1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 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 <errno.h> 50 #include <stdio.h> 51 #include <signal.h> 52 #include <stdlib.h> 53 #include <unistd.h> 54 #include <syslog.h> 55 #include <sys/time.h> 56 #include <sys/param.h> 57 #include <machine/cpu.h> 58 #include <sys/sysctl.h> 59 60 #include "pathnames.h" 61 62 /*#define DEBUG*/ 63 64 #define True (1) 65 #define False (0) 66 #define Unknown (-1) 67 68 #define REPORT_PERIOD (30*60) 69 70 static void fake(int); 71 static void usage(void); 72 73 static void 74 fake(int unused __unused) 75 { 76 77 /* Do nothing. */ 78 } 79 80 int 81 main(int argc, char *argv[]) 82 { 83 struct tm local; 84 struct timeval tv, *stv; 85 struct timezone tz, *stz; 86 int kern_offset, wall_clock, disrtcset; 87 size_t len; 88 /* Avoid time_t here, can be unsigned long or worse */ 89 long offset, localsec, diff; 90 time_t initial_sec, final_sec; 91 int ch; 92 int initial_isdst = -1, final_isdst; 93 int need_restore = False, sleep_mode = False, looping, 94 init = Unknown; 95 sigset_t mask, emask; 96 97 while ((ch = getopt(argc, argv, "ais")) != -1) 98 switch((char)ch) { 99 case 'i': /* initial call, save offset */ 100 if (init != Unknown) 101 usage(); 102 init = True; 103 break; 104 case 'a': /* adjustment call, use saved offset */ 105 if (init != Unknown) 106 usage(); 107 init = False; 108 break; 109 case 's': 110 sleep_mode = True; 111 break; 112 default: 113 usage(); 114 } 115 if (init == Unknown) 116 usage(); 117 118 if (access(_PATH_CLOCK, F_OK) != 0) 119 return 0; 120 121 if (init) 122 sleep_mode = True; 123 124 sigemptyset(&mask); 125 sigemptyset(&emask); 126 sigaddset(&mask, SIGTERM); 127 128 openlog("adjkerntz", LOG_PID|LOG_PERROR, LOG_DAEMON); 129 130 (void) signal(SIGHUP, SIG_IGN); 131 132 if (init && daemon(0, 133 #ifdef DEBUG 134 1 135 #else 136 0 137 #endif 138 )) { 139 syslog(LOG_ERR, "daemon: %m"); 140 return 1; 141 } 142 143 again: 144 (void) sigprocmask(SIG_BLOCK, &mask, NULL); 145 (void) signal(SIGTERM, fake); 146 147 diff = 0; 148 stv = NULL; 149 stz = NULL; 150 looping = False; 151 152 wall_clock = (access(_PATH_CLOCK, F_OK) == 0); 153 if (init && !sleep_mode) { 154 init = False; 155 if (!wall_clock) 156 return 0; 157 } 158 159 tzset(); 160 161 len = sizeof(kern_offset); 162 if (sysctlbyname("machdep.adjkerntz", &kern_offset, &len, NULL, 0) == -1) { 163 if (errno == EPERM && !init && geteuid() == 0) 164 /* 165 * Surplus call from jailed root crontab. 166 * Avoid spamming logs. 167 */ 168 return 1; 169 syslog(LOG_ERR, "sysctl(\"machdep.adjkerntz\"): %m"); 170 return 1; 171 } 172 173 /****** Critical section, do all things as fast as possible ******/ 174 175 /* get local CMOS clock and possible kernel offset */ 176 if (gettimeofday(&tv, &tz)) { 177 syslog(LOG_ERR, "gettimeofday: %m"); 178 return 1; 179 } 180 181 /* get the actual local timezone difference */ 182 initial_sec = tv.tv_sec; 183 184 recalculate: 185 local = *localtime(&initial_sec); 186 if (diff == 0) 187 initial_isdst = local.tm_isdst; 188 local.tm_isdst = initial_isdst; 189 190 /* calculate local CMOS diff from GMT */ 191 192 localsec = mktime(&local); 193 if (localsec == -1) { 194 /* 195 * XXX user can only control local time, and it is 196 * unacceptable to fail here for init. 2:30 am in the 197 * middle of the nonexistent hour means 3:30 am. 198 */ 199 if (!sleep_mode) { 200 syslog(LOG_WARNING, 201 "Warning: nonexistent local time, try to run later."); 202 syslog(LOG_WARNING, "Giving up."); 203 return 1; 204 } 205 syslog(LOG_WARNING, 206 "Warning: nonexistent local time."); 207 syslog(LOG_WARNING, "Will retry after %d minutes.", 208 REPORT_PERIOD / 60); 209 (void) signal(SIGTERM, SIG_DFL); 210 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL); 211 (void) sleep(REPORT_PERIOD); 212 goto again; 213 } 214 offset = -local.tm_gmtoff; 215 #ifdef DEBUG 216 fprintf(stderr, "Initial offset: %ld secs\n", offset); 217 #endif 218 219 /* correct the kerneltime for this diffs */ 220 /* subtract kernel offset, if present, old offset too */ 221 222 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 223 224 if (diff != 0) { 225 #ifdef DEBUG 226 fprintf(stderr, "Initial diff: %ld secs\n", diff); 227 #endif 228 /* Yet one step for final time */ 229 230 final_sec = initial_sec + diff; 231 232 /* get the