1 /* $OpenBSD: readdir.c,v 1.14 2008/05/01 19:49:18 otto Exp $ */ 2 /* 3 * Copyright (c) 1983, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Neither the name of the University nor the names of its contributors 15 * may be used to endorse or promote products derived from this software 16 * without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31 #include <sys/param.h> 32 #include <dirent.h> 33 #include <string.h> 34 #include <errno.h> 35 #include "thread_private.h" 36 37 /* 38 * get next entry in a directory. 39 */ 40 int 41 _readdir_unlocked(DIR *dirp, struct dirent **result, int skipdeleted) 42 { 43 struct dirent *dp; 44 45 *result = NULL; 46 for (;;) { 47 if (dirp->dd_loc >= dirp->dd_size) 48 dirp->dd_loc = 0; 49 if (dirp->dd_loc == 0) { 50 dirp->dd_size = getdirentries(dirp->dd_fd, 51 dirp->dd_buf, dirp->dd_len, &dirp->dd_seek); 52 if (dirp->dd_size == 0) 53 return (0); 54 if (dirp->dd_size < 0) 55 return (-1); 56 } 57 dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc); 58 if ((long)dp & 03) /* bogus pointer check */ 59 return (-1); 60 if (dp->d_reclen <= 0 || 61 dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc) 62 return (-1); 63 dirp->dd_loc += dp->d_reclen; 64 /* 65 * When called from seekdir(), we let it decide on 66 * the end condition to avoid overshooting: the next 67 * readdir call should produce the next non-deleted entry, 68 * and we already advanced dd_loc. 69 */ 70 if (dp->d_ino == 0 && skipdeleted) 71 continue; 72 *result = dp; 73 return (0); 74 } 75 } 76 77 struct dirent * 78 readdir(DIR *dirp) 79 { 80 struct dirent *dp; 81 82 _MUTEX_LOCK(&dirp->dd_lock); 83 _readdir_unlocked(dirp, &dp, 1); 84 _MUTEX_UNLOCK(&dirp->dd_lock); 85 86 return (dp); 87 } 88 89 int 90 readdir_r(DIR *dirp, struct dirent *entry, struct dirent **result) 91 { 92 struct dirent *dp; 93 94 _MUTEX_LOCK(&dirp->dd_lock); 95 if (_readdir_unlocked(dirp, &dp, 1) != 0) { 96 _MUTEX_UNLOCK(&dirp->dd_lock); 97 return errno; 98 } 99 if (dp != NULL) 100 memcpy(entry, dp, 101 sizeof (struct dirent) - MAXNAMLEN + dp->d_namlen); 102 _MUTEX_UNLOCK(&dirp->dd_lock); 103 if (dp != NULL) 104 *result = entry; 105 else 106 *result = NULL; 107 return 0; 108 } 109