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 /* 30 * Andrey A. Chernov <ache@astral.msk.su> Dec 20 1993 31 * 32 * Fix kernel time value if machine run wall CMOS clock 33 * (and /etc/wall_cmos_clock file present) 34 * using zoneinfo rules or direct TZ environment variable set. 35 * Use Joerg Wunsch idea for seconds accurate offset calculation 36 * with Garrett Wollman and Bruce Evans fixes. 37 * 38 */ 39 #include <stdio.h> 40 #include <signal.h> 41 #include <stdlib.h> 42 #include <unistd.h> 43 #include <syslog.h> 44 #include <sys/time.h> 45 #include <sys/param.h> 46 #include <machine/cpu.h> 47 #include <sys/sysctl.h> 48 49 #include "pathnames.h" 50 51 /*#define DEBUG*/ 52 53 #define True (1) 54 #define False (0) 55 #define Unknown (-1) 56 57 #define REPORT_PERIOD (30*60) 58 59 static void fake(int); 60 static void usage(void) __dead2; 61 62 static void 63 fake(int unused __unused) 64 { 65 66 /* Do nothing. */ 67 } 68 69 int 70 main(int argc, char *argv[]) 71 { 72 struct tm local; 73 struct timeval tv, *stv; 74 struct timezone tz, *stz; 75 int kern_offset, wall_clock, disrtcset; 76 size_t len; 77 /* Avoid time_t here, can be unsigned long or worse */ 78 long offset, localsec, diff; 79 time_t initial_sec, final_sec; 80 int ch; 81 int initial_isdst = -1, final_isdst; 82 int need_restore = False, sleep_mode = False, looping, 83 init = Unknown; 84 sigset_t mask, emask; 85 86 while ((ch = getopt(argc, argv, "ais")) != -1) 87 switch((char)ch) { 88 case 'i': /* initial call, save offset */ 89 if (init != Unknown) 90 usage(); 91 init = True; 92 break; 93 case 'a': /* adjustment call, use saved offset */ 94 if (init != Unknown) 95 usage(); 96 init = False; 97 break; 98 case 's': 99 sleep_mode = True; 100 break; 101 default: 102 usage(); 103 } 104 if (init == Unknown) 105 usage(); 106 107 if (access(_PATH_CLOCK, F_OK) != 0) 108 return 0; 109 110 if (init) 111 sleep_mode = True; 112 113 sigemptyset(&mask); 114 sigemptyset(&emask); 115 sigaddset(&mask, SIGTERM); 116 117 openlog("adjkerntz", LOG_PID|LOG_PERROR, LOG_DAEMON); 118 119 (void) signal(SIGHUP, SIG_IGN); 120 121 if (init && daemon(0, 122 #ifdef DEBUG 123 1 124 #else 125 0 126 #endif 127 )) { 128 syslog(LOG_ERR, "daemon: %m"); 129 return 1; 130 } 131 132 again: 133 (void) sigprocmask(SIG_BLOCK, &mask, NULL); 134 (void) signal(SIGTERM, fake); 135 136 diff = 0; 137 stv = NULL; 138 stz = NULL; 139 looping = False; 140 141 wall_clock = (access(_PATH_CLOCK, F_OK) == 0); 142 if (init && !sleep_mode) { 143 init = False; 144 if (!wall_clock) 145 return 0; 146 } 147 148 tzset(); 149 150 len = sizeof(kern_offset); 151 if (sysctlbyname("machdep.adjkerntz", &kern_offset, &len, NULL, 0) == -1) { 152 syslog(LOG_ERR, "sysctl(\"machdep.adjkerntz\"): %m"); 153 return 1; 154 } 155 156 /****** Critical section, do all things as fast as possible ******/ 157 158 /* get local CMOS clock and possible kernel offset */ 159 if (gettimeofday(&tv, &tz)) { 160 syslog(LOG_ERR, "gettimeofday: %m"); 161 return 1; 162 } 163 164 /* get the actual local timezone difference */ 165 initial_sec = tv.tv_sec; 166 167 recalculate: 168 local = *localtime(&initial_sec); 169 if (diff == 0) 170 initial_isdst = local.tm_isdst; 171 local.tm_isdst = initial_isdst; 172 173 /* calculate local CMOS diff from GMT */ 174 175 localsec = mktime(&local); 176 if (localsec == -1) { 177 /* 178 * XXX user can only control local time, and it is 179 * unacceptable to fail here for init. 2:30 am in the 180 * middle of the nonexistent hour means 3:30 am. 181 */ 182 if (!sleep_mode) { 183 syslog(LOG_WARNING, 184 "Warning: nonexistent local time, try to run later."); 185 syslog(LOG_WARNING, "Giving up."); 186 return 1; 187 } 188 syslog(LOG_WARNING, 189 "Warning: nonexistent local time."); 190 syslog(LOG_WARNING, "Will retry after %d minutes.", 191 REPORT_PERIOD / 60); 192 (void) signal(SIGTERM, SIG_DFL); 193 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL); 194 (void) sleep(REPORT_PERIOD); 195 goto again; 196 } 197 offset = -local.tm_gmtoff; 198 #ifdef DEBUG 199 fprintf(stderr, "Initial offset: %ld secs\n", offset); 200 #endif 201 202 /* correct the kerneltime for this diffs */ 203 /* subtract kernel offset, if present, old offset too */ 204 205 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 206 207 if (diff != 0) { 208 #ifdef DEBUG 209 fprintf(stderr, "Initial diff: %ld secs\n", diff); 210 #endif 211 /* Yet one step for