1 /* $OpenBSD: readdir.c,v 1.17 2012/03/22 04:11:53 matthew 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 <dirent.h> 32 #include <errno.h> 33 #include "telldir.h" 34 #include "thread_private.h" 35 36 /* 37 * get next entry in a directory. 38 */ 39 int 40 _readdir_unlocked(DIR *dirp, struct dirent **result, int skipdeleted) 41 { 42 struct dirent *dp; 43 44 *result = NULL; 45 for (;;) { 46 if (dirp->dd_loc >= dirp->dd_size) 47 dirp->dd_loc = 0; 48 if (dirp->dd_loc == 0) { 49 dirp->dd_size = getdirentries(dirp->dd_fd, 50 dirp->dd_buf, dirp->dd_len, &dirp->dd_seek); 51 if (dirp->dd_size == 0) 52 return (0); 53 if (dirp->dd_size < 0) 54 return (-1); 55 } 56 dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc); 57 if ((long)dp & 03 || /* bogus pointer check */ 58 dp->d_reclen <= 0 || 59 dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc) { 60 errno = EINVAL; 61 return (-1); 62 } 63 dirp->dd_loc += dp->d_reclen; 64 65 /* 66 * When called from seekdir(), we let it decide on 67 * the end condition to avoid overshooting: the next 68 * readdir call should produce the next non-deleted entry, 69 * and we already advanced dd_loc. 70 */ 71 if (dp->d_ino == 0 && skipdeleted) 72 continue; 73 *result = dp; 74 return (0); 75 } 76 } 77 78 struct dirent * 79 readdir(DIR *dirp) 80 { 81 struct dirent *dp; 82 83 _MUTEX_LOCK(&dirp->dd_lock); 84 _readdir_unlocked(dirp, &dp, 1); 85 _MUTEX_UNLOCK(&dirp->dd_lock); 86 87 return (dp); 88 } 89