1/*
2 * Copyright (C) 1993-1998 by Andrey A. Chernov, Moscow, Russia.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
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.
13 *
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
24 * SUCH DAMAGE.
25 */
26
27#if 0
28#ifndef lint
29static const char copyright[] =
30"@(#)Copyright (C) 1993-1996 by Andrey A. Chernov, Moscow, Russia.\n\
31 All rights reserved.\n";
32#endif /* not lint */
33#endif
34#include <sys/cdefs.h>
35__FBSDID("$FreeBSD$");
36
37/*
38 * Andrey A. Chernov   <ache@astral.msk.su>    Dec 20 1993
39 *
40 * Fix kernel time value if machine run wall CMOS clock
41 * (and /etc/wall_cmos_clock file present)
42 * using zoneinfo rules or direct TZ environment variable set.
43 * Use Joerg Wunsch idea for seconds accurate offset calculation
44 * with Garrett Wollman and Bruce Evans fixes.
45 *
46 */
47#include <stdio.h>
48#include <signal.h>
49#include <stdlib.h>
50#include <unistd.h>
51#include <syslog.h>
52#include <sys/time.h>
53#include <sys/param.h>
54#include <machine/cpu.h>
55#include <sys/sysctl.h>
56
57#include "pathnames.h"
58
59/*#define DEBUG*/
60
61#define True (1)
62#define False (0)
63#define Unknown (-1)
64
65#define REPORT_PERIOD (30*60)
66
67static void fake(int);
68static void usage(void);
69
70static void
71fake(int unused __unused)
72{
73
74	/* Do nothing. */
75}
76
77int
78main(int argc, char *argv[])
79{
80	struct tm local;
81	struct timeval tv, *stv;
82	struct timezone tz, *stz;
83	int kern_offset, wall_clock, disrtcset;
84	size_t len;
85	/* Avoid time_t here, can be unsigned long or worse */
86	long offset, localsec, diff;
87	time_t initial_sec, final_sec;
88	int ch;
89	int initial_isdst = -1, final_isdst;
90	int need_restore = False, sleep_mode = False, looping,
91	    init = Unknown;
92	sigset_t mask, emask;
93
94	while ((ch = getopt(argc, argv, "ais")) != -1)
95		switch((char)ch) {
96		case 'i':               /* initial call, save offset */
97			if (init != Unknown)
98				usage();
99			init = True;
100			break;
101		case 'a':               /* adjustment call, use saved offset */
102			if (init != Unknown)
103				usage();
104			init = False;
105			break;
106		case 's':
107			sleep_mode = True;
108			break;
109		default:
110			usage();
111		}
112	if (init == Unknown)
113		usage();
114
115	if (access(_PATH_CLOCK, F_OK) != 0)
116		return 0;
117
118	if (init)
119		sleep_mode = True;
120
121	sigemptyset(&mask);
122	sigemptyset(&emask);
123	sigaddset(&mask, SIGTERM);
124
125	openlog("adjkerntz", LOG_PID|LOG_PERROR, LOG_DAEMON);
126
127	(void) signal(SIGHUP, SIG_IGN);
128
129	if (init && daemon(0,
130#ifdef DEBUG
131	    1
132#else
133	    0
134#endif
135	    )) {
136		syslog(LOG_ERR, "daemon: %m");
137		return 1;
138	}
139
140again:
141	(void) sigprocmask(SIG_BLOCK, &mask, NULL);
142	(void) signal(SIGTERM, fake);
143
144	diff = 0;
145	stv = NULL;
146	stz = NULL;
147	looping = False;
148
149	wall_clock = (access(_PATH_CLOCK, F_OK) == 0);
150	if (init && !sleep_mode) {
151		init = False;
152		if (!wall_clock)
153			return 0;
154	}
155
156	tzset();
157
158	len = sizeof(kern_offset);
159	if (sysctlbyname("machdep.adjkerntz", &kern_offset, &len, NULL, 0) == -1) {
160		syslog(LOG_ERR, "sysctl(\"machdep.adjkerntz\"): %m");
161		return 1;
162	}
163
164/****** Critical section, do all things as fast as possible ******/
165
166	/* get local CMOS clock and possible kernel offset */
167	if (gettimeofday(&tv, &tz)) {
168		syslog(LOG_ERR, "gettimeofday: %m");
169		return 1;
170	}
171
172	/* get the actual local timezone difference */
173	initial_sec = tv.tv_sec;
174
175recalculate:
176	local = *localtime(&initial_sec);
177	if (diff == 0)
178		initial_isdst = local.tm_isdst;
179	local.tm_isdst = initial_isdst;
180
181	/* calculate local CMOS diff from GMT */
182
183	localsec = mktime(&local);
184	if (localsec == -1) {
185		/*
186		 * XXX user can only control local time, and it is
187		 * unacceptable to fail here for init.  2:30 am in the
188		 * middle of the nonexistent hour means 3:30 am.
