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 * @(#)Copyright (C) 1993-1996 by Andrey A. Chernov, Moscow, Russia. All rights reserved. 27 * $FreeBSD: src/sbin/adjkerntz/adjkerntz.c,v 1.25.2.1 2001/07/30 10:38:04 dd Exp $ 28 * $DragonFly: src/sbin/adjkerntz/adjkerntz.c,v 1.5 2004/12/18 21:43:38 swildner Exp $ 29 */ 30 31 /* 32 * Andrey A. Chernov <ache@astral.msk.su> Dec 20 1993 33 * 34 * Fix kernel time value if machine run wall CMOS clock 35 * (and /etc/wall_cmos_clock file present) 36 * using zoneinfo rules or direct TZ environment variable set. 37 * Use Joerg Wunsch idea for seconds accurate offset calculation 38 * with Garrett Wollman and Bruce Evans fixes. 39 * 40 */ 41 #include <stdio.h> 42 #include <signal.h> 43 #include <stdlib.h> 44 #include <unistd.h> 45 #include <syslog.h> 46 #include <sys/time.h> 47 #include <sys/param.h> 48 #include <machine/cpu.h> 49 #include <sys/sysctl.h> 50 51 #include "pathnames.h" 52 53 /*#define DEBUG*/ 54 55 #define True (1) 56 #define False (0) 57 #define Unknown (-1) 58 59 #define REPORT_PERIOD (30*60) 60 61 static void fake(int); 62 static void usage(void); 63 64 static void 65 fake(int unused __unused) 66 { 67 68 /* Do nothing. */ 69 } 70 71 int main(int argc, char **argv) 72 { 73 struct tm local; 74 struct timeval tv, *stv; 75 struct timezone tz, *stz; 76 int kern_offset, wall_clock, disrtcset; 77 size_t len; 78 int mib[2]; 79 /* Avoid time_t here, can be unsigned long or worse */ 80 long offset, localsec, diff; 81 time_t initial_sec, final_sec; 82 int ch; 83 int initial_isdst = -1, final_isdst; 84 int need_restore = False, sleep_mode = False, looping, 85 init = Unknown; 86 sigset_t mask, emask; 87 88 while ((ch = getopt(argc, argv, "ais")) != -1) 89 switch((char)ch) { 90 case 'i': /* initial call, save offset */ 91 if (init != Unknown) 92 usage(); 93 init = True; 94 break; 95 case 'a': /* adjustment call, use saved offset */ 96 if (init != Unknown) 97 usage(); 98 init = False; 99 break; 100 case 's': 101 sleep_mode = True; 102 break; 103 default: 104 usage(); 105 } 106 if (init == Unknown) 107 usage(); 108 109 if (access(_PATH_CLOCK, F_OK) != 0) 110 return 0; 111 112 if (init) 113 sleep_mode = True; 114 115 sigemptyset(&mask); 116 sigemptyset(&emask); 117 sigaddset(&mask, SIGTERM); 118 119 openlog("adjkerntz", LOG_PID|LOG_PERROR, LOG_DAEMON); 120 121 signal(SIGHUP, SIG_IGN); 122 123 if (init && daemon(0, 1)) { 124 syslog(LOG_ERR, "daemon: %m"); 125 return 1; 126 } 127 128 again: 129 sigprocmask(SIG_BLOCK, &mask, NULL); 130 signal(SIGTERM, fake); 131 132 diff = 0; 133 stv = NULL; 134 stz = NULL; 135 looping = False; 136 137 wall_clock = (access(_PATH_CLOCK, F_OK) == 0); 138 if (init && !sleep_mode) { 139 init = False; 140 if (!wall_clock) 141 return 0; 142 } 143 144 mib[0] = CTL_MACHDEP; 145 mib[1] = CPU_ADJKERNTZ; 146 len = sizeof(kern_offset); 147 if (sysctl(mib, 2, &kern_offset, &len, NULL, 0) == -1) { 148 syslog(LOG_ERR, "sysctl(get_offset): %m"); 149 return 1; 150 } 151 152 /****** Critical section, do