2 * Copyright (C) 1993-1998 by Andrey A. Chernov, Moscow, Russia.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * @(#)Copyright (C) 1993-1996 by Andrey A. Chernov, Moscow, Russia. All rights reserved.
27 * $FreeBSD: src/sbin/adjkerntz/adjkerntz.c,v 1.25.2.1 2001/07/30 10:38:04 dd Exp $
28 * $DragonFly: src/sbin/adjkerntz/adjkerntz.c,v 1.6 2005/11/06 12:03:15 swildner Exp $
32 * Andrey A. Chernov <ache@astral.msk.su> Dec 20 1993
34 * Fix kernel time value if machine run wall CMOS clock
35 * (and /etc/wall_cmos_clock file present)
36 * using zoneinfo rules or direct TZ environment variable set.
37 * Use Joerg Wunsch idea for seconds accurate offset calculation
38 * with Garrett Wollman and Bruce Evans fixes.
47 #include <sys/param.h>
48 #include <machine/cpu.h>
49 #include <sys/sysctl.h>
51 #include "pathnames.h"
59 #define REPORT_PERIOD (30*60)
61 static void fake(int);
62 static void usage(void);
65 fake(int unused __unused)
72 main(int argc, char **argv)
75 struct timeval tv, *stv;
76 struct timezone tz, *stz;
77 int kern_offset, wall_clock, disrtcset;
80 /* Avoid time_t here, can be unsigned long or worse */
81 long offset, localsec, diff;
82 time_t initial_sec, final_sec;
84 int initial_isdst = -1, final_isdst;
85 int need_restore = False, sleep_mode = False, looping,
89 while ((ch = getopt(argc, argv, "ais")) != -1)
91 case 'i': /* initial call, save offset */
96 case 'a': /* adjustment call, use saved offset */
110 if (access(_PATH_CLOCK, F_OK) != 0)
118 sigaddset(&mask, SIGTERM);
120 openlog("adjkerntz", LOG_PID|LOG_PERROR, LOG_DAEMON);
122 signal(SIGHUP, SIG_IGN);
124 if (init && daemon(0, 1)) {
125 syslog(LOG_ERR, "daemon: %m");
130 sigprocmask(SIG_BLOCK, &mask, NULL);
131 signal(SIGTERM, fake);
138 wall_clock = (access(_PATH_CLOCK, F_OK) == 0);
139 if (init && !sleep_mode) {
145 mib[0] = CTL_MACHDEP;
146 mib[1] = CPU_ADJKERNTZ;
147 len = sizeof(kern_offset);
148 if (sysctl(mib, 2, &kern_offset, &len, NULL, 0) == -1) {
149 syslog(LOG_ERR, "sysctl(get_offset): %m");
153 /****** Critical section, do all things as fast as possible ******/
155 /* get local CMOS clock and possible kernel offset */
156 if (gettimeofday(&tv, &tz)) {
157 syslog(LOG_ERR, "gettimeofday: %m");
161 /* get the actual local timezone difference */
162 initial_sec = tv.tv_sec;
165 local = *localtime(&initial_sec);
167 initial_isdst = local.tm_isdst;
168 local.tm_isdst = initial_isdst;
170 /* calculate local CMOS diff from GMT */
172 localsec = mktime(&local);
173 if (localsec == -1) {
175 * XXX user can only control local time, and it is
176 * unacceptable to fail here for init. 2:30 am in the
177 * middle of the nonexistent hour means 3:30 am.
181 "Warning: nonexistent local time, try to run later.");
182 syslog(LOG_WARNING, "Giving up.");
186 "Warning: nonexistent local time.");
187 syslog(LOG_WARNING, "Will retry after %d minutes.",
189 signal(SIGTERM, SIG_DFL);
190 sigprocmask(SIG_UNBLOCK, &mask, NULL);
191 sleep(REPORT_PERIOD);
194 offset = -local.tm_gmtoff;
196 fprintf(stderr, "Initial offset: %ld secs\n", offset);
199 /* correct the kerneltime for this diffs */
200 /* subtract kernel offset, if present, old offset too */
202 diff = offset - tz.tz_minuteswest * 60 - kern_offset;
206 fprintf(stderr, "Initial diff: %ld secs\n", diff);
208 /* Yet one step for final time */
210 final_sec = initial_sec + diff;
212 /* get the actual local timezone difference */
213 local = *localtime(&final_sec);
214 final_isdst = diff < 0 ? initial_isdst : local.tm_isdst;
215 if (diff > 0 && initial_isdst != final_isdst) {
219 initial_isdst = final_isdst;
222 local.tm_isdst = final_isdst;
224 localsec = mktime(&local);
225 if (localsec == -1) {
228 * XXX as above. The user has even less control,
229 * but perhaps we never get here.
