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 * 35 * @(#)opendir.c 8.8 (Berkeley) 5/1/95 36 */ 37 38 #include "namespace.h" 39 #include <sys/param.h> 40 #include <sys/stat.h> 41 42 #include <dirent.h> 43 #include <errno.h> 44 #include <fcntl.h> 45 #include <stdlib.h> 46 #include <string.h> 47 #include <unistd.h> 48 #include "un-namespace.h" 49 50 51 #define DEFAULT_FLAGS (DTF_HIDEW | DTF_NODUP) 52 53 /* 54 * Open a directory given its path. 55 */ 56 DIR * 57 opendir(const char *name) 58 { 59 return (__opendir2(name, DEFAULT_FLAGS)); 60 } 61 62 /* 63 * Open a directory given a descriptor representing it. 64 */ 65 DIR * 66 fdopendir(int fd) 67 { 68 return (__fdopendir2(fd, DEFAULT_FLAGS)); 69 } 70 71 DIR * 72 __opendir2(const char *name, int flags) 73 { 74 int fd; 75 struct stat statb; 76 DIR *dirp; 77 int saved_errno; 78 79 /* 80 * stat() before _open() because opening of special files may be 81 * harmful. 82 */ 83 if (stat(name, &statb) != 0) 84 return (NULL); 85 86 fd = _open(name, O_RDONLY | O_NONBLOCK | O_DIRECTORY | O_CLOEXEC); 87 if (fd == -1) 88 return (NULL); 89 dirp = __fdopendir2(fd, flags); 90 if (dirp == NULL) { 91 saved_errno = errno; 92 _close(fd); 93 errno = saved_errno; 94 } 95 96 return (dirp); 97 } 98 99 DIR * 100 __fdopendir2(int fd, int flags) 101 { 102 DIR *dirp; 103 int incr; 104 int saved_errno; 105 struct stat statb; 106 107 dirp = NULL; 108 109 if (_fstat(fd, &statb) != 0) 110 goto fail; 111 if (!S_ISDIR(statb.st_mode)) { 112 errno = ENOTDIR; 113 goto fail; 114 } 115 if (_fcntl(fd, F_SETFD, FD_CLOEXEC) == -1 || 116 (dirp = malloc(sizeof(DIR))) == NULL) 117 goto fail; 118 119 /* 120 * Use the system page size if that is a multiple of DIRBLKSIZ. 121 * Hopefully this can be a big win someday by allowing page 122 * trades to user space to be done by _getdirentries(). 123 */ 124 incr = getpagesize(); 125 if ((incr % DIRBLKSIZ) != 0) 126 incr = DIRBLKSIZ; 127 128 dirp->dd_len = incr; 129 dirp->dd_buf = malloc(dirp->dd_len); 130 if (dirp->dd_buf == NULL) 131 goto fail; 132 flags &= ~DTF_REWIND; 133 134 dirp->dd_loc = 0; 135 dirp->dd_fd = fd; 136 dirp->dd_flags = flags; 137 dirp->dd_lock = NULL; 138 139 /* 140 * Set up seek point for rewinddir. 141 */ 142 dirp->dd_seek = 0; 143 dirp->dd_rewind = telldir(dirp); 144 145 /* 146 * The file offset of the fd passed to fdopendir() determines the 147 * initial entry returned by readdir(). Save this offset so that 148 * telldir() right after fdopendir() returns a value pointing to this 149 * initial entry. 150 * We don't have to worry about misaligned file offsets. The kernel 151 * deals with these. 152 */ 153 if ((dirp->dd_seek = lseek(fd, 0, SEEK_CUR)) < 0) 154 goto fail; 155 156 return (dirp); 157 158 fail: 159 saved_errno = errno; 160 if (dirp != NULL) { 161 _reclaim_telldir(dirp); 162 free(dirp->dd_buf); 163 } 164 free(dirp); 165 errno = saved_errno; 166 return (NULL); 167 } 168