Staging
v0.5.1
v0.5.1
https://github.com/python/cpython
Revision 18056fb11e6fe6e5247cd03073bd74df8ac0acc7 authored by Miss Islington (bot) on 14 November 2017, 07:01:29 UTC, committed by Serhiy Storchaka on 14 November 2017, 07:01:29 UTC
(cherry picked from commit 56935a53b11b9a70f3e13e460777ec81a5b9195e)
1 parent 6ed9d4e
Tip revision: 18056fb11e6fe6e5247cd03073bd74df8ac0acc7 authored by Miss Islington (bot) on 14 November 2017, 07:01:29 UTC
bpo-32020: arraymodule: Correct missing Py_DECREF in failure case of make_array() (GH-4391) (#4392)
bpo-32020: arraymodule: Correct missing Py_DECREF in failure case of make_array() (GH-4391) (#4392)
Tip revision: 18056fb
mysnprintf.c
#include "Python.h"
/* snprintf() wrappers. If the platform has vsnprintf, we use it, else we
emulate it in a half-hearted way. Even if the platform has it, we wrap
it because platforms differ in what vsnprintf does in case the buffer
is too small: C99 behavior is to return the number of characters that
would have been written had the buffer not been too small, and to set
the last byte of the buffer to \0. At least MS _vsnprintf returns a
negative value instead, and fills the entire buffer with non-\0 data.
The wrappers ensure that str[size-1] is always \0 upon return.
PyOS_snprintf and PyOS_vsnprintf never write more than size bytes
(including the trailing '\0') into str.
If the platform doesn't have vsnprintf, and the buffer size needed to
avoid truncation exceeds size by more than 512, Python aborts with a
Py_FatalError.
Return value (rv):
When 0 <= rv < size, the output conversion was unexceptional, and
rv characters were written to str (excluding a trailing \0 byte at
str[rv]).
When rv >= size, output conversion was truncated, and a buffer of
size rv+1 would have been needed to avoid truncation. str[size-1]
is \0 in this case.
When rv < 0, "something bad happened". str[size-1] is \0 in this
case too, but the rest of str is unreliable. It could be that
an error in format codes was detected by libc, or on platforms
with a non-C99 vsnprintf simply that the buffer wasn't big enough
to avoid truncation, or on platforms without any vsnprintf that
PyMem_Malloc couldn't obtain space for a temp buffer.
CAUTION: Unlike C99, str != NULL and size > 0 are required.
*/
int
PyOS_snprintf(char *str, size_t size, const char *format, ...)
{
int rc;
va_list va;
va_start(va, format);
rc = PyOS_vsnprintf(str, size, format, va);
va_end(va);
return rc;
}
int
PyOS_vsnprintf(char *str, size_t size, const char *format, va_list va)
{
int len; /* # bytes written, excluding \0 */
#ifdef HAVE_SNPRINTF
#define _PyOS_vsnprintf_EXTRA_SPACE 1
#else
#define _PyOS_vsnprintf_EXTRA_SPACE 512
char *buffer;
#endif
assert(str != NULL);
assert(size > 0);
assert(format != NULL);
/* We take a size_t as input but return an int. Sanity check
* our input so that it won't cause an overflow in the
* vsnprintf return value or the buffer malloc size. */
if (size > INT_MAX - _PyOS_vsnprintf_EXTRA_SPACE) {
len = -666;
goto Done;
}
#ifdef HAVE_SNPRINTF
len = vsnprintf(str, size, format, va);
#else
/* Emulate it. */
buffer = PyMem_MALLOC(size + _PyOS_vsnprintf_EXTRA_SPACE);
if (buffer == NULL) {
len = -666;
goto Done;
}
len = vsprintf(buffer, format, va);
if (len < 0)
/* ignore the error */;
else if ((size_t)len >= size + _PyOS_vsnprintf_EXTRA_SPACE)
Py_FatalError("Buffer overflow in PyOS_snprintf/PyOS_vsnprintf");
else {
const size_t to_copy = (size_t)len < size ?
(size_t)len : size - 1;
assert(to_copy < size);
memcpy(str, buffer, to_copy);
str[to_copy] = '\0';
}
PyMem_FREE(buffer);
#endif
Done:
if (size > 0)
str[size-1] = '\0';
return len;
#undef _PyOS_vsnprintf_EXTRA_SPACE
}
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