1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (C) 1993-1998 by Andrey A. Chernov, Moscow, Russia. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #if 0 30 #ifndef lint 31 static const char copyright[] = 32 "@(#)Copyright (C) 1993-1996 by Andrey A. Chernov, Moscow, Russia.\n\ 33 All rights reserved.\n"; 34 #endif /* not lint */ 35 #endif 36 #include <sys/cdefs.h> 37 __FBSDID("$FreeBSD$"); 38 39 /* 40 * Andrey A. Chernov <ache@astral.msk.su> Dec 20 1993 41 * 42 * Fix kernel time value if machine run wall CMOS clock 43 * (and /etc/wall_cmos_clock file present) 44 * using zoneinfo rules or direct TZ environment variable set. 45 * Use Joerg Wunsch idea for seconds accurate offset calculation 46 * with Garrett Wollman and Bruce Evans fixes. 47 * 48 */ 49 #include <stdio.h> 50 #include <signal.h> 51 #include <stdlib.h> 52 #include <unistd.h> 53 #include <syslog.h> 54 #include <sys/time.h> 55 #include <sys/param.h> 56 #include <machine/cpu.h> 57 #include <sys/sysctl.h> 58 59 #include "pathnames.h" 60 61 /*#define DEBUG*/ 62 63 #define True (1) 64 #define False (0) 65 #define Unknown (-1) 66 67 #define REPORT_PERIOD (30*60) 68 69 static void fake(int); 70 static void usage(void); 71 72 static void 73 fake(int unused __unused) 74 { 75 76 /* Do nothing. */ 77 } 78 79 int 80 main(int argc, char *argv[]) 81 { 82 struct tm local; 83 struct timeval tv, *stv; 84 struct timezone tz, *stz; 85 int kern_offset, wall_clock, disrtcset; 86 size_t len; 87 /* Avoid time_t here, can be unsigned long or worse */ 88 long offset, localsec, diff; 89 time_t initial_sec, final_sec; 90 int ch; 91 int initial_isdst = -1, final_isdst; 92 int need_restore = False, sleep_mode = False, looping, 93 init = Unknown; 94 sigset_t mask, emask; 95 96 while ((ch = getopt(argc, argv, "ais")) != -1) 97 switch((char)ch) { 98 case 'i': /* initial call, save offset */ 99 if (init != Unknown) 100 usage(); 101 init = True; 102 break; 103 case 'a': /* adjustment call, use saved offset */ 104 if (init != Unknown) 105 usage(); 106 init = False; 107 break; 108 case 's': 109 sleep_mode = True; 110 break; 111 default: 112 usage(); 113 } 114 if (init == Unknown) 115 usage(); 116 117 if (access(_PATH_CLOCK, F_OK) != 0) 118 return 0; 119 120 if (init) 121 sleep_mode = True; 122 123 sigemptyset(&mask); 124 sigemptyset(&emask); 125 sigaddset(&mask, SIGTERM); 126 127 openlog("adjkerntz", LOG_PID|LOG_PERROR, LOG_DAEMON); 128 129 (void) signal(SIGHUP, SIG_IGN); 130 131 if (init && daemon(0, 132 #ifdef DEBUG 133 1 134 #else 135 0 136 #endif 137 )) { 138 syslog(LOG_ERR, "daemon: %m"); 139 return 1; 140 } 141 142 again: 143 (void) sigprocmask(SIG_BLOCK, &mask, NULL); 144 (void) signal(SIGTERM, fake); 145 146 diff = 0; 147 stv = NULL; 148 stz = NULL; 149 looping = False; 150 151 wall_clock = (access(_PATH_CLOCK, F_OK) == 0); 152 if (init && !sleep_mode) { 153 init = False; 154 if (!wall_clock) 155 return 0; 156 } 157 158 tzset(); 159 160 len = sizeof(kern_offset); 161 if (sysctlbyname("machdep.adjkerntz", &kern_offset, &len, NULL, 0) == -1) { 162 