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/* $OpenBSD: dir.c,v 1.6 2003/02/02 16:57:58 deraadt 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 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 rcsid[] = ": opendir.c,v 1.6 1998/08/15 08:10:14 deraadt Exp $";
#endif /* LIBC_SCCS and not lint */
#include <syscall.h>
#include <sys/param.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <dirent.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "util.h"
#include "archdep.h"
long _dl_telldir(const DIR *dirp);
void _dl_seekdir(DIR *dirp, long loc);
/*
* Open a directory.
*/
DIR *
_dl_opendir(const char *name)
{
DIR *dirp;
int fd;
struct stat sb;
int incr;
int flags = DTF_HIDEW|DTF_NODUP;
if ((fd = _dl_open(name, O_RDONLY | O_NONBLOCK)) < 0)
return (NULL);
if (_dl_fstat(fd, &sb) || !S_ISDIR(sb.st_mode)) {
_dl_close(fd);
return (NULL);
}
if (_dl_fcntl(fd, F_SETFD, FD_CLOEXEC) < 0 ||
(dirp = (DIR *)_dl_malloc(sizeof(DIR))) == NULL) {
_dl_close(fd);
return (NULL);
}
/*
* If the machine's page size is an exact multiple of DIRBLKSIZ,
* use a buffer that is cluster boundary aligned.
* Hopefully this can be a big win someday by allowing page trades
* to user space to be done by getdirentries()
* - not done in ld.so.
*/
incr = DIRBLKSIZ;
/* UNION mount support removed */
dirp->dd_len = incr;
dirp->dd_buf = _dl_malloc(dirp->dd_len);
if (dirp->dd_buf == NULL) {
_dl_free(dirp);
_dl_close (fd);
return (NULL);
}
dirp->dd_seek = 0;
flags &= ~DTF_REWIND;
dirp->dd_loc = 0;
dirp->dd_fd = fd;
dirp->dd_flags = flags;
/*
* Set up seek point for rewinddir.
*/
dirp->dd_rewind = _dl_telldir(dirp);
return (dirp);
}
#if defined(LIBC_SCCS) && !defined(lint)
static char rcsid[] = "$ closedir.c,v 1.3 1998/11/20 11:18:37 d Exp $";
#endif /* LIBC_SCCS and not lint */
/*
* close a directory.
*/
int
_dl_closedir(DIR *dirp)
{
int fd;
int ret;
_dl_seekdir(dirp, dirp->dd_rewind); /* free seekdir storage */
fd = dirp->dd_fd;
dirp->dd_fd = -1;
dirp->dd_loc = 0;
_dl_free((void *)dirp->dd_buf);
_dl_free((void *)dirp);
ret = _dl_close(fd);
return (ret);
}
#if defined(LIBC_SCCS) && !defined(lint)
static char rcsid[] = "$ readdir.c,v 1.5 2001/05/17 20:20:36 rees Exp $";
#endif /* LIBC_SCCS and not lint */
/*
* get next entry in a directory.
*/
struct dirent *
_dl_readdir(DIR *dirp)
{
struct dirent *dp;
for (;;) {
if (dirp->dd_loc >= dirp->dd_size) {
if (dirp->dd_flags & __DTF_READALL)
return (NULL);
dirp->dd_loc = 0;
}
if (dirp->dd_loc == 0 && !(dirp->dd_flags & __DTF_READALL)) {
dirp->dd_size = _dl_getdirentries(dirp->dd_fd,
dirp->dd_buf, dirp->dd_len, &dirp->dd_seek);
if (dirp->dd_size <= 0)
return (NULL);
}
dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
if ((long)dp & 03) /* bogus pointer check */
return (NULL);
if (dp->d_reclen <= 0 ||
dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc)
return (NULL);
dirp->dd_loc += dp->d_reclen;
if (dp->d_ino == 0)
continue;
if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW))
continue;
return (dp);
}
}
#if defined(LIBC_SCCS) && !defined(lint)
static char rcsid[] = "$ telldir.c,v 1.2 1996/08/19 08:26:35 tholo Exp $";
#endif /* LIBC_SCCS and not lint */
/*
* The option SINGLEUSE may be defined to say that a telldir
* cookie may be used only once before it is freed. This option
* is used to avoid having memory usage grow without bound.
*/
#define SINGLEUSE
/*
* One of these structures is malloced to describe the current directory
* position each time telldir is called. It records the current magic
* cookie returned by getdirentries and the offset within the buffer
* associated with that return value.
*/
struct ddloc {
struct ddloc *loc_next;/* next structure in list */
long loc_index; /* key associated with structure */
long loc_seek; /* magic cookie returned by getdirentries */
long loc_loc; /* offset of entry in buffer */
};
#define NDIRHASH 32 /* Num of hash lists, must be a power of 2 */
#define LOCHASH(i) ((i)&(NDIRHASH-1))
static long dd_loccnt; /* Index of entry for sequential readdir's */
static struct ddloc *dd_hash[NDIRHASH]; /* Hash list heads for ddlocs */
/*
* return a pointer into a directory
*/
long
_dl_telldir(const DIR *dirp)
{
int index;
struct ddloc *lp;
if ((lp = (struct ddloc *)_dl_malloc(sizeof(struct ddloc))) == NULL)
return (-1);
index = dd_loccnt++;
lp->loc_index = index;
lp->loc_seek = dirp->dd_seek;
lp->loc_loc = dirp->dd_loc;
lp->loc_next = dd_hash[LOCHASH(index)];
dd_hash[LOCHASH(index)] = lp;
return (index);
}
/*
* seek to an entry in a directory.
* Only values returned by "telldir" should be passed to seekdir.
*/
void
_dl_seekdir(DIR *dirp, long loc)
{
struct ddloc *lp;
struct ddloc **prevlp;
struct dirent *dp;
prevlp = &dd_hash[LOCHASH(loc)];
lp = *prevlp;
while (lp != NULL) {
if (lp->loc_index == loc)
break;
prevlp = &lp->loc_next;
lp = lp->loc_next;
}
if (lp == NULL)
return;
if (lp->loc_loc == dirp->dd_loc && lp->loc_seek == dirp->dd_seek)
goto found;
_dl_lseek(dirp->dd_fd, (off_t)lp->loc_seek, SEEK_SET);
dirp->dd_seek = lp->loc_seek;
dirp->dd_loc = 0;
while (dirp->dd_loc < lp->loc_loc) {
dp = _dl_readdir(dirp);
if (dp == NULL)
break;
}
found:
#ifdef SINGLEUSE
*prevlp = lp->loc_next;
_dl_free((caddr_t)lp);
#endif
}
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