1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (C) 1993-1998 by Andrey A. Chernov, Moscow, Russia.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #if 0
30 #ifndef lint
31 static const char copyright[] =
32 "@(#)Copyright (C) 1993-1996 by Andrey A. Chernov, Moscow, Russia.\n\
33 All rights reserved.\n";
34 #endif /* not lint */
35 #endif
36 #include <sys/cdefs.h>
37 /*
38 * Andrey A. Chernov <[email protected]> Dec 20 1993
39 *
40 * Fix kernel time value if machine run wall CMOS clock
41 * (and /etc/wall_cmos_clock file present)
42 * using zoneinfo rules or direct TZ environment variable set.
43 * Use Joerg Wunsch idea for seconds accurate offset calculation
44 * with Garrett Wollman and Bruce Evans fixes.
45 *
46 */
47 #include <stdio.h>
48 #include <signal.h>
49 #include <stdlib.h>
50 #include <unistd.h>
51 #include <syslog.h>
52 #include <sys/time.h>
53 #include <sys/param.h>
54 #include <machine/cpu.h>
55 #include <sys/sysctl.h>
56
57 #include "pathnames.h"
58
59 /*#define DEBUG*/
60
61 #define True (1)
62 #define False (0)
63 #define Unknown (-1)
64
65 #define REPORT_PERIOD (30*60)
66
67 static void fake(int);
68 static void usage(void) __dead2;
69
70 static void
fake(int unused __unused)71 fake(int unused __unused)
72 {
73
74 /* Do nothing. */
75 }
76
77 int
main(int argc,char * argv[])78 main(int argc, char *argv[])
79 {
80 struct tm local;
81 struct timeval tv, *stv;
82 struct timezone tz, *stz;
83 int kern_offset, wall_clock, disrtcset;
84 size_t len;
85 /* Avoid time_t here, can be unsigned long or worse */
86 long offset, localsec, diff;
87 time_t initial_sec, final_sec;
88 int ch;
89 int initial_isdst = -1, final_isdst;
90 int need_restore = False, sleep_mode = False, looping,
91 init = Unknown;
92 sigset_t mask, emask;
93
94 while ((ch = getopt(argc, argv, "ais")) != -1)
95 switch((char)ch) {
96 case 'i': /* initial call, save offset */
97 if (init != Unknown)
98 usage();
99 init = True;
100 break;
101 case 'a': /* adjustment call, use saved offset */
102 if (init != Unknown)
103 usage();
104 init = False;
105 break;
106 case 's':
107 sleep_mode = True;
108 break;
109 default:
110 usage();
111 }
112 if (init == Unknown)
113 usage();
114
115 if (access(_PATH_CLOCK, F_OK) != 0)
116 return 0;
117
118 if (init)
119 sleep_mode = True;
120
121 sigemptyset(&mask);
122 sigemptyset(&emask);
123 sigaddset(&mask, SIGTERM);
124
125 openlog("adjkerntz", LOG_PID|LOG_PERROR, LOG_DAEMON);
126
127 (void) signal(SIGHUP, SIG_IGN);
128
129 if (init && daemon(0,
130 #ifdef DEBUG
131 1
132 #else
133 0
134 #endif
135 )) {
136 syslog(LOG_ERR, "daemon: %m");
137 return 1;
138 }
139
140 again:
141 (void) sigprocmask(SIG_BLOCK, &mask, NULL);
142 (void) signal(SIGTERM, fake);
143
144 diff = 0;
145 stv = NULL;
146 stz = NULL;
147 looping = False;
148
149 wall_clock = (access(_PATH_CLOCK, F_OK) == 0);
150 if (init && !sleep_mode) {
151 init = False;
152 if (!wall_clock)
153 return 0;
154 }
155
156 tzset();
157
158 len = sizeof(kern_offset);
159 if (sysctlbyname("machdep.adjkerntz", &kern_offset, &len, NULL, 0) == -1) {
160 syslog(LOG_ERR, "sysctl(\"machdep.adjkerntz\"): %m");
161 return 1;
162 }
163
164 /****** Critical section, do all things as fast as possible ******/
165
166 /* get local CMOS clock and possible kernel offset */
167 if (gettimeofday(&tv, &tz)) {
168 syslog(LOG_ERR, "gettimeofday: %m");
169 return 1;
170 }
171
172 /* get the actual local timezone difference */
173 initial_sec = tv.tv_sec;
174
175 recalculate:
176 local = *localtime(&initial_sec);
177 if (diff == 0)
178 initial_isdst = local.tm_isdst;
179 local.tm_isdst = initial_isdst;
180
181 /* calculate local CMOS diff from GMT */
182
183 localsec = mktime(&local);
184 if (localsec == -1) {
185 /*
186 * XXX user can only control local time, and it is
187 * unacceptable to fail here for init. 2:30 am in the
188 * middle of the nonexistent hour means 3:30 am.