syslog(LOG_ERR, "sysctl(\"machdep.adjkerntz\"): %m"); 163 return 1; 164 } 165 166 /****** Critical section, do all things as fast as possible ******/ 167 168 /* get local CMOS clock and possible kernel offset */ 169 if (gettimeofday(&tv, &tz)) { 170 syslog(LOG_ERR, "gettimeofday: %m"); 171 return 1; 172 } 173 174 /* get the actual local timezone difference */ 175 initial_sec = tv.tv_sec; 176 177 recalculate: 178 local = *localtime(&initial_sec); 179 if (diff == 0) 180 initial_isdst = local.tm_isdst; 181 local.tm_isdst = initial_isdst; 182 183 /* calculate local CMOS diff from GMT */ 184 185 localsec = mktime(&local); 186 if (localsec == -1) { 187 /* 188 * XXX user can only control local time, and it is 189 * unacceptable to fail here for init. 2:30 am in the 190 * middle of the nonexistent hour means 3:30 am. 191 */ 192 if (!sleep_mode) { 193 syslog(LOG_WARNING, 194 "Warning: nonexistent local time, try to run later."); 195 syslog(LOG_WARNING, "Giving up."); 196 return 1; 197 } 198 syslog(LOG_WARNING, 199 "Warning: nonexistent local time."); 200 syslog(LOG_WARNING, "Will retry after %d minutes.", 201 REPORT_PERIOD / 60); 202 (void) signal(SIGTERM, SIG_DFL); 203 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL); 204 (void) sleep(REPORT_PERIOD); 205 goto again; 206 } 207 offset = -local.tm_gmtoff; 208 #ifdef DEBUG 209 fprintf(stderr, "Initial offset: %ld secs\n", offset); 210 #endif 211 212 /* correct the kerneltime for this diffs */ 213 /* subtract kernel offset, if present, old offset too */ 214 215 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 216 217 if (diff != 0) { 218 #ifdef DEBUG 219 fprintf(stderr, "Initial diff: %ld secs\n", diff); 220 #endif 221 /* Yet one step for final time */ 222 223 final_sec = initial_sec + diff; 224 225 /* get the actual local timezone difference */ 226 local = *localtime(&final_sec); 227 final_isdst = diff < 0 ? initial_isdst : local.tm_isdst; 228 if (diff > 0 && initial_isdst != final_isdst) { 229 if (looping) 230 goto bad_final; 231 looping = True; 232 initial_isdst = final_isdst; 233 goto recalculate; 234 } 235 local.tm_isdst = final_isdst; 236 237 localsec = mktime(&local); 238 if (localsec == -1) { 239 bad_final: 240 /* 241 * XXX as above. The user has even less control, 242 * but perhaps we never get here. 243 */ 244 if (!sleep_mode) { 245 syslog(LOG_WARNING, 246 "Warning: nonexistent final local time, try to run later."); 247 syslog(LOG_WARNING, "Giving up."); 248 return 1; 249 } 250 syslog(LOG_WARNING, 251 "Warning: nonexistent final local time."); 252 syslog(LOG_WARNING, "Will retry after %d minutes.", 253 REPORT_PERIOD / 60); 254 (void) signal(SIGTERM, SIG_DFL); 255 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL); 256 (void) sleep(REPORT_PERIOD); 257 goto again; 258 } 259 offset = -local.tm_gmtoff; 260 #ifdef DEBUG 261 fprintf(stderr, "Final offset: %ld secs\n", offset); 262 #endif 263 264 /* correct the kerneltime for this diffs */ 265 /* subtract kernel offset, if present, old offset too */ 266 267 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 268 269 if (diff != 0) { 270 #ifdef DEBUG 271 fprintf(stderr, "Final diff: %ld secs\n", diff); 272 #endif 273 /* 274 * stv is abused as a flag. The important value 275 * is in `diff'. 