Issue #8184: multiprocessing: On Windows, don't set SO_REUSEADDR on Connection
sockets, and set FILE_FLAG_FIRST_PIPE_INSTANCE on named pipes, to make sure two
listeners can't bind to the same socket/pipe (or any existing socket/pipe).
diff --git a/Lib/multiprocessing/connection.py b/Lib/multiprocessing/connection.py
index 615f55d..8807618 100644
--- a/Lib/multiprocessing/connection.py
+++ b/Lib/multiprocessing/connection.py
@@ -544,7 +544,8 @@
obsize, ibsize = 0, BUFSIZE
h1 = win32.CreateNamedPipe(
- address, openmode | win32.FILE_FLAG_OVERLAPPED,
+ address, openmode | win32.FILE_FLAG_OVERLAPPED |
+ win32.FILE_FLAG_FIRST_PIPE_INSTANCE,
win32.PIPE_TYPE_MESSAGE | win32.PIPE_READMODE_MESSAGE |
win32.PIPE_WAIT,
1, obsize, ibsize, win32.NMPWAIT_WAIT_FOREVER, win32.NULL
@@ -576,7 +577,10 @@
def __init__(self, address, family, backlog=1):
self._socket = socket.socket(getattr(socket, family))
try:
- self._socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+ # SO_REUSEADDR has different semantics on Windows (issue #2550).
+ if os.name == 'posix':
+ self._socket.setsockopt(socket.SOL_SOCKET,
+ socket.SO_REUSEADDR, 1)
self._socket.bind(address)
self._socket.listen(backlog)
self._address = self._socket.getsockname()
@@ -630,7 +634,8 @@
def __init__(self, address, backlog=None):
self._address = address
handle = win32.CreateNamedPipe(
- address, win32.PIPE_ACCESS_DUPLEX,
+ address, win32.PIPE_ACCESS_DUPLEX |
+ win32.FILE_FLAG_FIRST_PIPE_INSTANCE,
win32.PIPE_TYPE_MESSAGE | win32.PIPE_READMODE_MESSAGE |
win32.PIPE_WAIT,
win32.PIPE_UNLIMITED_INSTANCES, BUFSIZE, BUFSIZE,