1 /* $OpenBSD: opendir.c,v 1.27 2014/03/10 07:54:14 schwarze 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/types.h> 32 #include <sys/stat.h> 33 34 #include <dirent.h> 35 #include <errno.h> 36 #include <fcntl.h> 37 #include <stdlib.h> 38 #include <unistd.h> 39 40 #include "telldir.h" 41 42 static DIR *__fdopendir(int fd); 43 44 /* 45 * Open a directory specified by name. 46 */ 47 DIR * 48 opendir(const char *name) 49 { 50 DIR *dirp; 51 int fd; 52 53 if ((fd = open(name, O_RDONLY | O_DIRECTORY | O_CLOEXEC)) == -1) 54 return (NULL); 55 dirp = __fdopendir(fd); 56 if (dirp == NULL) 57 close(fd); 58 return (dirp); 59 } 60 61 /* 62 * Open a directory specified by file descriptor. 63 */ 64 DIR * 65 fdopendir(int fd) 66 { 67 DIR *dirp; 68 int flags; 69 70 if ((flags = fcntl(fd, F_GETFL)) == -1) 71 return (NULL); 72 if ((flags & O_ACCMODE) != O_RDONLY && (flags & O_ACCMODE) != O_RDWR) { 73 errno = EBADF; 74 return (NULL); 75 } 76 dirp = __fdopendir(fd); 77 if (dirp != NULL) { 78 /* Record current offset for immediate telldir() */ 79 dirp->dd_bufpos = dirp->dd_curpos = lseek(fd, 0, SEEK_CUR); 80 81 /* 82 * POSIX doesn't require fdopendir() to set 83 * FD_CLOEXEC, so it's okay for this to fail. 84 */ 85 (void)fcntl(fd, F_SETFD, FD_CLOEXEC); 86 } 87 return (dirp); 88 } 89 90 static DIR * 91 __fdopendir(int fd) 92 { 93 DIR *dirp; 94 struct stat sb; 95 int pageoffset; 96 97 if (fstat(fd, &sb)) 98 return (NULL); 99 if (!S_ISDIR(sb.st_mode)) { 100 errno = ENOTDIR; 101 return (NULL); 102 } 103 if ((dirp = malloc(sizeof(DIR))) == NULL) 104 return (NULL); 105 106 pageoffset = getpagesize() - 1; 107 dirp->dd_len = ((int)sb.st_blksize + pageoffset) & ~pageoffset; 108 dirp->dd_buf = malloc((size_t)dirp->dd_len); 109 if (dirp->dd_buf == NULL) { 110 free(dirp); 111 return (NULL); 112 } 113 114 dirp->dd_size = 0; 115 dirp->dd_loc = 0; 116 dirp->dd_fd = fd; 117 dirp->dd_lock = NULL; 118 dirp->dd_curpos = 0; 119 dirp->dd_bufpos = 0; 120 121 return (dirp); 122 } 123