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 * 3. 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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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
55 struct ddloc *lp, *flp;
59 _pthread_mutex_lock(&dirp->dd_lock);
61 LIST_FOREACH(lp, &dirp->dd_td->td_locq, loc_lqe) {
62 if (lp->loc_seek == dirp->dd_seek) {
65 if (lp->loc_loc == dirp->dd_loc)
67 } else if (flp != NULL) {
73 lp = malloc(sizeof(struct ddloc));
76 _pthread_mutex_unlock(&dirp->dd_lock);
79 lp->loc_index = dirp->dd_td->td_loccnt++;
80 lp->loc_seek = dirp->dd_seek;
81 lp->loc_loc = dirp->dd_loc;
83 LIST_INSERT_BEFORE(flp, lp, loc_lqe);
85 LIST_INSERT_HEAD(&dirp->dd_td->td_locq, lp, loc_lqe);
89 _pthread_mutex_unlock(&dirp->dd_lock);
94 * seek to an entry in a directory.
95 * Only values returned by "telldir" should be passed to seekdir.
98 _seekdir(DIR *dirp, long loc)
103 LIST_FOREACH(lp, &dirp->dd_td->td_locq, loc_lqe) {
104 if (lp->loc_index == loc)
109 if (lp->loc_loc == dirp->dd_loc && lp->loc_seek == dirp->dd_seek)
112 /* If it's within the same chunk of data, don't bother reloading. */
113 if (lp->loc_seek == dirp->dd_seek) {
115 * If we go back to 0 don't make the next readdir
116 * trigger a call to getdirentries().
118 if (lp->loc_loc == 0)
119 dirp->dd_flags |= __DTF_SKIPREAD;
120 dirp->dd_loc = lp->loc_loc;
123 (void) lseek(dirp->dd_fd, (off_t)lp->loc_seek, SEEK_SET);
124 dirp->dd_seek = lp->loc_seek;
126 dirp->dd_flags &= ~__DTF_SKIPREAD; /* current contents are invalid */
127 while (dirp->dd_loc < lp->loc_loc) {
128 dp = _readdir_unlocked(dirp, 0);
135 * After readdir returns the last entry in a block, a call to telldir
136 * returns a location that is after the end of that last entry.
137 * However, that location doesn't refer to a valid directory entry.
138 * Ideally, the call to telldir would return a location that refers to
139 * the first entry in the next block. That location is not known
140 * until the next block is read, so readdir calls this function after
141 * fetching a new block to fix any such telldir locations.
144 _fixtelldir(DIR *dirp, long oldseek, long oldloc)
148 lp = LIST_FIRST(&dirp->dd_td->td_locq);
150 if (lp->loc_loc == oldloc &&
151 lp->loc_seek == oldseek) {
152 lp->loc_seek = dirp->dd_seek;
153 lp->loc_loc = dirp->dd_loc;
159 * Reclaim memory for telldir cookies which weren't used.
162 _reclaim_telldir(DIR *dirp)
165 struct ddloc *templp;
167 lp = LIST_FIRST(&dirp->dd_td->td_locq);
170 lp = LIST_NEXT(lp, loc_lqe);
173 LIST_INIT(&dirp->dd_td->td_locq);