https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=ef95c03522f65d5956a8dc82d869c6bc378ef3f9
commit ef95c03522f65d5956a8dc82d869c6bc378ef3f9 Author: Corinna Vinschen <[email protected]> Date: Tue Apr 6 21:35:43 2021 +0200 Cygwin: select: Fix FD_CLOSE handling An FD_CLOSE event sets a socket descriptor ready for writing. This is incorrect if the FD_CLOSE is a result of shutdown(SHUT_RD). Only set the socket descriptor ready for writing if the FD_CLOSE is indicating an connection abort or reset error condition. This requires to tweak fhandler_socket_wsock::evaluate_events. FD_CLOSE in conjunction with FD_ACCEPT/FD_CONNECT special cases a shutdown condition by setting an error code. This is correct for accept/connect, but not for select. In this case, make sure to return with an error code only if FD_CLOSE indicates a connection error. Signed-off-by: Corinna Vinschen <[email protected]> Diff: --- winsup/cygwin/fhandler_socket_inet.cc | 26 ++++++++++++++++++-------- winsup/cygwin/select.cc | 7 +++++-- 2 files changed, 23 insertions(+), 10 deletions(-) diff --git a/winsup/cygwin/fhandler_socket_inet.cc b/winsup/cygwin/fhandler_socket_inet.cc index bc08d3cf1..4ecb31a27 100644 --- a/winsup/cygwin/fhandler_socket_inet.cc +++ b/winsup/cygwin/fhandler_socket_inet.cc @@ -361,20 +361,30 @@ fhandler_socket_wsock::evaluate_events (const long event_mask, long &events, wsock_events->events |= FD_WRITE; wsock_events->connect_errorcode = 0; } - /* This test makes accept/connect behave as on Linux when accept/connect - is called on a socket for which shutdown has been called. The second - half of this code is in the shutdown method. */ if (events & FD_CLOSE) { - if ((event_mask & FD_ACCEPT) && saw_shutdown_read ()) + if (evts.iErrorCode[FD_CLOSE_BIT]) { - WSASetLastError (WSAEINVAL); + WSASetLastError (evts.iErrorCode[FD_CLOSE_BIT]); ret = SOCKET_ERROR; } - if (event_mask & FD_CONNECT) + /* This test makes accept/connect behave as on Linux when accept/ + connect is called on a socket for which shutdown has been called. + The second half of this code is in the shutdown method. Note that + we only do this when called from accept/connect, not from select. + In this case erase == false, just as with read (MSG_PEEK). */ + if (erase) { - WSASetLastError (WSAECONNRESET); - ret = SOCKET_ERROR; + if ((event_mask & FD_ACCEPT) && saw_shutdown_read ()) + { + WSASetLastError (WSAEINVAL); + ret = SOCKET_ERROR; + } + if (event_mask & FD_CONNECT) + { + WSASetLastError (WSAECONNRESET); + ret = SOCKET_ERROR; + } } } if (erase) diff --git a/winsup/cygwin/select.cc b/winsup/cygwin/select.cc index 956cd9bc1..b493ccc11 100644 --- a/winsup/cygwin/select.cc +++ b/winsup/cygwin/select.cc @@ -1709,7 +1709,8 @@ peek_socket (select_record *me, bool) fhandler_socket_wsock *fh = (fhandler_socket_wsock *) me->fh; long events; /* Don't play with the settings again, unless having taken a deep look into - Richard W. Stevens Network Programming book. Thank you. */ + Richard W. Stevens Network Programming book and how these flags are + defined in Winsock. Thank you. */ long evt_mask = (me->read_selected ? (FD_READ | FD_ACCEPT | FD_CLOSE) : 0) | (me->write_selected ? (FD_WRITE | FD_CONNECT | FD_CLOSE) : 0) | (me->except_selected ? FD_OOB : 0); @@ -1717,7 +1718,9 @@ peek_socket (select_record *me, bool) if (me->read_selected) me->read_ready |= ret || !!(events & (FD_READ | FD_ACCEPT | FD_CLOSE)); if (me->write_selected) - me->write_ready |= ret || !!(events & (FD_WRITE | FD_CONNECT | FD_CLOSE)); + /* Don't check for FD_CLOSE here. Only an error case (ret == -1) + will set ready for writing. */ + me->write_ready |= ret || !!(events & (FD_WRITE | FD_CONNECT)); if (me->except_selected) me->except_ready |= !!(events & FD_OOB);
