[Qemu-devel] [PATCH RFC 1/4] gdbstub: do not set SO_REUSEADDR on Windows

[Sebastian Ottlik <ottlik@fzi.de>]

If a socket is closed it may remain in TIME_WAIT state for some time. On most
operating systems the local port of the connection or socket may not be reeused
while in this state unless SO_REUSEADDR was set on the socket. On windows on the
other hand the default behaviour is to allow reuse (i.e. identical to
SO_REUSEADDR on other operating systems) and setting SO_REUSEADDR on a socket
allows it to be bound to a endpoint even if the endpoint is already used by
another socket independently of the other sockets state. This may result in
undefined behaviour. Fix this issue by no setting SO_REUSEADDR on windows.

Signed-off-by: Sebastian Ottlik <ottlik@fzi.de>
---
 gdbstub.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/gdbstub.c b/gdbstub.c
index 2b7f22b..3d60acf 100644
--- a/gdbstub.c
+++ b/gdbstub.c
@@ -1565,8 +1565,10 @@ static int gdbserver_open(int port)
 #endif
 
     /* allow fast reuse */
+#ifndef _WIN32
     val = 1;
     qemu_setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
+#endif
 
     sockaddr.sin_family = AF_INET;
     sockaddr.sin_port = htons(port);
-- 
1.7.9.5