freebsd-skq/lib/libc/gen/readdir.c
kib c697e6f360 Do not read away the target directory entry when encountering deleted
files after a seekdir().

The seekdir shall set the position for the next readdir operation.
When the _readdir_unlocked() encounters deleted entry, dd_loc is
already advanced. Continuing the loop leads to premature read of
the target entry.

Submitted by:	Marc Balmer <mbalmer at openbsd org>
Obtained from:	OpenBSD
MFC after:	2 weeks
2008-05-05 14:05:23 +00:00

133 lines
3.7 KiB
C

/*
* Copyright (c) 1983, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)readdir.c 8.3 (Berkeley) 9/29/94";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "namespace.h"
#include <sys/param.h>
#include <dirent.h>
#include <errno.h>
#include <string.h>
#include <pthread.h>
#include "un-namespace.h"
#include "libc_private.h"
#include "telldir.h"
/*
* get next entry in a directory.
*/
struct dirent *
_readdir_unlocked(dirp, skip)
DIR *dirp;
int skip;
{
struct dirent *dp;
for (;;) {
if (dirp->dd_loc >= dirp->dd_size) {
if (dirp->dd_flags & __DTF_READALL)
return (NULL);
dirp->dd_loc = 0;
}
if (dirp->dd_loc == 0 && !(dirp->dd_flags & __DTF_READALL)) {
dirp->dd_size = _getdirentries(dirp->dd_fd,
dirp->dd_buf, dirp->dd_len, &dirp->dd_seek);
if (dirp->dd_size <= 0)
return (NULL);
}
dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
if ((long)dp & 03L) /* bogus pointer check */
return (NULL);
if (dp->d_reclen <= 0 ||
dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc)
return (NULL);
dirp->dd_loc += dp->d_reclen;
if (dp->d_ino == 0 && skip)
continue;
if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW))
continue;
return (dp);
}
}
struct dirent *
readdir(dirp)
DIR *dirp;
{
struct dirent *dp;
if (__isthreaded) {
_pthread_mutex_lock(&dirp->dd_lock);
dp = _readdir_unlocked(dirp, 1);
_pthread_mutex_unlock(&dirp->dd_lock);
}
else
dp = _readdir_unlocked(dirp, 1);
return (dp);
}
int
readdir_r(dirp, entry, result)
DIR *dirp;
struct dirent *entry;
struct dirent **result;
{
struct dirent *dp;
int saved_errno;
saved_errno = errno;
errno = 0;
if (__isthreaded) {
_pthread_mutex_lock(&dirp->dd_lock);
if ((dp = _readdir_unlocked(dirp, 1)) != NULL)
memcpy(entry, dp, _GENERIC_DIRSIZ(dp));
_pthread_mutex_unlock(&dirp->dd_lock);
}
else if ((dp = _readdir_unlocked(dirp, 1)) != NULL)
memcpy(entry, dp, _GENERIC_DIRSIZ(dp));
if (errno != 0) {
if (dp == NULL)
return (errno);
} else
errno = saved_errno;
if (dp != NULL)
*result = entry;
else
*result = NULL;
return (0);
}