1 /* 2 * Copyright (C) 1993, 1994, 1995 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, 1994, 1995 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 #define REPORT_PERIOD (30*60) 58 59 void fake() {} 60 61 int main(argc, argv) 62 int argc; 63 char **argv; 64 { 65 struct tm local, utc; 66 struct timeval tv, *stv; 67 struct timezone tz, *stz; 68 int kern_offset; 69 size_t len; 70 int mib[2]; 71 /* Avoid time_t here, can be unsigned long or worse */ 72 long offset, utcsec, localsec, diff; 73 time_t initial_sec, final_sec; 74 int ch, init = -1; 75 int initial_isdst = -1, final_isdst, looping; 76 int disrtcset, need_restore = 0; 77 sigset_t mask, emask; 78 79 while ((ch = getopt(argc, argv, "ai")) != EOF) 80 switch((char)ch) { 81 case 'i': /* initial call, save offset */ 82 if (init != -1) 83 goto usage; 84 init = 1; 85 break; 86 case 'a': /* adjustment call, use saved offset */ 87 if (init != -1) 88 goto usage; 89 init = 0; 90 break; 91 default: 92 usage: 93 fprintf(stderr, "Usage:\n\ 94 \tadjkerntz -i\t(initial call from /etc/rc)\n\ 95 \tadjkerntz -a\t(adjustment call from crontab)\n"); 96 return 2; 97 } 98 if (init == -1) 99 goto usage; 100 101 if (access(_PATH_CLOCK, F_OK)) 102 return 0; 103 104 sigemptyset(&mask); 105 sigemptyset(&emask); 106 sigaddset(&mask, SIGTERM); 107 108 openlog("adjkerntz", LOG_PID|LOG_PERROR, LOG_DAEMON); 109 110 (void) signal(SIGHUP, SIG_IGN); 111 112 if (init && daemon(0, 1)) { 113 syslog(LOG_ERR, "daemon: %m"); 114 return 1; 115 } 116 117 again: 118 119 (void) sigprocmask(SIG_BLOCK, &mask, NULL); 120 (void) signal(SIGTERM, fake); 121 122 diff = 0; 123 stv = NULL; 124 stz = NULL; 125 looping = 0; 126 127 mib[0] = CTL_MACHDEP; 128 mib[1] = CPU_ADJKERNTZ; 129 len = sizeof(kern_offset); 130 if (sysctl(mib, 2, &kern_offset, &len, NULL, 0) == -1) { 131 syslog(LOG_ERR, "sysctl(get_offset): %m"); 132 return 1; 133 } 134 135 /****** Critical section, do all things as fast as possible ******/ 136 137 /* get local CMOS clock and possible kernel offset */ 138 if (gettimeofday(&tv, &tz)) { 139 syslog(LOG_ERR, "gettimeofday: %m"); 140 return 1; 141 } 142 143 /* get the actual local timezone difference */ 144 initial_sec = tv.tv_sec; 145 146 recalculate: 147 local = *localtime(&initial_sec); 148 if (diff == 0) 149 initial_isdst = local.tm_isdst; 150 utc = *gmtime(&initial_sec); 151 local.tm_isdst = utc.tm_isdst = initial_isdst; 152 153 /* calculate local CMOS diff from GMT */ 154 155 utcsec = mktime(&utc); 156 localsec = mktime(&local); 157 if (utcsec == -1 || localsec == -1) { 158 /* 159 * XXX user can only control local time, and it is 160 * unacceptable to fail here for init. 2:30 am in the 161 * middle of the nonexistent hour means 3:30 am. 162 */ 163 syslog(LOG_WARNING, 164 "Nonexistent local time -- will retry after %d secs", REPORT_PERIOD); 165 (void) signal(SIGTERM, SIG_DFL); 166 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL); 167 (void) sleep(REPORT_PERIOD); 168 goto again; 169 } 170 offset = utcsec - localsec; 171 #ifdef DEBUG 172 fprintf(stderr, "Initial offset: %ld secs\n", offset); 173 #endif 174 175 /* correct the kerneltime for this diffs */ 176 /* subtract kernel offset, if present, old offset too */ 177 178 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 179 180 if (diff != 0) { 181 #ifdef DEBUG 182 fprintf(stderr, "Initial diff: %ld secs\n", diff); 183 #endif 184 /* Yet one step for final time */ 185 186 final_sec = initial_sec + diff; 187 188 /* get the actual local timezone difference */ 189 local = *localtime(&final_sec); 190 final_isdst = diff < 0 ? initial_isdst : local.tm_isdst; 191 if (diff > 0 && initial_isdst != final_isdst) { 192 if (looping) 193 goto bad_final; 194 looping++; 195 initial_isdst = final_isdst; 196 goto recalculate; 197 } 198 utc = *gmtime(&final_sec); 199 local.tm_isdst = utc.tm_isdst = final_isdst; 200 201 utcsec = mktime(&utc); 202 localsec = mktime(&local); 203 if (utcsec == -1 || localsec == -1) { 204 bad_final: 205 /* 206 * XXX as above. The user has even less control, 207 * but perhaps we never get here. 208 */ 209 syslog(LOG_WARNING, 210 "Nonexistent (final) local time -- will retry after %d secs", REPORT_PERIOD); 211 (void) signal(SIGTERM, SIG_DFL); 212 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL); 213 (void) sleep(REPORT_PERIOD); 214 goto again; 215 } 216 offset = utcsec - localsec; 217 #ifdef DEBUG 218 fprintf(stderr, "Final offset: %ld secs\n", offset); 219 #endif 220 221 /* correct the kerneltime for this diffs */ 222 /* subtract kernel offset, if present, old offset too */ 223 224 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 225 226 if (diff != 0) { 227 #ifdef DEBUG 228 fprintf(stderr, "Final diff: %ld secs\n", diff); 229 #endif 230 tv.tv_sec += diff; 231 tv.tv_usec = 0; /* we are restarting here... */ 232 stv = &tv; 233 } 234 } 235 236 if (tz.tz_dsttime != 0 || tz.tz_minuteswest != 0) { 237 tz.tz_dsttime = tz.tz_minuteswest = 0; /* zone info is garbage */ 238 stz = &tz; 239 } 240 241 /* if init and something will be changed, don't touch RTC at all */ 242 if (init && (stv != NULL || kern_offset != offset)) { 243 mib[0] = CTL_MACHDEP; 244 mib[1] = CPU_DISRTCSET; 245 len = sizeof(disrtcset); 246 if (sysctl(mib, 2, &disrtcset, &len, NULL, 0) == -1) { 247 syslog(LOG_ERR, "sysctl(get_disrtcset): %m"); 248 return 1; 249 } 250 if (disrtcset == 0) { 251 disrtcset = 1; 252 need_restore = 1; 253 if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) { 254 syslog(LOG_ERR, "sysctl(set_disrtcset): %m"); 255 return 1; 256 } 257 } 258 } 259 260 if (( (init && (stv != NULL || stz != NULL)) 261 || (stz != NULL && stv == NULL) 262 ) 263 && settimeofday(stv, stz) 264 ) { 265 syslog(LOG_ERR, "settimeofday: %m"); 266 return 1; 267 } 268 269 /* init: don't write RTC, !init: write RTC */ 270 if (kern_offset != offset) { 271 kern_offset = offset; 272 mib[0] = CTL_MACHDEP; 273 mib[1] = CPU_ADJKERNTZ; 274 len = sizeof(kern_offset); 275 if (sysctl(mib, 2, NULL, NULL, &kern_offset, len) == -1) { 276 syslog(LOG_ERR, "sysctl(update_offset): %m"); 277 return 1; 278 } 279 } 280 281 if (need_restore) { 282 need_restore = 0; 283 mib[0] = CTL_MACHDEP; 284 mib[1] = CPU_DISRTCSET; 285 disrtcset = 0; 286 len = sizeof(disrtcset); 287 if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) { 288 syslog(LOG_ERR, "sysctl(restore_disrtcset): %m"); 289 return 1; 290 } 291 } 292 293 /****** End of critical section ******/ 294 295 if (init) { 296 init = 0; 297 /* wait for signals and acts like -a */ 298 (void) sigsuspend(&emask); 299 goto again; 300 } 301 302 return 0; 303 } 304