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: NetBSD: clock_subr.c,v 1.6 2001/07/07 17:04:02 thorpej Exp
38 *	and
39 *	from: src/sys/i386/isa/clock.c,v 1.176 2001/09/04
40 */
41
42#include <sys/param.h>
43#include <sys/systm.h>
44#include <sys/kernel.h>
45#include <sys/bus.h>
46#include <sys/clock.h>
47#include <sys/limits.h>
48#include <sys/sysctl.h>
49#include <sys/timetc.h>
50
51/*
52 * The adjkerntz and wall_cmos_clock sysctls are in the "machdep" sysctl
53 * namespace because they were misplaced there originally.
54 */
55static int adjkerntz;
56static int
57sysctl_machdep_adjkerntz(SYSCTL_HANDLER_ARGS)
58{
59	int error;
60	error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
61	if (!error && req->newptr)
62		resettodr();
63	return (error);
64}
65SYSCTL_PROC(_machdep, OID_AUTO, adjkerntz, CTLTYPE_INT | CTLFLAG_RW |
66    CTLFLAG_MPSAFE, &adjkerntz, 0, sysctl_machdep_adjkerntz, "I",
67    "Local offset from UTC in seconds");
68
69static int ct_debug;
70SYSCTL_INT(_debug, OID_AUTO, clocktime, CTLFLAG_RWTUN,
71    &ct_debug, 0, "Enable printing of clocktime debugging");
72
73static int wall_cmos_clock;
74SYSCTL_INT(_machdep, OID_AUTO, wall_cmos_clock, CTLFLAG_RW,
75    &wall_cmos_clock, 0, "Enables application of machdep.adjkerntz");
76
77/*--------------------------------------------------------------------*
78 * Generic routines to convert between a POSIX date
79 * (seconds since 1/1/1970) and yr/mo/day/hr/min/sec
80 * Derived from NetBSD arch/hp300/hp300/clock.c
81 */
82
83#define	FEBRUARY	2
84#define	days_in_year(y) 	(leapyear(y) ? 366 : 365)
85#define	days_in_month(y, m) \
86	(month_days[(m) - 1] + (m == FEBRUARY ? leapyear(y) : 0))
87/* Day of week. Days are counted from 1/1/1970, which was a Thursday */
88#define	day_of_week(days)	(((days) + 4) % 7)
89
90static const int month_days[12] = {
91	31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
92};
93
94/*
95 * Optimization: using a precomputed count of days between POSIX_BASE_YEAR and
96 * some recent year avoids lots of unnecessary loop iterations in conversion.
97 * recent_base_days is the number of days before the start of recent_base_year.
98 */
99static const int recent_base_year = 2017;
100static const int recent_base_days = 17167;
101
102/*
103 * Table to 'calculate' pow(10, 9 - nsdigits) via lookup of nsdigits.
104 * Before doing the lookup, the code asserts 0 <= nsdigits <= 9.
105 */
106static u_int nsdivisors[] = {
107    1000000000, 100000000, 10000000, 1000000, 100000, 10000, 1000, 100, 10, 1
108};
109
110/*
111 * This inline avoids some unnecessary modulo operations
112 * as compared with the usual macro:
113 *   ( ((year % 4) == 0 &&
114 *      (year % 100) != 0) ||
115 *     ((year % 400) == 0) )
116 * It is otherwise equivalent.
117 */
118static int
119leapyear(int year)
120{
121	int rv = 0;
122
123	if ((year & 3) == 0) {
124		rv = 1;
125		if ((year % 100) == 0) {
126			rv = 0;
127			if ((year % 400) == 0)
128				rv = 1;
129		}
130	}
131	return (rv);
132}
133
134int
135clock_ct_to_ts(const struct clocktime *ct, struct timespec *ts)
136{
137	int i, year, days;
138
139	if (ct_debug) {
140		printf("ct_to_ts([");
141		clock_print_ct(ct, 9);
142		printf("])");
143	}
144
145	/*
146	 * Many realtime clocks store the year as 2-digit BCD; pivot on 70 to
147	 * determine century.  Some clocks have a "century bit" and drivers do
148	 * year += 100, so interpret values between 70-199 as relative to 1900.
