Merge from vendor branch NTPD:
[dragonfly.git] / sys / kern / kern_time.c
CommitLineData
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1/*
2 * Copyright (c) 1982, 1986, 1989, 1993
3 * The Regents of the University of California. 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 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)kern_time.c 8.1 (Berkeley) 6/10/93
34 * $FreeBSD: src/sys/kern/kern_time.c,v 1.68.2.1 2002/10/01 08:00:41 bde Exp $
4026c000 35 * $DragonFly: src/sys/kern/kern_time.c,v 1.20 2005/04/14 07:55:36 joerg Exp $
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36 */
37
38#include <sys/param.h>
39#include <sys/systm.h>
40#include <sys/buf.h>
41#include <sys/sysproto.h>
42#include <sys/resourcevar.h>
43#include <sys/signalvar.h>
44#include <sys/kernel.h>
45#include <sys/systm.h>
46#include <sys/sysent.h>
df2244e3 47#include <sys/sysunion.h>
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48#include <sys/proc.h>
49#include <sys/time.h>
50#include <sys/vnode.h>
a94976ad 51#include <sys/sysctl.h>
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52#include <vm/vm.h>
53#include <vm/vm_extern.h>
245e4f17 54#include <sys/msgport2.h>
88c4d2f6 55#include <sys/thread2.h>
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56
57struct timezone tz;
58
59/*
60 * Time of day and interval timer support.
61 *
62 * These routines provide the kernel entry points to get and set
63 * the time-of-day and per-process interval timers. Subroutines
64 * here provide support for adding and subtracting timeval structures
65 * and decrementing interval timers, optionally reloading the interval
66 * timers when they expire.
67 */
68
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69static int nanosleep1 (struct timespec *rqt,
70 struct timespec *rmt);
71static int settime (struct timeval *);
72static void timevalfix (struct timeval *);
73static void no_lease_updatetime (int);
984263bc 74
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75static int sleep_hard_us = 100;
76SYSCTL_INT(_kern, OID_AUTO, sleep_hard_us, CTLFLAG_RW, &sleep_hard_us, 0, "")
a94976ad 77
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78static void
79no_lease_updatetime(deltat)
80 int deltat;
81{
82}
83
402ed7e1 84void (*lease_updatetime) (int) = no_lease_updatetime;
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85
86static int
87settime(tv)
88 struct timeval *tv;
89{
90 struct timeval delta, tv1, tv2;
91 static struct timeval maxtime, laststep;
92 struct timespec ts;
984263bc 93
88c4d2f6 94 crit_enter();
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95 microtime(&tv1);
96 delta = *tv;
97 timevalsub(&delta, &tv1);
98
99 /*
100 * If the system is secure, we do not allow the time to be
101 * set to a value earlier than 1 second less than the highest
102 * time we have yet seen. The worst a miscreant can do in
103 * this circumstance is "freeze" time. He couldn't go
104 * back to the past.
105 *
106 * We similarly do not allow the clock to be stepped more
107 * than one second, nor more than once per second. This allows
108 * a miscreant to make the clock march double-time, but no worse.
109 */
110 if (securelevel > 1) {
111 if (delta.tv_sec < 0 || delta.tv_usec < 0) {
112 /*
113 * Update maxtime to latest time we've seen.
