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 #ifndef lint 28 static const char copyright[] = 29 "@(#)Copyright (C) 1993-1996 by Andrey A. Chernov, Moscow, Russia.\n\ 30 All rights reserved.\n"; 31 #endif /* not lint */ 32 33 #ifndef lint 34 static const char rcsid[] = 35 "$FreeBSD$"; 36 #endif /* not lint */ 37 38 /* 39 * Andrey A. Chernov <ache@astral.msk.su> Dec 20 1993 40 * 41 * Fix kernel time value if machine run wall CMOS clock 42 * (and /etc/wall_cmos_clock file present) 43 * using zoneinfo rules or direct TZ environment variable set. 44 * Use Joerg Wunsch idea for seconds accurate offset calculation 45 * with Garrett Wollman and Bruce Evans fixes. 46 * 47 */ 48 #include <stdio.h> 49 #include <signal.h> 50 #include <stdlib.h> 51 #include <unistd.h> 52 #include <syslog.h> 53 #include <sys/time.h> 54 #include <sys/param.h> 55 #include <machine/cpu.h> 56 #include <sys/sysctl.h> 57 58 #include "pathnames.h" 59 60 /*#define DEBUG*/ 61 62 #define True (1) 63 #define False (0) 64 #define Unknown (-1) 65 66 #define REPORT_PERIOD (30*60) 67 68 static void fake(int); 69 static void usage(void); 70 71 static void 72 fake(int unused __unused) 73 { 74 75 /* Do nothing. */ 76 } 77 78 int 79 main(int argc, char *argv[]) 80 { 81 struct tm local; 82 struct timeval tv, *stv; 83 struct timezone tz, *stz; 84 int kern_offset, wall_clock, disrtcset; 85 size_t len; 86 int mib[2]; 87 /* Avoid time_t here, can be unsigned long or worse */ 88 long offset, localsec, diff; 89 time_t initial_sec, final_sec; 90 int ch; 91 int initial_isdst = -1, final_isdst; 92 int need_restore = False, sleep_mode = False, looping, 93 init = Unknown; 94 sigset_t mask, emask; 95 96 while ((ch = getopt(argc, argv, "ais")) != -1) 97 switch((char)ch) { 98 case 'i': /* initial call, save offset */ 99 if (init != Unknown) 100 usage(); 101 init = True; 102 break; 103 case 'a': /* adjustment call, use saved offset */ 104 if (init != Unknown) 105 usage(); 106 init = False; 107 break; 108 case 's': 109 sleep_mode = True; 110 break; 111 default: 112 usage(); 113 } 114 if (init == Unknown) 115 usage(); 116 117 if (access(_PATH_CLOCK, F_OK) != 0) 118 return 0; 119 120 if (init) 121 sleep_mode = True; 122 123 sigemptyset(&mask); 124 sigemptyset(&emask); 125 sigaddset(&mask, SIGTERM); 126 127 openlog("adjkerntz", LOG_PID|LOG_PERROR, LOG_DAEMON); 128 129 (void) signal(SIGHUP, SIG_IGN); 130 131 if (init && daemon(0, 1)) { 132 syslog(LOG_ERR, "daemon: %m"); 133 return 1; 134 } 135 136 again: 137 (void) sigprocmask(SIG_BLOCK, &mask, NULL); 138 (void) signal(SIGTERM, fake); 139 140 diff = 0; 141 stv = NULL; 142 stz = NULL; 143 looping = False; 144 145 wall_clock = (access(_PATH_CLOCK, F_OK) == 0); 146 if (init && !sleep_mode) { 147 init = False; 148 if (!wall_clock) 149 return 0; 150 } 151 152 mib[0] = CTL_MACHDEP; 153 mib[1] = CPU_ADJKERNTZ; 154 len = sizeof(kern_offset); 155 if (sysctl(mib, 2, &kern_offset, &len, NULL, 0) == -1) { 156 syslog(LOG_ERR, "sysctl(get_offset): %m"); 157 return 1; 158 } 159 160 /****** Critical section, do all