Issue #10350: Read and save errno before calling a function which might overwrite it.
Original patch by Hallvard B Furuseth.
diff --git a/Modules/_io/fileio.c b/Modules/_io/fileio.c
index be5c9f8..f39f8b0 100644
--- a/Modules/_io/fileio.c
+++ b/Modules/_io/fileio.c
@@ -506,6 +506,7 @@
{
Py_buffer pbuf;
Py_ssize_t n, len;
+ int err;
if (self->fd < 0)
return err_closed();
@@ -529,10 +530,12 @@
Py_END_ALLOW_THREADS
} else
n = -1;
+ err = errno;
PyBuffer_Release(&pbuf);
if (n < 0) {
- if (errno == EAGAIN)
+ if (err == EAGAIN)
Py_RETURN_NONE;
+ errno = err;
PyErr_SetFromErrno(PyExc_IOError);
return NULL;
}
@@ -675,9 +678,11 @@
n = -1;
if (n < 0) {
+ int err = errno;
Py_DECREF(bytes);
- if (errno == EAGAIN)
+ if (err == EAGAIN)
Py_RETURN_NONE;
+ errno = err;
PyErr_SetFromErrno(PyExc_IOError);
return NULL;
}
@@ -697,6 +702,7 @@
{
Py_buffer pbuf;
Py_ssize_t n, len;
+ int err;
if (self->fd < 0)
return err_closed();
@@ -727,12 +733,14 @@
Py_END_ALLOW_THREADS
} else
n = -1;
+ err = errno;
PyBuffer_Release(&pbuf);
if (n < 0) {
- if (errno == EAGAIN)
+ if (err == EAGAIN)
Py_RETURN_NONE;
+ errno = err;
PyErr_SetFromErrno(PyExc_IOError);
return NULL;
}