114 */
115 if (tv1.tv_sec > maxtime.tv_sec)
116 maxtime = tv1;
117 tv2 = *tv;
118 timevalsub(&tv2, &maxtime);
119 if (tv2.tv_sec < -1) {
120 tv->tv_sec = maxtime.tv_sec - 1;
121 printf("Time adjustment clamped to -1 second\n");
122 }
123 } else {
124 if (tv1.tv_sec == laststep.tv_sec) {
88c4d2f6 125 crit_exit();
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126 return (EPERM);
127 }
128 if (delta.tv_sec > 1) {
129 tv->tv_sec = tv1.tv_sec + 1;
130 printf("Time adjustment clamped to +1 second\n");
131 }
132 laststep = *tv;
133 }
134 }
135
136 ts.tv_sec = tv->tv_sec;
137 ts.tv_nsec = tv->tv_usec * 1000;
88c4d2f6 138 set_timeofday(&ts);
984263bc 139 lease_updatetime(delta.tv_sec);
88c4d2f6 140 crit_exit();
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141 resettodr();
142 return (0);
143}
144
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145/* ARGSUSED */
146int
41c20dac 147clock_gettime(struct clock_gettime_args *uap)
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148{
149 struct timespec ats;
150
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151 switch(uap->clock_id) {
152 case CLOCK_REALTIME:
153 nanotime(&ats);
154 return (copyout(&ats, uap->tp, sizeof(ats)));
155 case CLOCK_MONOTONIC:
156 nanouptime(&ats);
157 return (copyout(&ats, uap->tp, sizeof(ats)));
158 default:
984263bc 159 return (EINVAL);
26be1876 160 }
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161}
162
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163/* ARGSUSED */
164int
41c20dac 165clock_settime(struct clock_settime_args *uap)
984263bc 166{
dadab5e9 167 struct thread *td = curthread;
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168 struct timeval atv;
169 struct timespec ats;
170 int error;
171
dadab5e9 172 if ((error = suser(td)) != 0)
984263bc 173 return (error);
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174 switch(uap->clock_id) {
175 case CLOCK_REALTIME:
176 if ((error = copyin(uap->tp, &ats, sizeof(ats))) != 0)
177 return (error);
178 if (ats.tv_nsec < 0 || ats.tv_nsec >= 1000000000)
179 return (EINVAL);
180 /* XXX Don't convert nsec->usec and back */
181 TIMESPEC_TO_TIMEVAL(&atv, &ats);
182 error = settime(&atv);
984263bc 183 return (error);
26be1876 184 default:
984263bc 185 return (EINVAL);
26be1876 186 }
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187}
188
984263bc 189int
41c20dac 190clock_getres(struct clock_getres_args *uap)
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191{
192 struct timespec ts;
984263bc 193
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194 switch(uap->clock_id) {
195 case CLOCK_REALTIME:
196 case CLOCK_MONOTONIC:
984263bc 197 /*
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198 * Round up the result of the division cheaply
199 * by adding 1. Rounding up is especially important
200 * if rounding down would give 0. Perfect rounding
201 * is unimportant.
984263bc 202 */
26be1876 203 ts.tv_sec = 0;
88c4d2f6 204 ts.tv_nsec = 1000000000 / cputimer_freq + 1;
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205 return(copyout(&ts, uap->tp, sizeof(ts)));
206 default:
207 return(EINVAL);
984263bc 208 }
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209}
210
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211/*
212 * nanosleep1()
213 *
214 * This is a general helper function for nanosleep() (aka sleep() aka
215 * usleep()).
216 *
217 * If there is less then one tick's worth of time left and
218 * we haven't done a yield, or the remaining microseconds is
219 * ridiculously low, do a yield. This avoids having
220 * to deal with systimer overheads when the system is under
221 * heavy loads. If we have done a yield already then use
222 * a systimer and an uninterruptable thread wait.
223 *
224 * If there is more then a tick's worth of time left,
225 * calculate the baseline ticks and use an interruptable
226 * tsleep, then handle the fine-grained delay on the next
227 * loop. This usually results in two sleeps occuring, a long one
228 * and a short one.
