[Python-checkins] cpython (2.7): Issue #9090 : Error code 10035 calling socket.recv() on a socket with a timeout
kristjan.jonsson
python-checkins at python.org
Tue Mar 19 19:08:13 CET 2013
http://hg.python.org/cpython/rev/8ec39bfd1f01
changeset: 82764:8ec39bfd1f01
branch: 2.7
parent: 82740:b10ec5083a53
user: Kristján Valur Jónsson <sweskman at gmail.com>
date: Tue Mar 19 10:58:59 2013 -0700
summary:
Issue #9090 : Error code 10035 calling socket.recv() on a socket with a timeout
(WSAEWOULDBLOCK - A non-blocking socket operation could not be completed
immediately)
files:
Misc/NEWS | 5 +
Modules/socketmodule.c | 104 ++++++++++++++++++++++++----
Modules/timemodule.c | 7 +
3 files changed, 101 insertions(+), 15 deletions(-)
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -214,6 +214,11 @@
Library
-------
+- Issue #9090: When a socket with a timeout fails with EWOULDBLOCK or EAGAIN,
+ retry the select() loop instead of bailing out. This is because select()
+ can incorrectly report a socket as ready for reading (for example, if it
+ received some data with an invalid checksum).
+
- Issue #1285086: Get rid of the refcounting hack and speed up urllib.unquote().
- Issue #17368: Fix an off-by-one error in the Python JSON decoder that caused
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -473,6 +473,17 @@
return NULL;
}
+#ifdef MS_WINDOWS
+#ifndef WSAEAGAIN
+#define WSAEAGAIN WSAEWOULDBLOCK
+#endif
+#define CHECK_ERRNO(expected) \
+ (WSAGetLastError() == WSA ## expected)
+#else
+#define CHECK_ERRNO(expected) \
+ (errno == expected)
+#endif
+
/* Convenience function to raise an error according to errno
and return a NULL pointer from a function. */
@@ -661,7 +672,7 @@
after they've reacquired the interpreter lock.
Returns 1 on timeout, -1 on error, 0 otherwise. */
static int
-internal_select(PySocketSockObject *s, int writing)
+internal_select_ex(PySocketSockObject *s, int writing, double interval)
{
int n;
@@ -673,6 +684,10 @@
if (s->sock_fd < 0)
return 0;
+ /* Handling this condition here simplifies the select loops */
+ if (interval < 0.0)
+ return 1;
+
/* Prefer poll, if available, since you can poll() any fd
* which can't be done with select(). */
#ifdef HAVE_POLL
@@ -684,7 +699,7 @@
pollfd.events = writing ? POLLOUT : POLLIN;
/* s->sock_timeout is in seconds, timeout in ms */
- timeout = (int)(s->sock_timeout * 1000 + 0.5);
+ timeout = (int)(interval * 1000 + 0.5);
n = poll(&pollfd, 1, timeout);
}
#else
@@ -692,8 +707,8 @@
/* Construct the arguments to select */
fd_set fds;
struct timeval tv;
- tv.tv_sec = (int)s->sock_timeout;
- tv.tv_usec = (int)((s->sock_timeout - tv.tv_sec) * 1e6);
+ tv.tv_sec = (int)interval;
+ tv.tv_usec = (int)((interval - tv.tv_sec) * 1e6);
FD_ZERO(&fds);
FD_SET(s->sock_fd, &fds);
@@ -712,6 +727,49 @@
return 0;
}
+static int
+internal_select(PySocketSockObject *s, int writing)
+{
+ return internal_select_ex(s, writing, s->sock_timeout);
+}
+
+/*
+ Two macros for automatic retry of select() in case of false positives
+ (for example, select() could indicate a socket is ready for reading
+ but the data then discarded by the OS because of a wrong checksum).
