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 int mib[2]; 86 /* Avoid time_t here, can be unsigned long or worse */ 87 long offset, localsec, diff; 88 time_t initial_sec, final_sec; 89 int ch; 90 int initial_isdst = -1, final_isdst; 91 int need_restore = False, sleep_mode = False, looping, 92 init = Unknown; 93 sigset_t mask, emask; 94 95 while ((ch = getopt(argc, argv, "ais")) != -1) 96 switch((char)ch) { 97 case 'i': /* initial call, save offset */ 98 if (init != Unknown) 99 usage(); 100 init = True; 101 break; 102 case 'a': /* adjustment call, use saved offset */ 103 if (init != Unknown) 104 usage(); 105 init = False; 106 break; 107 case 's': 108 sleep_mode = True; 109 break; 110 default: 111 usage(); 112 } 113 if (init == Unknown) 114 usage(); 115 116 if (access(_PATH_CLOCK, F_OK) != 0) 117 return 0; 118 119 if (init) 120 sleep_mode = True; 121 122 sigemptyset(&mask); 123 sigemptyset(&emask); 124 sigaddset(&mask, SIGTERM); 125 126 openlog("adjkerntz", LOG_PID|LOG_PERROR, LOG_DAEMON); 127 128 (void) signal(SIGHUP, SIG_IGN); 129 130 if (init && daemon(0, 1)) { 131 syslog(LOG_ERR, "daemon: %m"); 132 return 1; 133 } 134 135 again: 136 (void) sigprocmask(SIG_BLOCK, &mask, NULL); 137 (void) signal(SIGTERM, fake); 138 139 diff = 0; 140 stv = NULL; 141 stz = NULL; 142 looping = False; 143 144 wall_clock = (access(_PATH_CLOCK, F_OK) == 0); 145 if (init && !sleep_mode) { 146 init = False; 147 if (!wall_clock) 148 return 0; 149 } 150 151 tzset(); 152 153 mib[0] = CTL_MACHDEP; 154 mib[1] = CPU_ADJKERNTZ; 155 len = sizeof(kern_offset); 156 if (sysctl(mib, 2, &kern_offset, &len, NULL, 0) == -1) { 157 syslog(LOG_ERR, "sysctl(get_offset): %m"); 158 return 1; 159 } 160 161 /****** Critical section, do all things as fast as possible ******/ 162 163 /* get local CMOS clock and possible kernel offset */ 164 if (gettimeofday(&tv, &tz)) { 165 syslog(LOG_ERR, "gettimeofday: %m"); 166 return 1; 167 } 168 169 /* get the actual local timezone difference */ 170 initial_sec = tv.tv_sec; 171 172 recalculate: 173 local = *localtime(&initial_sec); 174 if (diff == 0) 175 initial_isdst = local.tm_isdst; 176 local.tm_isdst = initial_isdst; 177 178 /* calculate local CMOS diff from GMT */ 179 180 localsec = mktime(&local); 181 if (localsec == -1) { 182 /* 183 * XXX user can only control local time, and it is 184 * unacceptable to fail here for init. 2:30 am in the 185 * middle of the nonexistent hour means 3:30 am. 186 */ 187 if (!sleep_mode) { 188 syslog(LOG_WARNING, 189 "Warning: nonexistent local time, try to run later."); 190 syslog(LOG_WARNING, "Giving up."); 191 return 1; 192 } 193 syslog(LOG_WARNING, 194 "Warning: nonexistent local time."); 195 syslog(LOG_WARNING, "Will retry after %d minutes.", 196 REPORT_PERIOD / 60); 197 (void) signal(SIGTERM, SIG_DFL); 198 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL); 199 (void) sleep(REPORT_PERIOD); 200 goto again; 201 } 202 offset = -local.tm_gmtoff; 203 #ifdef DEBUG 204 fprintf(stderr, "Initial offset: %ld secs\n", offset); 205 #endif 206 207 /* correct the kerneltime for this diffs */ 208 /* subtract kernel offset, if present, old offset too */ 209 210 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 211 212 if (diff != 0) { 213 #ifdef DEBUG 214 fprintf(stderr, "Initial diff: %ld secs\n", diff); 215 #endif 216 /* Yet one step for final time */ 217 218 final_sec = initial_sec + diff; 219 220 /* get the actual local timezone difference */ 221 local = *localtime(&final_sec); 222 final_isdst = diff < 0 ? initial_isdst : local.tm_isdst; 223 if (diff > 0 && initial_isdst != final_isdst) { 224 if (looping) 225 goto bad_final; 226 looping = True; 227 initial_isdst = final_isdst; 228 goto recalculate; 229 } 230 local.tm_isdst = final_isdst; 231 232 localsec = mktime(&local); 233 if (localsec == -1) { 234 bad_final: 235 /* 236 * XXX as above. The user has even less control, 237 * but perhaps we never get