sys/kern/subr_clock.c

   1 /*-
   2  * Copyright (c) 1988 University of Utah.
   3  * Copyright (c) 1982, 1990, 1993
   4  *      The Regents of the University of California.  All rights reserved.
   5  *
   6  * This code is derived from software contributed to Berkeley by
   7  * the Systems Programming Group of the University of Utah Computer
   8  * Science Department.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 4. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  *      from: Utah $Hdr: clock.c 1.18 91/01/21$
  35  *      from: @(#)clock.c       8.2 (Berkeley) 1/12/94
  36  *      from: NetBSD: clock_subr.c,v 1.6 2001/07/07 17:04:02 thorpej Exp
  37  *      and
  38  *      from: src/sys/i386/isa/clock.c,v 1.176 2001/09/04
  39  */
  40
  41 #include <sys/cdefs.h>
  42 __FBSDID("$FreeBSD$");
  43
  44 #include <sys/param.h>
  45 #include <sys/systm.h>
  46 #include <sys/kernel.h>
  47 #include <sys/bus.h>
  48 #include <sys/clock.h>
  49 #include <sys/sysctl.h>
  50 #include <sys/timetc.h>
  51
  52 #define ct_debug bootverbose
  53 static int adjkerntz;           /* local offset from GMT in seconds */
  54 static int wall_cmos_clock;     /* wall CMOS clock assumed if != 0 */
  55
  56 int tz_minuteswest;
  57 int tz_dsttime;
  58
  59 /*
  60  * This have traditionally been in machdep, but should probably be moved to
  61  * kern.
  62  */
  63 SYSCTL_INT(_machdep, OID_AUTO, wall_cmos_clock,
  64         CTLFLAG_RW, &wall_cmos_clock, 0, "");
  65
  66 static int
  67 sysctl_machdep_adjkerntz(SYSCTL_HANDLER_ARGS)
  68 {
  69         int error;
  70         error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
  71         if (!error && req->newptr)
  72                 resettodr();
  73         return (error);
  74 }
  75
  76 SYSCTL_PROC(_machdep, OID_AUTO, adjkerntz, CTLTYPE_INT|CTLFLAG_RW,
  77         &adjkerntz, 0, sysctl_machdep_adjkerntz, "I", "");
  78
  79 /*--------------------------------------------------------------------*
  80  * Generic routines to convert between a POSIX date
  81  * (seconds since 1/1/1970) and yr/mo/day/hr/min/sec
  82  * Derived from NetBSD arch/hp300/hp300/clock.c
  83  */
  84
  85
  86 #define FEBRUARY        2
  87 #define days_in_year(y)         (leapyear(y) ? 366 : 365)
  88 #define days_in_month(y, m) \
  89         (month_days[(m) - 1] + (m == FEBRUARY ? leapyear(y) : 0))
  90 /* Day of week. Days are counted from 1/1/1970, which was a Thursday */
  91 #define day_of_week(days)       (((days) + 4) % 7)
  92
  93 static const int month_days[12] = {
  94         31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
  95 };
  96
  97
  98 /*
  99  * This inline avoids some unnecessary modulo operations
 100  * as compared with the usual macro:
 101  *   ( ((year % 4) == 0 &&
 102  *      (year % 100) != 0) ||
 103  *     ((year % 400) == 0) )
 104  * It is otherwise equivalent.
 105  */
 106 static int
 107 leapyear(int year)
 108 {
 109         int rv = 0;
 110
 111         if ((year & 3) == 0) {
 112                 rv = 1;
 113                 if ((year % 100) == 0) {
 114                         rv = 0;
 115                         if ((year % 400) == 0)
 116                                 rv = 1;
 117                 }
 118         }
 119         return (rv);
 120 }
 121
 122 static void
 123 print_ct(struct clocktime *ct)
 124 {
 125         printf("[%04d-%02d-%02d %02d:%02d:%02d]",
 126             ct->year, ct->mon, ct->day,
 127             ct->hour, ct->min, ct->sec);
 128 }
 129
 130 int
 131 clock_ct_to_ts(struct clocktime *ct, struct timespec *ts)
 132 {
 133         time_t secs;
 134         int i, year, days;
 135
 136         year = ct->year;
 137
 138         if (ct_debug) {
 139                 printf("ct_to_ts(");
 140                 print_ct(ct);
 141                 printf(")");
 142         }
 143
 144         /* Sanity checks. */
 145         if (ct->mon < 1 || ct->mon > 12 || ct->day < 1 ||
 146             ct->day > days_in_month(year, ct->mon) ||
 147             ct->hour > 23 ||  ct->min > 59 || ct->sec > 59 ||
 148             ct->year > 2037) {          /* time_t overflow */
 149                 if (ct_debug)
 150                         printf(" = EINVAL\n");
 151                 return (EINVAL);
 152         }
 153
 154         /*
 155          * Compute days since start of time
 156          * First from years, then from months.
 157          */
 158         days = 0;
 159         for (i = POSIX_BASE_YEAR; i < year; i++)
 160                 days += days_in_year(i);
 161
 162         /* Months */
 163         for (i = 1; i < ct->mon; i++)
 164                 days += days_in_month(year, i);
 165         days += (ct->day - 1);
 166
 167         /* XXX Dow sanity check. Dow is not used, so should we check it? */
 168         if (ct->dow != -1 && ct->dow != day_of_week(days))
 169                 return (EINVAL);
 170
 171         /* Add hours, minutes, seconds. */
 172         secs = ((days * 24 + ct->hour) * 60 + ct->min) * 60 + ct->sec;
 173
 174         ts->tv_sec = secs;
 175         ts->tv_nsec = ct->nsec;
 176         if (ct_debug)
 177                 printf(" = %ld.%09ld\n", (long)ts->tv_sec, (long)ts->tv_nsec);
 178         return (0);
 179 }
 180
 181 void
 182 clock_ts_to_ct(struct timespec *ts, struct clocktime *ct)
 183 {
 184         int i, year, days;
 185         time_t rsec;    /* remainder seconds */
 186         time_t secs;
 187
 188         secs = ts->tv_sec;
 189         days = secs / SECDAY;
 190         rsec = secs % SECDAY;
 191
 192         ct->dow = day_of_week(days);
 193
 194         /* Subtract out whole years, counting them in i. */
 195         for (year = POSIX_BASE_YEAR; days >= days_in_year(year); year++)
 196                 days -= days_in_year(year);
 197         ct->year = year;
 198
 199         /* Subtract out whole months, counting them in i. */
 200         for (i = 1; days >= days_in_month(year, i); i++)
 201                 days -= days_in_month(year, i);
 202         ct->mon = i;
 203
 204         /* Days are what is left over (+1) from all that. */
 205         ct->day = days + 1;
 206
 207         /* Hours, minutes, seconds are easy */
 208         ct->hour = rsec / 3600;
 209         rsec = rsec % 3600;
 210         ct->min  = rsec / 60;
 211         rsec = rsec % 60;
 212         ct->sec  = rsec;
 213         ct->nsec = ts->tv_nsec;
 214         if (ct_debug) {
 215                 printf("ts_to_ct(%ld.%09ld) = ",
 216                     (long)ts->tv_sec, (long)ts->tv_nsec);
 217                 print_ct(ct);
 218                 printf("\n");
 219         }
 220 }
 221
 222 int
 223 utc_offset(void)
 224 {
 225
 226         return (tz_minuteswest * 60 + (wall_cmos_clock ? adjkerntz : 0));
 227 }