1 /* $OpenBSD: dir.c,v 1.25 2022/01/08 06:49:41 guenther 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/stat.h> 32 33 #include <dirent.h> 34 #include <fcntl.h> 35 36 #include "syscall.h" 37 #include "util.h" 38 #include "dir.h" 39 40 struct _dl_dirdesc { 41 long dd_loc; /* offset in current buffer */ 42 long dd_size; /* amount of data returned by getdents() */ 43 char *dd_buf; /* data buffer */ 44 int dd_len; /* size of data buffer */ 45 int dd_fd; /* file descriptor associated with directory */ 46 }; 47 48 /* 49 * Open a directory. 50 */ 51 _dl_DIR * 52 _dl_opendir(const char *name) 53 { 54 _dl_DIR *dirp; 55 int fd; 56 struct stat sb; 57 58 if ((fd = _dl_open(name, O_RDONLY | O_DIRECTORY | O_CLOEXEC)) < 0) 59 return (NULL); 60 if (_dl_fstat(fd, &sb) || (dirp = _dl_malloc(sizeof(*dirp))) == NULL) { 61 _dl_close(fd); 62 return (NULL); 63 } 64 65 dirp->dd_fd = fd; 66 dirp->dd_loc = 0; 67 dirp->dd_size = 0; 68 dirp->dd_len = _dl_round_page(sb.st_blksize); 69 dirp->dd_buf = _dl_malloc(dirp->dd_len); 70 if (dirp->dd_buf == NULL) { 71 _dl_free(dirp); 72 _dl_close(fd); 73 return (NULL); 74 } 75 76 return (dirp); 77 } 78 79 80 /* 81 * close a directory. 82 */ 83 int 84 _dl_closedir(_dl_DIR *dirp) 85 { 86 int ret; 87 88 ret = _dl_close(dirp->dd_fd); 89 _dl_free(dirp->dd_buf); 90 _dl_free(dirp); 91 return ret; 92 } 93 94 95 /* 96 * get next entry in a directory. 97 */ 98 struct dirent * 99 _dl_readdir(_dl_DIR *dirp) 100 { 101 struct dirent *dp; 102 103 for (;;) { 104 if (dirp->dd_loc >= dirp->dd_size) { 105 dirp->dd_loc = 0; 106 } 107 if (dirp->dd_loc == 0) { 108 dirp->dd_size = _dl_getdents(dirp->dd_fd, 109 dirp->dd_buf, dirp->dd_len); 110 if (dirp->dd_size <= 0) 111 return (NULL); 112 } 113 dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc); 114 if ((long)dp & 03) /* bogus pointer check */ 115 return (NULL); 116 if (dp->d_reclen <= 0 || 117 dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc) 118 return (NULL); 119 dirp->dd_loc += dp->d_reclen; 120 if (dp->d_ino == 0) 121 continue; 122 return (dp); 123 } 124 } 125