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 */
55 static int adjkerntz;
56 static int
sysctl_machdep_adjkerntz(SYSCTL_HANDLER_ARGS)57 sysctl_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 }
65 SYSCTL_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
69 static int ct_debug;
70 SYSCTL_INT(_debug, OID_AUTO, clocktime, CTLFLAG_RWTUN,
71 &ct_debug, 0, "Enable printing of clocktime debugging");
72
73 static int wall_cmos_clock;
74 SYSCTL_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
90 static 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 */
99 static const int recent_base_year = 2017;
100 static 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 */
106 static 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 */
118 static int
leapyear(int year)119 leapyear(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
134 int
clock_ct_to_ts(const struct clocktime * ct,struct timespec * ts)135 clock_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
194 int
clock_bcd_to_ts(const struct bcd_clocktime * bct,struct timespec * ts,bool ampm)195 clock_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
243 void
clock_ts_to_ct(const struct timespec * ts,struct clocktime * ct)244 clock_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
304 void
clock_ts_to_bcd(const struct timespec * ts,struct bcd_clocktime * bct,bool ampm)305 clock_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
332 void
clock_print_bcd(const struct bcd_clocktime * bct,int nsdigits)333 clock_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
350 void
clock_print_ct(const struct clocktime * ct,int nsdigits)351 clock_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
368 void
clock_print_ts(const struct timespec * ts,int nsdigits)369 clock_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
377 int
utc_offset(void)378 utc_offset(void)
379 {
380
381 return (wall_cmos_clock ? adjkerntz : 0);
382 }
383