Implement ignorefd for TCP

Ignore fd is a feature used by sendfile to temporarily remove
all driver_select calls on that fd so that another driver can
select on it. It also delays all actions which sends or receives
data in that fd until in the fd is no longer ignored.

Only the controlling_process should use the feature as it is otherwise
possible that the ignore will never be cleaned up and hence create
a memory leak in the driver.

An ignored driver will not detect that an fd has been closed until
it is unignored.

1 files changed, 4 insertions, 3 deletions

diff --git a/lib/kernel/src/gen_tcp.erl b/lib/kernel/src/gen_tcp.erl
index 26afed4ff9..3f1e432f7a 100644
--- a/lib/kernel/src/gen_tcp.erl
+++ b/lib/kernel/src/gen_tcp.erl
@@ -420,15 +420,16 @@ mod([], Address) ->
 sendfile(#file_descriptor{ module = Mod } = Fd, Sock, Offset, Bytes,
 	 ChunkSize, Headers, Trailers, Nodiskio, MNowait, Sync)
   when is_port(Sock) ->
-    {ok,SockFd} = prim_inet:stealfd(Sock),
+    ok = prim_inet:ignorefd(Sock,true),
+    {ok, SockFd} = prim_inet:getfd(Sock),
     case Mod:sendfile(Fd, SockFd, Offset, Bytes, ChunkSize, Headers, Trailers,
 		      Nodiskio, MNowait, Sync) of
 	{error, enotsup} ->
-	    prim_inet:returnfd(Sock),
+	    ok = prim_inet:ignorefd(Sock,false),
 	    sendfile_fallback(Fd, Sock, Offset, Bytes, ChunkSize,
 			      Headers, Trailers);
 	Else ->
-	    prim_inet:returnfd(Sock),
+	    ok = prim_inet:ignorefd(Sock,false),
 	    Else
     end;
 sendfile(_,_,_,_,_,_,_,_,_,_) ->