Fix for client accessing a named pipe after the server closes it.

server/fd.c

@@ -987,7 +987,7 @@ static struct fd *get_handle_fd_obj( struct process *process, obj_handle_t handl
 
     if ((obj = get_handle_obj( process, handle, access, NULL )))
     {
-        if (!(fd = get_obj_fd( obj ))) set_error( STATUS_OBJECT_TYPE_MISMATCH );
+        fd = get_obj_fd( obj );
         release_object( obj );
     }
     return fd;

server/named_pipe.c

@@ -163,7 +163,9 @@ static void notify_waiter( struct pipe_user *user, unsigned int status)
 static struct fd *pipe_user_get_fd( struct object *obj )
 {
     struct pipe_user *user = (struct pipe_user *)obj;
-    return (struct fd *)grab_object( user->fd );
+    if (user->fd) return (struct fd *)grab_object( user->fd );
+    set_error( STATUS_PIPE_DISCONNECTED );
+    return NULL;
 }
 
 static void pipe_user_destroy( struct object *obj)