276 */ 277 stv = &tv; 278 } 279 } 280 281 if (tz.tz_dsttime != 0 || tz.tz_minuteswest != 0) { 282 tz.tz_dsttime = tz.tz_minuteswest = 0; /* zone info is garbage */ 283 stz = &tz; 284 } 285 if (!wall_clock && stz == NULL) 286 stv = NULL; 287 288 /* if init or UTC clock and offset/date will be changed, */ 289 /* disable RTC modification for a while. */ 290 291 if ( (init && stv != NULL) 292 || ((init || !wall_clock) && kern_offset != offset) 293 ) { 294 len = sizeof(disrtcset); 295 if (sysctlbyname("machdep.disable_rtc_set", &disrtcset, &len, NULL, 0) == -1) { 296 syslog(LOG_ERR, "sysctl(get: \"machdep.disable_rtc_set\"): %m"); 297 return 1; 298 } 299 if (disrtcset == 0) { 300 disrtcset = 1; 301 need_restore = True; 302 if (sysctlbyname("machdep.disable_rtc_set", NULL, NULL, &disrtcset, len) == -1) { 303 syslog(LOG_ERR, "sysctl(set: \"machdep.disable_rtc_set\"): %m"); 304 return 1; 305 } 306 } 307 } 308 309 if ( (init && (stv != NULL || stz != NULL)) 310 || (stz != NULL && stv == NULL) 311 ) { 312 if (stv != NULL) { 313 /* 314 * Get the time again, as close as possible to 315 * adjusting it, to minimise drift. 316 * XXX we'd better not fail between here and 317 * restoring disrtcset, since we don't clean up 318 * anything. 319 */ 320 (void)gettimeofday(&tv, NULL); 321 tv.tv_sec += diff; 322 stv = &tv; 323 } 324 if (settimeofday(stv, stz)) { 325 syslog(LOG_ERR, "settimeofday: %m"); 326 return 1; 327 } 328 } 329 330 /* setting machdep.adjkerntz have a side effect: resettodr(), which */ 331 /* can be disabled by machdep.disable_rtc_set, so if init or UTC clock */ 332 /* -- don't write RTC, else write RTC. */ 333 334 if (kern_offset != offset) { 335 kern_offset = offset; 336 len = sizeof(kern_offset); 337 if (sysctlbyname("machdep.adjkerntz", NULL, NULL, &kern_offset, len) == -1) { 338 syslog(LOG_ERR, "sysctl(set: \"machdep.adjkerntz\"): %m"); 339 return 1; 340 } 341 } 342 343 len = sizeof(wall_clock); 344 if (sysctlbyname("machdep.wall_cmos_clock", NULL, NULL, &wall_clock, len) == -1) { 345 syslog(LOG_ERR, "sysctl(set: \"machdep.wall_cmos_clock\"): %m"); 346 return 1; 347 } 348 349 if (need_restore) { 350 need_restore = False; 351 disrtcset = 0; 352 len = sizeof(disrtcset); 353 if (sysctlbyname("machdep.disable_rtc_set", NULL, NULL, &disrtcset, len) == -1) { 354 syslog(LOG_ERR, "sysctl(set: \"machdep.disable_rtc_set\"): %m"); 355 return 1; 356 } 357 } 358 359 /****** End of critical section ******/ 360 361 if (init && wall_clock) { 362 sleep_mode = False; 363 /* wait for signals and acts like -a */ 364 (void) sigsuspend(&emask); 365 goto again; 366 } 367 368 return 0; 369 } 370 371 static void 372 usage(void) 373 { 374 fprintf(stderr, "%s\n%s\n%s\n%s\n", 375 "usage: adjkerntz -i", 376 "\t\t(initial call from /etc/rc)", 377 " adjkerntz -a [-s]", 378 "\t\t(adjustment call, -s for sleep/retry mode)"); 379 exit(2); 380 } 381