1 /* $NetBSD: readdir.c,v 1.22 2006/01/24 19:33:10 christos 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 1.22 2006/01/24 19:33:10 christos Exp $"); 38 #endif 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include "namespace.h" 42 #include "reentrant.h" 43 #include "extern.h" 44 #include <sys/param.h> 45 46 #include <dirent.h> 47 #include <errno.h> 48 #include <string.h> 49 #include <unistd.h> 50 51 /* 52 * get next entry in a directory. 53 */ 54 struct dirent * 55 _readdir_unlocked(DIR *dirp) 56 { 57 struct dirent *dp; 58 59 60 for (;;) { 61 if (dirp->dd_loc >= dirp->dd_size) { 62 if (dirp->dd_flags & __DTF_READALL) 63 return (NULL); 64 dirp->dd_loc = 0; 65 } 66 if (dirp->dd_loc == 0 && !(dirp->dd_flags & __DTF_READALL)) { 67 dirp->dd_seek = lseek(dirp->dd_fd, (off_t)0, SEEK_CUR); 68 dirp->dd_size = getdents(dirp->dd_fd, 69 dirp->dd_buf, (size_t)dirp->dd_len); 70 if (dirp->dd_size <= 0) 71 return (NULL); 72 } 73 dp = (struct dirent *) 74 (void *)(dirp->dd_buf + (size_t)dirp->dd_loc); 75 if ((intptr_t)dp & _DIRENT_ALIGN(dp))/* bogus pointer check */ 76 return (NULL); 77 /* d_reclen is unsigned; no need to compare it <= 0 */ 78 if (dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc) 79 return (NULL); 80 dirp->dd_loc += dp->d_reclen; 81 if (dp->d_ino == 0) 82 continue; 83 if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW)) 84 continue; 85 return (dp); 86 } 87 } 88 89 struct dirent * 90 readdir(dirp) 91 DIR *dirp; 92 { 93 struct dirent *dp; 94 95 #ifdef _REENTRANT 96 if (__isthreaded) { 97 mutex_lock((mutex_t *)dirp->dd_lock); 98 dp = _readdir_unlocked(dirp); 99 mutex_unlock((mutex_t *)dirp->dd_lock); 100 } 101 else 102 #endif 103 dp = _readdir_unlocked(dirp); 104 return (dp); 105 } 106 107 int 108 readdir_r(dirp, entry, result) 109 DIR *dirp; 110 struct dirent *entry; 111 struct dirent **result; 112 { 113 struct dirent *dp; 114 int saved_errno; 115 116 saved_errno = errno; 117 errno = 0; 118 #ifdef _REENTRANT 119 if (__isthreaded) { 120 mutex_lock((mutex_t *)dirp->dd_lock); 121 if ((dp = _readdir_unlocked(dirp)) != NULL) 122 memcpy(entry, dp, (size_t)_DIRENT_SIZE(dp)); 123 mutex_unlock((mutex_t *)dirp->dd_lock); 124 } 125 else 126 #endif 127 if ((dp = _readdir_unlocked(dirp)) != NULL) 128 memcpy(entry, dp, (size_t)_DIRENT_SIZE(dp)); 129 130 if (errno != 0) { 131 if (dp == NULL) 132 return (errno); 133 } else 134 errno = saved_errno; 135 136 if (dp != NULL) 137 *result = entry; 138 else 139 *result = NULL; 140 141 return (0); 142 } 143