229 */
230static void
231ns1_systimer(systimer_t info)
232{
233 lwkt_schedule(info->data);
234}
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235
236static int
41c20dac 237nanosleep1(struct timespec *rqt, struct timespec *rmt)
984263bc 238{
88c4d2f6 239 static int nanowait;
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240 struct timespec ts, ts2, ts3;
241 struct timeval tv;
242 int error;
88c4d2f6 243 int tried_yield;
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244
245 if (rqt->tv_nsec < 0 || rqt->tv_nsec >= 1000000000)
246 return (EINVAL);
247 if (rqt->tv_sec < 0 || (rqt->tv_sec == 0 && rqt->tv_nsec == 0))
248 return (0);
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249 nanouptime(&ts);
250 timespecadd(&ts, rqt); /* ts = target timestamp compare */
251 TIMESPEC_TO_TIMEVAL(&tv, rqt); /* tv = sleep interval */
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252 tried_yield = 0;
253
984263bc 254 for (;;) {
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255 int ticks;
256 struct systimer info;
257
258 ticks = tv.tv_usec / tick; /* approximate */
a94976ad 259
88c4d2f6 260 if (tv.tv_sec == 0 && ticks == 0) {
37af14fe 261 thread_t td = curthread;
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262 if (tried_yield || tv.tv_usec < sleep_hard_us) {
263 tried_yield = 0;
a94976ad 264 uio_yield();
a94976ad 265 } else {
37af14fe 266 crit_enter_quick(td);
88c4d2f6 267 systimer_init_oneshot(&info, ns1_systimer,
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268 td, tv.tv_usec);
269 lwkt_deschedule_self(td);
270 crit_exit_quick(td);
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271 lwkt_switch();
272 systimer_del(&info); /* make sure it's gone */
a94976ad 273 }
37af14fe 274 error = iscaught(td->td_proc);
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275 } else if (tv.tv_sec == 0) {
276 error = tsleep(&nanowait, PCATCH, "nanslp", ticks);
a94976ad 277 } else {
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278 ticks = tvtohz_low(&tv); /* also handles overflow */
279 error = tsleep(&nanowait, PCATCH, "nanslp", ticks);
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280 }
281 nanouptime(&ts2);
88c4d2f6 282 if (error && error != EWOULDBLOCK) {
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283 if (error == ERESTART)
284 error = EINTR;
285 if (rmt != NULL) {
286 timespecsub(&ts, &ts2);
287 if (ts.tv_sec < 0)
288 timespecclear(&ts);
289 *rmt = ts;
290 }
291 return (error);
292 }
293 if (timespeccmp(&ts2, &ts, >=))
294 return (0);
295 ts3 = ts;
296 timespecsub(&ts3, &ts2);
297 TIMESPEC_TO_TIMEVAL(&tv, &ts3);
298 }
299}
300
245e4f17 301static void nanosleep_done(void *arg);
df2244e3 302static void nanosleep_copyout(union sysunion *sysun);
245e4f17 303
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304/* ARGSUSED */
305int
41c20dac 306nanosleep(struct nanosleep_args *uap)
984263bc 307{
245e4f17 308 int error;
df2244e3 309 struct sysmsg_sleep *smsleep = &uap->sysmsg.sm.sleep;
984263bc 310
df2244e3 311 error = copyin(uap->rqtp, &smsleep->rqt, sizeof(smsleep->rqt));
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312 if (error)
313 return (error);
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314 /*
315 * YYY clean this up to always use the callout, note that an abort
316 * implementation should record the residual in the async case.
317 */
df2244e3 318 if (uap->sysmsg.lmsg.ms_flags & MSGF_ASYNC) {
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319 quad_t ticks;
320
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321 ticks = (quad_t)smsleep->rqt.tv_nsec * hz / 1000000000LL;
322 if (smsleep->rqt.tv_sec)
323 ticks += (quad_t)smsleep->rqt.tv_sec * hz;
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324 if (ticks <= 0) {
325 if (ticks == 0)
326 error = 0;
327 else
328 error = EINVAL;
329 } else {
df2244e3 330 uap->sysmsg.copyout = nanosleep_copyout;
1fa2b4b4 331 uap->sysmsg.lmsg.ms_flags &= ~MSGF_DONE;
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332 callout_init(&smsleep->timer);
333 callout_reset(&smsleep->timer, ticks, nanosleep_done, uap);
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334 error = EASYNC;
335 }
336 } else {
337 /*
338 * Old synchronous sleep code, copyout the residual if
339 * nanosleep was interrupted.
