bpo-28134: Auto-detect socket values from file descriptor (#1349)
Fix socket(fileno=fd) by auto-detecting the socket's family, type,
and proto from the file descriptor. The auto-detection can be overruled
by passing in family, type, and proto explicitly.
Without the fix, all socket except for TCP/IP over IPv4 are basically broken:
>>> s = socket.create_connection(('www.python.org', 443))
>>> s
<socket.socket fd=3, family=AddressFamily.AF_INET6, type=SocketKind.SOCK_STREAM, proto=6, laddr=('2003:58:bc4a:3b00:56ee:75ff:fe47:ca7b', 59730, 0, 0), raddr=('2a04:4e42:1b::223', 443, 0, 0)>
>>> socket.socket(fileno=s.fileno())
<socket.socket fd=3, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0, laddr=('2003:58:bc4a:3b00::%2550471192', 59730, 0, 2550471192), raddr=('2a04:4e42:1b:0:700c:e70b:ff7f:0%2550471192', 443, 0, 2550471192)>
Signed-off-by: Christian Heimes <christian@python.org>diff --git a/Doc/library/socket.rst b/Doc/library/socket.rst
index faa260e..7f0d4ed 100644
--- a/Doc/library/socket.rst
+++ b/Doc/library/socket.rst
@@ -461,10 +461,15 @@
:const:`SOCK_DGRAM`, :const:`SOCK_RAW` or perhaps one of the other ``SOCK_``
constants. The protocol number is usually zero and may be omitted or in the
case where the address family is :const:`AF_CAN` the protocol should be one
- of :const:`CAN_RAW`, :const:`CAN_BCM` or :const:`CAN_ISOTP`. If *fileno* is specified, the other
- arguments are ignored, causing the socket with the specified file descriptor
- to return. Unlike :func:`socket.fromfd`, *fileno* will return the same
- socket and not a duplicate. This may help close a detached socket using
+ of :const:`CAN_RAW`, :const:`CAN_BCM` or :const:`CAN_ISOTP`
+
+ If *fileno* is specified, the values for *family*, *type*, and *proto* are
+ auto-detected from the specified file descriptor. Auto-detection can be
+ overruled by calling the function with explicit *family*, *type*, or *proto*
+ arguments. This only affects how Python represents e.g. the return value
+ of :meth:`socket.getpeername` but not the actual OS resource. Unlike
+ :func:`socket.fromfd`, *fileno* will return the same socket and not a
+ duplicate. This may help close a detached socket using
:meth:`socket.close()`.
The newly created socket is :ref:`non-inheritable <fd_inheritance>`.
diff --git a/Lib/socket.py b/Lib/socket.py
index 2d8aee3..cfa605a 100644
--- a/Lib/socket.py
+++ b/Lib/socket.py
@@ -136,11 +136,18 @@
__slots__ = ["__weakref__", "_io_refs", "_closed"]
- def __init__(self, family=AF_INET, type=SOCK_STREAM, proto=0, fileno=None):
+ def __init__(self, family=-1, type=-1, proto=-1, fileno=None):
# For user code address family and type values are IntEnum members, but
# for the underlying _socket.socket they're just integers. The
# constructor of _socket.socket converts the given argument to an
# integer automatically.
+ if fileno is None:
+ if family == -1:
+ family = AF_INET
+ if type == -1:
+ type = SOCK_STREAM
+ if proto == -1:
+ proto = 0
_socket.socket.__init__(self, family, type, proto, fileno)
self._io_refs = 0
self._closed = False
diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py
index 05166b9..1e497a5 100644
--- a/Lib/test/_test_multiprocessing.py
+++ b/Lib/test/_test_multiprocessing.py
@@ -4204,7 +4204,7 @@
def close(self, fd):
if WIN32:
- socket.socket(fileno=fd).close()
+ socket.socket(socket.AF_INET, socket.SOCK_STREAM, fileno=fd).close()
else:
os.close(fd)
diff --git a/Lib/test/test_socket.py b/Lib/test/test_socket.py
index 365da36..89cf1fa 100644
--- a/Lib/test/test_socket.py
+++ b/Lib/test/test_socket.py
@@ -20,6 +20,7 @@
import pickle
import struct
import random
+import shutil
import string
import _thread as thread
import threading
@@ -1284,6 +1285,7 @@
def testCloseException(self):
sock = socket.socket()
+ sock.bind((socket._LOCALHOST, 0))
socket.socket(fileno=sock.fileno()).close()
try:
sock.close()
@@ -1636,9 +1638,11 @@
) + 1
with socket.socket(
- family=unknown_family, type=unknown_type, fileno=fd) as s:
+ family=unknown_family, type=unknown_type, proto=23,
+ fileno=fd) as s:
self.assertEqual(s.family, unknown_family)
self.assertEqual(s.type, unknown_type)
+ self.assertEqual(s.proto, 23)
@unittest.skipUnless(hasattr(os, 'sendfile'), 'test needs os.sendfile()')
def test__sendfile_use_sendfile(self):
@@ -1658,6 +1662,45 @@
with self.assertRaises(TypeError):
sock._sendfile_use_sendfile(File(None))
+ def _test_socket_fileno(self, s, family, stype):
+ self.assertEqual(s.family, family)
+ self.assertEqual(s.type, stype)
+
+ fd = s.fileno()
+ s2 = socket.socket(fileno=fd)
+ self.addCleanup(s2.close)
+ # detach old fd to avoid double close
+ s.detach()
+ self.assertEqual(s2.family, family)
+ self.assertEqual(s2.type, stype)
+ self.assertEqual(s2.fileno(), fd)
+
+ def test_socket_fileno(self):
+ s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+ self.addCleanup(s.close)
+ s.bind((support.HOST, 0))
+ self._test_socket_fileno(s, socket.AF_INET, socket.SOCK_STREAM)
+
+ if hasattr(socket, "SOCK_DGRAM"):
+ s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+ self.addCleanup(s.close)
+ s.bind((support.HOST, 0))
+ self._test_socket_fileno(s, socket.AF_INET, socket.SOCK_DGRAM)
+
+ if support.IPV6_ENABLED:
+ s = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
+ self.addCleanup(s.close)
+ s.bind((support.HOSTv6, 0, 0, 0))
+ self._test_socket_fileno(s, socket.AF_INET6, socket.SOCK_STREAM)
+
+ if hasattr(socket, "AF_UNIX"):
+ tmpdir = tempfile.mkdtemp()
+ self.addCleanup(shutil.rmtree, tmpdir)
+ s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+ self.addCleanup(s.close)
+ s.bind(os.path.join(tmpdir, 'socket'))
+ self._test_socket_fileno(s, socket.AF_UNIX, socket.SOCK_STREAM)
+
@unittest.skipUnless(HAVE_SOCKET_CAN, 'SocketCan required for this test.')
