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 1.6 2005/11/06 12:03:15 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 72 main(int argc, char **argv) 73 { 74 struct tm local; 75 struct timeval tv, *stv; 76 struct timezone tz, *stz; 77 int kern_offset, wall_clock, disrtcset; 78 size_t len; 79 int mib[2]; 80 /* Avoid time_t here, can be unsigned long or worse */ 81 long offset, localsec, diff; 82 time_t initial_sec, final_sec; 83 int ch; 84 int initial_isdst = -1, final_isdst; 85 int need_restore = False, sleep_mode = False, looping, 86 init = Unknown; 87 sigset_t mask, emask; 88 89 while ((ch = getopt(argc, argv, "ais")) != -1) 90 switch((char)ch) { 91 case 'i': /* initial call, save offset */ 92 if (init != Unknown) 93 usage(); 94 init = True; 95 break; 96 case 'a': /* adjustment call, use saved offset */ 97 if (init != Unknown) 98 usage(); 99 init = False; 100 break; 101 case 's': 102 sleep_mode = True; 103 break; 104 default: 105 usage(); 106 } 107 if (init == Unknown) 108 usage(); 109 110 if (access(_PATH_CLOCK, F_OK) != 0) 111 return 0; 112 113 if (init) 114 sleep_mode = True; 115 116 sigemptyset(&mask); 117 sigemptyset(&emask); 118 sigaddset(&mask, SIGTERM); 119 120 openlog("adjkerntz", LOG_PID|LOG_PERROR, LOG_DAEMON); 121 122 signal(SIGHUP, SIG_IGN); 123 124 if (init && daemon(0, 1)) { 125 syslog(LOG_ERR, "daemon: %m"); 126 return 1; 127 } 128 129 again: 130 sigprocmask(SIG_BLOCK, &mask, NULL); 131 signal(SIGTERM, fake); 132 133 diff = 0; 134 stv = NULL; 135 stz = NULL; 136 looping = False; 137 138 wall_clock = (access(_PATH_CLOCK, F_OK) == 0); 139 if (init && !sleep_mode) { 140 init = False; 141 if (!wall_clock) 142 return 0; 143 } 144 145 mib[0] = CTL_MACHDEP; 146 mib[1] = CPU_ADJKERNTZ; 147 len = sizeof(kern_offset); 148 if (sysctl(mib, 2, &kern_offset, &len, NULL, 0) == -1) { 149 syslog(LOG_ERR, "sysctl(get_offset): %m"); 150 return 1; 151 } 152 153 /****** Critical section, do all things as fast as possible ******/ 154 155 /* get local CMOS clock and possible kernel offset */ 156 if (gettimeofday(&tv, &tz)) { 157 syslog(LOG_ERR, "gettimeofday: %m"); 158 return 1; 159 } 160 161 /* get the actual local timezone difference */ 162 initial_sec = tv.tv_sec; 163 164 recalculate: 165 local = *localtime(&initial_sec); 166 if (diff == 0) 167 initial_isdst = local.tm_isdst; 168 local.tm_isdst = initial_isdst; 169 170 /* calculate local CMOS diff from GMT */ 171 172 localsec = mktime(&local); 173 if (localsec == -1) { 174 /* 175 * XXX user can only control local time, and it is 176 * unacceptable to fail here for init. 2:30 am in the 177 * middle of the nonexistent hour means 3:30 am. 178 */ 179 if (!sleep_mode) { 180 syslog(LOG_WARNING, 181 "Warning: nonexistent local time, try to run later."); 182 syslog(LOG_WARNING, "Giving up."); 183 return 1; 184 } 185 syslog(LOG_WARNING, 186 "Warning: nonexistent local time."); 187 syslog(LOG_WARNING, "Will retry after %d minutes.", 188 REPORT_PERIOD / 60); 189 signal(SIGTERM, SIG_DFL); 190 sigprocmask(SIG_UNBLOCK, &mask, NULL); 191 sleep(REPORT_PERIOD); 192 goto again; 193 } 194 offset = -local.tm_gmtoff; 195 #ifdef DEBUG 196 fprintf(stderr, "Initial offset: %ld secs\n", offset); 197 #endif 198 199 /* correct the kerneltime for this diffs */ 200 /* subtract kernel offset, if present, old offset too */ 201 202 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 203 204 if (diff != 0) { 205 #ifdef DEBUG 206 fprintf(stderr, "Initial diff: %ld secs\n", diff); 207 #endif 208 /* Yet one step for final time */ 209 210 final_sec = initial_sec + diff; 211 212 /* get the actual local timezone difference */ 213 local = *localtime(&final_sec); 214 final_isdst = diff < 0 ? initial_isdst : local.tm_isdst; 215 if (diff > 0 && initial_isdst != final_isdst) { 216 if (looping) 217 goto bad_final; 218 looping = True; 219 initial_isdst = final_isdst; 220 goto recalculate; 221 } 222 local.tm_isdst = final_isdst; 223 224 localsec = mktime(&local); 225 if (localsec == -1) { 226 bad_final: 227 /* 228 * XXX as above. The user has even less control, 229 * but perhaps we never get here. 230 */ 231 if (!sleep_mode) { 232 syslog(LOG_WARNING, 233 "Warning: nonexistent final local time, try to run later."); 234 syslog(LOG_WARNING, "Giving up."); 235 return 1; 236 } 237 syslog(LOG_WARNING, 238 "Warning: nonexistent final local time."); 239 syslog(LOG_WARNING, "Will retry after %d minutes.", 240 REPORT_PERIOD / 60); 241 signal(SIGTERM, SIG_DFL); 242 sigprocmask(SIG_UNBLOCK, &mask, NULL); 243 sleep(REPORT_PERIOD); 244 goto again; 245 } 246 offset = -local.tm_gmtoff; 247 #ifdef DEBUG 248 fprintf(stderr, "Final offset: %ld secs\n", offset); 249 #endif 250 251 /* correct the kerneltime for this diffs */ 252 /* subtract kernel offset, if present, old offset too */ 253 254 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 255 256 if (diff != 0) { 257 #ifdef DEBUG 258 fprintf(stderr, "Final diff: %ld secs\n", diff); 259 #endif 260 /* 261 * stv is abused as a flag. The important value 262 * is in `diff'. 263 */ 264 stv = &tv; 265 } 266 } 267 268 if (tz.tz_dsttime != 0 || tz.tz_minuteswest != 0) { 269 tz.tz_dsttime = tz.tz_minuteswest = 0; /* zone info is garbage */ 270 stz = &tz; 271 } 272 if (!wall_clock && stz == NULL) 273 stv = NULL; 274 275 /* if init or UTC clock and offset/date will be changed, */ 276 /* disable RTC modification for a while. */ 277 278 if ( (init && stv != NULL) 279 || ((init || !wall_clock) && kern_offset != offset) 280 ) { 281 mib[0] = CTL_MACHDEP; 282 mib[1] = CPU_DISRTCSET; 283 len = sizeof(disrtcset); 284 if (sysctl(mib, 2, &disrtcset, &len, NULL, 0) == -1) { 285 syslog(LOG_ERR, "sysctl(get_disrtcset): %m"); 286 return 1; 287 } 288 if (disrtcset == 0) { 289 disrtcset = 1; 290 need_restore = True; 291 if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) { 292 syslog(LOG_ERR, "sysctl(set_disrtcset): %m"); 293 return 1; 294 } 295 } 296 } 297 298 if ( (init && (stv != NULL || stz != NULL)) 299 || (stz != NULL && stv == NULL) 300 ) { 301 if (stv != NULL) { 302 /* 303 * Get the time again, as close as possible to 304 * adjusting it, to minimise drift. 305 * XXX we'd better not fail between here and 306 * restoring disrtcset, since we don't clean up 307 * anything. 308 */ 309 if (gettimeofday(&tv, NULL)) { 310 syslog(LOG_ERR, "gettimeofday: %m"); 311 return 1; 312 } 313 tv.tv_sec += diff; 314 stv = &tv; 315 } 316 if (settimeofday(stv, stz)) { 317 syslog(LOG_ERR, "settimeofday: %m"); 318 return 1; 319 } 320 } 321 322 /* setting CPU_ADJKERNTZ have a side effect: resettodr(), which */ 323 /* can be disabled by CPU_DISRTCSET, so if init or UTC clock */ 324 /* -- don't write RTC, else write RTC. */ 325 326 if (kern_offset != offset) { 327 kern_offset = offset; 328 mib[0] = CTL_MACHDEP; 329 mib[1] = CPU_ADJKERNTZ; 330 len = sizeof(kern_offset); 331 if (sysctl(mib, 2, NULL, NULL, &kern_offset, len) == -1) { 332 syslog(LOG_ERR, "sysctl(update_offset): %m"); 333 return 1; 334 } 335 } 336 337 mib[0] = CTL_MACHDEP; 338 mib[1] = CPU_WALLCLOCK; 339 len = sizeof(wall_clock); 340 if (sysctl(mib, 2, NULL, NULL, &wall_clock, len) == -1) { 341 syslog(LOG_ERR, "sysctl(put_wallclock): %m"); 342 return 1; 343 } 344 345 if (need_restore) { 346 need_restore = False; 347 mib[0] = CTL_MACHDEP; 348 mib[1] = CPU_DISRTCSET; 349 disrtcset = 0; 350 len = sizeof(disrtcset); 351 if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) { 352 syslog(LOG_ERR, "sysctl(restore_disrtcset): %m"); 353 return 1; 354 } 355 } 356 357 /****** End of critical section ******/ 358 359 if (init && wall_clock) { 360 sleep_mode = False; 361 /* wait for signals and acts like -a */ 362 sigsuspend(&emask); 363 goto again; 364 } 365 366 return 0; 367 } 368 369 static void 370 usage(void) 371 { 372 fprintf(stderr, "%s\n%s\n%s\n%s\n", 373 "usage: adjkerntz -i", 374 "\t\t(initial call from /etc/rc)", 375 " adjkerntz -a [-s]", 376 "\t\t(adjustment call, -s for sleep/retry mode)"); 377 exit(2); 378 } 379