149	 */
150	year = ct->year;
151	if (year < 70)
152		year += 2000;
153	else if (year < 200)
154		year += 1900;
155
156	/* Sanity checks. */
157	if (ct->mon < 1 || ct->mon > 12 || ct->day < 1 ||
158	    ct->day > days_in_month(year, ct->mon) ||
159	    ct->hour > 23 ||  ct->min > 59 || ct->sec > 59 || year < 1970 ||
160	    (sizeof(time_t) == 4 && year > 2037)) {	/* time_t overflow */
161		if (ct_debug)
162			printf(" = EINVAL\n");
163		return (EINVAL);
164	}
165
166	/*
167	 * Compute days since start of time
168	 * First from years, then from months.
169	 */
170	if (year >= recent_base_year) {
171		i = recent_base_year;
172		days = recent_base_days;
173	} else {
174		i = POSIX_BASE_YEAR;
175		days = 0;
176	}
177	for (; i < year; i++)
178		days += days_in_year(i);
179
180	/* Months */
181	for (i = 1; i < ct->mon; i++)
182	  	days += days_in_month(year, i);
183	days += (ct->day - 1);
184
185	ts->tv_sec = (((time_t)days * 24 + ct->hour) * 60 + ct->min) * 60 +
186	    ct->sec;
187	ts->tv_nsec = ct->nsec;
188
189	if (ct_debug)
190		printf(" = %jd.%09ld\n", (intmax_t)ts->tv_sec, ts->tv_nsec);
191	return (0);
192}
193
194int
195clock_bcd_to_ts(const struct bcd_clocktime *bct, struct timespec *ts, bool ampm)
196{
197	struct clocktime ct;
198	int bcent, byear;
199
200	/*
201	 * Year may come in as 2-digit or 4-digit BCD.  Split the value into
202	 * separate BCD century and year values for validation and conversion.
203	 */
204	bcent = bct->year >> 8;
205	byear = bct->year & 0xff;
206
207	/*
208	 * Ensure that all values are valid BCD numbers, to avoid assertions in
209	 * the BCD-to-binary conversion routines.  clock_ct_to_ts() will further
210	 * validate the field ranges (such as 0 <= min <= 59) during conversion.
211	 */
212	if (!validbcd(bcent) || !validbcd(byear) || !validbcd(bct->mon) ||
213	    !validbcd(bct->day) || !validbcd(bct->hour) ||
214	    !validbcd(bct->min) || !validbcd(bct->sec)) {
215		if (ct_debug)
216			printf("clock_bcd_to_ts: bad BCD: "
217			    "[%04x-%02x-%02x %02x:%02x:%02x]\n",
218			    bct->year, bct->mon, bct->day,
219			    bct->hour, bct->min, bct->sec);
220		return (EINVAL);
221	}
222
223	ct.year = FROMBCD(byear) + FROMBCD(bcent) * 100;
224	ct.mon  = FROMBCD(bct->mon);
225	ct.day  = FROMBCD(bct->day);
226	ct.hour = FROMBCD(bct->hour);
227	ct.min  = FROMBCD(bct->min);
228	ct.sec  = FROMBCD(bct->sec);
229	ct.dow  = bct->dow;
230	ct.nsec = bct->nsec;
231
232	/* If asked to handle am/pm, convert from 12hr+pmflag to 24hr. */
233	if (ampm) {
234		if (ct.hour == 12)
235			ct.hour = 0;
236		if (bct->ispm)
237			ct.hour += 12;
238	}
239
240	return (clock_ct_to_ts(&ct, ts));
241}
242
243void
244clock_ts_to_ct(const struct timespec *ts, struct clocktime *ct)
245{
246	time_t i, year, days;
247	time_t rsec;	/* remainder seconds */
248	time_t secs;
249
250	secs = ts->tv_sec;
251	days = secs / SECDAY;
252	rsec = secs % SECDAY;
253
254	ct->dow = day_of_week(days);
255
256	/* Subtract out whole years. */
257	if (days >= recent_base_days) {
258		year = recent_base_year;
259		days -= recent_base_days;
260	} else {
261		year = POSIX_BASE_YEAR;
262	}
263	for (; days >= days_in_year(year); year++)
264		days -= days_in_year(year);
265	ct->year = year;
266
