1 /* $NetBSD: ntp_adjtime.c,v 1.13 2012/03/20 16:26:12 matt 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: ntp_adjtime.c,v 1.13 2012/03/20 16:26:12 matt Exp $"); 37 #endif /* LIBC_SCCS and not lint */ 38 39 #include "namespace.h" 40 #include <sys/types.h> 41 #include <sys/time.h> 42 #include <sys/timex.h> 43 #include <sys/ioctl.h> 44 #include <sys/syscall.h> 45 46 #include <sys/clockctl.h> 47 48 #include <errno.h> 49 #include <fcntl.h> 50 #include <paths.h> 51 #include <string.h> 52 #include <unistd.h> 53 54 #ifdef __weak_alias 55 __weak_alias(ntp_adjtime,_ntp_adjtime) 56 #endif 57 58 #if defined(__minix) && !defined(O_CLOEXEC) 59 #define O_CLOEXEC 0 60 #endif 61 62 extern int __clockctl_fd; 63 64 int __ntp_adjtime(struct timex *); 65 66 int 67 ntp_adjtime(struct timex *tp) 68 { 69 struct clockctl_ntp_adjtime args; 70 int error; 71 int rv; 72 73 /* 74 * we always attempt to use the syscall unless we had to 75 * use the clockctl device before 76 * 77 * ntp_adjtime() is callable for mortals if tp->modes == 0 ! 78 */ 79 if (__clockctl_fd == -1) { 80 rv = __ntp_adjtime(tp); 81 82 /* 83 * if we fail with EPERM we try the clockctl device 84 */ 85 if (rv != -1 || errno != EPERM) 86 return rv; 87 88 /* 89 * If this fails, it means that we are not root 90 * and we cannot open clockctl. This is a true 91 * failure. 92 */ 93 __clockctl_fd = open(_PATH_CLOCKCTL, O_WRONLY | O_CLOEXEC, 0); 94 if (__clockctl_fd == -1) { 95 /* original error was EPERM - don't leak open errors */ 96 errno = EPERM; 97 return -1; 98 } 99 } 100 101 /* 102 * If __clockctl_fd >=0, clockctl has already been open 103 * and used, so we carry on using it. 104 */ 105 args.tp = tp; 106 error = ioctl(__clockctl_fd, CLOCKCTL_NTP_ADJTIME, &args); 107 108 /* 109 * There is no way to get retval set through ioctl(), hence we 110 * have to handle it here, using args.retval 111 */ 112 if (error == 0) { 113 rv = (int)args.retval; 114 return rv; 115 } 116 117 return error; 118 } 119