1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1988 University of Utah.
5 * Copyright (c) 1982, 1990, 1993
6 *	The Regents of the University of California.  All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * the Systems Programming Group of the University of Utah Computer
10 * Science Department.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 *    notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 *    notice, this list of conditions and the following disclaimer in the
19 *    documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 *	from: Utah $Hdr: clock.c 1.18 91/01/21$
37 *	from: @(#)clock.c	8.2 (Berkeley) 1/12/94
38 *	from: NetBSD: clock_subr.c,v 1.6 2001/07/07 17:04:02 thorpej Exp
39 *	and
40 *	from: src/sys/i386/isa/clock.c,v 1.176 2001/09/04
41 */
42
43#include <sys/cdefs.h>
44__FBSDID("$FreeBSD$");
45
46#include <sys/param.h>
47#include <sys/systm.h>
48#include <sys/kernel.h>
49#include <sys/bus.h>
50#include <sys/clock.h>
51#include <sys/limits.h>
52#include <sys/sysctl.h>
53#include <sys/timetc.h>
54
55int tz_minuteswest;
56int tz_dsttime;
57
58/*
59 * The adjkerntz and wall_cmos_clock sysctls are in the "machdep" sysctl
60 * namespace because they were misplaced there originally.
61 */
62static int adjkerntz;
63static int
64sysctl_machdep_adjkerntz(SYSCTL_HANDLER_ARGS)
65{
66	int error;
67	error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
68	if (!error && req->newptr)
69		resettodr();
70	return (error);
71}
72SYSCTL_PROC(_machdep, OID_AUTO, adjkerntz, CTLTYPE_INT | CTLFLAG_RW |
73    CTLFLAG_MPSAFE, &adjkerntz, 0, sysctl_machdep_adjkerntz, "I",
74    "Local offset from UTC in seconds");
75
76static int ct_debug;
77SYSCTL_INT(_debug, OID_AUTO, clocktime, CTLFLAG_RWTUN,
78    &ct_debug, 0, "Enable printing of clocktime debugging");
79
80static int wall_cmos_clock;
81SYSCTL_INT(_machdep, OID_AUTO, wall_cmos_clock, CTLFLAG_RW,
82    &wall_cmos_clock, 0, "Enables application of machdep.adjkerntz");
83
84/*--------------------------------------------------------------------*
85 * Generic routines to convert between a POSIX date
86 * (seconds since 1/1/1970) and yr/mo/day/hr/min/sec
87 * Derived from NetBSD arch/hp300/hp300/clock.c
88 */
89
90
91#define	FEBRUARY	2
92#define	days_in_year(y) 	(leapyear(y) ? 366 : 365)
93#define	days_in_month(y, m) \
94	(month_days[(m) - 1] + (m == FEBRUARY ? leapyear(y) : 0))
95/* Day of week. Days are counted from 1/1/1970, which was a Thursday */
96#define	day_of_week(days)	(((days) + 4) % 7)
97
98static const int month_days[12] = {
99	31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
100};
101
102/*
103 * Optimization: using a precomputed count of days between POSIX_BASE_YEAR and
104 * some recent year avoids lots of unnecessary loop iterations in conversion.
105 * recent_base_days is the number of days before the start of recent_base_year.
106 */
107static const int recent_base_year = 2017;
108static const int recent_base_days = 17167;
109
110/*
111 * Table to 'calculate' pow(10, 9 - nsdigits) via lookup of nsdigits.
112 * Before doing the lookup, the code asserts 0 <= nsdigits <= 9.
113 */
114static u_int nsdivisors[] = {
115    1000000000, 100000000, 10000000, 1000000, 100000, 10000, 1000, 100, 10, 1
116};
117
118/*
119 * This inline avoids some unnecessary modulo operations
120 * as compared with the usual macro:
121 *   ( ((year % 4) == 0 &&
122 *      (year % 100) != 0) ||
123 *     ((year % 400) == 0) )
124 * It is otherwise equivalent.
125 */
126static int
127leapyear(int year)
128{
129	int rv = 0;
130
131	if ((year & 3) == 0) {
132		rv = 1;
133		if ((year % 100) == 0) {
134			rv = 0;
135			if ((year % 400) == 0)
136				rv = 1;
137		}
138	}
139	return (rv);
140}
141
142int
143clock_ct_to_ts(const struct clocktime *ct, struct timespec *ts)
144{
145	int i, year, days;
146
147	if (ct_debug) {
148		printf("ct_to_ts([");
149		clock_print_ct(ct, 9);
150		printf("])");
151	}
152
153	/*
154	 * Many realtime clocks store the year as 2-digit BCD; pivot on 70 to
155	 * determine century.  Some clocks have a "century bit" and drivers do
156	 * year += 100, so interpret values between 70-199 as relative to 1900.
