BUG#13431369 - MAIN.VARIABLES-NOTEMBEDDED CRASHES THE SERVER SPORADICALLY ON WINDOWS

On shutdown(), Windows can drop traffic still queued for sending even if that
wasn't specifically requested. As a result, fatal errors (those after
signaling which the server will drop the connection) were sometimes only
seen as "connection lost" on the client side, because the server-side
shutdown() erraneously discarded the correct error message before sending
it.

If on Windows, we now use the Windows API to access the (non-broken) equivalent
of shutdown().

Backport from trunk

include/violite.h:
  export mysql_socket_shutdown(). It lives in vio in the backport.
sql/mysqld.cc:
  Go through our own shutdown() rather than straight to the POSIX one.
vio/viosocket.c:
  Define mysql_socket_shutdown(). On UNIXoid systems, it's just a wrapper for shutdown(), but
  on Window, it uses DisconnectEx, which is magic.

include/violite.h

@@ -61,6 +61,9 @@ int vio_close_pipe(Vio * vio);
 #define HANDLE void *
 #endif /* __WIN__ */
 
+/* backport from 5.6 where it is part of PSI, not vio_*() */
+int	mysql_socket_shutdown(my_socket mysql_socket, int how);
+
 void	vio_delete(Vio* vio);
 int	vio_close(Vio* vio);
 void    vio_reset(Vio* vio, enum enum_vio_type type,

sql/mysqld.cc

@@ -932,7 +932,7 @@ static void close_connections(void)
   {
     if (ip_sock != INVALID_SOCKET)
     {
-      (void) shutdown(ip_sock, SHUT_RDWR);
+      (void) mysql_socket_shutdown(ip_sock, SHUT_RDWR);
       (void) closesocket(ip_sock);
       ip_sock= INVALID_SOCKET;
     }
@@ -964,7 +964,7 @@ static void close_connections(void)
 #ifdef HAVE_SYS_UN_H
   if (unix_sock != INVALID_SOCKET)
   {
-    (void) shutdown(unix_sock, SHUT_RDWR);
+    (void) mysql_socket_shutdown(unix_sock, SHUT_RDWR);
     (void) closesocket(unix_sock);
     (void) unlink(mysqld_unix_port);
     unix_sock= INVALID_SOCKET;
@@ -1069,7 +1069,7 @@ static void close_server_sock()
   {
     ip_sock=INVALID_SOCKET;
     DBUG_PRINT("info",("calling shutdown on TCP/IP socket"));
-    VOID(shutdown(tmp_sock, SHUT_RDWR));
+    VOID(mysql_socket_shutdown(tmp_sock, SHUT_RDWR));
 #if defined(__NETWARE__)
     /*
       The following code is disabled for normal systems as it causes MySQL
@@ -1084,7 +1084,7 @@ static void close_server_sock()
   {
     unix_sock=INVALID_SOCKET;
     DBUG_PRINT("info",("calling shutdown on unix socket"));
-    VOID(shutdown(tmp_sock, SHUT_RDWR));
+    VOID(mysql_socket_shutdown(tmp_sock, SHUT_RDWR));
 #if defined(__NETWARE__)
     /*
       The following code is disabled for normal systems as it may cause MySQL
@@ -5091,7 +5091,7 @@ pthread_handler_t handle_connections_sockets(void *arg __attribute__((unused)))
 	  if (req.sink)
 	    ((void (*)(int))req.sink)(req.fd);
 
-	  (void) shutdown(new_sock, SHUT_RDWR);
+	  (void) mysql_socket_shutdown(new_sock, SHUT_RDWR);
 	  (void) closesocket(new_sock);
 	  continue;
 	}
@@ -5106,7 +5106,7 @@ pthread_handler_t handle_connections_sockets(void *arg __attribute__((unused)))
       if (getsockname(new_sock,&dummy, &dummyLen) < 0)
       {
 	sql_perror("Error on new connection socket");
-	(void) shutdown(new_sock, SHUT_RDWR);
+	(void) mysql_socket_shutdown(new_sock, SHUT_RDWR);
 	(void) closesocket(new_sock);
 	continue;
       }
@@ -5118,7 +5118,7 @@ pthread_handler_t handle_connections_sockets(void *arg __attribute__((unused)))
 
     if (!(thd= new THD))
     {
-      (void) shutdown(new_sock, SHUT_RDWR);
+      (void) mysql_socket_shutdown(new_sock, SHUT_RDWR);
       VOID(closesocket(new_sock));
       continue;
     }
@@ -5137,7 +5137,7 @@ pthread_handler_t handle_connections_sockets(void *arg __attribute__((unused)))
         vio_delete(vio_tmp);
       else
       {
-	(void) shutdown(new_sock, SHUT_RDWR);
+	(void) mysql_socket_shutdown(new_sock, SHUT_RDWR);
 	(void) closesocket(new_sock);
       }
       delete thd;

vio/viosocket.c

@@ -23,8 +23,15 @@
   the file descriptior.
 */
 
+#ifdef __WIN__
+  #include <winsock2.h>
+  #include <MSWSock.h>
+  #pragma comment(lib, "ws2_32.lib")
+#endif
 #include "vio_priv.h"
 
+
+
 int vio_errno(Vio *vio __attribute__((unused)))
 {
   return socket_errno;		/* On Win32 this mapped to WSAGetLastError() */
@@ -260,6 +267,37 @@ vio_was_interrupted(Vio *vio __attribute__((unused)))
 }
 
 
+int
+mysql_socket_shutdown(my_socket mysql_socket, int how)
+{
+  int result;
+
+#ifdef __WIN__
+  static LPFN_DISCONNECTEX DisconnectEx = NULL;
+  if (DisconnectEx == NULL)
+  {
+    DWORD dwBytesReturned;
+    GUID guidDisconnectEx = WSAID_DISCONNECTEX;
+    WSAIoctl(mysql_socket, SIO_GET_EXTENSION_FUNCTION_POINTER,
+             &guidDisconnectEx, sizeof(GUID),
+             &DisconnectEx, sizeof(DisconnectEx), 
+             &dwBytesReturned, NULL, NULL);
+  }
+#endif
+
+  /* Non instrumented code */
+#ifdef __WIN__
+  if (DisconnectEx)
+    result= (DisconnectEx(mysql_socket, (LPOVERLAPPED) NULL,
+                          (DWORD) 0, (DWORD) 0) == TRUE) ? 0 : -1;
+  else
+#endif
+    result= shutdown(mysql_socket, how);
+
+  return result;
+}
+
+
 int vio_close(Vio * vio)
 {
   int r=0;
@@ -272,7 +310,7 @@ int vio_close(Vio * vio)
       vio->type == VIO_TYPE_SSL);
 
     DBUG_ASSERT(vio->sd >= 0);
-    if (shutdown(vio->sd, SHUT_RDWR))
+    if (mysql_socket_shutdown(vio->sd, SHUT_RDWR))
       r= -1;
     if (closesocket(vio->sd))
       r= -1;