1 /* 2 * Copyright (C) 1993, 1994 by Andrew 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 by Andrew A. Chernov, Moscow, Russia.\n\ 30 All rights reserved.\n"; 31 #endif /* not lint */ 32 33 /* 34 * Andrew 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 disrtcset, need_restore = 0; 76 sigset_t mask, emask; 77 78 while ((ch = getopt(argc, argv, "ai")) != EOF) 79 switch((char)ch) { 80 case 'i': /* initial call, save offset */ 81 if (init != -1) 82 goto usage; 83 init = 1; 84 break; 85 case 'a': /* adjustment call, use saved offset */ 86 if (init != -1) 87 goto usage; 88 init = 0; 89 break; 90 default: 91 usage: 92 fprintf(stderr, "Usage:\n\ 93 \tadjkerntz -i\t(initial call from /etc/rc)\n\ 94 \tadjkerntz -a\t(adjustment call from crontab)\n"); 95 return 2; 96 } 97 if (init == -1) 98 goto usage; 99 100 if (access(_PATH_CLOCK, F_OK)) 101 return 0; 102 103 sigemptyset(&mask); 104 sigemptyset(&emask); 105 sigaddset(&mask, SIGTERM); 106 107 openlog("adjkerntz", LOG_PID|LOG_PERROR, LOG_DAEMON); 108 109 (void) signal(SIGHUP, SIG_IGN); 110 111 if (init && daemon(0, 1)) { 112 syslog(LOG_ERR, "daemon: %m"); 113 return 1; 114 } 115 116 again: 117 118 (void) sigprocmask(SIG_BLOCK, &mask, NULL); 119 (void) signal(SIGTERM, fake); 120 121 /****** Critical section, do all things as fast as possible ******/ 122 123 /* get local CMOS clock and possible kernel offset */ 124 if (gettimeofday(&tv, &tz)) { 125 syslog(LOG_ERR, "gettimeofday: %m"); 126 return 1; 127 } 128 129 /* get the actual local timezone difference */ 130 initial_sec = tv.tv_sec; 131 local = *localtime(&initial_sec); 132 utc = *gmtime(&initial_sec); 133 134 /* calculate local CMOS diff from GMT */ 135 136 utcsec = timelocal(&utc); 137 localsec = timelocal(&local); 138 if (utcsec == -1 || localsec == -1) { 139 /* 140 * XXX user can only control local time, and it is 141 * unacceptable to fail here for init. 2:30 am in the 142 * middle of the nonexistent hour means 3:30 am. 143 */ 144 syslog(LOG_WARNING, 145 "Nonexistent local time -- will retry after %d secs", REPORT_PERIOD); 146 (void) signal(SIGTERM, SIG_DFL); 147 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL); 148 (void) sleep(REPORT_PERIOD); 149 goto again; 150 } 151 offset = utcsec - localsec; 152 #ifdef DEBUG 153 fprintf(stderr, "Initial offset: %ld secs\n", offset); 154 #endif 155 156 mib[0] = CTL_MACHDEP; 157 mib[1] = CPU_ADJKERNTZ; 158 len = sizeof(kern_offset); 159 if (sysctl(mib, 2, &kern_offset, &len, NULL, 0) == -1) { 160 syslog(LOG_ERR, "sysctl(get_offset): %m"); 161 return 1; 162 } 163 164 stv = NULL; 165 stz = NULL; 166 167 /* correct the kerneltime for this diffs */ 168 /* subtract kernel offset, if present, old offset too */ 169 170 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 171 172 if (diff != 0) { 173 #ifdef DEBUG 174 fprintf(stderr, "Initial diff: %ld secs\n", diff); 175 #endif 176 /* Yet one step for final time */ 177 178 final_sec = tv.tv_sec + diff; 179 180 /* get the actual local timezone difference */ 181 local = *localtime(&final_sec); 182 utc = *gmtime(&final_sec); 183 184 utcsec = timelocal(&utc); 185 localsec = timelocal(&local); 186 if (utcsec == -1 || localsec == -1) { 187 /* 188 * XXX as above. The user has even less control, 189 * but perhaps we never get here. 190 */ 191 syslog(LOG_WARNING, 192 "Nonexistent (final) local time -- will retry after %d secs", REPORT_PERIOD); 193 (void) signal(SIGTERM, SIG_DFL); 194 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL); 195 (void) sleep(REPORT_PERIOD); 196 goto again; 197 } 198 offset = utcsec - localsec; 199 #ifdef DEBUG 200 fprintf(stderr, "Final offset: %ld secs\n", offset); 201 #endif 202 203 /* correct the kerneltime for this diffs */ 204 /* subtract kernel offset, if present, old offset too */ 205 206 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 207 208 if (diff != 0) { 209 #ifdef DEBUG 210 fprintf(stderr, "Final diff: %ld secs\n", diff); 211 #endif 212 tv.tv_sec += diff; 213 tv.tv_usec = 0; /* we are restarting here... */ 214 stv = &tv; 215 } 216 } 217 218 if (tz.tz_dsttime != 0 || tz.tz_minuteswest != 0) { 219 tz.tz_dsttime = tz.tz_minuteswest = 0; /* zone info is garbage */ 220 stz = &tz; 221 } 222 223 /* if init and something will be changed, don't touch RTC at all */ 224 if (init && (stv != NULL || kern_offset != offset)) { 225 mib[0] = CTL_MACHDEP; 226 mib[1] = CPU_DISRTCSET; 227 len = sizeof(disrtcset); 228 if (sysctl(mib, 2, &disrtcset, &len, NULL, 0) == -1) { 229 syslog(LOG_ERR, "sysctl(get_disrtcset): %m"); 230 return 1; 231 } 232 if (disrtcset == 0) { 233 disrtcset = 1; 234 need_restore = 1; 235 if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) { 236 syslog(LOG_ERR, "sysctl(set_disrtcset): %m"); 237 return 1; 238 } 239 } 240 } 241 242 if (( (init && (stv != NULL || stz != NULL)) 243 || (stz != NULL && stv == NULL) 244 ) 245 && settimeofday(stv, stz) 246 ) { 247 syslog(LOG_ERR, "settimeofday: %m"); 248 return 1; 249 } 250 251 /* init: don't write RTC, !init: write RTC */ 252 if (kern_offset != offset) { 253 kern_offset = offset; 254 mib[0] = CTL_MACHDEP; 255 mib[1] = CPU_ADJKERNTZ; 256 len = sizeof(kern_offset); 257 if (sysctl(mib, 2, NULL, NULL, &kern_offset, len) == -1) { 258 syslog(LOG_ERR, "sysctl(update_offset): %m"); 259 return 1; 260 } 261 } 262 263 if (need_restore) { 264 need_restore = 0; 265 mib[0] = CTL_MACHDEP; 266 mib[1] = CPU_DISRTCSET; 267 disrtcset = 0; 268 len = sizeof(disrtcset); 269 if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) { 270 syslog(LOG_ERR, "sysctl(restore_disrtcset): %m"); 271 return 1; 272 } 273 } 274 275 /****** End of critical section ******/ 276 277 if (init) { 278 init = 0; 279 /* wait for signals and acts like -a */ 280 (void) sigsuspend(&emask); 281 goto again; 282 } 283 284 return 0; 285 } 286