Fix acceptor: do not crash on closed socket when setting opts

If the socket (port) is closed (by client) before sending
any data, acceptor may crash when setting active option.
In this commit, the error posix code is captured and logged,
then acceptor can stop.

Author: spring2maz

src/driver/gen_rpc_driver_ssl.erl

@@ -86,10 +86,9 @@ send(Socket, Data) when is_tuple(Socket), is_binary(Data) ->
             ok
     end.
 
--spec activate_socket(ssl:sslsocket()) -> ok.
+-spec activate_socket(ssl:sslsocket()) -> ok | {error, inet:posix()}.
 activate_socket(Socket) when is_tuple(Socket) ->
-    ok = ssl:setopts(Socket, [{active,once}]),
-    ok.
+    ssl:setopts(Socket, [{active, once}]).
 
 %% Authenticate to a server
 -spec authenticate_server(ssl:sslsocket()) -> ok | {error, {badtcp | badrpc, term()}}.

src/driver/gen_rpc_driver_tcp.erl

@@ -62,10 +62,9 @@ listen(Port) when is_integer(Port) ->
 accept(Socket) when is_port(Socket) ->
     gen_tcp:accept(Socket, infinity).
 
--spec activate_socket(port()) -> ok.
+-spec activate_socket(port()) -> ok | {error, inet:posix()}.
 activate_socket(Socket) when is_port(Socket) ->
-    ok = inet:setopts(Socket, [{active,true}]),
-    ok.
+    inet:setopts(Socket, [{active,true}]).
 
 -spec send(port(), binary()) -> ok | {error, term()}.
 send(Socket, Data) when is_port(Socket), is_binary(Data) ->

src/gen_rpc_acceptor.erl

@@ -83,14 +83,21 @@ callback_mode() ->
 
 waiting_for_socket({call,From}, {socket_ready,Socket}, #state{driver=Driver, driver_mod=DriverMod, peer=Peer} = State) ->
     ok = DriverMod:set_acceptor_opts(Socket),
-    ok = DriverMod:activate_socket(Socket),
+    ActivateResult = DriverMod:activate_socket(Socket),
     % Now we own the socket
     ?log(debug, "event=acquiring_socket_ownership driver=~s socket=\"~s\" peer=\"~p\" inet_opts: ~0p",
          [Driver, gen_rpc_helper:socket_to_string(Socket),
           gen_rpc_helper:peer_to_string(Peer),
           prim_inet:getopts(Socket, [gen_rpc_helper:user_tcp_opt_key(Opt)|| Opt <- ?USER_TCP_OPTS])]),
     ok = gen_statem:reply(From, ok),
-    {next_state, waiting_for_auth, State#state{socket=Socket}, gen_rpc_helper:get_authentication_timeout()}.
+    case ActivateResult of
+        ok ->
+            {next_state, waiting_for_auth, State#state{socket=Socket}, gen_rpc_helper:get_authentication_timeout()};
+        {error, _Posix} ->
+            ?log(notice, "message=channel_closed before receiving any data driver=~p socket=\"~s\" peer=\"~s\"",
+                 [Driver, gen_rpc_helper:socket_to_string(Socket), gen_rpc_helper:peer_to_string(Peer)]),
+            {stop, normal, State}
+    end.
 
 waiting_for_auth(info, {Driver,Socket,Data}, #state{socket=Socket, driver=Driver, driver_mod=DriverMod, peer=Peer} = State) ->
     case DriverMod:authenticate_client(Socket, Peer, Data) of
@@ -309,4 +316,4 @@ handle_cast(UnknownReq, #state{socket=Socket, driver=Driver, peer=Peer}) ->
     ?log(debug, "event=invalid_cast_req driver=~s socket=\"~s\" peer=\"~s\" req=\"~p\"",
          [Driver, gen_rpc_helper:socket_to_string(Socket),
           gen_rpc_helper:peer_to_string(Peer), UnknownReq]),
-    error(invalid_cast_req).
+    error(invalid_cast_req).