157	 */
158	year = ct->year;
159	if (year < 70)
160		year += 2000;
161	else if (year < 200)
162		year += 1900;
163
164	/* Sanity checks. */
165	if (ct->mon < 1 || ct->mon > 12 || ct->day < 1 ||
166	    ct->day > days_in_month(year, ct->mon) ||
167	    ct->hour > 23 ||  ct->min > 59 || ct->sec > 59 || year < 1970 ||
168	    (sizeof(time_t) == 4 && year > 2037)) {	/* time_t overflow */
169		if (ct_debug)
170			printf(" = EINVAL\n");
171		return (EINVAL);
172	}
173
174	/*
175	 * Compute days since start of time
176	 * First from years, then from months.
177	 */
178	if (year >= recent_base_year) {
179		i = recent_base_year;
180		days = recent_base_days;
181	} else {
182		i = POSIX_BASE_YEAR;
183		days = 0;
184	}
185	for (; i < year; i++)
186		days += days_in_year(i);
187
188	/* Months */
189	for (i = 1; i < ct->mon; i++)
190	  	days += days_in_month(year, i);
191	days += (ct->day - 1);
192
193	ts->tv_sec = (((time_t)days * 24 + ct->hour) * 60 + ct->min) * 60 +
194	    ct->sec;
195	ts->tv_nsec = ct->nsec;
196
197	if (ct_debug)
198		printf(" = %jd.%09ld\n", (intmax_t)ts->tv_sec, ts->tv_nsec);
199	return (0);
200}
201
202int
203clock_bcd_to_ts(const struct bcd_clocktime *bct, struct timespec *ts, bool ampm)
204{
205	struct clocktime ct;
206	int bcent, byear;
207
208	/*
209	 * Year may come in as 2-digit or 4-digit BCD.  Split the value into
210	 * separate BCD century and year values for validation and conversion.
211	 */
212	bcent = bct->year >> 8;
213	byear = bct->year & 0xff;
214
215	/*
216	 * Ensure that all values are valid BCD numbers, to avoid assertions in
217	 * the BCD-to-binary conversion routines.  clock_ct_to_ts() will further
218	 * validate the field ranges (such as 0 <= min <= 59) during conversion.
219	 */
220	if (!validbcd(bcent) || !validbcd(byear) || !validbcd(bct->mon) ||
221	    !validbcd(bct->day) || !validbcd(bct->hour) ||
222	    !validbcd(bct->min) || !validbcd(bct->sec)) {
223		if (ct_debug)
224			printf("clock_bcd_to_ts: bad BCD: "
225			    "[%04x-%02x-%02x %02x:%02x:%02x]\n",
226			    bct->year, bct->mon, bct->day,
227			    bct->hour, bct->min, bct->sec);
228		return (EINVAL);
229	}
230
231	ct.year = FROMBCD(byear) + FROMBCD(bcent) * 100;
232	ct.mon  = FROMBCD(bct->mon);
233	ct.day  = FROMBCD(bct->day);
234	ct.hour = FROMBCD(bct->hour);
235	ct.min  = FROMBCD(bct->min);
236	ct.sec  = FROMBCD(bct->sec);
237	ct.dow  = bct->dow;
238	ct.nsec = bct->nsec;
239
240	/* If asked to handle am/pm, convert from 12hr+pmflag to 24hr. */
241	if (ampm) {
242		if (ct.hour == 12)
243			ct.hour = 0;
244		if (bct->ispm)
245			ct.hour += 12;
246	}
247
248	return (clock_ct_to_ts(&ct, ts));
249}
250
251void
252clock_ts_to_ct(const struct timespec *ts, struct clocktime *ct)
253{
254	time_t i, year, days;
255	time_t rsec;	/* remainder seconds */
256	time_t secs;
257
258	secs = ts->tv_sec;
259	days = secs / SECDAY;
260	rsec = secs % SECDAY;
261
262	ct->dow = day_of_week(days);
263
264	/* Subtract out whole years. */
265	if (days >= recent_base_days) {
266		year = recent_base_year;
267		days -= recent_base_days;
268	} else {
269		year = POSIX_BASE_YEAR;
270	}
271	for (; days >= days_in_year(year); year++)
272		days -= days_in_year(year);
273	ct->year = year;
274
