1 /* $OpenBSD: opendir.c,v 1.19 2007/06/05 18:11:48 kurt 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/param.h> 32 #include <sys/mount.h> 33 #include <sys/stat.h> 34 35 #include <dirent.h> 36 #include <errno.h> 37 #include <fcntl.h> 38 #include <limits.h> 39 #include <stdlib.h> 40 #include <string.h> 41 #include <unistd.h> 42 43 #include "telldir.h" 44 45 /* 46 * Open a directory. 47 */ 48 DIR * 49 opendir(const char *name) 50 { 51 52 return (__opendir2(name, DTF_NODUP)); 53 } 54 55 DIR * 56 __opendir2(const char *name, int flags) 57 { 58 DIR *dirp; 59 int fd; 60 struct stat sb; 61 int pageoffset; 62 63 if ((fd = open(name, O_RDONLY | O_NONBLOCK)) == -1) 64 return (NULL); 65 if (fstat(fd, &sb) || !S_ISDIR(sb.st_mode)) { 66 close(fd); 67 errno = ENOTDIR; 68 return (NULL); 69 } 70 if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1 || 71 (dirp = malloc(sizeof(DIR) + sizeof(struct _telldir))) == NULL) { 72 close(fd); 73 return (NULL); 74 } 75 76 dirp->dd_td = (struct _telldir *)((char *)dirp + sizeof(DIR)); 77 dirp->dd_td->td_locs = NULL; 78 dirp->dd_td->td_sz = 0; 79 dirp->dd_td->td_loccnt = 0; 80 dirp->dd_td->td_last = 0; 81 82 /* 83 * Use a buffer that is page aligned. 84 * Hopefully this can be a big win someday by allowing page trades 85 * to user space to be done by getdirentries() 86 */ 87 pageoffset = getpagesize() - 1; 88 dirp->dd_len = ((int)sb.st_blksize + pageoffset) & ~pageoffset; 89 dirp->dd_buf = malloc((size_t)dirp->dd_len); 90 if (dirp->dd_buf == NULL) { 91 free(dirp); 92 close (fd); 93 return (NULL); 94 } 95 96 dirp->dd_seek = 0; 97 dirp->dd_loc = 0; 98 dirp->dd_fd = fd; 99 dirp->dd_flags = flags; 100 dirp->dd_lock = NULL; 101 102 /* 103 * Set up seek point for rewinddir. 104 */ 105 dirp->dd_rewind = telldir(dirp); 106 107 return (dirp); 108 } 109