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/* $OpenBSD: telldir.c,v 1.13 2008/05/01 19:49:18 otto 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/param.h>
#include <sys/queue.h>
#include <dirent.h>
#include <stdlib.h>
#include <unistd.h>
#include "thread_private.h"
#include "telldir.h"
int _readdir_unlocked(DIR *, struct dirent **, int);
/*
* return a pointer into a directory
*/
long
_telldir_unlocked(DIR *dirp)
{
long i;
struct ddloc *lp;
i = dirp->dd_td->td_last;
lp = &dirp->dd_td->td_locs[i];
/* return previous telldir, if there */
for (; i < dirp->dd_td->td_loccnt; i++, lp++) {
if (lp->loc_seek == dirp->dd_seek &&
lp->loc_loc == dirp->dd_loc) {
dirp->dd_td->td_last = i;
return (i);
}
}
if (dirp->dd_td->td_loccnt == dirp->dd_td->td_sz) {
size_t newsz = dirp->dd_td->td_sz * 2 + 1;
struct ddloc *p;
p = realloc(dirp->dd_td->td_locs, newsz * sizeof(*p));
if (p == NULL)
return (-1);
dirp->dd_td->td_sz = newsz;
dirp->dd_td->td_locs = p;
lp = &dirp->dd_td->td_locs[i];
}
dirp->dd_td->td_loccnt++;
lp->loc_seek = dirp->dd_seek;
lp->loc_loc = dirp->dd_loc;
dirp->dd_td->td_last = i;
return (i);
}
long
telldir(DIR *dirp)
{
long i;
_MUTEX_LOCK(&dirp->dd_lock);
i = _telldir_unlocked(dirp);
_MUTEX_UNLOCK(&dirp->dd_lock);
return (i);
}
/*
* seek to an entry in a directory.
* Only values returned by "telldir" should be passed to seekdir.
*/
void
__seekdir(DIR *dirp, long loc)
{
struct ddloc *lp;
struct dirent *dp;
if (loc < 0 || loc >= dirp->dd_td->td_loccnt)
return;
lp = &dirp->dd_td->td_locs[loc];
dirp->dd_td->td_last = loc;
if (lp->loc_loc == dirp->dd_loc && lp->loc_seek == dirp->dd_seek)
return;
(void) 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) {
_readdir_unlocked(dirp, &dp, 0);
if (dp == NULL)
break;
}
}
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