1 /* $NetBSD: readdir.c,v 1.17 2003/05/28 21:08:23 kleink Exp $ */ 2 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 #if defined(LIBC_SCCS) && !defined(lint) 38 #if 0 39 static char sccsid[] = "@(#)readdir.c 8.3 (Berkeley) 9/29/94"; 40 #else 41 __RCSID("$NetBSD: readdir.c,v 1.17 2003/05/28 21:08:23 kleink Exp $"); 42 #endif 43 #endif /* LIBC_SCCS and not lint */ 44 45 #include "namespace.h" 46 #include "reentrant.h" 47 #include <sys/param.h> 48 49 #include <dirent.h> 50 #include <errno.h> 51 #include <string.h> 52 #include <unistd.h> 53 54 #ifdef __weak_alias 55 __weak_alias(readdir,_readdir) 56 __weak_alias(readdir_r,_readdir_r) 57 #endif 58 59 /* 60 * get next entry in a directory. 61 */ 62 static struct dirent * 63 _readdir_unlocked(DIR *dirp) 64 { 65 struct dirent *dp; 66 67 68 for (;;) { 69 if (dirp->dd_loc >= dirp->dd_size) { 70 if (dirp->dd_flags & __DTF_READALL) 71 return (NULL); 72 dirp->dd_loc = 0; 73 } 74 if (dirp->dd_loc == 0 && !(dirp->dd_flags & __DTF_READALL)) { 75 dirp->dd_seek = lseek(dirp->dd_fd, (off_t)0, SEEK_CUR); 76 dirp->dd_size = getdents(dirp->dd_fd, 77 dirp->dd_buf, (size_t)dirp->dd_len); 78 if (dirp->dd_size <= 0) 79 return (NULL); 80 } 81 dp = (struct dirent *) 82 (void *)(dirp->dd_buf + (size_t)dirp->dd_loc); 83 if ((long)dp & 03) /* bogus pointer check */ 84 return (NULL); 85 /* d_reclen is unsigned; no need to compare it <= 0 */ 86 if (dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc) 87 return (NULL); 88 dirp->dd_loc += dp->d_reclen; 89 if (dp->d_ino == 0) 90 continue; 91 if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW)) 92 continue; 93 return (dp); 94 } 95 } 96 97 struct dirent * 98 readdir(dirp) 99 DIR *dirp; 100 { 101 struct dirent *dp; 102 103 #ifdef _REENTRANT 104 if (__isthreaded) { 105 mutex_lock((mutex_t *)dirp->dd_lock); 106 dp = _readdir_unlocked(dirp); 107 mutex_unlock((mutex_t *)dirp->dd_lock); 108 } 109 else 110 #endif 111 dp = _readdir_unlocked(dirp); 112 return (dp); 113 } 114 115 int 116 readdir_r(dirp, entry, result) 117 DIR *dirp; 118 struct dirent *entry; 119 struct dirent **result; 120 { 121 struct dirent *dp; 122 int saved_errno; 123 124 saved_errno = errno; 125 errno = 0; 126 #ifdef _REENTRANT 127 if (__isthreaded) { 128 mutex_lock((mutex_t *)dirp->dd_lock); 129 if ((dp = _readdir_unlocked(dirp)) != NULL) 130 memcpy(entry, dp, DIRENT_SIZE(dp)); 131 mutex_unlock((mutex_t *)dirp->dd_lock); 132 } 133 else 134 #endif 135 if ((dp = _readdir_unlocked(dirp)) != NULL) 136 memcpy(entry, dp, DIRENT_SIZE(dp)); 137 138 if (errno != 0) { 139 if (dp == NULL) 140 return (errno); 141 } else 142 errno = saved_errno; 143 144 if (dp != NULL) 145 *result = entry; 146 else 147 *result = NULL; 148 149 return (0); 150 } 151