Fix tests in test_socket to use correctly CMSG_LEN (GH-9594)

miss-islington · pablogsal · web-flow · commit fe48b6df101a · 2018-09-27T06:30:55.000-07:00
After some failures in AMD64 FreeBSD CURRENT Debug 3.x buildbots regarding tests in test_socket that are using testFDPassSeparateMinSpace(), FreeBDS revision 337423 was pointed out to be the reason the test started to fail. A close examination of the manpage for cmsg_space(3) reveals that the number of file descriptors needs to be taken into account when using CMSG_LEN(). This commit fixes tests in test_socket to use correctly CMSG_LEN, taking into account the number of FDs. (cherry picked from commit 7291108) Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>
diff --git a/Lib/test/test_socket.py b/Lib/test/test_socket.py
@@ -2858,10 +2858,11 @@ def _testFDPassSeparate(self):
     def testFDPassSeparateMinSpace(self):
         # Pass two FDs in two separate arrays, receiving them into the
         # minimum space for two arrays.
-        self.checkRecvmsgFDs(2,
+        num_fds = 2
+        self.checkRecvmsgFDs(num_fds,
                              self.doRecvmsg(self.serv_sock, len(MSG),
                                             socket.CMSG_SPACE(SIZEOF_INT) +
-                                            socket.CMSG_LEN(SIZEOF_INT)),
+                                            socket.CMSG_LEN(SIZEOF_INT * num_fds)),
                              maxcmsgs=2, ignoreflags=socket.MSG_CTRUNC)
 
     @testFDPassSeparateMinSpace.client_skip
