2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (C) 1993-1998 by Andrey A. Chernov, Moscow, Russia.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 static const char copyright[] =
32 "@(#)Copyright (C) 1993-1996 by Andrey A. Chernov, Moscow, Russia.\n\
33 All rights reserved.\n";
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
40 * Andrey A. Chernov <ache@astral.msk.su> Dec 20 1993
42 * Fix kernel time value if machine run wall CMOS clock
43 * (and /etc/wall_cmos_clock file present)
44 * using zoneinfo rules or direct TZ environment variable set.
45 * Use Joerg Wunsch idea for seconds accurate offset calculation
46 * with Garrett Wollman and Bruce Evans fixes.
55 #include <sys/param.h>
56 #include <machine/cpu.h>
57 #include <sys/sysctl.h>
59 #include "pathnames.h"
67 #define REPORT_PERIOD (30*60)
69 static void fake(int);
70 static void usage(void);
73 fake(int unused __unused)
80 main(int argc, char *argv[])
83 struct timeval tv, *stv;
84 struct timezone tz, *stz;
85 int kern_offset, wall_clock, disrtcset;
87 /* Avoid time_t here, can be unsigned long or worse */
88 long offset, localsec, diff;
89 time_t initial_sec, final_sec;
91 int initial_isdst = -1, final_isdst;
92 int need_restore = False, sleep_mode = False, looping,
96 while ((ch = getopt(argc, argv, "ais")) != -1)
98 case 'i': /* initial call, save offset */
103 case 'a': /* adjustment call, use saved offset */
117 if (access(_PATH_CLOCK, F_OK) != 0)
125 sigaddset(&mask, SIGTERM);
127 openlog("adjkerntz", LOG_PID|LOG_PERROR, LOG_DAEMON);
129 (void) signal(SIGHUP, SIG_IGN);
131 if (init && daemon(0,
138 syslog(LOG_ERR, "daemon: %m");
143 (void) sigprocmask(SIG_BLOCK, &mask, NULL);
144 (void) signal(SIGTERM, fake);
151 wall_clock = (access(_PATH_CLOCK, F_OK) == 0);
152 if (init && !sleep_mode) {
160 len = sizeof(kern_offset);
161 if (sysctlbyname("machdep.adjkerntz", &kern_offset, &len, NULL, 0) == -1) {
162 syslog(LOG_ERR, "sysctl(\"machdep.adjkerntz\"): %m");
166 /****** Critical section, do all things as fast as possible ******/
168 /* get local CMOS clock and possible kernel offset */
169 if (gettimeofday(&tv, &tz)) {
170 syslog(LOG_ERR, "gettimeofday: %m");
174 /* get the actual local timezone difference */
175 initial_sec = tv.tv_sec;
178 local = *localtime(&initial_sec);
180 initial_isdst = local.tm_isdst;
181 local.tm_isdst = initial_isdst;
183 /* calculate local CMOS diff from GMT */
185 localsec = mktime(&local);
186 if (localsec == -1) {
188 * XXX user can only control local time, and it is
189 * unacceptable to fail here for init. 2:30 am in the
190 * middle of the nonexistent hour means 3:30 am.
194 "Warning: nonexistent local time, try to run later.");
195 syslog(LOG_WARNING, "Giving up.");
199 "Warning: nonexistent local time.");
200 syslog(LOG_WARNING, "Will retry after %d minutes.",
202 (void) signal(SIGTERM, SIG_DFL);
203 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL);
204 (void) sleep(REPORT_PERIOD);
207 offset = -local.tm_gmtoff;
209 fprintf(stderr, "Initial offset: %ld secs\n", offset);
212 /* correct the kerneltime for this diffs */
213 /* subtract kernel offset, if present, old offset too */
215 diff = offset - tz.tz_minuteswest * 60 - kern_offset;
219 fprintf(stderr, "Initial diff: %ld secs\n", diff);
221 /* Yet one step for final time */
223 final_sec = initial_sec + diff;
225 /* get the actual local timezone difference */
226 local = *localtime(&final_sec);
227 final_isdst = diff < 0 ? initial_isdst : local.tm_isdst;
228 if (diff > 0 && initial_isdst != final_isdst) {
232 initial_isdst = final_isdst;
235 local.tm_isdst = final_isdst;
237 localsec = mktime(&local);
238 if (localsec == -1) {
241 * XXX as above. The user has even less control,
242 * but perhaps we never get here.
