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/limits.h>
50#include <sys/sysctl.h>
51#include <sys/timetc.h>
52
53int tz_minuteswest;
54int tz_dsttime;
55
56/*
57 * The adjkerntz and wall_cmos_clock sysctls are in the "machdep" sysctl
58 * namespace because they were misplaced there originally.
59 */
60static int adjkerntz;
61static int
62sysctl_machdep_adjkerntz(SYSCTL_HANDLER_ARGS)
63{
64	int error;
65	error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
66	if (!error && req->newptr)
67		resettodr();
68	return (error);
69}
70SYSCTL_PROC(_machdep, OID_AUTO, adjkerntz, CTLTYPE_INT|CTLFLAG_RW,
71    &adjkerntz, 0, sysctl_machdep_adjkerntz, "I",
72    "Local offset from UTC in seconds");
73
74static int ct_debug;
75SYSCTL_INT(_debug, OID_AUTO, clocktime, CTLFLAG_RW,
76    &ct_debug, 0, "Enable printing of clocktime debugging");
77
78static int wall_cmos_clock;
79SYSCTL_INT(_machdep, OID_AUTO, wall_cmos_clock, CTLFLAG_RW,
80    &wall_cmos_clock, 0, "Enables application of machdep.adjkerntz");
81
82/*--------------------------------------------------------------------*
83 * Generic routines to convert between a POSIX date
84 * (seconds since 1/1/1970) and yr/mo/day/hr/min/sec
85 * Derived from NetBSD arch/hp300/hp300/clock.c
86 */
87
88
89#define	FEBRUARY	2
90#define	days_in_year(y) 	(leapyear(y) ? 366 : 365)
91#define	days_in_month(y, m) \
92	(month_days[(m) - 1] + (m == FEBRUARY ? leapyear(y) : 0))
93/* Day of week. Days are counted from 1/1/1970, which was a Thursday */
94#define	day_of_week(days)	(((days) + 4) % 7)
95
96static const int month_days[12] = {
97	31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
98};
99
100
101/*
102 * This inline avoids some unnecessary modulo operations
103 * as compared with the usual macro:
104 *   ( ((year % 4) == 0 &&
105 *      (year % 100) != 0) ||
106 *     ((year % 400) == 0) )
107 * It is otherwise equivalent.
108 */
109static int
110leapyear(int year)
111{
112	int rv = 0;
113
114	if ((year & 3) == 0) {
115		rv = 1;
116		if ((year % 100) == 0) {
117			rv = 0;
118			if ((year % 400) == 0)
119				rv = 1;
120		}
121	}
122	return (rv);
123}
124
125static void
126print_ct(struct clocktime *ct)
127{
128	printf("[%04d-%02d-%02d %02d:%02d:%02d]",
129	    ct->year, ct->mon, ct->day,
130	    ct->hour, ct->min, ct->sec);
131}
132
133int
134clock_ct_to_ts(struct clocktime *ct, struct timespec *ts)
135{
136	time_t secs;
137	int i, year, days;
138
139	year = ct->year;
140
141	if (ct_debug) {
142		printf("ct_to_ts(");
143		print_ct(ct);
144		printf(")");
145	}
146
147	/* Sanity checks. */
148	if (ct->mon < 1 || ct->mon > 12 || ct->day < 1 ||
149	    ct->day > days_in_month(year, ct->mon) ||
150	    ct->hour > 23 ||  ct->min > 59 || ct->sec > 59 ||
151	    (sizeof(time_t) == 4 && year > 2037)) {	/* time_t overflow */
152		if (ct_debug)
153			printf(" = EINVAL\n");
154		return (EINVAL);
155	}
156
157	/*
158	 * Compute days since start of time
159	 * First from years, then from months.
160	 */
161	days = 0;
162	for (i = POSIX_BASE_YEAR; i < year; i++)
163		days += days_in_year(i);
164
165	/* Months */
166	for (i = 1; i < ct->mon; i++)
167	  	days += days_in_month(year, i);
168	days += (ct->day - 1);
169
170	/* Add hours, minutes, seconds. */
171	secs = ((days * 24 + ct->hour) * 60 + ct->min) * 60 + ct->sec;
172
173	ts->tv_sec = secs;
174	ts->tv_nsec = ct->nsec;
175	if (ct_debug)
176		printf(" = %ld.%09ld\n", (long)ts->tv_sec, (long)ts->tv_nsec);
177	return (0);
178}
179
180void
181clock_ts_to_ct(struct timespec *ts, struct clocktime *ct)
182{
183	int i, year, days;
184	time_t rsec;	/* remainder seconds */
185	time_t secs;
186
187	secs = ts->tv_sec;
188	days = secs / SECDAY;
189	rsec = secs % SECDAY;
190
191	ct->dow = day_of_week(days);
192
193	/* Subtract out whole years, counting them in i. */
194	for (year = POSIX_BASE_YEAR; days >= days_in_year(year); year++)
195		days -= days_in_year(year);
196	ct->year = year;
197
198	/* Subtract out whole months, counting them in i. */
199	for (i = 1; days >= days_in_month(year, i); i++)
200		days -= days_in_month(year, i);
201	ct->mon = i;
202
203	/* Days are what is left over (+1) from all that. */
204	ct->day = days + 1;
205
206	/* Hours, minutes, seconds are easy */
207	ct->hour = rsec / 3600;
208	rsec = rsec % 3600;
209	ct->min  = rsec / 60;
210	rsec = rsec % 60;
211	ct->sec  = rsec;
212	ct->nsec = ts->tv_nsec;
213	if (ct_debug) {
214		printf("ts_to_ct(%ld.%09ld) = ",
215		    (long)ts->tv_sec, (long)ts->tv_nsec);
216		print_ct(ct);
217		printf("\n");
218	}
219}
220
221int
222utc_offset(void)
223{
224
225	return (tz_minuteswest * 60 + (wall_cmos_clock ? adjkerntz : 0));
226}
227