+ Here is an example of use:
+
+ BEGIN_SELECT_LOOP(s)
+ Py_BEGIN_ALLOW_THREADS
+ timeout = internal_select_ex(s, 0, interval);
+ if (!timeout)
+ outlen = recv(s->sock_fd, cbuf, len, flags);
+ Py_END_ALLOW_THREADS
+ if (timeout == 1) {
+ PyErr_SetString(socket_timeout, "timed out");
+ return -1;
+ }
+ END_SELECT_LOOP(s)
+*/
+PyAPI_FUNC(double) _PyTime_floattime(void); /* defined in timemodule.c */
+#define BEGIN_SELECT_LOOP(s) \
+ { \
+ double deadline, interval = s->sock_timeout; \
+ int has_timeout = s->sock_timeout > 0.0; \
+ if (has_timeout) { \
+ deadline = _PyTime_floattime() + s->sock_timeout; \
+ } \
+ while (1) { \
+ errno = 0; \
+
+#define END_SELECT_LOOP(s) \
+ if (!has_timeout || \
+ (!CHECK_ERRNO(EWOULDBLOCK) && !CHECK_ERRNO(EAGAIN))) \
+ break; \
+ interval = deadline - _PyTime_floattime(); \
+ } \
+ } \
+
/* Initialize a new socket object. */
static double defaulttimeout = -1.0; /* Default timeout for new sockets */
@@ -1656,8 +1714,9 @@
if (!IS_SELECTABLE(s))
return select_error();
+ BEGIN_SELECT_LOOP(s)
Py_BEGIN_ALLOW_THREADS
- timeout = internal_select(s, 0);
+ timeout = internal_select_ex(s, 0, interval);
if (!timeout)
newfd = accept(s->sock_fd, SAS2SA(&addrbuf), &addrlen);
Py_END_ALLOW_THREADS
@@ -1666,6 +1725,7 @@
PyErr_SetString(socket_timeout, "timed out");
return NULL;
}
+ END_SELECT_LOOP(s)
#ifdef MS_WINDOWS
if (newfd == INVALID_SOCKET)
@@ -2355,8 +2415,9 @@
}
#ifndef __VMS
+ BEGIN_SELECT_LOOP(s)
Py_BEGIN_ALLOW_THREADS
- timeout = internal_select(s, 0);
+ timeout = internal_select_ex(s, 0, interval);
if (!timeout)
outlen = recv(s->sock_fd, cbuf, len, flags);
Py_END_ALLOW_THREADS
@@ -2365,6 +2426,7 @@
PyErr_SetString(socket_timeout, "timed out");
return -1;
}
+ END_SELECT_LOOP(s)
if (outlen < 0) {
/* Note: the call to errorhandler() ALWAYS indirectly returned
NULL, so ignore its return value */
@@ -2386,8 +2448,9 @@
segment = remaining;
}
+ BEGIN_SELECT_LOOP(s)
Py_BEGIN_ALLOW_THREADS
- timeout = internal_select(s, 0);
+ timeout = internal_select_ex(s, 0, interval);
if (!timeout)
nread = recv(s->sock_fd, read_buf, segment, flags);
Py_END_ALLOW_THREADS
@@ -2396,6 +2459,8 @@
PyErr_SetString(socket_timeout, "timed out");
return -1;
}
+ END_SELECT_LOOP(s)
+
if (nread < 0) {
s->errorhandler();
return -1;
@@ -2559,9 +2624,10 @@
return -1;
}
+ BEGIN_SELECT_LOOP(s)
Py_BEGIN_ALLOW_THREADS
memset(&addrbuf, 0, addrlen);
- timeout = internal_select(s, 0);
+ timeout = internal_select_ex(s, 0, interval);
if (!timeout) {
#ifndef MS_WINDOWS
#if defined(PYOS_OS2) && !defined(PYCC_GCC)
@@ -2582,6 +2648,7 @@
PyErr_SetString(socket_timeout, "timed out");
return -1;
}
+ END_SELECT_LOOP(s)
if (n < 0) {
s->errorhandler();
return -1;
@@ -2719,8 +2786,9 @@
buf = pbuf.buf;
len = pbuf.len;
+ BEGIN_SELECT_LOOP(s)
Py_BEGIN_ALLOW_THREADS
- timeout = internal_select(s, 1);
+ timeout = internal_select_ex(s, 1, interval);
if (!timeout)
#ifdef __VMS
n = sendsegmented(s->sock_fd, buf, len, flags);
@@ -2728,13 +2796,14 @@
n = send(s->sock_fd, buf, len, flags);
#endif
Py_END_ALLOW_THREADS
-
- PyBuffer_Release(&pbuf);
-
if (timeout == 1) {
+ PyBuffer_Release(&pbuf);
PyErr_SetString(socket_timeout, "timed out");
return NULL;
}
+ END_SELECT_LOOP(s)
+
+ PyBuffer_Release(&pbuf);
if (n < 0)
return s->errorhandler();
return PyInt_FromLong((long)n);
@@ -2768,8 +2837,9 @@
}
do {
+ BEGIN_SELECT_LOOP(s)
Py_BEGIN_ALLOW_THREADS
- timeout = internal_select(s, 1);
+ timeout = internal_select_ex(s, 1, interval);
n = -1;
if (!timeout) {
#ifdef __VMS
@@ -2784,6 +2854,7 @@
PyErr_SetString(socket_timeout, "timed out");
return NULL;
}
+ END_SELECT_LOOP(s)
/* PyErr_CheckSignals() might change errno */
saved_errno = errno;
/* We must run our signal handlers before looping again.
@@ -2863,17 +2934,20 @@
return NULL;
}
+ BEGIN_SELECT_LOOP(s)
Py_BEGIN_ALLOW_THREADS
- timeout = internal_select(s, 1);
+ timeout = internal_select_ex(s, 1, interval);
if (!timeout)
n = sendto(s->sock_fd, buf, len, flags, SAS2SA(&addrbuf), addrlen);
Py_END_ALLOW_THREADS
- PyBuffer_Release(&pbuf);
if (timeout == 1) {
+ PyBuffer_Release(&pbuf);
PyErr_SetString(socket_timeout, "timed out");
return NULL;
}
+ END_SELECT_LOOP(s)
+ PyBuffer_Release(&pbuf);
if (n < 0)
return s->errorhandler();
return PyInt_FromLong((long)n);
diff --git a/Modules/timemodule.c b/Modules/timemodule.c
--- a/Modules/timemodule.c
+++ b/Modules/timemodule.c
@@ -1055,3 +1055,10 @@
return 0;
}
+
+/* export floattime to socketmodule.c */
+PyAPI_FUNC(double)
+_PyTime_floattime(void)
+{
+ return floattime();
+}
--
Repository URL: http://hg.python.org/cpython
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