glibc/dirent/scandir-tail.c
Aurelien Jarno 72f29e3aab scandir: fix wrong assumption about errno [BZ #17804]
malloc and realloc may set errno to ENOMEM even if they are successful.
The scandir code wrongly assume that they do not change errno, this
causes scandir to fail with ENOMEM even if malloc succeed.

The code already handles that readdir might set errno by calling
__set_errno (0) to clear the error. Move that part at the end of the
loop to also take malloc and realloc into account.

Changelog:
	[BZ #17804]
	* dirent/scandir-tail.c (SCANDIR_TAIL): Move __set_errno (0) at the
	end of the loop. Improve comments.
2017-12-29 14:45:35 +01:00

113 lines
3.0 KiB
C

/* Logic guts of scandir*.
Copyright (C) 1992-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <dirent.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <libc-lock.h>
#ifndef SCANDIR_TAIL
# define SCANDIR_TAIL __scandir_tail
# define READDIR __readdir
# define DIRENT_TYPE struct dirent
#endif
int
SCANDIR_TAIL (DIR *dp,
DIRENT_TYPE ***namelist,
int (*select) (const DIRENT_TYPE *),
int (*cmp) (const DIRENT_TYPE **, const DIRENT_TYPE **))
{
if (dp == NULL)
return -1;
int save = errno;
__set_errno (0);
int result;
struct scandir_cancel_struct c = { .dp = dp };
__libc_cleanup_push (&__scandir_cancel_handler, &c);
DIRENT_TYPE **v = NULL;
size_t vsize = 0;
DIRENT_TYPE *d;
while ((d = READDIR (dp)) != NULL)
{
if (select != NULL)
{
int selected = (*select) (d);
/* The SELECT function might have set errno to non-zero on
success. It was zero before and it needs to be again to
make the later tests work. */
__set_errno (0);
if (!selected)
continue;
}
if (__glibc_unlikely (c.cnt == vsize))
{
if (vsize == 0)
vsize = 10;
else
vsize *= 2;
DIRENT_TYPE **new = realloc (v, vsize * sizeof *v);
if (new == NULL)
break;
c.v = v = new;
}
size_t dsize = &d->d_name[_D_ALLOC_NAMLEN (d)] - (char *) d;
DIRENT_TYPE *vnew = malloc (dsize);
if (vnew == NULL)
break;
v[c.cnt++] = (DIRENT_TYPE *) memcpy (vnew, d, dsize);
/* Ignore errors from readdir, malloc or realloc. These functions
might have set errno to non-zero on success. It was zero before
and it needs to be again to make the latter tests work. */
__set_errno (0);
}
if (__glibc_likely (errno == 0))
{
__closedir (dp);
/* Sort the list if we have a comparison function to sort with. */
if (cmp != NULL)
qsort (v, c.cnt, sizeof *v, (__compar_fn_t) cmp);
*namelist = v;
result = c.cnt;
}
else
{
/* This frees everything and calls closedir. */
__scandir_cancel_handler (&c);
result = -1;
}
__libc_cleanup_pop (0);
if (result >= 0)
__set_errno (save);
return result;
}