1 /* $NetBSD: adjtime.c,v 1.12 2011/10/15 23:00:02 christos Exp $ */ 2 3 /* 4 * Copyright (c) 2001 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Emmanuel Dreyfus. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 27 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * 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 34 #include <sys/cdefs.h> 35 #if defined(LIBC_SCCS) && !defined(lint) 36 __RCSID("$NetBSD: adjtime.c,v 1.12 2011/10/15 23:00:02 christos Exp $"); 37 #endif /* LIBC_SCCS and not lint */ 38 39 #include "namespace.h" 40 #include <errno.h> 41 #include <fcntl.h> 42 #include <paths.h> 43 #include <unistd.h> 44 #include <time.h> 45 #include <string.h> 46 #include <sys/types.h> 47 #include <sys/ioctl.h> 48 #include <sys/syscall.h> 49 50 #include <sys/clockctl.h> 51 52 #if defined(__minix) && !defined(O_CLOEXEC) 53 #define O_CLOEXEC 0 54 #endif 55 56 extern int __clockctl_fd; 57 58 int ____adjtime50(const struct timeval *, struct timeval *); 59 60 int 61 adjtime(const struct timeval *delta, struct timeval *olddelta) 62 { 63 struct clockctl_adjtime args; 64 int rv; 65 66 /* 67 * we always attempt the syscall first and switch to 68 * clockctl if that fails with EPERM 69 */ 70 if (__clockctl_fd == -1) { 71 rv = ____adjtime50(delta, olddelta); 72 73 /* 74 * try via clockctl if the call fails with EPERM 75 */ 76 if (rv != -1 || errno != EPERM) 77 return rv; 78 79 /* 80 * If this fails, it means that we are not root 81 * and we cannot open clockctl. This is a failure. 82 */ 83 __clockctl_fd = open(_PATH_CLOCKCTL, O_WRONLY | O_CLOEXEC, 0); 84 if (__clockctl_fd == -1) { 85 /* original error was EPERM - don't leak open errors */ 86 errno = EPERM; 87 return -1; 88 } 89 } 90 91 /* 92 * If __clockctl_fd >=0, clockctl has already been open 93 * and used, so we carry on using it. 94 */ 95 args.delta = delta; 96 args.olddelta = olddelta; 97 return ioctl(__clockctl_fd, CLOCKCTL_ADJTIME, &args); 98 } 99