1 /* $NetBSD: readdir.c,v 1.20 2005/09/13 01:44:09 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 1.20 2005/09/13 01:44:09 christos 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 /* 51 * get next entry in a directory. 52 */ 53 static struct dirent * 54 _readdir_unlocked(DIR *dirp) 55 { 56 struct dirent *dp; 57 58 59 for (;;) { 60 if (dirp->dd_loc >= dirp->dd_size) { 61 if (dirp->dd_flags & __DTF_READALL) 62 return (NULL); 63 dirp->dd_loc = 0; 64 } 65 if (dirp->dd_loc == 0 && !(dirp->dd_flags & __DTF_READALL)) { 66 dirp->dd_seek = lseek(dirp->dd_fd, (off_t)0, SEEK_CUR); 67 dirp->dd_size = getdents(dirp->dd_fd, 68 dirp->dd_buf, (size_t)dirp->dd_len); 69 if (dirp->dd_size <= 0) 70 return (NULL); 71 } 72 dp = (struct dirent *) 73 (void *)(dirp->dd_buf + (size_t)dirp->dd_loc); 74 if ((intptr_t)dp & _DIRENT_ALIGN(dp))/* bogus pointer check */ 75 return (NULL); 76 /* d_reclen is unsigned; no need to compare it <= 0 */ 77 if (dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc) 78 return (NULL); 79 dirp->dd_loc += dp->d_reclen; 80 if (dp->d_ino == 0) 81 continue; 82 if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW)) 83 continue; 84 return (dp); 85 } 86 } 87 88 struct dirent * 89 readdir(dirp) 90 DIR *dirp; 91 { 92 struct dirent *dp; 93 94 #ifdef _REENTRANT 95 if (__isthreaded) { 96 mutex_lock((mutex_t *)dirp->dd_lock); 97 dp = _readdir_unlocked(dirp); 98 mutex_unlock((mutex_t *)dirp->dd_lock); 99 } 100 else 101 #endif 102 dp = _readdir_unlocked(dirp); 103 return (dp); 104 } 105 106 int 107 readdir_r(dirp, entry, result) 108 DIR *dirp; 109 struct dirent *entry; 110 struct dirent **result; 111 { 112 struct dirent *dp; 113 int saved_errno; 114 115 saved_errno = errno; 116 errno = 0; 117 #ifdef _REENTRANT 118 if (__isthreaded) { 119 mutex_lock((mutex_t *)dirp->dd_lock); 120 if ((dp = _readdir_unlocked(dirp)) != NULL) 121 memcpy(entry, dp, (size_t)_DIRENT_SIZE(dp)); 122 mutex_unlock((mutex_t *)dirp->dd_lock); 123 } 124 else 125 #endif 126 if ((dp = _readdir_unlocked(dirp)) != NULL) 127 memcpy(entry, dp, (size_t)_DIRENT_SIZE(dp)); 128 129 if (errno != 0) { 130 if (dp == NULL) 131 return (errno); 132 } else 133 errno = saved_errno; 134 135 if (dp != NULL) 136 *result = entry; 137 else 138 *result = NULL; 139 140 return (0); 141 } 142