340 */
df2244e3 341 error = nanosleep1(&smsleep->rqt, &smsleep->rmt);
ab2eb4eb
DR
342 if (error && uap->rmtp)
343 error = copyout(&smsleep->rmt, uap->rmtp, sizeof(smsleep->rmt));
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344 }
345 return (error);
346}
347
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348/*
349 * Asynch completion for the nanosleep() syscall. This function may be
350 * called from any context and cannot legally access the originating
351 * thread, proc, or its user space.
352 *
353 * YYY change the callout interface API so we can simply assign the replymsg
354 * function to it directly.
355 */
356static void
357nanosleep_done(void *arg)
358{
359 struct nanosleep_args *uap = arg;
1fa2b4b4 360 lwkt_msg_t msg = &uap->sysmsg.lmsg;
245e4f17 361
1fa2b4b4 362 lwkt_replymsg(msg, 0);
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MD
363}
364
365/*
366 * Asynch return for the nanosleep() syscall, called in the context of the
367 * originating thread when it pulls the message off the reply port. This
368 * function is responsible for any copyouts to userland. Kernel threads
369 * which do their own internal system calls will not usually call the return
370 * function.
371 */
372static void
df2244e3 373nanosleep_copyout(union sysunion *sysun)
245e4f17 374{
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375 struct nanosleep_args *uap = &sysun->nanosleep;
376 struct sysmsg_sleep *smsleep = &uap->sysmsg.sm.sleep;
245e4f17 377
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378 if (sysun->lmsg.ms_error && uap->rmtp) {
379 sysun->lmsg.ms_error =
380 copyout(&smsleep->rmt, uap->rmtp, sizeof(smsleep->rmt));
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381 }
382}
383
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384/* ARGSUSED */
385int
41c20dac 386gettimeofday(struct gettimeofday_args *uap)
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387{
388 struct timeval atv;
389 int error = 0;
390
391 if (uap->tp) {
392 microtime(&atv);
393 if ((error = copyout((caddr_t)&atv, (caddr_t)uap->tp,
394 sizeof (atv))))
395 return (error);
396 }
397 if (uap->tzp)
398 error = copyout((caddr_t)&tz, (caddr_t)uap->tzp,
399 sizeof (tz));
400 return (error);
401}
402
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403/* ARGSUSED */
404int
41c20dac 405settimeofday(struct settimeofday_args *uap)
984263bc 406{
dadab5e9 407 struct thread *td = curthread;
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408 struct timeval atv;
409 struct timezone atz;
410 int error;
411
dadab5e9 412 if ((error = suser(td)))
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413 return (error);
414 /* Verify all parameters before changing time. */
415 if (uap->tv) {
416 if ((error = copyin((caddr_t)uap->tv, (caddr_t)&atv,
417 sizeof(atv))))
418 return (error);
419 if (atv.tv_usec < 0 || atv.tv_usec >= 1000000)
420 return (EINVAL);
421 }
422 if (uap->tzp &&
423 (error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, sizeof(atz))))
424 return (error);
425 if (uap->tv && (error = settime(&atv)))
426 return (error);
427 if (uap->tzp)
428 tz = atz;
429 return (0);
430}
431
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432static void
433kern_adjtime_common(void)
434{