246 "Warning: nonexistent final local time, try to run later.");
247 syslog(LOG_WARNING, "Giving up.");
251 "Warning: nonexistent final local time.");
252 syslog(LOG_WARNING, "Will retry after %d minutes.",
254 (void) signal(SIGTERM, SIG_DFL);
255 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL);
256 (void) sleep(REPORT_PERIOD);
259 offset = -local.tm_gmtoff;
261 fprintf(stderr, "Final offset: %ld secs\n", offset);
264 /* correct the kerneltime for this diffs */
265 /* subtract kernel offset, if present, old offset too */
267 diff = offset - tz.tz_minuteswest * 60 - kern_offset;
271 fprintf(stderr, "Final diff: %ld secs\n", diff);
274 * stv is abused as a flag. The important value
281 if (tz.tz_dsttime != 0 || tz.tz_minuteswest != 0) {
282 tz.tz_dsttime = tz.tz_minuteswest = 0; /* zone info is garbage */
285 if (!wall_clock && stz == NULL)
288 /* if init or UTC clock and offset/date will be changed, */
289 /* disable RTC modification for a while. */
291 if ( (init && stv != NULL)
292 || ((init || !wall_clock) && kern_offset != offset)
294 len = sizeof(disrtcset);
295 if (sysctlbyname("machdep.disable_rtc_set", &disrtcset, &len, NULL, 0) == -1) {
296 syslog(LOG_ERR, "sysctl(get: \"machdep.disable_rtc_set\"): %m");
299 if (disrtcset == 0) {
302 if (sysctlbyname("machdep.disable_rtc_set", NULL, NULL, &disrtcset, len) == -1) {
303 syslog(LOG_ERR, "sysctl(set: \"machdep.disable_rtc_set\"): %m");
309 if ( (init && (stv != NULL || stz != NULL))
310 || (stz != NULL && stv == NULL)
314 * Get the time again, as close as possible to
315 * adjusting it, to minimise drift.
316 * XXX we'd better not fail between here and
317 * restoring disrtcset, since we don't clean up
320 (void)gettimeofday(&tv, NULL);
324 if (settimeofday(stv, stz)) {
325 syslog(LOG_ERR, "settimeofday: %m");
330 /* setting machdep.adjkerntz have a side effect: resettodr(), which */
331 /* can be disabled by machdep.disable_rtc_set, so if init or UTC clock */
332 /* -- don't write RTC, else write RTC. */
334 if (kern_offset != offset) {
335 kern_offset = offset;
336 len = sizeof(kern_offset);
337 if (sysctlbyname("machdep.adjkerntz", NULL, NULL, &kern_offset, len) == -1) {
338 syslog(LOG_ERR, "sysctl(set: \"machdep.adjkerntz\"): %m");
343 len = sizeof(wall_clock);
344 if (sysctlbyname("machdep.wall_cmos_clock", NULL, NULL, &wall_clock, len) == -1) {
345 syslog(LOG_ERR, "sysctl(set: \"machdep.wall_cmos_clock\"): %m");
350 need_restore = False;
352 len = sizeof(disrtcset);
353 if (sysctlbyname("machdep.disable_rtc_set", NULL, NULL, &disrtcset, len) == -1) {
354 syslog(LOG_ERR, "sysctl(set: \"machdep.disable_rtc_set\"): %m");
359 /****** End of critical section ******/
361 if (init && wall_clock) {
363 /* wait for signals and acts like -a */
364 (void) sigsuspend(&emask);
374 fprintf(stderr, "%s\n%s\n%s\n%s\n",
375 "usage: adjkerntz -i",
376 "\t\t(initial call from /etc/rc)",
377 " adjkerntz -a [-s]",
378 "\t\t(adjustment call, -s for sleep/retry mode)");