2 * Copyright (c) 1983, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 #if defined(LIBC_SCCS) && !defined(lint)
31 static char sccsid[] = "@(#)telldir.c 8.1 (Berkeley) 6/4/93";
32 #endif /* LIBC_SCCS and not lint */
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
36 #include "namespace.h"
37 #include <sys/param.h>
38 #include <sys/queue.h>
43 #include "un-namespace.h"
45 #include "libc_private.h"
46 #include "gen-private.h"
50 * return a pointer into a directory
56 struct ddloc *lp, *flp;
60 _pthread_mutex_lock(&dirp->dd_lock);
62 LIST_FOREACH(lp, &dirp->dd_td->td_locq, loc_lqe) {
63 if (lp->loc_seek == dirp->dd_seek) {
66 if (lp->loc_loc == dirp->dd_loc)
68 } else if (flp != NULL) {
74 lp = malloc(sizeof(struct ddloc));
77 _pthread_mutex_unlock(&dirp->dd_lock);
80 lp->loc_index = dirp->dd_td->td_loccnt++;
81 lp->loc_seek = dirp->dd_seek;
82 lp->loc_loc = dirp->dd_loc;
84 LIST_INSERT_BEFORE(flp, lp, loc_lqe);
86 LIST_INSERT_HEAD(&dirp->dd_td->td_locq, lp, loc_lqe);
90 _pthread_mutex_unlock(&dirp->dd_lock);
95 * seek to an entry in a directory.
96 * Only values returned by "telldir" should be passed to seekdir.
106 LIST_FOREACH(lp, &dirp->dd_td->td_locq, loc_lqe) {
107 if (lp->loc_index == loc)
112 if (lp->loc_loc == dirp->dd_loc && lp->loc_seek == dirp->dd_seek)
115 /* If it's within the same chunk of data, don't bother reloading. */
116 if (lp->loc_seek == dirp->dd_seek) {
118 * If we go back to 0 don't make the next readdir
119 * trigger a call to getdirentries().
121 if (lp->loc_loc == 0)
122 dirp->dd_flags |= __DTF_SKIPREAD;
123 dirp->dd_loc = lp->loc_loc;
126 (void) lseek(dirp->dd_fd, (off_t)lp->loc_seek, SEEK_SET);
127 dirp->dd_seek = lp->loc_seek;
129 dirp->dd_flags &= ~__DTF_SKIPREAD; /* current contents are invalid */
130 while (dirp->dd_loc < lp->loc_loc) {
131 dp = _readdir_unlocked(dirp, 0);
138 * After readdir returns the last entry in a block, a call to telldir
139 * returns a location that is after the end of that last entry.
140 * However, that location doesn't refer to a valid directory entry.
141 * Ideally, the call to telldir would return a location that refers to
142 * the first entry in the next block. That location is not known
143 * until the next block is read, so readdir calls this function after
144 * fetching a new block to fix any such telldir locations.
147 _fixtelldir(DIR *dirp, long oldseek, long oldloc)
151 lp = LIST_FIRST(&dirp->dd_td->td_locq);
153 if (lp->loc_loc == oldloc &&
154 lp->loc_seek == oldseek) {
155 lp->loc_seek = dirp->dd_seek;
156 lp->loc_loc = dirp->dd_loc;
162 * Reclaim memory for telldir cookies which weren't used.
165 _reclaim_telldir(dirp)
169 struct ddloc *templp;
171 lp = LIST_FIRST(&dirp->dd_td->td_locq);
174 lp = LIST_NEXT(lp, loc_lqe);
177 LIST_INIT(&dirp->dd_td->td_locq);