189		 */
190		if (!sleep_mode) {
191			syslog(LOG_WARNING,
192			"Warning: nonexistent local time, try to run later.");
193			syslog(LOG_WARNING, "Giving up.");
194			return 1;
195		}
196		syslog(LOG_WARNING,
197			"Warning: nonexistent local time.");
198		syslog(LOG_WARNING, "Will retry after %d minutes.",
199			REPORT_PERIOD / 60);
200		(void) signal(SIGTERM, SIG_DFL);
201		(void) sigprocmask(SIG_UNBLOCK, &mask, NULL);
202		(void) sleep(REPORT_PERIOD);
203		goto again;
204	}
205	offset = -local.tm_gmtoff;
206#ifdef DEBUG
207	fprintf(stderr, "Initial offset: %ld secs\n", offset);
208#endif
209
210	/* correct the kerneltime for this diffs */
211	/* subtract kernel offset, if present, old offset too */
212
213	diff = offset - tz.tz_minuteswest * 60 - kern_offset;
214
215	if (diff != 0) {
216#ifdef DEBUG
217		fprintf(stderr, "Initial diff: %ld secs\n", diff);
218#endif
219		/* Yet one step for final time */
220
221		final_sec = initial_sec + diff;
222
223		/* get the actual local timezone difference */
224		local = *localtime(&final_sec);
225		final_isdst = diff < 0 ? initial_isdst : local.tm_isdst;
226		if (diff > 0 && initial_isdst != final_isdst) {
227			if (looping)
228				goto bad_final;
229			looping = True;
230			initial_isdst = final_isdst;
231			goto recalculate;
232		}
233		local.tm_isdst =  final_isdst;
234
235		localsec = mktime(&local);
236		if (localsec == -1) {
237		bad_final:
238			/*
239			 * XXX as above.  The user has even less control,
240			 * but perhaps we never get here.
241			 */
242			if (!sleep_mode) {
243				syslog(LOG_WARNING,
244					"Warning: nonexistent final local time, try to run later.");
245				syslog(LOG_WARNING, "Giving up.");
246				return 1;
247			}
248			syslog(LOG_WARNING,
249				"Warning: nonexistent final local time.");
250			syslog(LOG_WARNING, "Will retry after %d minutes.",
251				REPORT_PERIOD / 60);
252			(void) signal(SIGTERM, SIG_DFL);
253			(void) sigprocmask(SIG_UNBLOCK, &mask, NULL);
254			(void) sleep(REPORT_PERIOD);
255			goto again;
256		}
257		offset = -local.tm_gmtoff;
258#ifdef DEBUG
259		fprintf(stderr, "Final offset: %ld secs\n", offset);
260#endif
261
262		/* correct the kerneltime for this diffs */
263		/* subtract kernel offset, if present, old offset too */
264
265		diff = offset - tz.tz_minuteswest * 60 - kern_offset;
266
267		if (diff != 0) {
268#ifdef DEBUG
269			fprintf(stderr, "Final diff: %ld secs\n", diff);
270#endif
271			/*
272			 * stv is abused as a flag.  The important value
273			 * is in `diff'.
