1 /* 2 * Copyright (C) 1993-1998 by Andrey A. Chernov, Moscow, Russia. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #if 0 28 #ifndef lint 29 static const char copyright[] = 30 "@(#)Copyright (C) 1993-1996 by Andrey A. Chernov, Moscow, Russia.\n\ 31 All rights reserved.\n"; 32 #endif /* not lint */ 33 #endif 34 #include <sys/cdefs.h> 35 __FBSDID("$FreeBSD$"); 36 37 /* 38 * Andrey A. Chernov <ache@astral.msk.su> Dec 20 1993 39 * 40 * Fix kernel time value if machine run wall CMOS clock 41 * (and /etc/wall_cmos_clock file present) 42 * using zoneinfo rules or direct TZ environment variable set. 43 * Use Joerg Wunsch idea for seconds accurate offset calculation 44 * with Garrett Wollman and Bruce Evans fixes. 45 * 46 */ 47 #include <stdio.h> 48 #include <signal.h> 49 #include <stdlib.h> 50 #include <unistd.h> 51 #include <syslog.h> 52 #include <sys/time.h> 53 #include <sys/param.h> 54 #include <machine/cpu.h> 55 #include <sys/sysctl.h> 56 57 #include "pathnames.h" 58 59 /*#define DEBUG*/ 60 61 #define True (1) 62 #define False (0) 63 #define Unknown (-1) 64 65 #define REPORT_PERIOD (30*60) 66 67 static void fake(int); 68 static void usage(void); 69 70 static void 71 fake(int unused __unused) 72 { 73 74 /* Do nothing. */ 75 } 76 77 int 78 main(int argc, char *argv[]) 79 { 80 struct tm local; 81 struct timeval tv, *stv; 82 struct timezone tz, *stz; 83 int kern_offset, wall_clock, disrtcset; 84 size_t len; 85 /* Avoid time_t here, can be unsigned long or worse */ 86 long offset, localsec, diff; 87 time_t initial_sec, final_sec; 88 int ch; 89 int initial_isdst = -1, final_isdst; 90 int need_restore = False, sleep_mode = False, looping, 91 init = Unknown; 92 sigset_t mask, emask; 93 94 while ((ch = getopt(argc, argv, "ais")) != -1) 95 switch((char)ch) { 96 case 'i': /* initial call, save offset */ 97 if (init != Unknown) 98 usage(); 99 init = True; 100 break; 101 case 'a': /* adjustment call, use saved offset */ 102 if (init != Unknown) 103 usage(); 104 init = False; 105 break; 106 case 's': 107 sleep_mode = True; 108 break; 109 default: 110 usage(); 111 } 112 if (init == Unknown) 113 usage(); 114 115 if (access(_PATH_CLOCK, F_OK) != 0) 116 return 0; 117 118 if (init) 119 sleep_mode = True; 120 121 sigemptyset(&mask); 122 sigemptyset(&emask); 123 sigaddset(&mask, SIGTERM); 124 125 openlog("adjkerntz", LOG_PID|LOG_PERROR, LOG_DAEMON); 126 127 (void) signal(SIGHUP, SIG_IGN); 128 129 if (init && daemon(0, 130 #ifdef DEBUG 131 1 132 #else 133 0 134 #endif 135 )) { 136 syslog(LOG_ERR, "daemon: %m"); 137 return 1; 138 } 139 140 again: 141 (void) sigprocmask(SIG_BLOCK, &mask, NULL); 142 (void) signal(SIGTERM, fake); 143 144 diff = 0; 145 stv = NULL; 146 stz = NULL; 147 looping = False; 148 149 wall_clock = (access(_PATH_CLOCK, F_OK) == 0); 150 if (init && !sleep_mode) { 151 init = False; 152 if (!wall_clock) 153 return 0; 154 } 155 156 tzset(); 157 158 len = sizeof(kern_offset); 159 if (sysctlbyname("machdep.adjkerntz", &kern_offset, &len, NULL, 0) == -1) { 160 syslog(LOG_ERR, "sysctl(\"machdep.adjkerntz\"): %m"); 161 return 