class BasicCANTest(unittest.TestCase):
diff --git a/Misc/NEWS.d/next/Library/2017-12-24-20-01-09.bpo-28134.HJ8Beb.rst b/Misc/NEWS.d/next/Library/2017-12-24-20-01-09.bpo-28134.HJ8Beb.rst
new file mode 100644
index 0000000..9c4c683
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2017-12-24-20-01-09.bpo-28134.HJ8Beb.rst
@@ -0,0 +1,2 @@
+Sockets now auto-detect family, type and protocol from file descriptor by
+default.
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index 8744ea0..8cc5d14 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -102,7 +102,8 @@
/* Socket object documentation */
PyDoc_STRVAR(sock_doc,
-"socket(family=AF_INET, type=SOCK_STREAM, proto=0, fileno=None) -> socket object\n\
+"socket(family=AF_INET, type=SOCK_STREAM, proto=0) -> socket object\n\
+socket(family=-1, type=-1, proto=-1, fileno=None) -> socket object\n\
\n\
Open a socket of the given type. The family argument specifies the\n\
address family; it defaults to AF_INET. The type argument specifies\n\
@@ -111,6 +112,9 @@
specifying the default protocol. Keyword arguments are accepted.\n\
The socket is created as non-inheritable.\n\
\n\
+When a fileno is passed in, family, type and proto are auto-detected,\n\
+unless they are explicitly set.\n\
+\n\
A socket object represents one endpoint of a network connection.\n\
\n\
Methods of socket objects (keyword arguments not allowed):\n\
@@ -4792,7 +4796,7 @@
PySocketSockObject *s = (PySocketSockObject *)self;
PyObject *fdobj = NULL;
SOCKET_T fd = INVALID_SOCKET;
- int family = AF_INET, type = SOCK_STREAM, proto = 0;
+ int family = -1, type = -1, proto = -1;
static char *keywords[] = {"family", "type", "proto", "fileno", 0};
#ifndef MS_WINDOWS
#ifdef SOCK_CLOEXEC
@@ -4842,9 +4846,72 @@
"can't use invalid socket value");
return -1;
}
+
+ if (family == -1) {
+ sock_addr_t addrbuf;
+ socklen_t addrlen = sizeof(sock_addr_t);
+
+ memset(&addrbuf, 0, addrlen);
+ if (getsockname(fd, SAS2SA(&addrbuf), &addrlen) == 0) {
+ family = SAS2SA(&addrbuf)->sa_family;
+ } else {
+#ifdef MS_WINDOWS
+ PyErr_SetFromWindowsErrWithFilename(0, "family");
+#else
+ PyErr_SetFromErrnoWithFilename(PyExc_OSError, "family");
+#endif
+ return -1;
+ }
+ }
+#ifdef SO_TYPE
+ if (type == -1) {
+ int tmp;
+ socklen_t slen = sizeof(tmp);
+ if (getsockopt(fd, SOL_SOCKET, SO_TYPE, &tmp, &slen) == 0) {
+ type = tmp;
+ } else {
+#ifdef MS_WINDOWS
+ PyErr_SetFromWindowsErrWithFilename(0, "type");
+#else
+ PyErr_SetFromErrnoWithFilename(PyExc_OSError, "type");
+#endif
+ return -1;
+ }
+ }
+#else
+ type = SOCK_STREAM;
+#endif
+#ifdef SO_PROTOCOL
+ if (proto == -1) {
+ int tmp;
+ socklen_t slen = sizeof(tmp);
+ if (getsockopt(fd, SOL_SOCKET, SO_PROTOCOL, &tmp, &slen) == 0) {
+ proto = tmp;
+ } else {
+#ifdef MS_WINDOWS
+ PyErr_SetFromWindowsErrWithFilename(0, "protocol");
+#else
+ PyErr_SetFromErrnoWithFilename(PyExc_OSError, "protocol");
+#endif
+ return -1;
+ }
+ }
+#else
+ proto = 0;
+#endif
}
}
else {
+ /* No fd, default to AF_INET and SOCK_STREAM */
+ if (family == -1) {
+ family = AF_INET;
+ }
+ if (type == -1) {
+ type = SOCK_STREAM;
+ }
+ if (proto == -1) {
+ proto = 0;
+ }
#ifdef MS_WINDOWS
/* Windows implementation */
#ifndef WSA_FLAG_NO_HANDLE_INHERIT