274			 */
275			stv = &tv;
276		}
277	}
278
279	if (tz.tz_dsttime != 0 || tz.tz_minuteswest != 0) {
280		tz.tz_dsttime = tz.tz_minuteswest = 0;  /* zone info is garbage */
281		stz = &tz;
282	}
283	if (!wall_clock && stz == NULL)
284		stv = NULL;
285
286	/* if init or UTC clock and offset/date will be changed, */
287	/* disable RTC modification for a while.                      */
288
289	if (   (init && stv != NULL)
290	    || ((init || !wall_clock) && kern_offset != offset)
291	   ) {
292		len = sizeof(disrtcset);
293		if (sysctlbyname("machdep.disable_rtc_set", &disrtcset, &len, NULL, 0) == -1) {
294			syslog(LOG_ERR, "sysctl(get: \"machdep.disable_rtc_set\"): %m");
295			return 1;
296		}
297		if (disrtcset == 0) {
298			disrtcset = 1;
299			need_restore = True;
300			if (sysctlbyname("machdep.disable_rtc_set", NULL, NULL, &disrtcset, len) == -1) {
301				syslog(LOG_ERR, "sysctl(set: \"machdep.disable_rtc_set\"): %m");
302				return 1;
303			}
304		}
305	}
306
307	if (   (init && (stv != NULL || stz != NULL))
308	    || (stz != NULL && stv == NULL)
309	   ) {
310		if (stv != NULL) {
311			/*
312			 * Get the time again, as close as possible to
313			 * adjusting it, to minimise drift.
314			 * XXX we'd better not fail between here and
315			 * restoring disrtcset, since we don't clean up
316			 * anything.
317			 */
318			(void)gettimeofday(&tv, NULL);
319			tv.tv_sec += diff;
320			stv = &tv;
321		}
322		if (settimeofday(stv, stz)) {
323			syslog(LOG_ERR, "settimeofday: %m");
324			return 1;
325		}
326	}
327
328	/* setting machdep.adjkerntz have a side effect: resettodr(), which */
329	/* can be disabled by machdep.disable_rtc_set, so if init or UTC clock    */
330	/* -- don't write RTC, else write RTC.                          */
331
332	if (kern_offset != offset) {
333		kern_offset = offset;
334		len = sizeof(kern_offset);
335		if (sysctlbyname("machdep.adjkerntz", NULL, NULL, &kern_offset, len) == -1) {
336			syslog(LOG_ERR, "sysctl(set: \"machdep.adjkerntz\"): %m");
337			return 1;
338		}
339	}
340
341	len = sizeof(wall_clock);
342	if (sysctlbyname("machdep.wall_cmos_clock",  NULL, NULL, &wall_clock, len) == -1) {
343		syslog(LOG_ERR, "sysctl(set: \"machdep.wall_cmos_clock\"): %m");
344		return 1;
345	}
346
347	if (need_restore) {
348		need_restore = False;
349		disrtcset = 0;
350		len = sizeof(disrtcset);
351		if (sysctlbyname("machdep.disable_rtc_set", NULL, NULL, &disrtcset, len) == -1) {
352			syslog(LOG_ERR, "sysctl(set: \"machdep.disable_rtc_set\"): %m");
353			return 1;
354		}
355	}
356
357/****** End of critical section ******/
358
359	if (init && wall_clock) {
360		sleep_mode = False;
361		/* wait for signals and acts like -a */
362		(void) sigsuspend(&emask);
363		goto again;
364	}
365
366	return 0;
367}
368
369static void
370usage(void)
371{
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)");
377	exit(2);
378}
379