The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_clock.c

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    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 static int adjkerntz;           /* local offset from GMT in seconds */
   53 static int wall_cmos_clock;     /* wall CMOS clock assumed if != 0 */
   54 int disable_rtc_set;            /* disable resettodr() if != 0 */
   55 
   56 int tz_minuteswest;
   57 int tz_dsttime;
   58 
   59 /*
   60  * These have traditionally been in machdep, but should probably be moved to
   61  * kern.
   62  */
   63 SYSCTL_INT(_machdep, OID_AUTO, disable_rtc_set,
   64         CTLFLAG_RW, &disable_rtc_set, 0, "");
   65 
   66 SYSCTL_INT(_machdep, OID_AUTO, wall_cmos_clock,
   67         CTLFLAG_RW, &wall_cmos_clock, 0, "");
   68 
   69 static int
   70 sysctl_machdep_adjkerntz(SYSCTL_HANDLER_ARGS)
   71 {
   72         int error;
   73         error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2,
   74                 req);
   75         if (!error && req->newptr)
   76                 resettodr();
   77         return (error);
   78 }
   79 
   80 SYSCTL_PROC(_machdep, OID_AUTO, adjkerntz, CTLTYPE_INT|CTLFLAG_RW,
   81         &adjkerntz, 0, sysctl_machdep_adjkerntz, "I", "");
   82 
   83 /*--------------------------------------------------------------------*
   84  * Generic routines to convert between a POSIX date
   85  * (seconds since 1/1/1970) and yr/mo/day/hr/min/sec
   86  * Derived from NetBSD arch/hp300/hp300/clock.c
   87  */
   88 
   89 
   90 #define FEBRUARY        2
   91 #define days_in_year(y)         (leapyear(y) ? 366 : 365)
   92 #define days_in_month(y, m) \
   93         (month_days[(m) - 1] + (m == FEBRUARY ? leapyear(y) : 0))
   94 /* Day of week. Days are counted from 1/1/1970, which was a Thursday */
   95 #define day_of_week(days)       (((days) + 4) % 7)
   96 
   97 static const int month_days[12] = {
   98         31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
   99 };
  100 
  101 
  102 /*
  103  * This inline avoids some unnecessary modulo operations
  104  * as compared with the usual macro:
  105  *   ( ((year % 4) == 0 &&
  106  *      (year % 100) != 0) ||
  107  *     ((year % 400) == 0) )
  108  * It is otherwise equivalent.
  109  */
  110 static __inline int
  111 leapyear(int year)
  112 {
  113         int rv = 0;
  114 
  115         if ((year & 3) == 0) {
  116                 rv = 1;
  117                 if ((year % 100) == 0) {
  118                         rv = 0;
  119                         if ((year % 400) == 0)
  120                                 rv = 1;
  121                 }
  122         }
  123         return (rv);
  124 }
  125 
  126 int
  127 clock_ct_to_ts(struct clocktime *ct, struct timespec *ts)
  128 {
  129         time_t secs;
  130         int i, year, days;
  131 
  132         year = ct->year;
  133 
  134         /* Sanity checks. */
  135         if (ct->mon < 1 || ct->mon > 12 || ct->day < 1 ||
  136             ct->day > days_in_month(year, ct->mon) ||
  137             ct->hour > 23 ||  ct->min > 59 || ct->sec > 59 ||
  138             ct->year > 2037)            /* time_t overflow */
  139                 return (EINVAL);
  140 
  141         /*
  142          * Compute days since start of time
  143          * First from years, then from months.
  144          */
  145         days = 0;
  146         for (i = POSIX_BASE_YEAR; i < year; i++)
  147                 days += days_in_year(i);
  148 
  149         /* Months */
  150         for (i = 1; i < ct->mon; i++)
  151                 days += days_in_month(year, i);
  152         days += (ct->day - 1);
  153 
  154         /* XXX Dow sanity check. Dow is not used, so should we check it? */
  155         if (ct->dow != -1 && ct->dow != day_of_week(days))
  156                 return (EINVAL);
  157 
  158         /* Add hours, minutes, seconds. */
  159         secs = ((days * 24 + ct->hour) * 60 + ct->min) * 60 + ct->sec;
  160 
  161         ts->tv_sec = secs;
  162         ts->tv_nsec = ct->nsec;
  163         return (0);
  164 }
  165 
  166 void
  167 clock_ts_to_ct(struct timespec *ts, struct clocktime *ct)
  168 {
  169         int i, year, days;
  170         time_t rsec;    /* remainder seconds */
  171         time_t secs;
  172 
  173         secs = ts->tv_sec;
  174         days = secs / SECDAY;
  175         rsec = secs % SECDAY;
  176 
  177         ct->dow = day_of_week(days);
  178 
  179         /* Subtract out whole years, counting them in i. */
  180         for (year = POSIX_BASE_YEAR; days >= days_in_year(year); year++)
  181                 days -= days_in_year(year);
  182         ct->year = year;
  183 
  184         /* Subtract out whole months, counting them in i. */
  185         for (i = 1; days >= days_in_month(year, i); i++)
  186                 days -= days_in_month(year, i);
  187         ct->mon = i;
  188 
  189         /* Days are what is left over (+1) from all that. */
  190         ct->day = days + 1;
  191 
  192         /* Hours, minutes, seconds are easy */
  193         ct->hour = rsec / 3600;
  194         rsec = rsec % 3600;
  195         ct->min  = rsec / 60;
  196         rsec = rsec % 60;
  197         ct->sec  = rsec;
  198         ct->nsec = ts->tv_nsec;
  199 }
  200 
  201 int
  202 utc_offset(void)
  203 {
  204 
  205         return (tz_minuteswest * 60 + (wall_cmos_clock ? adjkerntz : 0));
  206 }

Cache object: b193d54fb2fcc934e2d47d7e026f3c6d


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