all things as fast as possible ******/ 153 154 /* get local CMOS clock and possible kernel offset */ 155 if (gettimeofday(&tv, &tz)) { 156 syslog(LOG_ERR, "gettimeofday: %m"); 157 return 1; 158 } 159 160 /* get the actual local timezone difference */ 161 initial_sec = tv.tv_sec; 162 163 recalculate: 164 local = *localtime(&initial_sec); 165 if (diff == 0) 166 initial_isdst = local.tm_isdst; 167 local.tm_isdst = initial_isdst; 168 169 /* calculate local CMOS diff from GMT */ 170 171 localsec = mktime(&local); 172 if (localsec == -1) { 173 /* 174 * XXX user can only control local time, and it is 175 * unacceptable to fail here for init. 2:30 am in the 176 * middle of the nonexistent hour means 3:30 am. 177 */ 178 if (!sleep_mode) { 179 syslog(LOG_WARNING, 180 "Warning: nonexistent local time, try to run later."); 181 syslog(LOG_WARNING, "Giving up."); 182 return 1; 183 } 184 syslog(LOG_WARNING, 185 "Warning: nonexistent local time."); 186 syslog(LOG_WARNING, "Will retry after %d minutes.", 187 REPORT_PERIOD / 60); 188 signal(SIGTERM, SIG_DFL); 189 sigprocmask(SIG_UNBLOCK, &mask, NULL); 190 sleep(REPORT_PERIOD); 191 goto again; 192 } 193 offset = -local.tm_gmtoff; 194 #ifdef DEBUG 195 fprintf(stderr, "Initial offset: %ld secs\n", offset); 196 #endif 197 198 /* correct the kerneltime for this diffs */ 199 /* subtract kernel offset, if present, old offset too */ 200 201 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 202 203 if (diff != 0) { 204 #ifdef DEBUG 205 fprintf(stderr, "Initial diff: %ld secs\n", diff); 206 #endif 207 /* Yet one step for final time */ 208 209 final_sec = initial_sec + diff; 210 211 /* get the actual local timezone difference */ 212 local = *localtime(&final_sec); 213 final_isdst = diff < 0 ? initial_isdst : local.tm_isdst; 214 if (diff > 0 && initial_isdst != final_isdst) { 215 if (looping) 216 goto bad_final; 217 looping = True; 218 initial_isdst = final_isdst; 219 goto recalculate; 220 } 221 local.tm_isdst = final_isdst; 222 223 localsec = mktime(&local); 224 if (localsec == -1) { 225 bad_final: 226 /* 227 * XXX as above. The user has even less control, 228 * but perhaps we never get here. 229 */ 230 if (!sleep_mode) { 231 syslog(LOG_WARNING, 232 "Warning: nonexistent final local time, try to run later."); 233 syslog(LOG_WARNING, "Giving up."); 234 return 1; 235 } 236 syslog(LOG_WARNING, 237 "Warning: nonexistent final local time."); 238 syslog(LOG_WARNING, "Will retry after %d minutes.", 239 REPORT_PERIOD / 60); 240 signal(SIGTERM, SIG_DFL); 241 sigprocmask(SIG_UNBLOCK, &mask, NULL); 242 sleep(REPORT_PERIOD); 243 goto again; 244 } 245 offset = -local.tm_gmtoff; 246 #ifdef DEBUG 247 fprintf(stderr, "Final offset: %ld secs\n", offset); 248 #endif 249 250 /* correct the kerneltime for this diffs */ 251 /* subtract kernel offset, if present, old offset too */ 252 253 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 254 255 if (diff != 0) { 256 #ifdef DEBUG 257 fprintf(stderr, "Final diff: %ld secs\n", diff); 258 #endif 259 /* 260 * stv is abused as a flag. The important value 261 * is in `diff'. 