diff options
Diffstat (limited to 'winsup/cygwin/fhandler_socket.cc')
| -rw-r--r-- | winsup/cygwin/fhandler_socket.cc | 28 |
1 files changed, 22 insertions, 6 deletions
diff --git a/winsup/cygwin/fhandler_socket.cc b/winsup/cygwin/fhandler_socket.cc index 52d03ed07..3e218347d 100644 --- a/winsup/cygwin/fhandler_socket.cc +++ b/winsup/cygwin/fhandler_socket.cc @@ -1379,14 +1379,30 @@ fhandler_socket::recv_internal (LPWSAMSG wsamsg) { if (use_recvmsg) res = WSARecvMsg (get_socket (), wsamsg, &wret, NULL, NULL); + /* This is working around a really weird problem in WinSock. + + Assume you create a socket, fork the process (thus duplicating + the socket), connect the socket in the child, then call recv + on the original socket handle in the parent process. + In this scenario, calls to WinSock's recvfrom and WSARecvFrom + in the parent will fail with WSAEINVAL, regardless whether both + address parameters, name and namelen, are NULL or point to valid + storage. However, calls to recv and WSARecv succeed as expected. + Per MSDN, WSAEINVAL in the context of recv means "The socket has not + been bound". It is as if the recvfrom functions test if the socket + is bound locally, but in the parent process, WinSock doesn't know + about that and fails, while the same test is omitted in the recv + functions. + + This also covers another weird case: Winsock returns WSAEFAULT if + namelen is a valid pointer while name is NULL. Both parameters are + ignored for TCP sockets, so this only occurs when using UDP socket. */ + else if (!wsamsg->name) + res = WSARecv (get_socket (), wsabuf, wsacnt, &wret, &wsamsg->dwFlags, + NULL, NULL); else res = WSARecvFrom (get_socket (), wsabuf, wsacnt, &wret, - &wsamsg->dwFlags, wsamsg->name, - /* Winsock returns WSAEFAULT if namelen is a valid - pointer while name is NULL. Both parameters are - ignored for TCP sockets, so this only occurs when - using UDP socket. */ - wsamsg->name ? &wsamsg->namelen : NULL, + &wsamsg->dwFlags, wsamsg->name, &wsamsg->namelen, NULL, NULL); if (!res) { |