[Bug 949] New: - shutdown() never does anything for overlapped sockets

[wine-bugs at winehq.com]

http://bugs.winehq.com/show_bug.cgi?id=949

           Summary: shutdown() never does anything for overlapped sockets
           Product: Wine
           Version: CVS
          Platform: PC
               URL: http://www.proxomitron.org/
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: wine-net
        AssignedTo: wine-bugs at winehq.com
        ReportedBy: prupe at myrealbox.com


A problem appeared with version 4.3 of Proxomitron (<http://www.proxomitron.org/>), a local 
web filtering proxy.  The client (the web browser, Opera 6.02/Linux in this case) never sees 
the connection close, despite the fact that the proxy does indeed call closesocket.  So the 
browser keeps waiting for more data until the user aborts.  I've verified this with "telnet 
localhost 8080".

The relevant section of the log with -debugmsg +winsock is
  trace:winsock:WS_shutdown socket 0058, how 1 3 1 
  trace:winsock:WS2_register_async_shutdown s 88 fd 16 type 2
  trace:winsock:WSACreateEvent 
  trace:winsock:WS2_make_async wsa 0x4026bf08
  trace:winsock:WS2_make_async wsa 0x4026bf08, ops 0x408858f8, h 88, ev 72, fd 16, func 
0x40878db4, ov 0x4026be98, uov 0x4026be98, cfunc (nil)
  trace:winsock:WS_closesocket socket 00000058
Proxomitron 4.2, which works fine, does only
  trace:winsock:WS_closesocket socket 00000058
In both cases, socket 0058 is the connection between the web browser and the proxy.

I've traced this behavior to WS_shutdown, dlls/winsock/socket.c.  When the socket is 
overlapped, WS_shutdown does things differently.  Rather than shut down the connection right 
away, it registers a function to be called... well, that's the thing, I don't know when it will be 
called.  In this case there are no other outstanding overlapped I/O requests for that socket (in 
fact, this app never uses overlapped I/O, the attribute just happens to be on by default), and 
the other end of the socket (the browser) will never send anything because it's waiting for 
read/close events.  So what is supposed to trigger the call to WS2_async_shutdown?

Removing the "if (flags & FD_FLAG_OVERLAPPED)" branch fixes the problem, but is 
incorrect according to the check-in comment for v1.92 of socket.c.

Possible solutions:
(1) Make sure closesocket cancels the overlapped shutdown request if called before the 
shutdown occurs.  However, this is just hiding the problem since shutdown is still effectively a 
no-op.  On the other hand, shouldn't closesocket cancel any pending requests anyway?
(2) In WS_shutdown, don't do the special async stuff unless there is actually a pending 
overlapped read or write on that socket.
(3) More generally, don't do any special processing for an overlapped socket until the app 
actually uses that capability.  In other words, a socket isn't really considered overlapped until 
the app calls WSARecvFrom, etc. with a real OVERLAPPED structure.

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