From 2599a694a6c3b74a9c6424e933d964a4fee06309 Mon Sep 17 00:00:00 2001 From: Corinna Vinschen Date: Tue, 14 Oct 2014 19:08:27 +0000 Subject: [PATCH] * fhandler_socket.cc (fhandler_socket::connect): Init connect_state to connect_pending only on unconnected socket. Set connect_state to connected on WSAEISCONN error. Set connect_state to connect_failed on any other error except WSAEWOULDBLOCK if connect is still pending. Add lots of comment to explain why all of the above. --- winsup/cygwin/ChangeLog | 8 ++++++++ winsup/cygwin/fhandler_socket.cc | 25 +++++++++++++++++++++---- 2 files changed, 29 insertions(+), 4 deletions(-) diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog index 9c7395943..5650c6342 100644 --- a/winsup/cygwin/ChangeLog +++ b/winsup/cygwin/ChangeLog @@ -1,3 +1,11 @@ +2014-10-14 Corinna Vinschen + + * fhandler_socket.cc (fhandler_socket::connect): Init connect_state to + connect_pending only on unconnected socket. Set connect_state to + connected on WSAEISCONN error. Set connect_state to connect_failed + on any other error except WSAEWOULDBLOCK if connect is still pending. + Add lots of comment to explain why all of the above. + 2014-10-13 Corinna Vinschen * net.cc (cygwin_setsockopt): Drop redundant test for AF_LOCAL and diff --git a/winsup/cygwin/fhandler_socket.cc b/winsup/cygwin/fhandler_socket.cc index ff150448e..d27b5baaf 100644 --- a/winsup/cygwin/fhandler_socket.cc +++ b/winsup/cygwin/fhandler_socket.cc @@ -1166,8 +1166,16 @@ fhandler_socket::connect (const struct sockaddr *name, int namelen) to "connected" or "connect_failed" in wait_for_events when the FD_CONNECT event occurs. Note that the underlying OS sockets are always non-blocking and a successfully initiated non-blocking Winsock connect always returns - WSAEWOULDBLOCK. Thus it's safe to rely on event handling. */ - connect_state (connect_pending); + WSAEWOULDBLOCK. Thus it's safe to rely on event handling. + + Check for either unconnected or connect_failed since in both cases it's + allowed to retry connecting the socket. It's also ok (albeit ugly) to + call connect to check if a previous non-blocking connect finished. + + Set connect_state before calling connect, otherwise a race condition with + an already running select or poll might occur. */ + if (connect_state () == unconnected || connect_state () == connect_failed) + connect_state (connect_pending); int res = ::connect (get_socket (), (struct sockaddr *) &sst, namelen); if (!is_nonblocking () @@ -1179,14 +1187,23 @@ fhandler_socket::connect (const struct sockaddr *name, int namelen) { DWORD err = WSAGetLastError (); + /* Some applications use the ugly technique to check if a non-blocking + connect succeeded by calling connect again, until it returns EISCONN. + This circumvents the event handling and connect_state is never set. + Thus we check for this situation here. */ + if (err == WSAEISCONN) + connect_state (connected); /* Winsock returns WSAEWOULDBLOCK if the non-blocking socket cannot be conected immediately. Convert to POSIX/Linux compliant EINPROGRESS. */ - if (is_nonblocking () && err == WSAEWOULDBLOCK) + else if (is_nonblocking () && err == WSAEWOULDBLOCK) WSASetLastError (WSAEINPROGRESS); /* Winsock returns WSAEINVAL if the socket is already a listener. Convert to POSIX/Linux compliant EISCONN. */ - else if (err == WSAEINVAL) + else if (err == WSAEINVAL && connect_state () == listener) WSASetLastError (WSAEISCONN); + /* Any other error means the connmect failed. */ + else if (connect_state () == connect_pending) + connect_state (connect_failed); set_winsock_errno (); }