1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1983, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include "namespace.h"
33#include <sys/param.h>
34#include <dirent.h>
35#include <errno.h>
36#include <string.h>
37#include <pthread.h>
38#include "un-namespace.h"
39
40#include "libc_private.h"
41#include "gen-private.h"
42#include "telldir.h"
43
44/*
45 * get next entry in a directory.
46 */
47struct dirent *
48_readdir_unlocked(DIR *dirp, int flags)
49{
50	struct dirent *dp;
51	long initial_seek;
52	long initial_loc = 0;
53
54	for (;;) {
55		if (dirp->dd_loc >= dirp->dd_size) {
56			if (dirp->dd_flags & __DTF_READALL)
57				return (NULL);
58			initial_loc = dirp->dd_loc;
59			dirp->dd_flags &= ~__DTF_SKIPREAD;
60			dirp->dd_loc = 0;
61		}
62		if (dirp->dd_loc == 0 &&
63		    !(dirp->dd_flags & (__DTF_READALL | __DTF_SKIPREAD))) {
64			initial_seek = dirp->dd_seek;
65			dirp->dd_size = _getdirentries(dirp->dd_fd,
66			    dirp->dd_buf, dirp->dd_len, &dirp->dd_seek);
67			if (dirp->dd_size <= 0)
68				return (NULL);
69			_fixtelldir(dirp, initial_seek, initial_loc);
70		}
71		dirp->dd_flags &= ~__DTF_SKIPREAD;
72		dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
73		if ((long)dp & 03L)	/* bogus pointer check */
74			return (NULL);
75		if (dp->d_reclen <= 0 ||
76		    dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc)
77			return (NULL);
78		dirp->dd_loc += dp->d_reclen;
79		if (dp->d_ino == 0 && (flags & RDU_SKIP) != 0)
80			continue;
81		if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW))
82			continue;
83		if (dp->d_namlen >= sizeof(dp->d_name) &&
84		    (flags & RDU_SHORT) != 0)
85			continue;
86		return (dp);
87	}
88}
89
90struct dirent *
91readdir(DIR *dirp)
92{
93	struct dirent *dp;
94
95	if (__isthreaded)
96		_pthread_mutex_lock(&dirp->dd_lock);
97	dp = _readdir_unlocked(dirp, RDU_SKIP);
98	if (__isthreaded)
99		_pthread_mutex_unlock(&dirp->dd_lock);
100	return (dp);
101}
102
103int
104__readdir_r(DIR *dirp, struct dirent *entry, struct dirent **result)
105{
106	struct dirent *dp;
107	int saved_errno;
108
109	saved_errno = errno;
110	errno = 0;
111	if (__isthreaded)
112		_pthread_mutex_lock(&dirp->dd_lock);
113	dp = _readdir_unlocked(dirp, RDU_SKIP | RDU_SHORT);
114	if (dp != NULL)
115		memcpy(entry, dp, _GENERIC_DIRSIZ(dp));
116	if (__isthreaded)
117		_pthread_mutex_unlock(&dirp->dd_lock);
118
119	if (errno != 0) {
120		if (dp == NULL)
121			return (errno);
122	} else
123		errno = saved_errno;
124
125	if (dp != NULL)
126		*result = entry;
127	else
128		*result = NULL;
129
130	return (0);
131}
132
133__strong_reference(__readdir_r, readdir_r);
134