Don't let a receiver to crash if a controller is unavailable

Fixes #1796

src/ejabberd_c2s.erl

@@ -67,7 +67,10 @@
 start(SockData, Opts) ->
     case proplists:get_value(supervisor, Opts, true) of
 	true ->
-	    supervisor:start_child(ejabberd_c2s_sup, [SockData, Opts]);
+	    case supervisor:start_child(ejabberd_c2s_sup, [SockData, Opts]) of
+		{ok, undefined} -> ignore;
+		Res -> Res
+	    end;
 	_ ->
 	    xmpp_stream_in:start(?MODULE, [SockData, Opts],
 				 ejabberd_config:fsm_limit_opts(Opts))

src/ejabberd_s2s_in.erl

@@ -57,7 +57,10 @@
 start(SockData, Opts) ->
     case proplists:get_value(supervisor, Opts, true) of
 	true ->
-	    supervisor:start_child(ejabberd_s2s_in_sup, [SockData, Opts]);
+	    case supervisor:start_child(ejabberd_s2s_in_sup, [SockData, Opts]) of
+		{ok, undefined} -> ignore;
+		Res -> Res
+	    end;
 	_ ->
 	    xmpp_stream_in:start(?MODULE, [SockData, Opts],
 				 ejabberd_config:fsm_limit_opts(Opts))

src/ejabberd_s2s_out.erl

@@ -54,10 +54,13 @@
 %%%===================================================================
 start(From, To, Opts) ->
     case proplists:get_value(supervisor, Opts, true) of
-	   true ->
+	true ->
-	    supervisor:start_child(ejabberd_s2s_out_sup,
+	    case supervisor:start_child(ejabberd_s2s_out_sup,
-				   [From, To, Opts]);
+					[From, To, Opts]) of
-		_ ->
+		{ok, undefined} -> ignore;
+		Res -> Res
+	    end;
+	_ ->
 	    xmpp_stream_out:start(?MODULE, [ejabberd_socket, From, To, Opts],
 				  ejabberd_config:fsm_limit_opts([]))
     end.

src/ejabberd_socket.erl

@@ -87,7 +87,7 @@
 %% API
 %%====================================================================
 -spec start(atom(), sockmod(), socket(), [proplists:property()])
-      -> {ok, pid() | independent} | {error, inet:posix() | any()}.
+      -> {ok, pid() | independent} | {error, inet:posix() | any()} | ignore.
 start(Module, SockMod, Socket, Opts) ->
     case Module:socket_type() of
 	independent -> {ok, independent};