435 if ((ntp_delta >= 0 && ntp_delta < ntp_default_tick_delta) ||
436 (ntp_delta < 0 && ntp_delta > ntp_default_tick_delta))
437 ntp_tick_delta = ntp_delta;
438 else if (ntp_delta > ntp_big_delta)
439 ntp_tick_delta = 10 * ntp_default_tick_delta;
440 else if (ntp_delta < -ntp_big_delta)
441 ntp_tick_delta = -10 * ntp_default_tick_delta;
442 else if (ntp_delta > 0)
443 ntp_tick_delta = ntp_default_tick_delta;
444 else
445 ntp_tick_delta = -ntp_default_tick_delta;
446}
447
448void
449kern_adjtime(int64_t delta, int64_t *odelta)
450{
451 int origcpu;
452
453 if ((origcpu = mycpu->gd_cpuid) != 0) {
454 lwkt_setcpu_self(globaldata_find(0));
455 cpu_mb1();
456 }
457
458 crit_enter();
459 *odelta = ntp_delta;
460 ntp_delta += delta;
461 kern_adjtime_common();
462 crit_exit();
463
464 if (origcpu != 0) {
465 lwkt_setcpu_self(globaldata_find(origcpu));
466 cpu_mb1();
467 }
468}
469
470void
471kern_reladjtime(int64_t delta)
472{
473 int origcpu;
474
475 if ((origcpu = mycpu->gd_cpuid) != 0) {
476 lwkt_setcpu_self(globaldata_find(0));
477 cpu_mb1();
478 }
479
480 crit_enter();
481 ntp_delta += delta;
482 kern_adjtime_common();
483 crit_exit();
484
485 if (origcpu != 0) {
486 lwkt_setcpu_self(globaldata_find(origcpu));
487 cpu_mb1();
488 }
489}
984263bc 490
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491/* ARGSUSED */
492int
41c20dac 493adjtime(struct adjtime_args *uap)
984263bc 494{
dadab5e9 495 struct thread *td = curthread;
984263bc 496 struct timeval atv;
4026c000 497 int64_t ndelta, odelta;
88c4d2f6 498 int error;
984263bc 499
dadab5e9 500 if ((error = suser(td)))
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501 return (error);
502 if ((error =
503 copyin((caddr_t)uap->delta, (caddr_t)&atv, sizeof(struct timeval))))
504 return (error);
505
506 /*
507 * Compute the total correction and the rate at which to apply it.
508 * Round the adjustment down to a whole multiple of the per-tick
509 * delta, so that after some number of incremental changes in
510 * hardclock(), tickdelta will become zero, lest the correction
511 * overshoot and start taking us away from the desired final time.
512 */
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513 ndelta = atv.tv_sec * 1000000000 + atv.tv_usec * 1000;
514 kern_adjtime(ndelta, &odelta);
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515
516 if (uap->olddelta) {
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517 atv.tv_sec = odelta / 1000000000;
518 atv.tv_usec = odelta % 1000000 / 1000;
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519 (void) copyout((caddr_t)&atv, (caddr_t)uap->olddelta,
520 sizeof(struct timeval));
521 }
522 return (0);
523}
524
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525static int
526sysctl_adjtime(SYSCTL_HANDLER_ARGS)
527{
528 int64_t delta;
529 int error;
530
531 if (req->oldptr != NULL) {
532 delta = 0;
533 error = SYSCTL_OUT(req, &delta, sizeof(delta));
534 if (error)
535 return (error);
536 }
537 if (req->newptr != NULL) {
538 if (suser(curthread))
539 return (EPERM);
540 error = SYSCTL_IN(req, &delta, sizeof(delta));
541 if (error)
542 return (error);
543 kern_reladjtime(delta);
544 }
545 return (0);
546}
547
548SYSCTL_NODE(_kern, OID_AUTO, ntp, CTLFLAG_RW, 0, "NTP related controls");
549SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, permanent, CTLFLAG_RW,
550 &ntp_tick_permanent, sizeof(ntp_tick_permanent),
551 "LU", "permanent per-tick correct");
552SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, delta, CTLFLAG_RD,
553 &ntp_delta, sizeof(ntp_delta), "LU",
554 "one-time delta");
555SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, big_delta, CTLFLAG_RD,
556 &ntp_big_delta, sizeof(ntp_big_delta), "LU",
557 "threshold for fast adjustment");
558SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, tick_delta, CTLFLAG_RD,
559 &ntp_tick_delta, sizeof(ntp_tick_delta), "LU",
560 "per-tick adjustment");
561SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, default_tick_delta, CTLFLAG_RD,
562 &ntp_default_tick_delta, sizeof(ntp_default_tick_delta), "LU",
563 "default per-tick adjustment");
564SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, next_leaf_second, CTLFLAG_RW,
565 &ntp_leaf_second, sizeof(ntp_leaf_second), "LU",
566 "next leaf second");
567SYSCTL_INT(_kern_ntp, OID_AUTO, insert_leaf_second, CTLFLAG_RW,
568 &ntp_leaf_insert, 0, "insert or remove leaf second");
569SYSCTL_PROC(_kern_ntp, OID_AUTO, adjust,
570 CTLTYPE_OPAQUE|CTLFLAG_RW, 0, 0,
571 sysctl_adjtime, "", "relative adjust for delta");
572
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573/*
574 * Get value of an interval timer. The process virtual and
575 * profiling virtual time timers are kept in the p_stats area, since
576 * they can be swapped out. These are kept internally in the
577 * way they are specified externally: in time until they expire.
578 *
579 * The real time interval timer is kept in the process table slot
580 * for the process, and its value (it_value) is kept as an
581 * absolute time rather than as a delta, so that it is easy to keep
582 * periodic real-time signals from drifting.
583 *
584 * Virtual time timers are processed in the hardclock() routine of
585 * kern_clock.c. The real time timer is processed by a timeout
586 * routine, called from the softclock() routine. Since a callout
587 * may be delayed in real time due to interrupt processing in the system,
588 * it is possible for the real time timeout routine (realitexpire, given below),
589 * to be delayed in real time past when it is supposed to occur. It
590 * does not suffice, therefore, to reload the real timer .it_value from the
591 * real time timers .it_interval. Rather, we compute the next time in
592 * absolute time the timer should go off.
593 */
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594/* ARGSUSED */
595int
41c20dac 596getitimer(struct getitimer_args *uap)
984263bc 597{
41c20dac 598 struct proc *p = curproc;
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599 struct timeval ctv;
600 struct itimerval aitv;
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601
602 if (uap->which > ITIMER_PROF)
603 return (EINVAL);
88c4d2f6 604 crit_enter();
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605 if (uap->which == ITIMER_REAL) {
606 /*
607 * Convert from absolute to relative time in .it_value
608 * part of real time timer. If time for real time timer
609 * has passed return 0, else return difference between
610 * current time and time for the timer to go off.
