minix/lib/libc/gen/readdir.c

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/* $NetBSD: readdir.c,v 1.26 2012/06/25 22:32:43 abs Exp $ */
/*
* 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.
* 3. 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.
*/
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)readdir.c 8.3 (Berkeley) 9/29/94";
#else
__RCSID("$NetBSD: readdir.c,v 1.26 2012/06/25 22:32:43 abs Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
#include "reentrant.h"
#include "extern.h"
#include <sys/param.h>
#include <dirent.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include "dirent_private.h"
/*
* get next entry in a directory.
*/
struct dirent *
_readdir_unlocked(DIR *dirp, int skipdeleted)
{
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_seek = lseek(dirp->dd_fd, (off_t)0, SEEK_CUR);
dirp->dd_size = getdents(dirp->dd_fd,
dirp->dd_buf, (size_t)dirp->dd_len);
if (dirp->dd_size <= 0)
return (NULL);
}
dp = (struct dirent *)
(void *)(dirp->dd_buf + (size_t)dirp->dd_loc);
if ((intptr_t)dp & _DIRENT_ALIGN(dp))/* bogus pointer check */
return (NULL);
/* d_reclen is unsigned; no need to compare it <= 0 */
if (dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc)
return (NULL);
dirp->dd_loc += dp->d_reclen;
if (dp->d_ino == 0 && skipdeleted)
continue;
#if !defined(__minix)
if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW))
continue;
#endif /* !defined(__minix) */
return (dp);
}
}
struct dirent *
readdir(DIR *dirp)
{
struct dirent *dp;
#ifdef _REENTRANT
if (__isthreaded) {
mutex_lock((mutex_t *)dirp->dd_lock);
dp = _readdir_unlocked(dirp, 1);
mutex_unlock((mutex_t *)dirp->dd_lock);
}
else
#endif
dp = _readdir_unlocked(dirp, 1);
return (dp);
}
int
readdir_r(DIR *dirp, struct dirent *entry, struct dirent **result)
{
struct dirent *dp;
int saved_errno;
saved_errno = errno;
errno = 0;
#ifdef _REENTRANT
if (__isthreaded) {
mutex_lock((mutex_t *)dirp->dd_lock);
if ((dp = _readdir_unlocked(dirp, 1)) != NULL)
memcpy(entry, dp, (size_t)_DIRENT_SIZE(dp));
mutex_unlock((mutex_t *)dirp->dd_lock);
}
else
#endif
if ((dp = _readdir_unlocked(dirp, 1)) != NULL)
memcpy(entry, dp, (size_t)_DIRENT_SIZE(dp));
if (errno != 0) {
if (dp == NULL)
return (errno);
} else
errno = saved_errno;
if (dp != NULL)
*result = entry;
else
*result = NULL;
return (0);
}