return -1;
 	}
 
-	res = app_subscribe_channel(app, chan);
-	if (res != 0) {
-		ast_log(LOG_ERROR, "Error subscribing app '%s' to channel '%s'\n",
-			app_name, ast_channel_name(chan));
-		remove_masquerade_store(chan);
-		return -1;
-	}
-
 	res = send_start_msg(app, chan, argc, argv);
 	if (res != 0) {
 		ast_log(LOG_ERROR,
@@ -1894,7 +1896,7 @@ static int unload_module(void)
 	ao2_cleanup(app_bridges_playback);
 	app_bridges_playback = NULL;
 
-	STASIS_MESSAGE_TYPE_CLEANUP(app_end_message_type);
+	STASIS_MESSAGE_TYPE_CLEANUP(end_message_type);
 	STASIS_MESSAGE_TYPE_CLEANUP(start_message_type);
 
 	return 0;
@@ -1938,28 +1940,6 @@ struct stasis_message_sanitizer *stasis_app_get_sanitizer(void)
 	return &app_sanitizer;
 }
 
-void app_end_message_handler(struct stasis_message *message)
-{
-	struct ast_channel_blob *payload;
-	struct ast_channel_snapshot *snapshot;
-	const char *app_name;
-	char *channel_uri;
-	size_t alloc_size;
-	const char *channels[1];
-
-	payload = stasis_message_data(message);
-	snapshot = payload->snapshot;
-	app_name = ast_json_string_get(ast_json_object_get(payload->blob, "app"));
-
-	/* +8 is for the length of "channel:" */
-	alloc_size = AST_MAX_UNIQUEID + 8;
-	channel_uri = ast_alloca(alloc_size);
-	snprintf(channel_uri, alloc_size, "channel:%s", snapshot->uniqueid);
-
-	channels[0] = channel_uri;
-	stasis_app_unsubscribe(app_name, channels, ARRAY_LEN(channels), NULL);
-}
-
 static const struct ast_datastore_info stasis_internal_channel_info = {
 	.type = "stasis-internal-channel",
 };
@@ -2033,7 +2013,7 @@ static int load_module(void)
 	if (STASIS_MESSAGE_TYPE_INIT(start_message_type) != 0) {
 		return AST_MODULE_LOAD_DECLINE;
 	}
-	if (STASIS_MESSAGE_TYPE_INIT(app_end_message_type) != 0) {
+	if (STASIS_MESSAGE_TYPE_INIT(end_message_type) != 0) {
 		return AST_MODULE_LOAD_DECLINE;
 	}
 	apps_registry = ao2_container_alloc(APPS_NUM_BUCKETS, app_hash, app_compare);