things as fast as possible ******/ 161 162 /* get local CMOS clock and possible kernel offset */ 163 if (gettimeofday(&tv, &tz)) { 164 syslog(LOG_ERR, "gettimeofday: %m"); 165 return 1; 166 } 167 168 /* get the actual local timezone difference */ 169 initial_sec = tv.tv_sec; 170 171 recalculate: 172 local = *localtime(&initial_sec); 173 if (diff == 0) 174 initial_isdst = local.tm_isdst; 175 local.tm_isdst = initial_isdst; 176 177 /* calculate local CMOS diff from GMT */ 178 179 localsec = mktime(&local); 180 if (localsec == -1) { 181 /* 182 * XXX user can only control local time, and it is 183 * unacceptable to fail here for init. 2:30 am in the 184 * middle of the nonexistent hour means 3:30 am. 185 */ 186 if (!sleep_mode) { 187 syslog(LOG_WARNING, 188 "Warning: nonexistent local time, try to run later."); 189 syslog(LOG_WARNING, "Giving up."); 190 return 1; 191 } 192 syslog(LOG_WARNING, 193 "Warning: nonexistent local time."); 194 syslog(LOG_WARNING, "Will retry after %d minutes.", 195 REPORT_PERIOD / 60); 196 (void) signal(SIGTERM, SIG_DFL); 197 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL); 198 (void) sleep(REPORT_PERIOD); 199 goto again; 200 } 201 offset = -local.tm_gmtoff; 202 #ifdef DEBUG 203 fprintf(stderr, "Initial offset: %ld secs\n", offset); 204 #endif 205 206 /* correct the kerneltime for this diffs */ 207 /* subtract kernel offset, if present, old offset too */ 208 209 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 210 211 if (diff != 0) { 212 #ifdef DEBUG 213 fprintf(stderr, "Initial diff: %ld secs\n", diff); 214 #endif 215 /* Yet one step for final time */ 216 217 final_sec = initial_sec + diff; 218 219 /* get the actual local timezone difference */ 220 local = *localtime(&final_sec); 221 final_isdst = diff < 0 ? initial_isdst : local.tm_isdst; 222 if (diff > 0 && initial_isdst != final_isdst) { 223 if (looping) 224 goto bad_final; 225 looping = True; 226 initial_isdst = final_isdst; 227 goto recalculate; 228 } 229 local.tm_isdst = final_isdst; 230 231 localsec = mktime(&local); 232 if (localsec == -1) { 233 bad_final: 234 /* 235 * XXX as above. The user has even less control, 236 * but perhaps we never get here. 237 */ 238 if (!sleep_mode) { 239 syslog(LOG_WARNING, 240 "Warning: nonexistent final local time, try to run later."); 241 syslog(LOG_WARNING, "Giving up."); 242 return 1; 243 } 244 syslog(LOG_WARNING, 245 "Warning: nonexistent final local time."); 246 syslog(LOG_WARNING, "Will retry after %d minutes.", 247 REPORT_PERIOD / 60); 248 (void) signal(SIGTERM, SIG_DFL); 249 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL); 250 (void) sleep(REPORT_PERIOD); 251 goto again; 252 } 253 offset = -local.tm_gmtoff; 254 #ifdef DEBUG 255 fprintf(stderr, "Final offset: %ld secs\n", offset); 256 #endif 257 258 /* correct the kerneltime for this diffs */ 259 /* subtract kernel offset, if present, old offset too */ 260 261 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 262 263 if (diff != 0) { 264 #ifdef DEBUG 265 fprintf(stderr, "Final diff: %ld secs\n", diff); 266 #endif 267 /* 268 * stv is abused as a flag. The important value 269 * is in `diff'. 