here. 238 */ 239 if (!sleep_mode) { 240 syslog(LOG_WARNING, 241 "Warning: nonexistent final local time, try to run later."); 242 syslog(LOG_WARNING, "Giving up."); 243 return 1; 244 } 245 syslog(LOG_WARNING, 246 "Warning: nonexistent final local time."); 247 syslog(LOG_WARNING, "Will retry after %d minutes.", 248 REPORT_PERIOD / 60); 249 (void) signal(SIGTERM, SIG_DFL); 250 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL); 251 (void) sleep(REPORT_PERIOD); 252 goto again; 253 } 254 offset = -local.tm_gmtoff; 255 #ifdef DEBUG 256 fprintf(stderr, "Final offset: %ld secs\n", offset); 257 #endif 258 259 /* correct the kerneltime for this diffs */ 260 /* subtract kernel offset, if present, old offset too */ 261 262 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 263 264 if (diff != 0) { 265 #ifdef DEBUG 266 fprintf(stderr, "Final diff: %ld secs\n", diff); 267 #endif 268 /* 269 * stv is abused as a flag. The important value 270 * is in `diff'. 271 */ 272 stv = &tv; 273 } 274 } 275 276 if (tz.tz_dsttime != 0 || tz.tz_minuteswest != 0) { 277 tz.tz_dsttime = tz.tz_minuteswest = 0; /* zone info is garbage */ 278 stz = &tz; 279 } 280 if (!wall_clock && stz == NULL) 281 stv = NULL; 282 283 /* if init or UTC clock and offset/date will be changed, */ 284 /* disable RTC modification for a while. */ 285 286 if ( (init && stv != NULL) 287 || ((init || !wall_clock) && kern_offset != offset) 288 ) { 289 mib[0] = CTL_MACHDEP; 290 mib[1] = CPU_DISRTCSET; 291 len = sizeof(disrtcset); 292 if (sysctl(mib, 2, &disrtcset, &len, NULL, 0) == -1) { 293 syslog(LOG_ERR, "sysctl(get_disrtcset): %m"); 294 return 1; 295 } 296 if (disrtcset == 0) { 297 disrtcset = 1; 298 need_restore = True; 299 if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) { 300 syslog(LOG_ERR, "sysctl(set_disrtcset): %m"); 301 return 1; 302 } 303 } 304 } 305 306 if ( (init && (stv != NULL || stz != NULL)) 307 || (stz != NULL && stv == NULL) 308 ) { 309 if (stv != NULL) { 310 /* 311 * Get the time again, as close as possible to 312 * adjusting it, to minimise drift. 313 * XXX we'd better not fail between here and 314 * restoring disrtcset, since we don't clean up 315 * anything. 316 */ 317 if (gettimeofday(&tv, (struct timezone *)NULL)) { 318 syslog(LOG_ERR, "gettimeofday: %m"); 319 return 1; 320 } 321 tv.tv_sec += diff; 322 stv = &tv; 323 } 324 if (settimeofday(stv, stz)) { 325 syslog(LOG_ERR, "settimeofday: %m"); 326 return 1; 327 } 328 } 329 330 /* setting CPU_ADJKERNTZ have a side effect: resettodr(), which */ 331 /* can be disabled by CPU_DISRTCSET, so if init or UTC clock */ 332 /* -- don't write RTC, else write RTC. */ 333 334 if (kern_offset != offset) { 335 kern_offset = offset; 336 mib[0] = CTL_MACHDEP; 337 mib[1] = CPU_ADJKERNTZ; 338 len = sizeof(kern_offset); 339 if (sysctl(mib, 2, NULL, NULL, &kern_offset, len) == -1) { 340 syslog(LOG_ERR, "sysctl(update_offset): %m"); 341 return 1; 342 } 343 } 344 345 mib[0] = CTL_MACHDEP; 346 mib[1] = CPU_WALLCLOCK; 347 len = sizeof(wall_clock); 348 if (sysctl(mib, 2, NULL, NULL, &wall_clock, len) == -1) { 349 syslog(LOG_ERR, "sysctl(put_wallclock): %m"); 350 return 1; 351 } 352 353 if (need_restore) { 354 need_restore = False; 355 mib[0] = CTL_MACHDEP; 356 mib[1] = CPU_DISRTCSET; 357 disrtcset = 0; 358 len = sizeof(disrtcset); 359 if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) { 360 syslog(LOG_ERR, "sysctl(restore_disrtcset): %m"); 361 return 1; 362 } 363 } 364 365 /****** End of critical section ******/ 366 367 if (init && wall_clock) { 368 sleep_mode = False; 369 /* wait for signals and acts like -a */ 370 (void) sigsuspend(&emask); 371 goto again; 372 } 373 374 return 0; 375 } 376 377 static void 378 usage(void) 379 { 380 fprintf(stderr, "%s\n%s\n%s\n%s\n", 381 "usage: adjkerntz -i", 382 "\t\t(initial call from /etc/rc)", 383 " adjkerntz -a [-s]", 384 "\t\t(adjustment call, -s for sleep/retry mode)"); 385 exit(2); 386 } 387