275	/* Subtract out whole months, counting them in i. */
276	for (i = 1; days >= days_in_month(year, i); i++)
277		days -= days_in_month(year, i);
278	ct->mon = i;
279
280	/* Days are what is left over (+1) from all that. */
281	ct->day = days + 1;
282
283	/* Hours, minutes, seconds are easy */
284	ct->hour = rsec / 3600;
285	rsec = rsec % 3600;
286	ct->min  = rsec / 60;
287	rsec = rsec % 60;
288	ct->sec  = rsec;
289	ct->nsec = ts->tv_nsec;
290	if (ct_debug) {
291		printf("ts_to_ct(%jd.%09ld) = [",
292		    (intmax_t)ts->tv_sec, ts->tv_nsec);
293		clock_print_ct(ct, 9);
294		printf("]\n");
295	}
296
297	KASSERT(ct->year >= 0 && ct->year < 10000,
298	    ("year %d isn't a 4 digit year", ct->year));
299	KASSERT(ct->mon >= 1 && ct->mon <= 12,
300	    ("month %d not in 1-12", ct->mon));
301	KASSERT(ct->day >= 1 && ct->day <= 31,
302	    ("day %d not in 1-31", ct->day));
303	KASSERT(ct->hour >= 0 && ct->hour <= 23,
304	    ("hour %d not in 0-23", ct->hour));
305	KASSERT(ct->min >= 0 && ct->min <= 59,
306	    ("minute %d not in 0-59", ct->min));
307	/* Not sure if this interface needs to handle leapseconds or not. */
308	KASSERT(ct->sec >= 0 && ct->sec <= 60,
309	    ("seconds %d not in 0-60", ct->sec));
310}
311
312void
313clock_ts_to_bcd(const struct timespec *ts, struct bcd_clocktime *bct, bool ampm)
314{
315	struct clocktime ct;
316
317	clock_ts_to_ct(ts, &ct);
318
319	/* If asked to handle am/pm, convert from 24hr to 12hr+pmflag. */
320	bct->ispm = false;
321	if (ampm) {
322		if (ct.hour >= 12) {
323			ct.hour -= 12;
324			bct->ispm = true;
325		}
326		if (ct.hour == 0)
327			ct.hour = 12;
328	}
329
330	bct->year = TOBCD(ct.year % 100) | (TOBCD(ct.year / 100) << 8);
331	bct->mon  = TOBCD(ct.mon);
332	bct->day  = TOBCD(ct.day);
333	bct->hour = TOBCD(ct.hour);
334	bct->min  = TOBCD(ct.min);
335	bct->sec  = TOBCD(ct.sec);
336	bct->dow  = ct.dow;
337	bct->nsec = ct.nsec;
338}
339
340void
341clock_print_bcd(const struct bcd_clocktime *bct, int nsdigits)
342{
343
344	KASSERT(nsdigits >= 0 && nsdigits <= 9, ("bad nsdigits %d", nsdigits));
345
346	if (nsdigits > 0) {
347		printf("%4.4x-%2.2x-%2.2x %2.2x:%2.2x:%2.2x.%*.*ld",
348		    bct->year, bct->mon, bct->day,
349		    bct->hour, bct->min, bct->sec,
350		    nsdigits, nsdigits, bct->nsec / nsdivisors[nsdigits]);
351	} else {
352		printf("%4.4x-%2.2x-%2.2x %2.2x:%2.2x:%2.2x",
353		    bct->year, bct->mon, bct->day,
354		    bct->hour, bct->min, bct->sec);
355	}
356}
357
358void
359clock_print_ct(const struct clocktime *ct, int nsdigits)
360{
361
362	KASSERT(nsdigits >= 0 && nsdigits <= 9, ("bad nsdigits %d", nsdigits));
363
364	if (nsdigits > 0) {
365		printf("%04d-%02d-%02d %02d:%02d:%02d.%*.*ld",
366		    ct->year, ct->mon, ct->day,
367		    ct->hour, ct->min, ct->sec,
368		    nsdigits, nsdigits, ct->nsec / nsdivisors[nsdigits]);
369	} else {
370		printf("%04d-%02d-%02d %02d:%02d:%02d",
371		    ct->year, ct->mon, ct->day,
372		    ct->hour, ct->min, ct->sec);
373	}
374}
375
376void
377clock_print_ts(const struct timespec *ts, int nsdigits)
378{
379	struct clocktime ct;
380
381	clock_ts_to_ct(ts, &ct);
382	clock_print_ct(&ct, nsdigits);
383}
384
385int
386utc_offset(void)
387{
388
389	return (tz_minuteswest * 60 + (wall_cmos_clock ? adjkerntz : 0));
390}
391