1 /* $OpenBSD: dir.c,v 1.22 2014/07/10 09:03:01 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 <sys/mount.h> 33 #include <sys/stat.h> 34 35 #include <dirent.h> 36 #include <fcntl.h> 37 #include <stdlib.h> 38 #include <unistd.h> 39 40 #include "syscall.h" 41 #include "archdep.h" 42 #include "util.h" 43 #include "dir.h" 44 45 struct _dl_dirdesc { 46 long dd_loc; /* offset in current buffer */ 47 long dd_size; /* amount of data returned by getdents() */ 48 char *dd_buf; /* data buffer */ 49 int dd_len; /* size of data buffer */ 50 int dd_fd; /* file descriptor associated with directory */ 51 }; 52 53 /* 54 * Open a directory. 55 */ 56 _dl_DIR * 57 _dl_opendir(const char *name) 58 { 59 _dl_DIR *dirp; 60 int fd; 61 struct stat sb; 62 63 if ((fd = _dl_open(name, O_RDONLY | O_DIRECTORY | O_CLOEXEC)) < 0) 64 return (NULL); 65 if (_dl_fstat(fd, &sb) || (dirp = _dl_malloc(sizeof(*dirp))) == NULL) { 66 _dl_close(fd); 67 return (NULL); 68 } 69 70 dirp->dd_fd = fd; 71 dirp->dd_loc = 0; 72 dirp->dd_size = 0; 73 dirp->dd_len = _dl_round_page(sb.st_blksize); 74 dirp->dd_buf = _dl_malloc(dirp->dd_len); 75 if (dirp->dd_buf == NULL) { 76 _dl_free(dirp); 77 _dl_close (fd); 78 return (NULL); 79 } 80 81 return (dirp); 82 } 83 84 85 /* 86 * close a directory. 87 */ 88 int 89 _dl_closedir(_dl_DIR *dirp) 90 { 91 int ret; 92 93 ret = _dl_close(dirp->dd_fd); 94 _dl_free(dirp->dd_buf); 95 _dl_free(dirp); 96 return ret; 97 } 98 99 100 /* 101 * get next entry in a directory. 102 */ 103 struct dirent * 104 _dl_readdir(_dl_DIR *dirp) 105 { 106 struct dirent *dp; 107 108 for (;;) { 109 if (dirp->dd_loc >= dirp->dd_size) { 110 dirp->dd_loc = 0; 111 } 112 if (dirp->dd_loc == 0) { 113 dirp->dd_size = _dl_getdents(dirp->dd_fd, 114 dirp->dd_buf, dirp->dd_len); 115 if (dirp->dd_size <= 0) 116 return (NULL); 117 } 118 dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc); 119 if ((long)dp & 03) /* bogus pointer check */ 120 return (NULL); 121 if (dp->d_reclen <= 0 || 122 dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc) 123 return (NULL); 124 dirp->dd_loc += dp->d_reclen; 125 if (dp->d_ino == 0) 126 continue; 127 return (dp); 128 } 129 } 130