611 */
612 aitv = p->p_realtimer;
613 if (timevalisset(&aitv.it_value)) {
614 getmicrouptime(&ctv);
615 if (timevalcmp(&aitv.it_value, &ctv, <))
616 timevalclear(&aitv.it_value);
617 else
618 timevalsub(&aitv.it_value, &ctv);
619 }
88c4d2f6 620 } else {
984263bc 621 aitv = p->p_stats->p_timer[uap->which];
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622 }
623 crit_exit();
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624 return (copyout((caddr_t)&aitv, (caddr_t)uap->itv,
625 sizeof (struct itimerval)));
626}
627
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628/* ARGSUSED */
629int
41c20dac 630setitimer(struct setitimer_args *uap)
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631{
632 struct itimerval aitv;
633 struct timeval ctv;
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634 struct itimerval *itvp;
635 struct proc *p = curproc;
88c4d2f6 636 int error;
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637
638 if (uap->which > ITIMER_PROF)
639 return (EINVAL);
640 itvp = uap->itv;
641 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv,
642 sizeof(struct itimerval))))
643 return (error);
644 if ((uap->itv = uap->oitv) &&
41c20dac 645 (error = getitimer((struct getitimer_args *)uap)))
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646 return (error);
647 if (itvp == 0)
648 return (0);
649 if (itimerfix(&aitv.it_value))
650 return (EINVAL);
651 if (!timevalisset(&aitv.it_value))
652 timevalclear(&aitv.it_interval);
653 else if (itimerfix(&aitv.it_interval))
654 return (EINVAL);
88c4d2f6 655 crit_enter();
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656 if (uap->which == ITIMER_REAL) {
657 if (timevalisset(&p->p_realtimer.it_value))
8fbf9130 658 callout_stop(&p->p_ithandle);
984263bc 659 if (timevalisset(&aitv.it_value))
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660 callout_reset(&p->p_ithandle,
661 tvtohz_high(&aitv.it_value), realitexpire, p);
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662 getmicrouptime(&ctv);
663 timevaladd(&aitv.it_value, &ctv);
664 p->p_realtimer = aitv;
88c4d2f6 665 } else {
984263bc 666 p->p_stats->p_timer[uap->which] = aitv;
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667 }
668 crit_exit();
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669 return (0);
670}
671
672/*
673 * Real interval timer expired:
674 * send process whose timer expired an alarm signal.
675 * If time is not set up to reload, then just return.
676 * Else compute next time timer should go off which is > current time.
677 * This is where delay in processing this timeout causes multiple
678 * SIGALRM calls to be compressed into one.
a94976ad 679 * tvtohz_high() always adds 1 to allow for the time until the next clock
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680 * interrupt being strictly less than 1 clock tick, but we don't want
681 * that here since we want to appear to be in sync with the clock
682 * interrupt even when we're delayed.
683 */
684void
685realitexpire(arg)
686 void *arg;
687{
1fd87d54 688 struct proc *p;
984263bc 689 struct timeval ctv, ntv;
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690
691 p = (struct proc *)arg;
692 psignal(p, SIGALRM);
693 if (!timevalisset(&p->p_realtimer.it_interval)) {
694 timevalclear(&p->p_realtimer.it_value);
695 return;
696 }
697 for (;;) {
88c4d2f6 698 crit_enter();
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699 timevaladd(&p->p_realtimer.it_value,
700 &p->p_realtimer.it_interval);
701 getmicrouptime(&ctv);
702 if (timevalcmp(&p->p_realtimer.it_value, &ctv, >)) {
703 ntv = p->p_realtimer.it_value;
704 timevalsub(&ntv, &ctv);
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705 callout_reset(&p->p_ithandle, tvtohz_low(&ntv),
706 realitexpire, p);
88c4d2f6 707 crit_exit();
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708 return;
709 }
88c4d2f6 710 crit_exit();
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711 }
712}
713
714/*
715 * Check that a proposed value to load into the .it_value or
716 * .it_interval part of an interval timer is acceptable, and
717 * fix it to have at least minimal value (i.e. if it is less
718 * than the resolution of the clock, round it up.)
719 */
720int
721itimerfix(tv)
722 struct timeval *tv;
723{
724
725 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 ||
726 tv->tv_usec < 0 || tv->tv_usec >= 1000000)
727 return (EINVAL);
728 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick)
729 tv->tv_usec = tick;
730 return (0);
731}
732
733/*
734 * Decrement an interval timer by a specified number
735 * of microseconds, which must be less than a second,
736 * i.e. < 1000000. If the timer expires, then reload
737 * it. In this case, carry over (usec - old value) to
738 * reduce the value reloaded into the timer so that
739 * the timer does not drift. This routine assumes
740 * that it is called in a context where the timers
741 * on which it is operating cannot change in value.
