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Issue #23708: Save/restore errno in _Py_read() and _Py_write() 

Save and then restore errno because PyErr_CheckSignals() and
PyErr_SetFromErrno() can modify it.
This commit is contained in:
Victor Stinner 2015-03-20 11:58:18 +01:00
parent f50e187724
commit a3c0202eb5
1 changed files with 21 additions and 15 deletions
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36
Python/fileutils.c
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@ -1137,6 +1137,7 @@ Py_ssize_t
_Py_read(int fd, void *buf, size_t count)
{
Py_ssize_t n;
int err;
int async_err = 0;
/* _Py_read() must not be called with an exception set, otherwise the
@ -1145,8 +1146,10 @@ _Py_read(int fd, void *buf, size_t count)
assert(!PyErr_Occurred());
if (!_PyVerify_fd(fd)) {
/* save/restore errno because PyErr_SetFromErrno() can modify it */
err = errno;
PyErr_SetFromErrno(PyExc_OSError);
assert(errno == EBADF);
errno = err;
return -1;
}
@ -1171,23 +1174,23 @@ _Py_read(int fd, void *buf, size_t count)
#else
n = read(fd, buf, count);
#endif
/* save/restore errno because PyErr_CheckSignals()
* and PyErr_SetFromErrno() can modify it */
err = errno;
Py_END_ALLOW_THREADS
} while (n < 0 && errno == EINTR &&
} while (n < 0 && err == EINTR &&
!(async_err = PyErr_CheckSignals()));
if (async_err) {
/* read() was interrupted by a signal (failed with EINTR)
* and the Python signal handler raised an exception */
assert(errno == EINTR);
assert(PyErr_Occurred());
errno = err;
assert(errno == EINTR && PyErr_Occurred());
return -1;
}
if (n < 0) {
#ifndef NDEBUG
int err = errno;
#endif
PyErr_SetFromErrno(PyExc_OSError);
assert(errno == err);
errno = err;
return -1;
}
@ -1209,6 +1212,7 @@ Py_ssize_t
_Py_write(int fd, const void *buf, size_t count)
{
Py_ssize_t n;
int err;
int async_err = 0;
/* _Py_write() must not be called with an exception set, otherwise the
@ -1217,8 +1221,10 @@ _Py_write(int fd, const void *buf, size_t count)
assert(!PyErr_Occurred());
if (!_PyVerify_fd(fd)) {
/* save/restore errno because PyErr_SetFromErrno() can modify it */
err = errno;
PyErr_SetFromErrno(PyExc_OSError);
assert(errno == EBADF);
errno = err;
return -1;
}
@ -1248,6 +1254,9 @@ _Py_write(int fd, const void *buf, size_t count)
#else
n = write(fd, buf, count);
#endif
/* save/restore errno because PyErr_CheckSignals()
* and PyErr_SetFromErrno() can modify it */
err = errno;
Py_END_ALLOW_THREADS
} while (n < 0 && errno == EINTR &&
!(async_err = PyErr_CheckSignals()));
@ -1255,16 +1264,13 @@ _Py_write(int fd, const void *buf, size_t count)
if (async_err) {
/* write() was interrupted by a signal (failed with EINTR)
* and the Python signal handler raised an exception */
assert(errno == EINTR);
assert(PyErr_Occurred());
errno = err;
assert(errno == EINTR && PyErr_Occurred());
return -1;
}
if (n < 0) {
#ifndef NDEBUG
int err = errno;
#endif
PyErr_SetFromErrno(PyExc_OSError);
assert(errno == err);
errno = err;
return -1;
}