adjkerntz.c revision 4107
1/* 2 * Copyright (C) 1993 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 28char 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 REPORT_PERIOD (30*60) 57 58void fake() {} 59 60int main(argc, argv) 61 int argc; 62 char **argv; 63{ 64 struct tm local, utc; 65 struct timeval tv, *stv; 66 struct timezone tz, *stz; 67 int kern_offset; 68 size_t len; 69 int mib[2]; 70 /* Avoid time_t here, can be unsigned long or worse */ 71 long offset, utcsec, localsec, diff; 72 time_t initial_sec, final_sec; 73 int ch, init = -1; 74 int disrtcset, need_restore = 0; 75 sigset_t mask, emask; 76 77 while ((ch = getopt(argc, argv, "ai")) != EOF) 78 switch((char)ch) { 79 case 'i': /* initial call, save offset */ 80 if (init != -1) 81 goto usage; 82 init = 1; 83 break; 84 case 'a': /* adjustment call, use saved offset */ 85 if (init != -1) 86 goto usage; 87 init = 0; 88 break; 89 default: 90 usage: 91 fprintf(stderr, "Usage:\n\ 92\tadjkerntz -i\t(initial call from /etc/rc)\n\ 93\tadjkerntz -a\t(adjustment call from crontab)\n"); 94 return 2; 95 } 96 if (init == -1) 97 goto usage; 98 99 if (access(_PATH_CLOCK, F_OK)) 100 return 0; 101 102 sigemptyset(&mask); 103 sigemptyset(&emask); 104 sigaddset(&mask, SIGTERM); 105 106 openlog("adjkerntz", LOG_PID|LOG_PERROR, LOG_DAEMON); 107 108 (void) signal(SIGHUP, SIG_IGN); 109 110 if (init && daemon(0, 1)) { 111 syslog(LOG_ERR, "daemon: %m"); 112 return 1; 113 } 114 115again: 116 117 (void) sigprocmask(SIG_BLOCK, &mask, NULL); 118 (void) signal(SIGTERM, fake); 119 120/****** Critical section, do all things as fast as possible ******/ 121 122 /* get local CMOS clock and possible kernel offset */ 123 if (gettimeofday(&tv, &tz)) { 124 syslog(LOG_ERR, "gettimeofday: %m"); 125 return 1; 126 } 127 128 /* get the actual local timezone difference */ 129 initial_sec = tv.tv_sec; 130 local = *localtime(&initial_sec); 131 utc = *gmtime(&initial_sec); 132 utc.tm_isdst = local.tm_isdst; /* Use current timezone for mktime(), */ 133 /* because it assumed local time */ 134 135 /* calculate local CMOS diff from GMT */ 136 137 utcsec = mktime(&utc); 138 localsec = mktime(&local); 139 if (utcsec == -1 || localsec == -1) { 140 /* 141 * XXX user can only control local time, and it is 142 * unacceptable to fail here for init. 2:30 am in the 143 * middle of the nonexistent hour means 3:30 am. 144 */ 145 syslog(LOG_WARNING, 146 "Nonexistent local time -- will retry after %d secs", REPORT_PERIOD); 147 (void) signal(SIGTERM, SIG_DFL); 148 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL); 149 (void) sleep(REPORT_PERIOD); 150 goto again; 151 } 152 offset = utcsec - localsec; 153 154 mib[0] = CTL_MACHDEP; 155 mib[1] = CPU_ADJKERNTZ; 156 len = sizeof(kern_offset); 157 if (sysctl(mib, 2, &kern_offset, &len, NULL, 0) == -1) { 158 syslog(LOG_ERR, "sysctl(get_offset): %m"); 159 return 1; 160 } 161 162 /* correct the kerneltime for this diffs */ 163 /* subtract kernel offset, if present, old offset too */ 164 165 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 166 167 if (diff != 0) { 168 169 /* Yet one step for final time */ 170 171 final_sec = tv.tv_sec + diff; 172 173 /* get the actual local timezone difference */ 174 local = *localtime(&final_sec); 175 utc = *gmtime(&final_sec); 176 utc.tm_isdst = local.tm_isdst; /* Use current timezone for mktime(), */ 177 /* because it assumed local time */ 178 179 utcsec = mktime(&utc); 180 localsec = mktime(&local); 181 if (utcsec == -1 || localsec == -1) { 182 /* 183 * XXX as above. The user has even less control, 184 * but perhaps we never get here. 185 */ 186 syslog(LOG_WARNING, 187 "Nonexistent (final) local time -- will retry after %d secs", REPORT_PERIOD); 188 (void) signal(SIGTERM, SIG_DFL); 189 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL); 190 (void) sleep(REPORT_PERIOD); 191 goto again; 192 } 193 offset = utcsec - localsec; 194 195 /* correct the kerneltime for this diffs */ 196 /* subtract kernel offset, if present, old offset too */ 197 198 diff = offset - tz.tz_minuteswest * 60 - kern_offset; 199 200 if (diff != 0) { 201 tv.tv_sec += diff; 202 tv.tv_usec = 0; /* we are restarting here... */ 203 stv = &tv; 204 } 205 else 206 stv = NULL; 207 } 208 else 209 stv = NULL; 210 211 if (tz.tz_dsttime != 0 || tz.tz_minuteswest != 0) { 212 tz.tz_dsttime = tz.tz_minuteswest = 0; /* zone info is garbage */ 213 stz = &tz; 214 } 215 else 216 stz = NULL; 217 218 if (stz != NULL || stv != NULL) { 219 if (init && stv != NULL) { 220 mib[0] = CTL_MACHDEP; 221 mib[1] = CPU_DISRTCSET; 222 len = sizeof(disrtcset); 223 if (sysctl(mib, 2, &disrtcset, &len, NULL, 0) == -1) { 224 syslog(LOG_ERR, "sysctl(get_disrtcset): %m"); 225 return 1; 226 } 227 if (disrtcset == 0) { 228 disrtcset = 1; 229 need_restore = 1; 230 if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) { 231 syslog(LOG_ERR, "sysctl(set_disrtcset): %m"); 232 return 1; 233 } 234 } 235 } 236 /* stz means that kernel zone shifted */ 237 /* clock needs adjustment even if !init */ 238 if ((init || stz != NULL) && settimeofday(stv, stz)) { 239 syslog(LOG_ERR, "settimeofday: %m"); 240 return 1; 241 } 242 } 243 244 if (kern_offset != offset) { 245 kern_offset = offset; 246 mib[0] = CTL_MACHDEP; 247 mib[1] = CPU_ADJKERNTZ; 248 len = sizeof(kern_offset); 249 if (sysctl(mib, 2, NULL, NULL, &kern_offset, len) == -1) { 250 syslog(LOG_ERR, "sysctl(update_offset): %m"); 251 return 1; 252 } 253 } 254 255 if (need_restore) { 256 need_restore = 0; 257 disrtcset = 0; 258 if (sysctl(mib, 2, NULL, NULL, &disrtcset, len) == -1) { 259 syslog(LOG_ERR, "sysctl(restore_disrtcset): %m"); 260 return 1; 261 } 262 } 263 264/****** End of critical section ******/ 265 266 if (init) { 267 init = 0; 268 /* wait for signals and acts like -a */ 269 (void) sigsuspend(&emask); 270 goto again; 271 } 272 273 return 0; 274} 275