1 /* $NetBSD: readdir.c,v 1.18 2003/08/07 16:42:55 agc 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. 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 <sys/cdefs.h> 33 #if defined(LIBC_SCCS) && !defined(lint) 34 #if 0 35 static char sccsid[] = "@(#)readdir.c 8.3 (Berkeley) 9/29/94"; 36 #else 37 __RCSID("$NetBSD: readdir.c,v 1.18 2003/08/07 16:42:55 agc Exp $"); 38 #endif 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include "namespace.h" 42 #include "reentrant.h" 43 #include <sys/param.h> 44 45 #include <dirent.h> 46 #include <errno.h> 47 #include <string.h> 48 #include <unistd.h> 49 50 #ifdef __weak_alias 51 __weak_alias(readdir,_readdir) 52 __weak_alias(readdir_r,_readdir_r) 53 #endif 54 55 /* 56 * get next entry in a directory. 57 */ 58 static struct dirent * 59 _readdir_unlocked(DIR *dirp) 60 { 61 struct dirent *dp; 62 63 64 for (;;) { 65 if (dirp->dd_loc >= dirp->dd_size) { 66 if (dirp->dd_flags & __DTF_READALL) 67 return (NULL); 68 dirp->dd_loc = 0; 69 } 70 if (dirp->dd_loc == 0 && !(dirp->dd_flags & __DTF_READALL)) { 71 dirp->dd_seek = lseek(dirp->dd_fd, (off_t)0, SEEK_CUR); 72 dirp->dd_size = getdents(dirp->dd_fd, 73 dirp->dd_buf, (size_t)dirp->dd_len); 74 if (dirp->dd_size <= 0) 75 return (NULL); 76 } 77 dp = (struct dirent *) 78 (void *)(dirp->dd_buf + (size_t)dirp->dd_loc); 79 if ((long)dp & 03) /* bogus pointer check */ 80 return (NULL); 81 /* d_reclen is unsigned; no need to compare it <= 0 */ 82 if (dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc) 83 return (NULL); 84 dirp->dd_loc += dp->d_reclen; 85 if (dp->d_ino == 0) 86 continue; 87 if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW)) 88 continue; 89 return (dp); 90 } 91 } 92 93 struct dirent * 94 readdir(dirp) 95 DIR *dirp; 96 { 97 struct dirent *dp; 98 99 #ifdef _REENTRANT 100 if (__isthreaded) { 101 mutex_lock((mutex_t *)dirp->dd_lock); 102 dp = _readdir_unlocked(dirp); 103 mutex_unlock((mutex_t *)dirp->dd_lock); 104 } 105 else 106 #endif 107 dp = _readdir_unlocked(dirp); 108 return (dp); 109 } 110 111 int 112 readdir_r(dirp, entry, result) 113 DIR *dirp; 114 struct dirent *entry; 115 struct dirent **result; 116 { 117 struct dirent *dp; 118 int saved_errno; 119 120 saved_errno = errno; 121 errno = 0; 122 #ifdef _REENTRANT 123 if (__isthreaded) { 124 mutex_lock((mutex_t *)dirp->dd_lock); 125 if ((dp = _readdir_unlocked(dirp)) != NULL) 126 memcpy(entry, dp, DIRENT_SIZE(dp)); 127 mutex_unlock((mutex_t *)dirp->dd_lock); 128 } 129 else 130 #endif 131 if ((dp = _readdir_unlocked(dirp)) != NULL) 132 memcpy(entry, dp, DIRENT_SIZE(dp)); 133 134 if (errno != 0) { 135 if (dp == NULL) 136 return (errno); 137 } else 138 errno = saved_errno; 139 140 if (dp != NULL) 141 *result = entry; 142 else 143 *result = NULL; 144 145 return (0); 146 } 147