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. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * $FreeBSD: src/lib/libc/gen/opendir.c,v 1.10.2.1 2001/06/04 20:59:48 joerg Exp $ 30 * 31 * @(#)opendir.c 8.8 (Berkeley) 5/1/95 32 */ 33 34 #include "namespace.h" 35 #include <sys/param.h> 36 #include <sys/stat.h> 37 38 #include <dirent.h> 39 #include <errno.h> 40 #include <fcntl.h> 41 #include <stdlib.h> 42 #include <string.h> 43 #include <unistd.h> 44 #include "un-namespace.h" 45 46 #include "gen_private.h" 47 48 #define DEFAULT_FLAGS (DTF_HIDEW | DTF_NODUP) 49 50 /* 51 * Open a directory given its path. 52 */ 53 DIR * 54 opendir(const char *name) 55 { 56 return (__opendir2(name, DEFAULT_FLAGS)); 57 } 58 59 /* 60 * Open a directory given a descriptor representing it. 61 */ 62 DIR * 63 fdopendir(int fd) 64 { 65 return (__fdopendir2(fd, DEFAULT_FLAGS)); 66 } 67 68 DIR * 69 __opendir2(const char *name, int flags) 70 { 71 int fd; 72 struct stat statb; 73 DIR *dirp; 74 int saved_errno; 75 76 /* 77 * stat() before _open() because opening of special files may be 78 * harmful. 79 */ 80 if (stat(name, &statb) != 0) 81 return (NULL); 82 83 fd = _open(name, O_RDONLY | O_NONBLOCK | O_DIRECTORY | O_CLOEXEC); 84 if (fd == -1) 85 return (NULL); 86 dirp = __fdopendir2(fd, flags); 87 if (dirp == NULL) { 88 saved_errno = errno; 89 _close(fd); 90 errno = saved_errno; 91 } 92 93 return (dirp); 94 } 95 96 DIR * 97 __fdopendir2(int fd, int flags) 98 { 99 DIR *dirp; 100 int incr; 101 int saved_errno; 102 struct stat statb; 103 104 dirp = NULL; 105 106 if (_fstat(fd, &statb) != 0) 107 goto fail; 108 if (!S_ISDIR(statb.st_mode)) { 109 errno = ENOTDIR; 110 goto fail; 111 } 112 if (_fcntl(fd, F_SETFD, FD_CLOEXEC) == -1 || 113 (dirp = malloc(sizeof(DIR))) == NULL) 114 goto fail; 115 116 /* 117 * Use a multiple of DIRBLKSIZ. Make sure the buffer size is 118 * decent (at least 16K) to avoid unnecessary excess system calls. 119 */ 120 incr = DIRBLKSIZ * 16; 121 if (incr < 16384) 122 incr = 16384; 123 if ((incr % DIRBLKSIZ) != 0) 124 incr = DIRBLKSIZ; 125 126 dirp->dd_len = incr; 127 dirp->dd_buf = malloc(dirp->dd_len); 128 if (dirp->dd_buf == NULL) 129 goto fail; 130 flags &= ~DTF_REWIND; 131 132 dirp->dd_loc = 0; 133 dirp->dd_fd = fd; 134 dirp->dd_flags = flags; 135 dirp->dd_lock = NULL; 136 137 /* 138 * Set up seek point for rewinddir. 139 */ 140 dirp->dd_seek = 0; 141 dirp->dd_rewind = telldir(dirp); 142 143 /* 144 * The file offset of the fd passed to fdopendir() determines the 145 * initial entry returned by readdir(). Save this offset so that 146 * telldir() right after fdopendir() returns a value pointing to this 147 * initial entry. 148 * We don't have to worry about misaligned file offsets. The kernel 149 * deals with these. 150 */ 151 if ((dirp->dd_seek = lseek(fd, 0, SEEK_CUR)) < 0) 152 goto fail; 153 154 return (dirp); 155 156 fail: 157 saved_errno = errno; 158 if (dirp != NULL) { 159 _reclaim_telldir(dirp); 160 free(dirp->dd_buf); 161 } 162 free(dirp); 163 errno = saved_errno; 164 return (NULL); 165 } 166