actual local timezone difference */ 233 local = *localtime(&final_sec); 234 final_isdst = diff < 0 ? initial_isdst : local.tm_isdst; 235 if (diff > 0 && initial_isdst != final_isdst) { 236 if (looping) 237 goto bad_final; 238 looping = True; 239 initial_isdst = final_isdst; 240 goto recalculate; 241 } 242 local.tm_isdst = final_isdst; 243 244 localsec = mktime(&local); 245 if (localsec == -1) { 246 bad_final: 247 /* 248 * XXX as above. The user has even less control, 249 * but perhaps we never get here. 250 */ 251 if (!sleep_mode) { 252 syslog(LOG_WARNING, 253 "Warning: nonexistent final local time, try to run later."); 254 syslog(LOG_WARNING, "Giving up."); 255 return 1; 256 } 257 syslog(LOG_WARNING, 258 "Warning: nonexistent final local time."); 259 syslog(LOG_WARNING, "Will retry after %d minutes.", 260 REPORT_PERIOD / 60); 261 (void) signal(SIGTERM, SIG_DFL); 262 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL); 263 (void) sleep(REPORT_PERIOD); 264 goto again; 265 } 266 offset = -local.tm_gmtoff; 267 #ifdef DEBUG 268 fprintf(stderr, "Final offset: %ld secs\n", offset); 269 #endif 270 271 /* correct the kerneltime for this diffs */ 272 /* subtract kernel offset, if present, old offset too */ 273 274 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 275 276 if (diff != 0) { 277 #ifdef DEBUG 278 fprintf(stderr, "Final diff: %ld secs\n", diff); 279 #endif 280 /* 281 * stv is abused as a flag. The important value 282 * is in `diff'. 283 */ 284 stv = &tv; 285 } 286 } 287 288 if (tz.tz_dsttime != 0 || tz.tz_minuteswest != 0) { 289 tz.tz_dsttime = tz.tz_minuteswest = 0; /* zone info is garbage */ 290 stz = &tz; 291 } 292 if (!wall_clock && stz == NULL) 293 stv = NULL; 294 295 /* if init or UTC clock and offset/date will be changed, */ 296 /* disable RTC modification for a while. */ 297 298 if ( (init && stv != NULL) 299 || ((init || !wall_clock) && kern_offset != offset) 300 ) { 301 len = sizeof(disrtcset); 302 if (sysctlbyname("machdep.disable_rtc_set", &disrtcset, &len, NULL, 0) == -1) { 303 syslog(LOG_ERR, "sysctl(get: \"machdep.disable_rtc_set\"): %m"); 304 return 1; 305 } 306 if (disrtcset == 0) { 307 disrtcset = 1; 308 need_restore = True; 309 if (sysctlbyname("machdep.disable_rtc_set", NULL, NULL, &disrtcset, len) == -1) { 310 syslog(LOG_ERR, "sysctl(set: \"machdep.disable_rtc_set\"): %m"); 311 return 1; 312 } 313 } 314 } 315 316 if ( (init && (stv != NULL || stz != NULL)) 317 || (stz != NULL && stv == NULL) 318 ) { 319 if (stv != NULL) { 320 /* 321 * Get the time again, as close as possible to 322 * adjusting it, to minimise drift. 323 * XXX we'd better not fail between here and 324 * restoring disrtcset, since we don't clean up 325 * anything. 326 */ 327 (void)gettimeofday(&tv, NULL); 328 tv.tv_sec += diff; 329 stv = &tv; 330 } 331 if (settimeofday(stv, stz)) { 332 syslog(LOG_ERR, "settimeofday: %m"); 333 return 1; 334 } 335 } 336 337 /* setting machdep.adjkerntz have a side effect: resettodr(), which */ 338 /* can be disabled by machdep.disable_rtc_set, so if init or UTC clock */ 339 /* -- don't write RTC, else write RTC. */ 340 341 if (kern_offset != offset) { 342 kern_offset = offset; 343 len = sizeof(kern_offset); 344 if (sysctlbyname("machdep.adjkerntz", NULL, NULL, &kern_offset, len) == -1) { 345 syslog(LOG_ERR, "sysctl(set: \"machdep.adjkerntz\"): %m"); 346 return 1; 347 } 348 } 349 350 len = sizeof(wall_clock); 351 if (sysctlbyname("machdep.wall_cmos_clock", NULL, NULL, &wall_clock, len) == -1) { 352 syslog(LOG_ERR, "sysctl(set: \"machdep.wall_cmos_clock\"): %m"); 353 return 1; 354 } 355 356 if (need_restore) { 357 need_restore = False; 358 disrtcset = 0; 359 len = sizeof(disrtcset); 360 if (sysctlbyname("machdep.disable_rtc_set", NULL, NULL, &disrtcset, len) == -1) { 361 syslog(LOG_ERR, "sysctl(set: \"machdep.disable_rtc_set\"): %m"); 362 return 1; 363 } 364 } 365 366 /****** End of critical section ******/ 367 368 if (init && wall_clock) { 369 sleep_mode = False; 370 /* wait for signals and acts like -a */ 371 (void) sigsuspend(&emask); 372 goto again; 373 } 374 375 return 0; 376 } 377 378 static void 379 usage(void) 380 { 381 fprintf(stderr, "%s\n%s\n%s\n%s\n", 382 "usage: adjkerntz -i", 383 "\t\t(initial call from /etc/rc)", 384 " adjkerntz -a [-s]", 385 "\t\t(adjustment call, -s for sleep/retry mode)"); 386 exit(2); 387 } 388