usr.sbin/dntpd/system.c

   1 /*
   2  * Copyright (c) 2005 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  * $DragonFly: src/usr.sbin/dntpd/system.c,v 1.9 2007/07/11 00:18:00 swildner Exp $
  35  */
  36
  37 #include "defs.h"
  38 #include <sys/sysctl.h>
  39 #include <sys/timex.h>
  40
  41 /*
  42  * If a system has multiple independant time-correcting mechanisms, this
  43  * function should clear out any corrections on those mechanisms that we
  44  * will NOT be using.  We can leave a prior correction intact on the
  45  * mechanism that we ARE using.
  46  *
  47  * However, it is usually a good idea to clean out any offset correction
  48  * that is still in progress anyway.  We leave the frequency correction
  49  * intact.
  50  */
  51 void
  52 sysntp_clear_alternative_corrections(void)
  53 {
  54     struct timex ntp;
  55     int64_t offset;
  56
  57     if (no_update_opt)
  58         return;
  59
  60     /*
  61      * Clear the ntp interface.  We will use the sysctl interface
  62      * (XXX)
  63      */
  64     bzero(&ntp, sizeof(ntp));
  65     ntp.modes = MOD_OFFSET | MOD_FREQUENCY;
  66     ntp.offset = 0;
  67     ntp.freq = 0;
  68     ntp_adjtime(&ntp);
  69
  70     /*
  71      * Clean out any offset still being applied to real time.  Leave
  72      * any prior frequency correction intact.
  73      */
  74     offset = 0;
  75     sysctlbyname("kern.ntp.delta", NULL, 0, &offset, sizeof(offset));
  76 }
  77
  78 /*
  79  * Obtain a timestamp that contains ONLY corrections made by the system
  80  * to the base time.  The actual value of the timestamp is not relevant,
  81  * only the delta from two queries to this routine.
  82  *
  83  * This is used by DNTPD to determine what corrections the system has made
  84  * to the system's real time so DNTPD can uncorrect them for the purpose
  85  * of calculating the linear regression.
  86  */
  87 void
  88 sysntp_getbasetime(struct timeval *tvp)
  89 {
  90     struct timespec ts;
  91     int error;
  92     int ts_size;
  93
  94     ts_size = sizeof(ts);
  95     error = sysctlbyname("kern.basetime", &ts, &ts_size, NULL, 0);
  96     if (error < 0) {
  97         logerr("sysctlbyname(\"kern.basetime\") failed, cannot continue");
  98         exit(1);
  99     }
 100     ts_to_tv(&ts, tvp);
 101 }
 102
 103 /*
 104  * Return 1 if an offset correction is still running, 0 if it isn't.
 105  */
 106 int
 107 sysntp_offset_correction_is_running(void)
 108 {
 109     int64_t delta;
 110     int delta_len;
 111
 112     delta_len = sizeof(delta);
 113     if (sysctlbyname("kern.ntp.delta", &delta, &delta_len, NULL, 0) == 0) {
 114         if (delta != 0)
 115             return(1);
 116     }
 117     return(0);
 118 }
 119
 120 /*
 121  * The offset error is passed as seconds per second.  Only fairly small
 122  * offsets are passed to this function (see sysntp_correct_course_offset()
 123  * for large corrections).  This function may request that the offset
 124  * be corrected by shifting the frequency by returning the frequency shift
 125  * (usually a small number in the 1E-6 range) (NOT YET IMPLEMENTED).
 126  *
 127  * The 64 bit delta is calculated as nanoseconds per second.  Since we are
 128  * passed an offset error we must negate the result to correct the error.
 129  *
 130  * Because offset corrections skew the accuracy of the clock while the
 131  * correction is in progress, we do not want to use them once we are
 132  * reasonably well synchronized.  We can make small offset corrections
 133  * by shifting the frequency a bit.  XXX
 134  */
 135 double
 136 sysntp_correct_offset(double offset)
 137 {
 138     int64_t delta;
 139
 140     /*
 141      * Course correction
 142      */
 143     if (offset < -0.001 || offset > 0.001) {
 144         logdebug(1, "issuing offset adjustment: %7.6fs", -offset);
 145         if (no_update_opt)
 146             logdebug(1, " (UPDATES DISABLED)");
 147         logdebug(1, "\n");
 148         delta = -(int64_t)(offset * 1.0E+9);
 149         if (no_update_opt == 0)
 150             sysctlbyname("kern.ntp.delta", NULL, 0, &delta, sizeof(delta));
 151         return(0.0);
 152     }
 153
 154     /*
 155      * Fine correction - do it by adjusting the frequency.
 156      * XXX
 157      */
 158     return(0.0);
 159 }
 160
 161 /*
 162  * This function is used for what should be a one-time correction on
 163  * startup.
 164  */
 165 double
 166 sysntp_correct_course_offset(double offset)
 167 {
 168     struct timeval tv;
 169     struct tm *tp;
 170     time_t t;
 171     char buf[64];
 172
 173     offset = -offset;   /* if we are ahead, correct backwards, and vise versa*/
 174     if (gettimeofday(&tv, NULL) == 0) {
 175         tv_add_offset(&tv, offset);
 176         if (no_update_opt == 0 && settimeofday(&tv, NULL) < 0) {
 177             logerr("settimeofday");
 178         } else {
 179             logdebug(1, "issuing COARSE offset adjustment: %7.6fs, ",
 180                     offset);
 181             t = tv.tv_sec;
 182             tp = localtime(&t);
 183             strftime(buf, sizeof(buf), "%d-%b-%Y %H:%M:%S", tp);
 184             logdebug(1, "%s.%03ld", buf, tv.tv_usec / 1000);
 185             if (no_update_opt)
 186                 logdebug(1, " (UPDATES DISABLED)");
 187             if (quickset_opt)
 188                 logdebug(1, " (ONE-TIME QUICKSET)");
 189             logdebug(1, "\n");
 190         }
 191     } else {
 192         logerr("gettimeofday");
 193     }
 194     return(0.0);
 195 }
 196
 197 /*
 198  * freq is passed as seconds per second.
 199  *
 200  * The calculated 64 bit correction is nanoseconds per second shifted
 201  * left 32.
 202  *
 203  * Frequency errors greater then 1 second per second will not be corrected.
 204  * It doesn't hurt to continue correcting the frequency.
 205  */
 206 void
 207 sysntp_correct_freq(double freq)
 208 {
 209     static double last_freq;
 210     int64_t delta;
 211     int loglevel;
 212
 213     if (last_freq == 0.0 || fabs(freq - last_freq) >= 20.0E-6)
 214         loglevel = 1;
 215     else if (fabs(freq - last_freq) >= 5.0E-6)
 216         loglevel = 2;
 217     else
 218         loglevel = 3;
 219     last_freq = freq;
 220
 221     if (freq >= -1.0 && freq < 1.0) {
 222         logdebug(loglevel, "issuing frequency adjustment: %6.3fppm",
 223                 -freq * 1000000.0);
 224         if (no_update_opt)
 225                 logdebug(loglevel, " (UPDATES DISABLED)");
 226         logdebug(loglevel, "\n");
 227         delta = -((int64_t)(freq * 1.0E+9) << 32);
 228         if (no_update_opt == 0)
 229             sysctlbyname("kern.ntp.permanent", NULL, 0, &delta, sizeof(delta));
 230     }
 231 }
 232