262 */ 263 stv = &tv; 264 } 265 } 266 267 if (tz.tz_dsttime != 0 || tz.tz_minuteswest != 0) { 268 tz.tz_dsttime = tz.tz_minuteswest = 0; /* zone info is garbage */ 269 stz = &tz; 270 } 271 if (!wall_clock && stz == NULL) 272 stv = NULL; 273 274 /* if init or UTC clock and offset/date will be changed, */ 275 /* disable RTC modification for a while. */ 276 277 if ( (init && stv != NULL) 278 || ((init || !wall_clock) && kern_offset != offset) 279 ) { 280 mib[0] = CTL_MACHDEP; 281 mib[1] = CPU_DISRTCSET; 282 len = sizeof(disrtcset); 283 if (sysctl(mib, 2, &disrtcset, &len, NULL, 0) == -1) { 284 syslog(LOG_ERR, "sysctl(get_disrtcset): %m"); 285 return 1; 286 } 287 if (disrtcset == 0) { 288 disrtcset = 1; 289 need_restore = True; 290 if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) { 291 syslog(LOG_ERR, "sysctl(set_disrtcset): %m"); 292 return 1; 293 } 294 } 295 } 296 297 if ( (init && (stv != NULL || stz != NULL)) 298 || (stz != NULL && stv == NULL) 299 ) { 300 if (stv != NULL) { 301 /* 302 * Get the time again, as close as possible to 303 * adjusting it, to minimise drift. 304 * XXX we'd better not fail between here and 305 * restoring disrtcset, since we don't clean up 306 * anything. 307 */ 308 if (gettimeofday(&tv, (struct timezone *)NULL)) { 309 syslog(LOG_ERR, "gettimeofday: %m"); 310 return 1; 311 } 312 tv.tv_sec += diff; 313 stv = &tv; 314 } 315 if (settimeofday(stv, stz)) { 316 syslog(LOG_ERR, "settimeofday: %m"); 317 return 1; 318 } 319 } 320 321 /* setting CPU_ADJKERNTZ have a side effect: resettodr(), which */ 322 /* can be disabled by CPU_DISRTCSET, so if init or UTC clock */ 323 /* -- don't write RTC, else write RTC. */ 324 325 if (kern_offset != offset) { 326 kern_offset = offset; 327 mib[0] = CTL_MACHDEP; 328 mib[1] = CPU_ADJKERNTZ; 329 len = sizeof(kern_offset); 330 if (sysctl(mib, 2, NULL, NULL, &kern_offset, len) == -1) { 331 syslog(LOG_ERR, "sysctl(update_offset): %m"); 332 return 1; 333 } 334 } 335 336 mib[0] = CTL_MACHDEP; 337 mib[1] = CPU_WALLCLOCK; 338 len = sizeof(wall_clock); 339 if (sysctl(mib, 2, NULL, NULL, &wall_clock, len) == -1) { 340 syslog(LOG_ERR, "sysctl(put_wallclock): %m"); 341 return 1; 342 } 343 344 if (need_restore) { 345 need_restore = False; 346 mib[0] = CTL_MACHDEP; 347 mib[1] = CPU_DISRTCSET; 348 disrtcset = 0; 349 len = sizeof(disrtcset); 350 if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) { 351 syslog(LOG_ERR, "sysctl(restore_disrtcset): %m"); 352 return 1; 353 } 354 } 355 356 /****** End of critical section ******/ 357 358 if (init && wall_clock) { 359 sleep_mode = False; 360 /* wait for signals and acts like -a */ 361 sigsuspend(&emask); 362 goto again; 363 } 364 365 return 0; 366 } 367 368 static void 369 usage(void) 370 { 371 fprintf(stderr, "%s\n%s\n%s\n%s\n", 372 "usage: adjkerntz -i", 373 "\t\t(initial call from /etc/rc)", 374 " adjkerntz -a [-s]", 375 "\t\t(adjustment call, -s for sleep/retry mode)"); 376 exit(2); 377 } 378