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 55 int tz_minuteswest; 56 int 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 */ 62 static int adjkerntz; 63 static int 64 sysctl_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 } 72 SYSCTL_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 76 static int ct_debug; 77 SYSCTL_INT(_debug, OID_AUTO, clocktime, CTLFLAG_RWTUN, 78 &ct_debug, 0, "Enable printing of clocktime debugging"); 79 80 static int wall_cmos_clock; 81 SYSCTL_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 98 static 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 */ 107 static const int recent_base_year = 2017; 108 static const int recent_base_days = 17167; 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 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 static void 135 print_ct(struct clocktime *ct) 136 { 137 printf("[%04d-%02d-%02d %02d:%02d:%02d]", 138 ct->year, ct->mon, ct->day, 139 ct->hour, ct->min, ct->sec); 140 } 141 142 int 143 clock_ct_to_ts(struct clocktime *ct, struct timespec *ts) 144 { 145 int i, year, days; 146 147 if (ct_debug) { 148 printf("ct_to_ts("); 149 print_ct(ct); 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 } 201 202 void 203 clock_ts_to_ct(struct timespec *ts, struct clocktime *ct) 204 { 205 time_t i, year, days; 206 time_t rsec; /* remainder seconds */ 207 time_t secs; 208 209 secs = ts->tv_sec; 210 days = secs / SECDAY; 211 rsec = secs % SECDAY; 212 213 ct->dow = day_of_week(days); 214 215 /* Subtract out whole years. */ 216 if (days >= recent_base_days) { 217 year = recent_base_year; 218 days -= recent_base_days; 219 } else { 220 year = POSIX_BASE_YEAR; 221 } 222 for (; days >= days_in_year(year); year++) 223 days -= days_in_year(year); 224 ct->year = year; 225 226 /* Subtract out whole months, counting them in i. */ 227 for (i = 1; days >= days_in_month(year, i); i++) 228 days -= days_in_month(year, i); 229 ct->mon = i; 230 231 /* Days are what is left over (+1) from all that. */ 232 ct->day = days + 1; 233 234 /* Hours, minutes, seconds are easy */ 235 ct->hour = rsec / 3600; 236 rsec = rsec % 3600; 237 ct->min = rsec / 60; 238 rsec = rsec % 60; 239 ct->sec = rsec; 240 ct->nsec = ts->tv_nsec; 241 if (ct_debug) { 242 printf("ts_to_ct(%jd.%09ld) = ", 243 (intmax_t)ts->tv_sec, ts->tv_nsec); 244 print_ct(ct); 245 printf("\n"); 246 } 247 248 KASSERT(ct->year >= 0 && ct->year < 10000, 249 ("year %d isn't a 4 digit year", ct->year)); 250 KASSERT(ct->mon >= 1 && ct->mon <= 12, 251 ("month %d not in 1-12", ct->mon)); 252 KASSERT(ct->day >= 1 && ct->day <= 31, 253 ("day %d not in 1-31", ct->day)); 254 KASSERT(ct->hour >= 0 && ct->hour <= 23, 255 ("hour %d not in 0-23", ct->hour)); 256 KASSERT(ct->min >= 0 && ct->min <= 59, 257 ("minute %d not in 0-59", ct->min)); 258 /* Not sure if this interface needs to handle leapseconds or not. */ 259 KASSERT(ct->sec >= 0 && ct->sec <= 60, 260 ("seconds %d not in 0-60", ct->sec)); 261 } 262 263 int 264 utc_offset(void) 265 { 266 267 return (tz_minuteswest * 60 + (wall_cmos_clock ? adjkerntz : 0)); 268 } 269