1 /*- 2 * Copyright (c) 2012 The FreeBSD Foundation 3 * All rights reserved. 4 * 5 * This software was developed by Pawel Jakub Dawidek under sponsorship from 6 * the FreeBSD Foundation. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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 30 #ifndef _OPENAT_H_ 31 #define _OPENAT_H_ 32 33 #include <fcntl.h> 34 #include <stdarg.h> 35 #include <unistd.h> 36 37 static int 38 openat(int fd, const char *path, int flags, ...) 39 { 40 int cfd, ffd, error; 41 42 cfd = open(".", O_RDONLY | O_DIRECTORY); 43 if (cfd == -1) 44 return (-1); 45 46 if (fchdir(fd) == -1) { 47 error = errno; 48 (void)close(cfd); 49 errno = error; 50 return (-1); 51 } 52 53 if ((flags & O_CREAT) != 0) { 54 va_list ap; 55 int mode; 56 57 va_start(ap, flags); 58 mode = va_arg(ap, int); 59 va_end(ap); 60 61 ffd = open(path, flags, mode); 62 } else { 63 ffd = open(path, flags); 64 } 65 66 error = errno; 67 (void)fchdir(cfd); 68 (void)close(cfd); 69 errno = error; 70 return (ffd); 71 } 72 73 #endif /* !_OPENAT_H_ */ 74