1; 162 } 163 164 /****** Critical section, do all things as fast as possible ******/ 165 166 /* get local CMOS clock and possible kernel offset */ 167 if (gettimeofday(&tv, &tz)) { 168 syslog(LOG_ERR, "gettimeofday: %m"); 169 return 1; 170 } 171 172 /* get the actual local timezone difference */ 173 initial_sec = tv.tv_sec; 174 175 recalculate: 176 local = *localtime(&initial_sec); 177 if (diff == 0) 178 initial_isdst = local.tm_isdst; 179 local.tm_isdst = initial_isdst; 180 181 /* calculate local CMOS diff from GMT */ 182 183 localsec = mktime(&local); 184 if (localsec == -1) { 185 /* 186 * XXX user can only control local time, and it is 187 * unacceptable to fail here for init. 2:30 am in the 188 * middle of the nonexistent hour means 3:30 am. 189 */ 190 if (!sleep_mode) { 191 syslog(LOG_WARNING, 192 "Warning: nonexistent local time, try to run later."); 193 syslog(LOG_WARNING, "Giving up."); 194 return 1; 195 } 196 syslog(LOG_WARNING, 197 "Warning: nonexistent local time."); 198 syslog(LOG_WARNING, "Will retry after %d minutes.", 199 REPORT_PERIOD / 60); 200 (void) signal(SIGTERM, SIG_DFL); 201 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL); 202 (void) sleep(REPORT_PERIOD); 203 goto again; 204 } 205 offset = -local.tm_gmtoff; 206 #ifdef DEBUG 207 fprintf(stderr, "Initial offset: %ld secs\n", offset); 208 #endif 209 210 /* correct the kerneltime for this diffs */ 211 /* subtract kernel offset, if present, old offset too */ 212 213 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 214 215 if (diff != 0) { 216 #ifdef DEBUG 217 fprintf(stderr, "Initial diff: %ld secs\n", diff); 218 #endif 219 /* Yet one step for final time */ 220 221 final_sec = initial_sec + diff; 222 223 /* get the actual local timezone difference */ 224 local = *localtime(&final_sec); 225 final_isdst = diff < 0 ? initial_isdst : local.tm_isdst; 226 if (diff > 0 && initial_isdst != final_isdst) { 227 if (looping) 228 goto bad_final; 229 looping = True; 230 initial_isdst = final_isdst; 231 goto recalculate; 232 } 233 local.tm_isdst = final_isdst; 234 235 localsec = mktime(&local); 236 if (localsec == -1) { 237 bad_final: 238 /* 239 * XXX as above. The user has even less control, 240 * but perhaps we never get here. 241 */ 242 if (!sleep_mode) { 243 syslog(LOG_WARNING, 244 "Warning: nonexistent final local time, try to run later."); 245 syslog(LOG_WARNING, "Giving up."); 246 return 1; 247 } 248 syslog(LOG_WARNING, 249 "Warning: nonexistent final local time."); 250 syslog(LOG_WARNING, "Will retry after %d minutes.", 251 REPORT_PERIOD / 60); 252 (void) signal(SIGTERM, SIG_DFL); 253 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL); 254 (void) sleep(REPORT_PERIOD); 255 goto again; 256 } 257 offset = -local.tm_gmtoff; 258 #ifdef DEBUG 259 fprintf(stderr, "Final offset: %ld secs\n", offset); 260 #endif 261 262 /* correct the kerneltime for this diffs */ 263 /* subtract kernel offset, if present, old offset too */ 264 265 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 266 267 if (diff != 0) { 268 #ifdef DEBUG 269 fprintf(stderr, "Final diff: %ld secs\n", diff); 270 #endif 271 /* 272 * stv is abused as a flag. The important value 273 * is in `diff'. 