1 /* 2 * Copyright (c) 1983, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * $FreeBSD: src/lib/libc/gen/opendir.c,v 1.10.2.1 2001/06/04 20:59:48 joerg Exp $ 34 * $DragonFly: src/lib/libc/gen/opendir.c,v 1.6 2005/11/13 00:07:42 swildner Exp $ 35 * 36 * @(#)opendir.c 8.8 (Berkeley) 5/1/95 37 */ 38 39 #include "namespace.h" 40 #include <sys/param.h> 41 #include <sys/stat.h> 42 43 #include <dirent.h> 44 #include <errno.h> 45 #include <fcntl.h> 46 #include <stdlib.h> 47 #include <string.h> 48 #include <unistd.h> 49 #include "un-namespace.h" 50 51 52 #define DEFAULT_FLAGS (DTF_HIDEW | DTF_NODUP) 53 54 /* 55 * Open a directory given its path. 56 */ 57 DIR * 58 opendir(const char *name) 59 { 60 return (__opendir2(name, DEFAULT_FLAGS)); 61 } 62 63 /* 64 * Open a directory given a descriptor representing it. 65 */ 66 DIR * 67 fdopendir(int fd) 68 { 69 return (__fdopendir2(fd, DEFAULT_FLAGS)); 70 } 71 72 DIR * 73 __opendir2(const char *name, int flags) 74 { 75 int fd; 76 struct stat statb; 77 DIR *dirp; 78 int saved_errno; 79 80 /* 81 * stat() before _open() because opening of special files may be 82 * harmful. 83 */ 84 if (stat(name, &statb) != 0) 85 return (NULL); 86 if (!S_ISDIR(statb.st_mode)) { 87 errno = ENOTDIR; 88 return (NULL); 89 } 90 91 if ((fd = _open(name, O_RDONLY | O_NONBLOCK)) == -1) 92 return (NULL); 93 dirp = __fdopendir2(fd, flags); 94 if (dirp == NULL) { 95 saved_errno = errno; 96 _close(fd); 97 errno = saved_errno; 98 } 99 100 return (dirp); 101 } 102 103 DIR * 104 __fdopendir2(int fd, int flags) 105 { 106 DIR *dirp; 107 int incr; 108 int saved_errno; 109 struct stat statb; 110 111 dirp = NULL; 112 113 if (_fstat(fd, &statb) != 0) 114 goto fail; 115 if (!S_ISDIR(statb.st_mode)) { 116 errno = ENOTDIR; 117 goto fail; 118 } 119 if (_fcntl(fd, F_SETFD, FD_CLOEXEC) == -1 || 120 (dirp = malloc(sizeof(DIR))) == NULL) 121 goto fail; 122 123 /* 124 * Use the system page size if that is a multiple of DIRBLKSIZ. 125 * Hopefully this can be a big win someday by allowing page 126 * trades to user space to be done by _getdirentries(). 127 */ 128 incr = getpagesize(); 129 if ((incr % DIRBLKSIZ) != 0) 130 incr = DIRBLKSIZ; 131 132 dirp->dd_len = incr; 133 dirp->dd_buf = malloc(dirp->dd_len); 134 if (dirp->dd_buf == NULL) 135 goto fail; 136 flags &= ~DTF_REWIND; 137 138 dirp->dd_loc = 0; 139 dirp->dd_fd = fd; 140 dirp->dd_flags = flags; 141 dirp->dd_lock = NULL; 142 143 /* 144 * Set up seek point for rewinddir. 145 */ 146 dirp->dd_seek = 0; 147 dirp->dd_rewind = telldir(dirp); 148 149 /* 150 * The file offset of the fd passed to fdopendir() determines the 151 * initial entry returned by readdir(). Save this offset so that 152 * telldir() right after fdopendir() returns a value pointing to this 153 * initial entry. 154 * We don't have to worry about misaligned file offsets. The kernel 155 * deals with these. 156 */ 157 if ((dirp->dd_seek = lseek(fd, 0, SEEK_CUR)) < 0) 158 goto fail; 159 160 return (dirp); 161 162 fail: 163 saved_errno = errno; 164 if (dirp != NULL) { 165 _reclaim_telldir(dirp); 166 free(dirp->dd_buf); 167 } 168 free(dirp); 169 errno = saved_errno; 170 return (NULL); 171 } 172