233 "Warning: nonexistent final local time, try to run later.");
234 syslog(LOG_WARNING, "Giving up.");
238 "Warning: nonexistent final local time.");
239 syslog(LOG_WARNING, "Will retry after %d minutes.",
241 signal(SIGTERM, SIG_DFL);
242 sigprocmask(SIG_UNBLOCK, &mask, NULL);
243 sleep(REPORT_PERIOD);
246 offset = -local.tm_gmtoff;
248 fprintf(stderr, "Final offset: %ld secs\n", offset);
251 /* correct the kerneltime for this diffs */
252 /* subtract kernel offset, if present, old offset too */
254 diff = offset - tz.tz_minuteswest * 60 - kern_offset;
258 fprintf(stderr, "Final diff: %ld secs\n", diff);
261 * stv is abused as a flag. The important value
268 if (tz.tz_dsttime != 0 || tz.tz_minuteswest != 0) {
269 tz.tz_dsttime = tz.tz_minuteswest = 0; /* zone info is garbage */
272 if (!wall_clock && stz == NULL)
275 /* if init or UTC clock and offset/date will be changed, */
276 /* disable RTC modification for a while. */
278 if ( (init && stv != NULL)
279 || ((init || !wall_clock) && kern_offset != offset)
281 mib[0] = CTL_MACHDEP;
282 mib[1] = CPU_DISRTCSET;
283 len = sizeof(disrtcset);
284 if (sysctl(mib, 2, &disrtcset, &len, NULL, 0) == -1) {
285 syslog(LOG_ERR, "sysctl(get_disrtcset): %m");
288 if (disrtcset == 0) {
291 if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) {
292 syslog(LOG_ERR, "sysctl(set_disrtcset): %m");
298 if ( (init && (stv != NULL || stz != NULL))
299 || (stz != NULL && stv == NULL)
303 * Get the time again, as close as possible to
304 * adjusting it, to minimise drift.
305 * XXX we'd better not fail between here and
306 * restoring disrtcset, since we don't clean up
309 if (gettimeofday(&tv, (struct timezone *)NULL)) {
310 syslog(LOG_ERR, "gettimeofday: %m");
316 if (settimeofday(stv, stz)) {
317 syslog(LOG_ERR, "settimeofday: %m");
322 /* setting CPU_ADJKERNTZ have a side effect: resettodr(), which */
323 /* can be disabled by CPU_DISRTCSET, so if init or UTC clock */
324 /* -- don't write RTC, else write RTC. */
326 if (kern_offset != offset) {
327 kern_offset = offset;
328 mib[0] = CTL_MACHDEP;
329 mib[1] = CPU_ADJKERNTZ;
330 len = sizeof(kern_offset);
331 if (sysctl(mib, 2, NULL, NULL, &kern_offset, len) == -1) {
332 syslog(LOG_ERR, "sysctl(update_offset): %m");
337 mib[0] = CTL_MACHDEP;
338 mib[1] = CPU_WALLCLOCK;
339 len = sizeof(wall_clock);
340 if (sysctl(mib, 2, NULL, NULL, &wall_clock, len) == -1) {
341 syslog(LOG_ERR, "sysctl(put_wallclock): %m");
346 need_restore = False;
347 mib[0] = CTL_MACHDEP;
348 mib[1] = CPU_DISRTCSET;
350 len = sizeof(disrtcset);
351 if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) {
352 syslog(LOG_ERR, "sysctl(restore_disrtcset): %m");
357 /****** End of critical section ******/
359 if (init && wall_clock) {
361 /* wait for signals and acts like -a */
372 fprintf(stderr, "%s\n%s\n%s\n%s\n",
373 "usage: adjkerntz -i",
374 "\t\t(initial call from /etc/rc)",
375 " adjkerntz -a [-s]",
376 "\t\t(adjustment call, -s for sleep/retry mode)");