1 /* 2 * Copyright (C) 1993-1996 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 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 /* 34 * Andrey A. Chernov <ache@astral.msk.su> Dec 20 1993 35 * 36 * Fix kernel time value if machine run wall CMOS clock 37 * (and /etc/wall_cmos_clock file present) 38 * using zoneinfo rules or direct TZ environment variable set. 39 * Use Joerg Wunsch idea for seconds accurate offset calculation 40 * with Garrett Wollman and Bruce Evans fixes. 41 * 42 */ 43 #include <stdio.h> 44 #include <signal.h> 45 #include <stdlib.h> 46 #include <unistd.h> 47 #include <syslog.h> 48 #include <sys/stat.h> 49 #include <sys/time.h> 50 #include <sys/param.h> 51 #include <machine/cpu.h> 52 #include <sys/sysctl.h> 53 54 #include "pathnames.h" 55 56 /*#define DEBUG*/ 57 58 #define True (1) 59 #define False (0) 60 #define Unknown (-1) 61 62 #define REPORT_PERIOD (30*60) 63 64 void fake() {} 65 66 int main(argc, argv) 67 int argc; 68 char **argv; 69 { 70 struct tm local, utc; 71 struct timeval tv, *stv; 72 struct timezone tz, *stz; 73 int kern_offset, wall_clock, disrtcset; 74 size_t len; 75 int mib[2]; 76 /* Avoid time_t here, can be unsigned long or worse */ 77 long offset, utcsec, localsec, diff; 78 time_t initial_sec, final_sec; 79 int ch; 80 int initial_isdst = -1, final_isdst; 81 int need_restore = False, sleep_mode = False, looping, 82 init = Unknown; 83 sigset_t mask, emask; 84 85 while ((ch = getopt(argc, argv, "ais")) != EOF) 86 switch((char)ch) { 87 case 'i': /* initial call, save offset */ 88 if (init != Unknown) 89 goto usage; 90 init = True; 91 break; 92 case 'a': /* adjustment call, use saved offset */ 93 if (init != Unknown) 94 goto usage; 95 init = False; 96 break; 97 case 's': 98 sleep_mode = True; 99 break; 100 default: 101 usage: 102 fprintf(stderr, "Usage:\n\ 103 \tadjkerntz -i\t\t(initial call from /etc/rc)\n\ 104 \tadjkerntz -a [-s]\t(adjustment call, -s for sleep/retry mode)\n"); 105 return 2; 106 } 107 if (init == Unknown) 108 goto 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 } 124 125 again: 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; 159 160 recalculate: 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.", 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.", 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 tv.tv_sec += diff; 261 tv.tv_usec = 0; /* we are restarting here... */ 262 stv = &tv; 263 } 264 } 265 266 if (tz.tz_dsttime != 0 || tz.tz_minuteswest != 0) { 267 tz.tz_dsttime = tz.tz_minuteswest = 0; /* zone info is garbage */ 268 stz = &tz; 269 } 270 if (!wall_clock && stz == NULL) 271 stv = NULL; 272 273 /* if init or UTC clock and offset/date will be changed, */ 274 /* disable RTC modification for a while. */ 275 276 if ( (init && stv != NULL) 277 || ((init || !wall_clock) && kern_offset != offset) 278 ) { 279 mib[0] = CTL_MACHDEP; 280 mib[1] = CPU_DISRTCSET; 281 len = sizeof(disrtcset); 282 if (sysctl(mib, 2, &disrtcset, &len, NULL, 0) == -1) { 283 syslog(LOG_ERR, "sysctl(get_disrtcset): %m"); 284 return 1; 285 } 286 if (disrtcset == 0) { 287 disrtcset = 1; 288 need_restore = True; 289 if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) { 290 syslog(LOG_ERR, "sysctl(set_disrtcset): %m"); 291 return 1; 292 } 293 } 294 } 295 296 if ( ( (init && (stv != NULL || stz != NULL)) 297 || (stz != NULL && stv == NULL) 298 ) 299 && settimeofday(stv, stz) 300 ) { 301 syslog(LOG_ERR, "settimeofday: %m"); 302 return 1; 303 } 304 305 /* setting CPU_ADJKERNTZ have a side effect: resettodr(), which */ 306 /* can be disabled by CPU_DISRTCSET, so if init or UTC clock */ 307 /* -- don't write RTC, else write RTC. */ 308 309 if (kern_offset != offset) { 310 kern_offset = offset; 311 mib[0] = CTL_MACHDEP; 312 mib[1] = CPU_ADJKERNTZ; 313 len = sizeof(kern_offset); 314 if (sysctl(mib, 2, NULL, NULL, &kern_offset, len) == -1) { 315 syslog(LOG_ERR, "sysctl(update_offset): %m"); 316 return 1; 317 } 318 } 319 320 mib[0] = CTL_MACHDEP; 321 mib[1] = CPU_WALLCLOCK; 322 len = sizeof(wall_clock); 323 if (sysctl(mib, 2, NULL, NULL, &wall_clock, len) == -1) { 324 syslog(LOG_ERR, "sysctl(put_wallclock): %m"); 325 return 1; 326 } 327 328 if (need_restore) { 329 need_restore = False; 330 mib[0] = CTL_MACHDEP; 331 mib[1] = CPU_DISRTCSET; 332 disrtcset = 0; 333 len = sizeof(disrtcset); 334 if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) { 335 syslog(LOG_ERR, "sysctl(restore_disrtcset): %m"); 336 return 1; 337 } 338 } 339 340 /****** End of critical section ******/ 341 342 if (init && wall_clock) { 343 sleep_mode = False; 344 /* wait for signals and acts like -a */ 345 (void) sigsuspend(&emask); 346 goto again; 347 } 348 349 return 0; 350 } 351