270 */ 271 stv = &tv; 272 } 273 } 274 275 if (tz.tz_dsttime != 0 || tz.tz_minuteswest != 0) { 276 tz.tz_dsttime = tz.tz_minuteswest = 0; /* zone info is garbage */ 277 stz = &tz; 278 } 279 if (!wall_clock && stz == NULL) 280 stv = NULL; 281 282 /* if init or UTC clock and offset/date will be changed, */ 283 /* disable RTC modification for a while. */ 284 285 if ( (init && stv != NULL) 286 || ((init || !wall_clock) && kern_offset != offset) 287 ) { 288 mib[0] = CTL_MACHDEP; 289 mib[1] = CPU_DISRTCSET; 290 len = sizeof(disrtcset); 291 if (sysctl(mib, 2, &disrtcset, &len, NULL, 0) == -1) { 292 syslog(LOG_ERR, "sysctl(get_disrtcset): %m"); 293 return 1; 294 } 295 if (disrtcset == 0) { 296 disrtcset = 1; 297 need_restore = True; 298 if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) { 299 syslog(LOG_ERR, "sysctl(set_disrtcset): %m"); 300 return 1; 301 } 302 } 303 } 304 305 if ( (init && (stv != NULL || stz != NULL)) 306 || (stz != NULL && stv == NULL) 307 ) { 308 if (stv != NULL) { 309 /* 310 * Get the time again, as close as possible to 311 * adjusting it, to minimise drift. 312 * XXX we'd better not fail between here and 313 * restoring disrtcset, since we don't clean up 314 * anything. 315 */ 316 if (gettimeofday(&tv, (struct timezone *)NULL)) { 317 syslog(LOG_ERR, "gettimeofday: %m"); 318 return 1; 319 } 320 tv.tv_sec += diff; 321 stv = &tv; 322 } 323 if (settimeofday(stv, stz)) { 324 syslog(LOG_ERR, "settimeofday: %m"); 325 return 1; 326 } 327 } 328 329 /* setting CPU_ADJKERNTZ have a side effect: resettodr(), which */ 330 /* can be disabled by CPU_DISRTCSET, so if init or UTC clock */ 331 /* -- don't write RTC, else write RTC. */ 332 333 if (kern_offset != offset) { 334 kern_offset = offset; 335 mib[0] = CTL_MACHDEP; 336 mib[1] = CPU_ADJKERNTZ; 337 len = sizeof(kern_offset); 338 if (sysctl(mib, 2, NULL, NULL, &kern_offset, len) == -1) { 339 syslog(LOG_ERR, "sysctl(update_offset): %m"); 340 return 1; 341 } 342 } 343 344 mib[0] = CTL_MACHDEP; 345 mib[1] = CPU_WALLCLOCK; 346 len = sizeof(wall_clock); 347 if (sysctl(mib, 2, NULL, NULL, &wall_clock, len) == -1) { 348 syslog(LOG_ERR, "sysctl(put_wallclock): %m"); 349 return 1; 350 } 351 352 if (need_restore) { 353 need_restore = False; 354 mib[0] = CTL_MACHDEP; 355 mib[1] = CPU_DISRTCSET; 356 disrtcset = 0; 357 len = sizeof(disrtcset); 358 if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) { 359 syslog(LOG_ERR, "sysctl(restore_disrtcset): %m"); 360 return 1; 361 } 362 } 363 364 /****** End of critical section ******/ 365 366 if (init && wall_clock) { 367 sleep_mode = False; 368 /* wait for signals and acts like -a */ 369 (void) sigsuspend(&emask); 370 goto again; 371 } 372 373 return 0; 374 } 375 376 static void 377 usage(void) 378 { 379 fprintf(stderr, "%s\n%s\n%s\n%s\n", 380 "usage: adjkerntz -i", 381 "\t\t(initial call from /etc/rc)", 382 " adjkerntz -a [-s]", 383 "\t\t(adjustment call, -s for sleep/retry mode)"); 384 exit(2); 385 } 386