adjkerntz.c revision 34960
1251607Sdim/* 2251607Sdim * Copyright (C) 1993-1996 by Andrey A. Chernov, Moscow, Russia. 3251607Sdim * All rights reserved. 4251607Sdim * 5251607Sdim * Redistribution and use in source and binary forms, with or without 6251607Sdim * modification, are permitted provided that the following conditions 7251607Sdim * are met: 8251607Sdim * 1. Redistributions of source code must retain the above copyright 9251607Sdim * notice, this list of conditions and the following disclaimer. 10251607Sdim * 2. Redistributions in binary form must reproduce the above copyright 11251607Sdim * notice, this list of conditions and the following disclaimer in the 12251607Sdim * documentation and/or other materials provided with the distribution. 13251607Sdim * 14251607Sdim * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND 15251607Sdim * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16251607Sdim * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17251607Sdim * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 18251607Sdim * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19251607Sdim * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20251607Sdim * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21251607Sdim * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22251607Sdim * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23251607Sdim * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24251607Sdim * SUCH DAMAGE. 25251607Sdim * 26251607Sdim * $Id: adjkerntz.c,v 1.21 1998/02/25 09:40:21 ache Exp $ 27251607Sdim */ 28251607Sdim 29251607Sdim#ifndef lint 30251607Sdimchar copyright[] = 31251607Sdim"@(#)Copyright (C) 1993-1996 by Andrey A. Chernov, Moscow, Russia.\n\ 32251607Sdim All rights reserved.\n"; 33251607Sdim#endif /* not lint */ 34251607Sdim 35/* 36 * Andrey A. Chernov <ache@astral.msk.su> Dec 20 1993 37 * 38 * Fix kernel time value if machine run wall CMOS clock 39 * (and /etc/wall_cmos_clock file present) 40 * using zoneinfo rules or direct TZ environment variable set. 41 * Use Joerg Wunsch idea for seconds accurate offset calculation 42 * with Garrett Wollman and Bruce Evans fixes. 43 * 44 */ 45#include <stdio.h> 46#include <signal.h> 47#include <stdlib.h> 48#include <unistd.h> 49#include <syslog.h> 50#include <sys/stat.h> 51#include <sys/time.h> 52#include <sys/param.h> 53#include <machine/cpu.h> 54#include <sys/sysctl.h> 55 56#include "pathnames.h" 57 58/*#define DEBUG*/ 59 60#define True (1) 61#define False (0) 62#define Unknown (-1) 63 64#define REPORT_PERIOD (30*60) 65 66static void usage __P((void)); 67 68void fake() {} 69 70int main(argc, argv) 71 int argc; 72 char **argv; 73{ 74 struct tm local, utc; 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, utcsec, 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 if (init) 110 sleep_mode = True; 111 112 sigemptyset(&mask); 113 sigemptyset(&emask); 114 sigaddset(&mask, SIGTERM); 115 116 openlog("adjkerntz", LOG_PID|LOG_PERROR, LOG_DAEMON); 117 118 (void) signal(SIGHUP, SIG_IGN); 119 120 if (init && daemon(0, 1)) { 121 syslog(LOG_ERR, "daemon: %m"); 122 return 1; 123 } 124 125again: 126 (void) sigprocmask(SIG_BLOCK, &mask, NULL); 127 (void) signal(SIGTERM, fake); 128 129 diff = 0; 130 stv = NULL; 131 stz = NULL; 132 looping = False; 133 134 wall_clock = (access(_PATH_CLOCK, F_OK) == 0); 135 if (init && !sleep_mode) { 136 init = False; 137 if (!wall_clock) 138 return 0; 139 } 140 141 mib[0] = CTL_MACHDEP; 142 mib[1] = CPU_ADJKERNTZ; 143 len = sizeof(kern_offset); 144 if (sysctl(mib, 2, &kern_offset, &len, NULL, 0) == -1) { 145 syslog(LOG_ERR, "sysctl(get_offset): %m"); 146 return 1; 147 } 148 149/****** Critical section, do all things as fast as possible ******/ 150 151 /* get local CMOS clock and possible kernel offset */ 152 if (gettimeofday(&tv, &tz)) { 153 syslog(LOG_ERR, "gettimeofday: %m"); 154 return 1; 155 } 156 157 /* get the actual local timezone difference */ 158 initial_sec = tv.tv_sec; 159 160recalculate: 161 local = *localtime(&initial_sec); 162 if (diff == 0) 163 initial_isdst = local.tm_isdst; 164 utc = *gmtime(&initial_sec); 165 local.tm_isdst = utc.tm_isdst = initial_isdst; 166 167 /* calculate local CMOS diff from GMT */ 168 169 utcsec = mktime(&utc); 170 localsec = mktime(&local); 171 if (utcsec == -1 || localsec == -1) { 172 /* 173 * XXX user can only control local time, and it is 174 * unacceptable to fail here for init. 2:30 am in the 175 * middle of the nonexistent hour means 3:30 am. 176 */ 177 syslog(LOG_WARNING, 178 "Warning: nonexistent %s time, try to run later.", 179 utcsec == -1 && localsec == -1 ? "UTC time and local" : 180 utcsec == -1 ? "UTC" : "local"); 181 if (!sleep_mode) { 182 syslog(LOG_WARNING, "Giving up."); 183 return 1; 184 } 185 syslog(LOG_WARNING, "Will retry after %d minutes.", 186 REPORT_PERIOD / 60); 187 (void) signal(SIGTERM, SIG_DFL); 188 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL); 189 (void) sleep(REPORT_PERIOD); 190 goto again; 191 } 192 offset = utcsec - localsec; 193#ifdef DEBUG 194 fprintf(stderr, "Initial offset: %ld secs\n", offset); 195#endif 196 197 /* correct the kerneltime for this diffs */ 198 /* subtract kernel offset, if present, old offset too */ 199 200 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 201 202 if (diff != 0) { 203#ifdef DEBUG 204 fprintf(stderr, "Initial diff: %ld secs\n", diff); 205#endif 206 /* Yet one step for final time */ 207 208 final_sec = initial_sec + diff; 209 210 /* get the actual local timezone difference */ 211 local = *localtime(&final_sec); 212 final_isdst = diff < 0 ? initial_isdst : local.tm_isdst; 213 if (diff > 0 && initial_isdst != final_isdst) { 214 if (looping) 215 goto bad_final; 216 looping = True; 217 initial_isdst = final_isdst; 218 goto recalculate; 219 } 220 utc = *gmtime(&final_sec); 221 local.tm_isdst = utc.tm_isdst = final_isdst; 222 223 utcsec = mktime(&utc); 224 localsec = mktime(&local); 225 if (utcsec == -1 || 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 syslog(LOG_WARNING, 232 "Warning: nonexistent final %s time, try to run later.", 233 utcsec == -1 && localsec == -1 ? "UTC time and local" : 234 utcsec == -1 ? "UTC" : "local"); 235 if (!sleep_mode) { 236 syslog(LOG_WARNING, "Giving up."); 237 return 1; 238 } 239 syslog(LOG_WARNING, "Will retry after %d minutes.", 240 REPORT_PERIOD / 60); 241 (void) signal(SIGTERM, SIG_DFL); 242 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL); 243 (void) sleep(REPORT_PERIOD); 244 goto again; 245 } 246 offset = utcsec - localsec; 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, (struct timezone *)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 (void) sigsuspend(&emask); 363 goto again; 364 } 365 366 return 0; 367} 368 369static void 370usage() 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