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/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