189 */
190 if (!sleep_mode) {
191 syslog(LOG_WARNING,
192 "Warning: nonexistent local time, try to run later.");
193 syslog(LOG_WARNING, "Giving up.");
194 return 1;
195 }
196 syslog(LOG_WARNING,
197 "Warning: nonexistent local time.");
198 syslog(LOG_WARNING, "Will retry after %d minutes.",
199 REPORT_PERIOD / 60);
200 (void) signal(SIGTERM, SIG_DFL);
201 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL);
202 (void) sleep(REPORT_PERIOD);
203 goto again;
204 }
205 offset = -local.tm_gmtoff;
206 #ifdef DEBUG
207 fprintf(stderr, "Initial offset: %ld secs\n", offset);
208 #endif
209
210 /* correct the kerneltime for this diffs */
211 /* subtract kernel offset, if present, old offset too */
212
213 diff = offset - tz.tz_minuteswest * 60 - kern_offset;
214
215 if (diff != 0) {
216 #ifdef DEBUG
217 fprintf(stderr, "Initial diff: %ld secs\n", diff);
218 #endif
219 /* Yet one step for final time */
220
221 final_sec = initial_sec + diff;
222
223 /* get the actual local timezone difference */
224 local = *localtime(&final_sec);
225 final_isdst = diff < 0 ? initial_isdst : local.tm_isdst;
226 if (diff > 0 && initial_isdst != final_isdst) {
227 if (looping)
228 goto bad_final;
229 looping = True;
230 initial_isdst = final_isdst;
231 goto recalculate;
232 }
233 local.tm_isdst = final_isdst;
234
235 localsec = mktime(&local);
236 if (localsec == -1) {
237 bad_final:
238 /*
239 * XXX as above. The user has even less control,
240 * but perhaps we never get here.
241 */
242 if (!sleep_mode) {
243 syslog(LOG_WARNING,
244 "Warning: nonexistent final local time, try to run later.");
245 syslog(LOG_WARNING, "Giving up.");
246 return 1;
247 }
248 syslog(LOG_WARNING,
249 "Warning: nonexistent final local time.");
250 syslog(LOG_WARNING, "Will retry after %d minutes.",
251 REPORT_PERIOD / 60);
252 (void) signal(SIGTERM, SIG_DFL);
253 (void) sigprocmask(SIG_UNBLOCK, &mask, NULL);
254 (void) sleep(REPORT_PERIOD);
255 goto again;
256 }
257 offset = -local.tm_gmtoff;
258 #ifdef DEBUG
259 fprintf(stderr, "Final offset: %ld secs\n", offset);
260 #endif
261
262 /* correct the kerneltime for this diffs */
263 /* subtract kernel offset, if present, old offset too */
264
265 diff = offset - tz.tz_minuteswest * 60 - kern_offset;
266
267 if (diff != 0) {
268 #ifdef DEBUG
269 fprintf(stderr, "Final diff: %ld secs\n", diff);
270 #endif
271 /*
272 * stv is abused as a flag. The important value
273 * is in `diff'.
274 */
275 stv = &tv;
276 }
277 }
278
279 if (tz.tz_dsttime != 0 || tz.tz_minuteswest != 0) {
280 tz.tz_dsttime = tz.tz_minuteswest = 0; /* zone info is garbage */
281 stz = &tz;
282 }
283 if (!wall_clock && stz == NULL)
284 stv = NULL;
285
286 /* if init or UTC clock and offset/date will be changed, */
287 /* disable RTC modification for a while. */
288
289 if ( (init && stv != NULL)
290 || ((init || !wall_clock) && kern_offset != offset)
291 ) {
292 len = sizeof(disrtcset);
293 if (sysctlbyname("machdep.disable_rtc_set", &disrtcset, &len, NULL, 0) == -1) {
294 syslog(LOG_ERR, "sysctl(get: \"machdep.disable_rtc_set\"): %m");
295 return 1;
296 }
297 if (disrtcset == 0) {
298 disrtcset = 1;
299 need_restore = True;
300 if (sysctlbyname("machdep.disable_rtc_set", NULL, NULL, &disrtcset, len) == -1) {
301 syslog(LOG_ERR, "sysctl(set: \"machdep.disable_rtc_set\"): %m");
302 return 1;
303 }
304 }
305 }
306
307 if ( (init && (stv != NULL || stz != NULL))
308 || (stz != NULL && stv == NULL)
309 ) {
310 if (stv != NULL) {
311 /*
312 * Get the time again, as close as possible to
313 * adjusting it, to minimise drift.
314 * XXX we'd better not fail between here and
315 * restoring disrtcset, since we don't clean up
316 * anything.
317 */
318 (void)gettimeofday(&tv, NULL);
319 tv.tv_sec += diff;
320 stv = &tv;
321 }
322 if (settimeofday(stv, stz)) {
323 syslog(LOG_ERR, "settimeofday: %m");
324 return 1;
325 }
326 }
327
328 /* setting machdep.adjkerntz have a side effect: resettodr(), which */
329 /* can be disabled by machdep.disable_rtc_set, so if init or UTC clock */
330 /* -- don't write RTC, else write RTC. */
331
332 if (kern_offset != offset) {
333 kern_offset = offset;
334 len = sizeof(kern_offset);
335 if (sysctlbyname("machdep.adjkerntz", NULL, NULL, &kern_offset, len) == -1) {
336 syslog(LOG_ERR, "sysctl(set: \"machdep.adjkerntz\"): %m");
337 return 1;
338 }
339 }
340
341 len = sizeof(wall_clock);
342 if (sysctlbyname("machdep.wall_cmos_clock", NULL, NULL, &wall_clock, len) == -1) {
343 syslog(LOG_ERR, "sysctl(set: \"machdep.wall_cmos_clock\"): %m");
344 return 1;
345 }
346
347 if (need_restore) {
348 need_restore = False;
349 disrtcset = 0;
350 len = sizeof(disrtcset);
351 if (sysctlbyname("machdep.disable_rtc_set", NULL, NULL, &disrtcset, len) == -1) {
352 syslog(LOG_ERR, "sysctl(set: \"machdep.disable_rtc_set\"): %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
369 static void
usage(void)370 usage(void)
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