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130 lines
3.7 KiB
C
130 lines
3.7 KiB
C
/*
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* Copyright (c) 1983, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)telldir.c 8.1 (Berkeley) 6/4/93";
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#endif /* LIBC_SCCS and not lint */
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "namespace.h"
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#include <sys/param.h>
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#include <sys/queue.h>
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#include <dirent.h>
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#include <pthread.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include "un-namespace.h"
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#include "libc_private.h"
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#include "telldir.h"
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/*
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* The option SINGLEUSE may be defined to say that a telldir
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* cookie may be used only once before it is freed. This option
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* is used to avoid having memory usage grow without bound.
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*/
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#define SINGLEUSE
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/*
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* return a pointer into a directory
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*/
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long
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telldir(dirp)
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DIR *dirp;
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{
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struct ddloc *lp;
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if ((lp = (struct ddloc *)malloc(sizeof(struct ddloc))) == NULL)
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return (-1);
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if (__isthreaded)
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_pthread_mutex_lock((pthread_mutex_t *)&dirp->dd_lock);
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lp->loc_index = dirp->dd_td->td_loccnt++;
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lp->loc_seek = dirp->dd_seek;
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lp->loc_loc = dirp->dd_loc;
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LIST_INSERT_HEAD(&dirp->dd_td->td_locq, lp, loc_lqe);
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if (__isthreaded)
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_pthread_mutex_unlock((pthread_mutex_t *)&dirp->dd_lock);
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return (lp->loc_index);
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}
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/*
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* seek to an entry in a directory.
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* Only values returned by "telldir" should be passed to seekdir.
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*/
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void
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_seekdir(dirp, loc)
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DIR *dirp;
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long loc;
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{
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struct ddloc *lp;
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struct dirent *dp;
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LIST_FOREACH(lp, &dirp->dd_td->td_locq, loc_lqe) {
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if (lp->loc_index == loc)
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break;
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}
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if (lp == NULL)
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return;
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if (lp->loc_loc == dirp->dd_loc && lp->loc_seek == dirp->dd_seek)
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goto found;
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(void) lseek(dirp->dd_fd, (off_t)lp->loc_seek, SEEK_SET);
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dirp->dd_seek = lp->loc_seek;
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dirp->dd_loc = 0;
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while (dirp->dd_loc < lp->loc_loc) {
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dp = _readdir_unlocked(dirp);
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if (dp == NULL)
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break;
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}
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found:
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#ifdef SINGLEUSE
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LIST_REMOVE(lp, loc_lqe);
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free((caddr_t)lp);
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#endif
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}
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/*
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* Reclaim memory for telldir cookies which weren't used.
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*/
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void
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_reclaim_telldir(dirp)
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DIR *dirp;
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{
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struct ddloc *lp;
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struct ddloc *templp;
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lp = LIST_FIRST(&dirp->dd_td->td_locq);
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while (lp != NULL) {
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templp = lp;
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lp = LIST_NEXT(lp, loc_lqe);
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free(templp);
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}
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LIST_INIT(&dirp->dd_td->td_locq);
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}
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