Zebediah Figura : server: Remove the socket from the polling loop if both it and the peer have SHUT_WR.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 361435f6095f8c759979600b06ed28785e7b3aec
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=361435f6095f8c759979600b0...

Author: Zebediah Figura <zfigura(a)codeweavers.com>
Date:   Mon Jul 26 11:53:44 2021 -0500

server: Remove the socket from the polling loop if both it and the peer have SHUT_WR.

Based on a patch by Torge Matthies.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=51319
Signed-off-by: Zebediah Figura <zfigura(a)codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard(a)winehq.org>

---

 server/sock.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/server/sock.c b/server/sock.c
index 85ea019ad92..2d2aa733565 100644
--- a/server/sock.c
+++ b/server/sock.c
@@ -1161,6 +1161,20 @@ static int sock_get_poll_events( struct fd *fd )
 
     case SOCK_CONNECTED:
     case SOCK_CONNECTIONLESS:
+        if (sock->hangup && sock->wr_shutdown && !sock->wr_shutdown_pending)
+        {
+            /* Linux returns POLLHUP if a socket is both SHUT_RD and SHUT_WR, or
+             * if both the socket and its peer are SHUT_WR.
+             *
+             * We don't use SHUT_RD, so we can only encounter this in the latter
+             * case. In that case there can't be any pending read requests (they
+             * would have already been completed with a length of zero), the
+             * above condition ensures that we don't have any pending write
+             * requests, and nothing that can change about the socket state that
+             * would complete a pending poll request. */
+            return -1;
+        }
+
         if (sock->accept_recv_req)
         {
             ev |= POLLIN;
@@ -1267,7 +1281,10 @@ static void sock_reselect_async( struct fd *fd, struct async_queue *queue )
     struct sock *sock = get_fd_user( fd );
 
     if (sock->wr_shutdown_pending && list_empty( &sock->write_q.queue ))
+    {
         shutdown( get_unix_fd( sock->fd ), SHUT_WR );
+        sock->wr_shutdown_pending = 0;
+    }
 
     /* Don't reselect the ifchange queue; we always ask for POLLIN.
      * Don't reselect an uninitialized socket; we can't call set_fd_events() on