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