bpo-40422: Move _Py_closerange to fileutils.c (GH-22680)

This API is relatively lightweight and organizationally, given that it's
used by multiple modules, it makes sense to move it to fileutils.

Requires making sure that _posixsubprocess is compiled with the appropriate
Py_BUIILD_CORE_BUILTIN macro.
This commit is contained in:
Kyle Evans 2020-10-13 15:04:44 -05:00 committed by GitHub
parent 8b2ff4c03d
commit 7992579cd2
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
7 changed files with 83 additions and 80 deletions

View file

@ -2106,3 +2106,79 @@ done:
PyMem_Free(oldloc);
return res;
}
/* Our selection logic for which function to use is as follows:
* 1. If close_range(2) is available, always prefer that; it's better for
* contiguous ranges like this than fdwalk(3) which entails iterating over
* the entire fd space and simply doing nothing for those outside the range.
* 2. If closefrom(2) is available, we'll attempt to use that next if we're
* closing up to sysconf(_SC_OPEN_MAX).
* 2a. Fallback to fdwalk(3) if we're not closing up to sysconf(_SC_OPEN_MAX),
* as that will be more performant if the range happens to have any chunk of
* non-opened fd in the middle.
* 2b. If fdwalk(3) isn't available, just do a plain close(2) loop.
*/
#ifdef __FreeBSD__
# define USE_CLOSEFROM
#endif /* __FreeBSD__ */
#ifdef HAVE_FDWALK
# define USE_FDWALK
#endif /* HAVE_FDWALK */
#ifdef USE_FDWALK
static int
_fdwalk_close_func(void *lohi, int fd)
{
int lo = ((int *)lohi)[0];
int hi = ((int *)lohi)[1];
if (fd >= hi) {
return 1;
}
else if (fd >= lo) {
/* Ignore errors */
(void)close(fd);
}
return 0;
}
#endif /* USE_FDWALK */
/* Closes all file descriptors in [first, last], ignoring errors. */
void
_Py_closerange(int first, int last)
{
first = Py_MAX(first, 0);
_Py_BEGIN_SUPPRESS_IPH
#ifdef HAVE_CLOSE_RANGE
if (close_range(first, last, 0) == 0 || errno != ENOSYS) {
/* Any errors encountered while closing file descriptors are ignored;
* ENOSYS means no kernel support, though,
* so we'll fallback to the other methods. */
}
else
#endif /* HAVE_CLOSE_RANGE */
#ifdef USE_CLOSEFROM
if (last >= sysconf(_SC_OPEN_MAX)) {
/* Any errors encountered while closing file descriptors are ignored */
closefrom(first);
}
else
#endif /* USE_CLOSEFROM */
#ifdef USE_FDWALK
{
int lohi[2];
lohi[0] = first;
lohi[1] = last + 1;
fdwalk(_fdwalk_close_func, lohi);
}
#else
{
for (int i = first; i <= last; i++) {
/* Ignore errors */
(void)close(i);
}
}
#endif /* USE_FDWALK */
_Py_END_SUPPRESS_IPH
}