742 */
743int
744itimerdecr(itp, usec)
1fd87d54 745 struct itimerval *itp;
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746 int usec;
747{
748
749 if (itp->it_value.tv_usec < usec) {
750 if (itp->it_value.tv_sec == 0) {
751 /* expired, and already in next interval */
752 usec -= itp->it_value.tv_usec;
753 goto expire;
754 }
755 itp->it_value.tv_usec += 1000000;
756 itp->it_value.tv_sec--;
757 }
758 itp->it_value.tv_usec -= usec;
759 usec = 0;
760 if (timevalisset(&itp->it_value))
761 return (1);
762 /* expired, exactly at end of interval */
763expire:
764 if (timevalisset(&itp->it_interval)) {
765 itp->it_value = itp->it_interval;
766 itp->it_value.tv_usec -= usec;
767 if (itp->it_value.tv_usec < 0) {
768 itp->it_value.tv_usec += 1000000;
769 itp->it_value.tv_sec--;
770 }
771 } else
772 itp->it_value.tv_usec = 0; /* sec is already 0 */
773 return (0);
774}
775
776/*
777 * Add and subtract routines for timevals.
778 * N.B.: subtract routine doesn't deal with
779 * results which are before the beginning,
780 * it just gets very confused in this case.
781 * Caveat emptor.
782 */
783void
784timevaladd(t1, t2)
785 struct timeval *t1, *t2;
786{
787
788 t1->tv_sec += t2->tv_sec;
789 t1->tv_usec += t2->tv_usec;
790 timevalfix(t1);
791}
792
793void
794timevalsub(t1, t2)
795 struct timeval *t1, *t2;
796{
797
798 t1->tv_sec -= t2->tv_sec;
799 t1->tv_usec -= t2->tv_usec;
800 timevalfix(t1);
801}
802
803static void
804timevalfix(t1)
805 struct timeval *t1;
806{
807
808 if (t1->tv_usec < 0) {
809 t1->tv_sec--;
810 t1->tv_usec += 1000000;
811 }
812 if (t1->tv_usec >= 1000000) {
813 t1->tv_sec++;
814 t1->tv_usec -= 1000000;
815 }
816}
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817
818/*
819 * ratecheck(): simple time-based rate-limit checking.
820 */
821int
822ratecheck(struct timeval *lasttime, const struct timeval *mininterval)
823{
824 struct timeval tv, delta;
825 int rv = 0;
826
827 getmicrouptime(&tv); /* NB: 10ms precision */
828 delta = tv;
829 timevalsub(&delta, lasttime);
830
831 /*
832 * check for 0,0 is so that the message will be seen at least once,
833 * even if interval is huge.
834 */
835 if (timevalcmp(&delta, mininterval, >=) ||
836 (lasttime->tv_sec == 0 && lasttime->tv_usec == 0)) {
837 *lasttime = tv;
838 rv = 1;
839 }
840
841 return (rv);
842}
843
844/*
845 * ppsratecheck(): packets (or events) per second limitation.
846 *
847 * Return 0 if the limit is to be enforced (e.g. the caller
848 * should drop a packet because of the rate limitation).
849 *
850 * maxpps of 0 always causes zero to be returned. maxpps of -1
851 * always causes 1 to be returned; this effectively defeats rate
852 * limiting.
853 *
854 * Note that we maintain the struct timeval for compatibility
855 * with other bsd systems. We reuse the storage and just monitor
856 * clock ticks for minimal overhead.
857 */
858int
859ppsratecheck(struct timeval *lasttime, int *curpps, int maxpps)
860{
861 int now;
862
863 /*
864 * Reset the last time and counter if this is the first call
865 * or more than a second has passed since the last update of
866 * lasttime.
867 */
868 now = ticks;
869 if (lasttime->tv_sec == 0 || (u_int)(now - lasttime->tv_sec) >= hz) {
870 lasttime->tv_sec = now;
871 *curpps = 1;
872 return (maxpps != 0);
873 } else {
874 (*curpps)++; /* NB: ignore potential overflow */
875 return (maxpps < 0 || *curpps < maxpps);
876 }
877}
878