sendfile caller now has to be the controlling_process

This is needed because otherwise there could be scenarios
when the efile driver blocks a fd and then crashes without
the inet driver ever finding out. Now when the process
crashes the port will close and we can cleanup in the inet
driver.

2 files changed, 18 insertions, 3 deletions

diff --git a/lib/kernel/src/gen_tcp.erl b/lib/kernel/src/gen_tcp.erl
index 9dd70ce5cc..2eaa44b966 100644
--- a/lib/kernel/src/gen_tcp.erl
+++ b/lib/kernel/src/gen_tcp.erl
@@ -412,16 +412,16 @@ mod([], Address) ->
 sendfile(#file_descriptor{ module = Mod } = Fd, Sock, Offset, Bytes,
 	 ChunkSize, Headers, Trailers, Nodiskio, MNowait, Sync)
   when is_port(Sock) ->
-    ok = prim_inet:ignorefd(Sock,true),
+    ok = inet:lock_socket(Sock,true),
     {ok, SockFd} = prim_inet:getfd(Sock),
     case Mod:sendfile(Fd, SockFd, Offset, Bytes, ChunkSize, Headers, Trailers,
 		      Nodiskio, MNowait, Sync) of
 	{error, enotsup} ->
-	    ok = prim_inet:ignorefd(Sock,false),
+	    ok = inet:lock_socket(Sock,false),
 	    sendfile_fallback(Fd, Sock, Offset, Bytes, ChunkSize,
 			      Headers, Trailers);
 	Else ->
-	    ok = prim_inet:ignorefd(Sock,false),
+	    ok = inet:lock_socket(Sock,false),
 	    Else
     end;
 sendfile(_,_,_,_,_,_,_,_,_,_) ->
diff --git a/lib/kernel/src/inet.erl b/lib/kernel/src/inet.erl
index b60c68e3a1..49f64a9236 100644
--- a/lib/kernel/src/inet.erl
+++ b/lib/kernel/src/inet.erl
@@ -40,6 +40,10 @@
 
 -export([tcp_controlling_process/2, udp_controlling_process/2,
 	 tcp_close/1, udp_close/1]).
+
+%% used by sendfile
+-export([lock_socket/2]).
+
 %% used by socks5
 -export([setsockname/2, setpeername/2]).
 
@@ -1353,3 +1357,14 @@ stop_timer(Timer) ->
 	    end;
 	T -> T
     end.
+
+
+lock_socket(S,Val) ->
+    case erlang:port_info(S, connected) of
+	{connected, Pid} when Pid =/= self() ->
+	    {error, not_owner};
+	undefined ->
+	    {error, einval};
+	_ ->
+	    prim_inet:ignorefd(S,Val)
+    end.