1 /* $OpenBSD: dir.c,v 1.23 2015/01/16 16:18:07 deraadt 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/types.h> 32 #include <sys/stat.h> 33 34 #include <dirent.h> 35 #include <fcntl.h> 36 #include <stdlib.h> 37 #include <unistd.h> 38 39 #include "syscall.h" 40 #include "archdep.h" 41 #include "util.h" 42 #include "dir.h" 43 44 struct _dl_dirdesc { 45 long dd_loc; /* offset in current buffer */ 46 long dd_size; /* amount of data returned by getdents() */ 47 char *dd_buf; /* data buffer */ 48 int dd_len; /* size of data buffer */ 49 int dd_fd; /* file descriptor associated with directory */ 50 }; 51 52 /* 53 * Open a directory. 54 */ 55 _dl_DIR * 56 _dl_opendir(const char *name) 57 { 58 _dl_DIR *dirp; 59 int fd; 60 struct stat sb; 61 62 if ((fd = _dl_open(name, O_RDONLY | O_DIRECTORY | O_CLOEXEC)) < 0) 63 return (NULL); 64 if (_dl_fstat(fd, &sb) || (dirp = _dl_malloc(sizeof(*dirp))) == NULL) { 65 _dl_close(fd); 66 return (NULL); 67 } 68 69 dirp->dd_fd = fd; 70 dirp->dd_loc = 0; 71 dirp->dd_size = 0; 72 dirp->dd_len = _dl_round_page(sb.st_blksize); 73 dirp->dd_buf = _dl_malloc(dirp->dd_len); 74 if (dirp->dd_buf == NULL) { 75 _dl_free(dirp); 76 _dl_close (fd); 77 return (NULL); 78 } 79 80 return (dirp); 81 } 82 83 84 /* 85 * close a directory. 86 */ 87 int 88 _dl_closedir(_dl_DIR *dirp) 89 { 90 int ret; 91 92 ret = _dl_close(dirp->dd_fd); 93 _dl_free(dirp->dd_buf); 94 _dl_free(dirp); 95 return ret; 96 } 97 98 99 /* 100 * get next entry in a directory. 101 */ 102 struct dirent * 103 _dl_readdir(_dl_DIR *dirp) 104 { 105 struct dirent *dp; 106 107 for (;;) { 108 if (dirp->dd_loc >= dirp->dd_size) { 109 dirp->dd_loc = 0; 110 } 111 if (dirp->dd_loc == 0) { 112 dirp->dd_size = _dl_getdents(dirp->dd_fd, 113 dirp->dd_buf, dirp->dd_len); 114 if (dirp->dd_size <= 0) 115 return (NULL); 116 } 117 dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc); 118 if ((long)dp & 03) /* bogus pointer check */ 119 return (NULL); 120 if (dp->d_reclen <= 0 || 121 dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc) 122 return (NULL); 123 dirp->dd_loc += dp->d_reclen; 124 if (dp->d_ino == 0) 125 continue; 126 return (dp); 127 } 128 } 129