274 */ 275 stv = &tv; 276 } 277 } 278 279 if (tz.tz_dsttime != 0 || tz.tz_minuteswest != 0) { 280 tz.tz_dsttime = tz.tz_minuteswest = 0; /* zone info is garbage */ 281 stz = &tz; 282 } 283 if (!wall_clock && stz == NULL) 284 stv = NULL; 285 286 /* if init or UTC clock and offset/date will be changed, */ 287 /* disable RTC modification for a while. */ 288 289 if ( (init && stv != NULL) 290 || ((init || !wall_clock) && kern_offset != offset) 291 ) { 292 len = sizeof(disrtcset); 293 if (sysctlbyname("machdep.disable_rtc_set", &disrtcset, &len, NULL, 0) == -1) { 294 syslog(LOG_ERR, "sysctl(get: \"machdep.disable_rtc_set\"): %m"); 295 return 1; 296 } 297 if (disrtcset == 0) { 298 disrtcset = 1; 299 need_restore = True; 300 if (sysctlbyname("machdep.disable_rtc_set", NULL, NULL, &disrtcset, len) == -1) { 301 syslog(LOG_ERR, "sysctl(set: \"machdep.disable_rtc_set\"): %m"); 302 return 1; 303 } 304 } 305 } 306 307 if ( (init && (stv != NULL || stz != NULL)) 308 || (stz != NULL && stv == NULL) 309 ) { 310 if (stv != NULL) { 311 /* 312 * Get the time again, as close as possible to 313 * adjusting it, to minimise drift. 314 * XXX we'd better not fail between here and 315 * restoring disrtcset, since we don't clean up 316 * anything. 317 */ 318 if (gettimeofday(&tv, (struct timezone *)NULL)) { 319 syslog(LOG_ERR, "gettimeofday: %m"); 320 return 1; 321 } 322 tv.tv_sec += diff; 323 stv = &tv; 324 } 325 if (settimeofday(stv, stz)) { 326 syslog(LOG_ERR, "settimeofday: %m"); 327 return 1; 328 } 329 } 330 331 /* setting machdep.adjkerntz have a side effect: resettodr(), which */ 332 /* can be disabled by machdep.disable_rtc_set, so if init or UTC clock */ 333 /* -- don't write RTC, else write RTC. */ 334 335 if (kern_offset != offset) { 336 kern_offset = offset; 337 len = sizeof(kern_offset); 338 if (sysctlbyname("machdep.adjkerntz", NULL, NULL, &kern_offset, len) == -1) { 339 syslog(LOG_ERR, "sysctl(set: \"machdep.adjkerntz\"): %m"); 340 return 1; 341 } 342 } 343 344 len = sizeof(wall_clock); 345 if (sysctlbyname("machdep.wall_cmos_clock", NULL, NULL, &wall_clock, len) == -1) { 346 syslog(LOG_ERR, "sysctl(set: \"machdep.wall_cmos_clock\"): %m"); 347 return 1; 348 } 349 350 if (need_restore) { 351 need_restore = False; 352 disrtcset = 0; 353 len = sizeof(disrtcset); 354 if (sysctlbyname("machdep.disable_rtc_set", NULL, NULL, &disrtcset, len) == -1) { 355 syslog(LOG_ERR, "sysctl(set: \"machdep.disable_rtc_set\"): %m"); 356 return 1; 357 } 358 } 359 360 /****** End of critical section ******/ 361 362 if (init && wall_clock) { 363 sleep_mode = False; 364 /* wait for signals and acts like -a */ 365 (void) sigsuspend(&emask); 366 goto again; 367 } 368 369 return 0; 370 } 371 372 static void 373 usage(void) 374 { 375 fprintf(stderr, "%s\n%s\n%s\n%s\n", 376 "usage: adjkerntz -i", 377 "\t\t(initial call from /etc/rc)", 378 " adjkerntz -a [-s]", 379 "\t\t(adjustment call, -s for sleep/retry mode)"); 380 exit(2); 381 } 382