267	/* Subtract out whole months, counting them in i. */
268	for (i = 1; days >= days_in_month(year, i); i++)
269		days -= days_in_month(year, i);
270	ct->mon = i;
271
272	/* Days are what is left over (+1) from all that. */
273	ct->day = days + 1;
274
275	/* Hours, minutes, seconds are easy */
276	ct->hour = rsec / 3600;
277	rsec = rsec % 3600;
278	ct->min  = rsec / 60;
279	rsec = rsec % 60;
280	ct->sec  = rsec;
281	ct->nsec = ts->tv_nsec;
282	if (ct_debug) {
283		printf("ts_to_ct(%jd.%09ld) = [",
284		    (intmax_t)ts->tv_sec, ts->tv_nsec);
285		clock_print_ct(ct, 9);
286		printf("]\n");
287	}
288
289	KASSERT(ct->year >= 0 && ct->year < 10000,
290	    ("year %d isn't a 4 digit year", ct->year));
291	KASSERT(ct->mon >= 1 && ct->mon <= 12,
292	    ("month %d not in 1-12", ct->mon));
293	KASSERT(ct->day >= 1 && ct->day <= 31,
294	    ("day %d not in 1-31", ct->day));
295	KASSERT(ct->hour >= 0 && ct->hour <= 23,
296	    ("hour %d not in 0-23", ct->hour));
297	KASSERT(ct->min >= 0 && ct->min <= 59,
298	    ("minute %d not in 0-59", ct->min));
299	/* Not sure if this interface needs to handle leapseconds or not. */
300	KASSERT(ct->sec >= 0 && ct->sec <= 60,
301	    ("seconds %d not in 0-60", ct->sec));
302}
303
304void
305clock_ts_to_bcd(const struct timespec *ts, struct bcd_clocktime *bct, bool ampm)
306{
307	struct clocktime ct;
308
309	clock_ts_to_ct(ts, &ct);
310
311	/* If asked to handle am/pm, convert from 24hr to 12hr+pmflag. */
312	bct->ispm = false;
313	if (ampm) {
314		if (ct.hour >= 12) {
315			ct.hour -= 12;
316			bct->ispm = true;
317		}
318		if (ct.hour == 0)
319			ct.hour = 12;
320	}
321
322	bct->year = TOBCD(ct.year % 100) | (TOBCD(ct.year / 100) << 8);
323	bct->mon  = TOBCD(ct.mon);
324	bct->day  = TOBCD(ct.day);
325	bct->hour = TOBCD(ct.hour);
326	bct->min  = TOBCD(ct.min);
327	bct->sec  = TOBCD(ct.sec);
328	bct->dow  = ct.dow;
329	bct->nsec = ct.nsec;
330}
331
332void
333clock_print_bcd(const struct bcd_clocktime *bct, int nsdigits)
334{
335
336	KASSERT(nsdigits >= 0 && nsdigits <= 9, ("bad nsdigits %d", nsdigits));
337
338	if (nsdigits > 0) {
339		printf("%4.4x-%2.2x-%2.2x %2.2x:%2.2x:%2.2x.%*.*ld",
340		    bct->year, bct->mon, bct->day,
341		    bct->hour, bct->min, bct->sec,
342		    nsdigits, nsdigits, bct->nsec / nsdivisors[nsdigits]);
343	} else {
344		printf("%4.4x-%2.2x-%2.2x %2.2x:%2.2x:%2.2x",
345		    bct->year, bct->mon, bct->day,
346		    bct->hour, bct->min, bct->sec);
347	}
348}
349
350void
351clock_print_ct(const struct clocktime *ct, int nsdigits)
352{
353
354	KASSERT(nsdigits >= 0 && nsdigits <= 9, ("bad nsdigits %d", nsdigits));
355
356	if (nsdigits > 0) {
357		printf("%04d-%02d-%02d %02d:%02d:%02d.%*.*ld",
358		    ct->year, ct->mon, ct->day,
359		    ct->hour, ct->min, ct->sec,
360		    nsdigits, nsdigits, ct->nsec / nsdivisors[nsdigits]);
361	} else {
362		printf("%04d-%02d-%02d %02d:%02d:%02d",
363		    ct->year, ct->mon, ct->day,
364		    ct->hour, ct->min, ct->sec);
365	}
366}
367
368void
369clock_print_ts(const struct timespec *ts, int nsdigits)
370{
371	struct clocktime ct;
372
373	clock_ts_to_ct(ts, &ct);
374	clock_print_ct(&ct, nsdigits);
375}
376
377int
378utc_offset(void)
379{
380
381	return (wall_cmos_clock ? adjkerntz : 0);
382}
383