[Python-checkins] cpython (3.2): Issue #11657: Fix sending file descriptors over 255 over a multiprocessing Pipe.

Tue Aug 23 19:52:08 CEST 2011

http://hg.python.org/cpython/rev/5b2f357989bb
changeset: 72051:5b2f357989bb
branch: 3.2
user: Antoine Pitrou <solipsis at pitrou.net>
date: Tue Aug 23 19:46:22 2011 +0200
summary:
 Issue #11657: Fix sending file descriptors over 255 over a multiprocessing Pipe.
Also added some tests.
files:
 Lib/test/test_multiprocessing.py | 82 +++++++++-
 Misc/NEWS | 3 +
 Modules/_multiprocessing/multiprocessing.c | 4 +-
 3 files changed, 86 insertions(+), 3 deletions(-)

diff --git a/Lib/test/test_multiprocessing.py b/Lib/test/test_multiprocessing.py
--- a/Lib/test/test_multiprocessing.py
+++ b/Lib/test/test_multiprocessing.py
@@ -35,7 +35,7 @@
 import multiprocessing.heap
 import multiprocessing.pool
 
-from multiprocessing import util
+from multiprocessing import util, reduction
 
 try:
 from multiprocessing.sharedctypes import Value, copy
@@ -43,6 +43,11 @@
 except ImportError:
 HAS_SHAREDCTYPES = False
 
+try:
+ import msvcrt
+except ImportError:
+ msvcrt = None
+
 #
 #
 #
@@ -72,6 +77,11 @@
 
 WIN32 = (sys.platform == "win32")
 
+try:
+ MAXFD = os.sysconf("SC_OPEN_MAX")
+except:
+ MAXFD = 256
+
 #
 # Some tests require ctypes
 #
@@ -1538,6 +1548,76 @@
 
 self.assertRaises(ValueError, a.send_bytes, msg, 4, -1)
 
+ @classmethod
+ def _is_fd_assigned(cls, fd):
+ try:
+ os.fstat(fd)
+ except OSError as e:
+ if e.errno == errno.EBADF:
+ return False
+ raise
+ else:
+ return True
+
+ @classmethod
+ def _writefd(cls, conn, data, create_dummy_fds=False):
+ if create_dummy_fds:
+ for i in range(0, 256):
+ if not cls._is_fd_assigned(i):
+ os.dup2(conn.fileno(), i)
+ fd = reduction.recv_handle(conn)
+ if msvcrt:
+ fd = msvcrt.open_osfhandle(fd, os.O_WRONLY)
+ os.write(fd, data)
+ os.close(fd)
+
+ def test_fd_transfer(self):
+ if self.TYPE != 'processes':
+ self.skipTest("only makes sense with processes")
+ conn, child_conn = self.Pipe(duplex=True)
+
+ p = self.Process(target=self._writefd, args=(child_conn, b"foo"))
+ p.start()
+ with open(test.support.TESTFN, "wb") as f:
+ fd = f.fileno()
+ if msvcrt:
+ fd = msvcrt.get_osfhandle(fd)
+ reduction.send_handle(conn, fd, p.pid)
+ p.join()
+ with open(test.support.TESTFN, "rb") as f:
+ self.assertEqual(f.read(), b"foo")
+
+ @unittest.skipIf(sys.platform == "win32",
+ "test semantics don't make sense on Windows")
+ @unittest.skipIf(MAXFD <= 256,
+ "largest assignable fd number is too small")
+ @unittest.skipUnless(hasattr(os, "dup2"),
+ "test needs os.dup2()")
+ def test_large_fd_transfer(self):
+ # With fd > 256 (issue #11657)
+ if self.TYPE != 'processes':
+ self.skipTest("only makes sense with processes")
+ conn, child_conn = self.Pipe(duplex=True)
+
+ p = self.Process(target=self._writefd, args=(child_conn, b"bar", True))
+ p.start()
+ with open(test.support.TESTFN, "wb") as f:
+ fd = f.fileno()
+ for newfd in range(256, MAXFD):
+ if not self._is_fd_assigned(newfd):
+ break
+ else:
+ self.fail("could not find an unassigned large file descriptor")
+ os.dup2(fd, newfd)
+ try:
+ reduction.send_handle(conn, newfd, p.pid)
+ finally:
+ os.close(newfd)
+ p.join()
+ with open(test.support.TESTFN, "rb") as f:
+ self.assertEqual(f.read(), b"bar")
+
+
 class _TestListenerClient(BaseTestCase):
 
 ALLOWED_TYPES = ('processes', 'threads')
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -22,6 +22,9 @@
 Library
 -------
 
+- Issue #11657: Fix sending file descriptors over 255 over a multiprocessing
+ Pipe.
+
 - Issue #12213: Fix a buffering bug with interleaved reads and writes that
 could appear on BufferedRandom streams.
 
diff --git a/Modules/_multiprocessing/multiprocessing.c b/Modules/_multiprocessing/multiprocessing.c
--- a/Modules/_multiprocessing/multiprocessing.c
+++ b/Modules/_multiprocessing/multiprocessing.c
@@ -122,7 +122,7 @@
 cmsg->cmsg_type = SCM_RIGHTS;
 cmsg->cmsg_len = CMSG_LEN(sizeof(int));
 msg.msg_controllen = cmsg->cmsg_len;
- *CMSG_DATA(cmsg) = fd;
+ * (int *) CMSG_DATA(cmsg) = fd;
 
 Py_BEGIN_ALLOW_THREADS
 res = sendmsg(conn, &msg, 0);
@@ -165,7 +165,7 @@
 if (res < 0)
 return PyErr_SetFromErrno(PyExc_OSError);
 
- fd = *CMSG_DATA(cmsg);
+ fd = * (int *) CMSG_DATA(cmsg);
 return Py_BuildValue("i", fd);
 }
 
-- 
Repository URL: http://hg.python.org/cpython
