1 /* $NetBSD: adjtime.c,v 1.10 2007/11/23 12:39:15 uebayasi 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 1.10 2007/11/23 12:39:15 uebayasi 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 #ifdef __weak_alias 53 __weak_alias(adjtime,_adjtime) 54 #endif 55 56 extern int __clockctl_fd; 57 58 int __adjtime(const struct timeval *, struct timeval *); 59 60 int 61 adjtime(delta, olddelta) 62 const struct timeval *delta; 63 struct timeval *olddelta; 64 { 65 struct clockctl_adjtime args; 66 int rv; 67 68 /* 69 * we always attempt the syscall first and switch to 70 * clockctl if that fails with EPERM 71 */ 72 if (__clockctl_fd == -1) { 73 rv = __adjtime(delta, olddelta); 74 75 /* 76 * try via clockctl if the call fails with EPERM 77 */ 78 if (rv != -1 || errno != EPERM) 79 return rv; 80 81 /* 82 * If this fails, it means that we are not root 83 * and we cannot open clockctl. This is a failure. 84 */ 85 __clockctl_fd = open(_PATH_CLOCKCTL, O_WRONLY, 0); 86 if (__clockctl_fd == -1) { 87 /* original error was EPERM - don't leak open errors */ 88 errno = EPERM; 89 return -1; 90 } 91 92 (void) fcntl(__clockctl_fd, F_SETFD, FD_CLOEXEC); 93 } 94 95 /* 96 * If __clockctl_fd >=0, clockctl has already been open 97 * and used, so we carry on using it. 98 */ 99 args.delta = delta; 100 args.olddelta = olddelta; 101 return ioctl(__clockctl_fd, CLOCKCTL_ADJTIME, &args); 102 } 103