/*
 * Copyright (c) 2005 The DragonFly Project.  All rights reserved.
 * 
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 * 
 * 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.
 * 3. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``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
 * COPYRIGHT HOLDERS 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.
 * 
 * $DragonFly: src/usr.sbin/dntpd/system.c,v 1.1 2005/04/24 02:36:50 dillon Exp $
 */

#include "defs.h"
#include <sys/sysctl.h>

void
sysntp_getbasetime(struct timeval *tvp)
{
    struct timespec ts;
    int error;
    int ts_size;

    ts_size = sizeof(ts);
    error = sysctlbyname("kern.basetime", &ts, &ts_size, NULL, 0);
    if (error < 0) {
	logerr("sysctlbyname(\"kern.basetime\") failed, cannot continue");
	exit(1);
    }
    ts_to_tv(&ts, tvp);
}

/*
 * The offset error is passed as seconds per second.
 *
 * The 64 bit delta is calculated as nanoseconds per second.  Since we are
 * passed an offset error we must negate the result to correct the error.
 *
 * Because offset corrections skew the accuracy of the clock while the
 * correction is in progress, we do not want to use them once we are
 * reasonably well synchronized.  We can make small offset corrections
 * by shifting the frequency a bit.  XXX
 */
double
sysntp_correct_offset(double offset)
{
    int64_t delta;

    /*
     * Course correction
     */
    if (offset < -0.001 || offset > 0.001) {
	if (debug_opt)
	    fprintf(stderr, "issuing offset adjustment: %7.6f\n", -offset);
	delta = -(int64_t)(offset * 1.0E+9);
	sysctlbyname("kern.ntp.delta", NULL, 0, &delta, sizeof(delta));
	return(0.0);
    }

    /*
     * Fine correction - do it by adjusting the frequency.
     * XXX
     */
    return(0.0);
}

/*
 * freq is passed as seconds per second.
 *
 * The calculated 64 bit correction is nanoseconds per second shifted
 * left 32.
 *
 * Frequency errors greater then 1 second per second will not be corrected.
 * It doesn't hurt to continue correcting the frequency.
 */
void
sysntp_correct_freq(double freq)
{
    int64_t delta;

    if (freq >= -1.0 && freq < 1.0) {
	if (debug_opt) {
	    fprintf(stderr, "issuing frequency adjustment: %6.3fppm\n", 
		    -freq * 1000000.0);
	}
	delta = -((int64_t)(freq * 1.0E+9) << 32);
	sysctlbyname("kern.ntp.permanent", NULL, 0, &delta, sizeof(delta));
    }
}