freebsd_amp_hwpstate/sbin/adjkerntz/adjkerntz.c

/*
 * Copyright (C) 1993 by Andrew A. Chernov, Moscow, Russia.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
char copyright[] =
"@(#)Copyright (C) 1993 by Andrew A. Chernov, Moscow, Russia.\n\
 All rights reserved.\n";
#endif /* not lint */

/*
 * Andrew A. Chernov   <ache@astral.msk.su>    Dec 20 1993
 *
 * Fix kernel time value if machine run wall CMOS clock
 * (and /etc/wall_cmos_clock file present)
 * using zoneinfo rules or direct TZ environment variable set.
 * Use Joerg Wunsch idea for seconds accurate offset calculation
 * with Garrett Wollman and Bruce Evans fixes.
 *
 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <syslog.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/param.h>
#include <machine/cpu.h>
#include <sys/sysctl.h>

#include "pathnames.h"

#define REPORT_PERIOD (30*60)

int main(argc, argv)
	int argc;
	char **argv;
{
	struct tm local, utc;
	struct timeval tv, *stv;
	struct timezone tz, *stz;
	int kern_offset;
	size_t len;
	int mib[2];
	/* Avoid time_t here, can be unsigned long or worse */
	long offset, utcsec, localsec, diff;
	time_t initial_sec, final_sec;
	int init = 1, nonex1 = 0, nonex2 = 0;
	int disrtcset, need_restore = 0;

	if (argc != 1) {
		fprintf(stderr, "Usage:\tadjkerntz\n");
		return 2;
	}

	if (access(_PATH_CLOCK, F_OK))
		return 0;

	if (daemon(0, 0)) {
		perror("daemon");
		return 1;
	}

	openlog("adjkerntz", LOG_PID, LOG_DAEMON);

	/* Spy on timezone changes with 1sec accurancy */
	for (;;sleep(1)) {

/****** Critical section, do all things as fast as possible ******/

		/* get local CMOS clock and possible kernel offset */
		if (gettimeofday(&tv, &tz)) {
			syslog(LOG_ERR, "gettimeofday: %m");
			return 1;
		}

		/* get the actual local timezone difference */
		initial_sec = tv.tv_sec;
		local = *localtime(&initial_sec);
		utc = *gmtime(&initial_sec);
		utc.tm_isdst = local.tm_isdst; /* Use current timezone for mktime(), */
					       /* because it assumed local time */

		/* calculate local CMOS diff from GMT */

		utcsec = mktime(&utc);
		localsec = mktime(&local);
		if (utcsec == -1 || localsec == -1) {
			/*
			 * XXX user can only control local time, and it is
			 * unacceptable to fail here for init.  2:30 am in the
			 * middle of the nonexistent hour means 3:30 am.
			 */
			if (!(nonex1++ % REPORT_PERIOD)) {
				if (nonex1 > 1)
					nonex1 = 0;
				syslog(LOG_WARNING,
				"Nonexistent local time -- retry each second");
			}
			continue;
		}
		offset = utcsec - localsec;

		mib[0] = CTL_MACHDEP;
		mib[1] = CPU_ADJKERNTZ;
		len = sizeof(kern_offset);
		if (sysctl(mib, 2, &kern_offset, &len, NULL, 0) == -1) {
			syslog(LOG_ERR, "sysctl(get_offset): %m");
			return 1;
		}

		/* correct the kerneltime for this diffs */
		/* subtract kernel offset, if present, old offset too */

		diff = offset - tz.tz_minuteswest * 60 - kern_offset;

		if (diff != 0) {

			/* Yet one step for final time */

			final_sec = tv.tv_sec + diff;

			/* get the actual local timezone difference */
			local = *localtime(&final_sec);
			utc = *gmtime(&final_sec);
			utc.tm_isdst = local.tm_isdst; /* Use current timezone for mktime(), */
						       /* because it assumed local time */

			utcsec = mktime(&utc);
			localsec = mktime(&local);
			if (utcsec == -1 || localsec == -1) {
				/*
				 * XXX as above.  The user has even less control,
				 * but perhaps we never get here.
				 */
				if (!(nonex2++ % REPORT_PERIOD)) {
					if (nonex2 > 1)
						nonex2 = 0;
					syslog(LOG_WARNING,
			"Nonexistent (final) local time -- retry each second");
				}
				continue;
			}
			offset = utcsec - localsec;

			/* correct the kerneltime for this diffs */
			/* subtract kernel offset, if present, old offset too */

			diff = offset - tz.tz_minuteswest * 60 - kern_offset;

			if (diff != 0) {
				tv.tv_sec += diff;
				tv.tv_usec = 0;       /* we are restarting here... */
				stv = &tv;
			}
			else
				stv = NULL;
		}
		else
			stv = NULL;

		if (tz.tz_dsttime != 0 || tz.tz_minuteswest != 0) {
			tz.tz_dsttime = tz.tz_minuteswest = 0;  /* zone info is garbage */
			stz = &tz;
		}
		else
			stz = NULL;

		if (stz != NULL || stv != NULL) {
			if (init && stv != NULL) {
				mib[0] = CTL_MACHDEP;
				mib[1] = CPU_DISRTCSET;
				len = sizeof(disrtcset);
				if (sysctl(mib, 2, &disrtcset, &len, NULL, 0) == -1) {
					syslog(LOG_ERR, "sysctl(get_disrtcset): %m");
					return 1;
				}
				if (disrtcset == 0) {
					disrtcset = 1;
					need_restore = 1;
					if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) {
						syslog(LOG_ERR, "sysctl(set_disrtcset): %m");
						return 1;
					}
				}
			}
			/* stz means that kernel zone shifted */
			/* clock needs adjustment even if !init */
			if ((init || stz != NULL) && settimeofday(stv, stz)) {
				syslog(LOG_ERR, "settimeofday: %m");
				return 1;
			}
		}

		if (kern_offset != offset) {
			kern_offset = offset;
			mib[0] = CTL_MACHDEP;
			mib[1] = CPU_ADJKERNTZ;
			len = sizeof(kern_offset);
			if (sysctl(mib, 2, NULL, NULL, &kern_offset, len) == -1) {
				syslog(LOG_ERR, "sysctl(update_offset): %m");
				return 1;
			}
		}

		if (need_restore) {
			need_restore = 0;
			disrtcset = 0;
			if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) {
				syslog(LOG_ERR, "sysctl(restore_disrtcset): %m");
				return 1;
			}
		}

/****** End of critical section ******/

		init = 0;
	}
	return 1;
}