final time */ 212 213 final_sec = initial_sec + diff; 214 215 /* get the actual local timezone difference */ 216 local = *localtime(&final_sec); 217 final_isdst = diff < 0 ? initial_isdst : local.tm_isdst; 218 if (diff > 0 && initial_isdst != final_isdst) { 219 if (looping) 220 goto bad_final; 221 looping = True; 222 initial_isdst = final_isdst; 223 goto recalculate; 224 } 225 local.tm_isdst = final_isdst; 226 227 localsec = mktime(&local); 228 if (localsec == -1) { 229 bad_final: 230 /* 231 * XXX as above. The user has even less control, 232 * but perhaps we never get here. 233 */ 234 if (!sleep_mode) { 235 syslog(LOG_WARNING, 236 "Warning: nonexistent final local time, try to run later."); 237 syslog(LOG_WARNING, "Giving up."); 238 return 1; 239 } 240 syslog(LOG_WARNING, 241 "Warning: nonexistent final local time."); 242 syslog(LOG_WARNING, "Will retry after %d minutes.", 243 REPORT_PERIOD / 60); 244 (void) signal(SIGTERM, SIG_DFL); 245 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL); 246 (void) sleep(REPORT_PERIOD); 247 goto again; 248 } 249 offset = -local.tm_gmtoff; 250 #ifdef DEBUG 251 fprintf(stderr, "Final offset: %ld secs\n", offset); 252 #endif 253 254 /* correct the kerneltime for this diffs */ 255 /* subtract kernel offset, if present, old offset too */ 256 257 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 258 259 if (diff != 0) { 260 #ifdef DEBUG 261 fprintf(stderr, "Final diff: %ld secs\n", diff); 262 #endif 263 /* 264 * stv is abused as a flag. The important value 265 * is in `diff'. 266 */ 267 stv = &tv; 268 } 269 } 270 271 if (tz.tz_dsttime != 0 || tz.tz_minuteswest != 0) { 272 tz.tz_dsttime = tz.tz_minuteswest = 0; /* zone info is garbage */ 273 stz = &tz; 274 } 275 if (!wall_clock && stz == NULL) 276 stv = NULL; 277 278 /* if init or UTC clock and offset/date will be changed, */ 279 /* disable RTC modification for a while. */ 280 281 if ( (init && stv != NULL) 282 || ((init || !wall_clock) && kern_offset != offset) 283 ) { 284 len = sizeof(disrtcset); 285 if (sysctlbyname("machdep.disable_rtc_set", &disrtcset, &len, NULL, 0) == -1) { 286 syslog(LOG_ERR, "sysctl(get: \"machdep.disable_rtc_set\"): %m"); 287 return 1; 288 } 289 if (disrtcset == 0) { 290 disrtcset = 1; 291 need_restore = True; 292 if (sysctlbyname("machdep.disable_rtc_set", NULL, NULL, &disrtcset, len) == -1) { 293 syslog(LOG_ERR, "sysctl(set: \"machdep.disable_rtc_set\"): %m"); 294 return 1; 295 } 296 } 297 } 298 299 if ( (init && (stv != NULL || stz != NULL)) 300 || (stz != NULL && stv == NULL) 301 ) { 302 if (stv != NULL) { 303 /* 304 * Get the time again, as close as possible to 305 * adjusting it, to minimise drift. 306 * XXX we'd better not fail between here and 307 * restoring disrtcset, since we don't clean up 308 * anything. 309 */ 310 (void)gettimeofday(&tv, NULL); 311 tv.tv_sec += diff; 312 stv = &tv; 313 } 314 if (settimeofday(stv, stz)) { 315 syslog(LOG_ERR, "settimeofday: %m"); 316 return 1; 317 } 318 } 319 320 /* setting machdep.adjkerntz have a side effect: resettodr(), which */ 321 /* can be disabled by machdep.disable_rtc_set, so if init or UTC clock */ 322 /* -- don't write RTC, else write RTC. */ 323 324 if (kern_offset != offset) { 325 kern_offset = offset; 326 len = sizeof(kern_offset); 327 if (sysctlbyname("machdep.adjkerntz", NULL, NULL, &kern_offset, len) == -1) { 328 syslog(LOG_ERR, "sysctl(set: \"machdep.adjkerntz\"): %m"); 329 return 1; 330 } 331 } 332 333 len = sizeof(wall_clock); 334 if (sysctlbyname("machdep.wall_cmos_clock", NULL, NULL, &wall_clock, len) == -1) { 335 syslog(LOG_ERR, "sysctl(set: \"machdep.wall_cmos_clock\"): %m"); 336 return 1; 337 } 338 339 if (need_restore) { 340 need_restore = False; 341 disrtcset = 0; 342 len = sizeof(disrtcset); 343 if (sysctlbyname("machdep.disable_rtc_set", NULL, NULL, &disrtcset, len) == -1) { 344 syslog(LOG_ERR, "sysctl(set: \"machdep.disable_rtc_set\"): %m"); 345 return 1; 346 } 347 } 348 349 /****** End of critical section ******/ 350 351 if (init && wall_clock) { 352 sleep_mode = False; 353 /* wait for signals and acts like -a */ 354 (void) sigsuspend(&emask); 355 goto again; 356 } 357 358 return 0; 359 } 360 361 static void 362 usage(void) 363 { 364 fprintf(stderr, "%s\n%s\n%s\n%s\n", 365 "usage: adjkerntz -i", 366 "\t\t(initial call from /etc/rc)", 367 " adjkerntz -a [-s]", 368 "\t\t(adjustment call, -s for sleep/retry mode)"); 369 exit(2); 370 } 371