FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_time.c
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. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)kern_time.c 8.1 (Berkeley) 6/10/93
30 * $FreeBSD: src/sys/kern/kern_time.c,v 1.68.2.1 2002/10/01 08:00:41 bde Exp $
31 */
32
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/buf.h>
36 #include <sys/sysproto.h>
37 #include <sys/resourcevar.h>
38 #include <sys/signalvar.h>
39 #include <sys/kernel.h>
40 #include <sys/sysent.h>
41 #include <sys/sysunion.h>
42 #include <sys/proc.h>
43 #include <sys/priv.h>
44 #include <sys/time.h>
45 #include <sys/vnode.h>
46 #include <sys/sysctl.h>
47 #include <sys/kern_syscall.h>
48 #include <vm/vm.h>
49 #include <vm/vm_extern.h>
50
51 #include <sys/msgport2.h>
52 #include <sys/thread2.h>
53 #include <sys/mplock2.h>
54
55 struct timezone tz;
56
57 /*
58 * Time of day and interval timer support.
59 *
60 * These routines provide the kernel entry points to get and set
61 * the time-of-day and per-process interval timers. Subroutines
62 * here provide support for adding and subtracting timeval structures
63 * and decrementing interval timers, optionally reloading the interval
64 * timers when they expire.
65 */
66
67 static int settime(struct timeval *);
68 static void timevalfix(struct timeval *);
69
70 /*
71 * Nanosleep tries very hard to sleep for a precisely requested time
72 * interval, down to 1uS. The administrator can impose a minimum delay
73 * and a delay below which we hard-loop instead of initiate a timer
74 * interrupt and sleep.
75 *
76 * For machines under high loads it might be beneficial to increase min_us
77 * to e.g. 1000uS (1ms) so spining processes sleep meaningfully.
78 */
79 static int nanosleep_min_us = 10;
80 static int nanosleep_hard_us = 100;
81 static int gettimeofday_quick = 0;
82 SYSCTL_INT(_kern, OID_AUTO, nanosleep_min_us, CTLFLAG_RW,
83 &nanosleep_min_us, 0, "")
84 SYSCTL_INT(_kern, OID_AUTO, nanosleep_hard_us, CTLFLAG_RW,
85 &nanosleep_hard_us, 0, "")
86 SYSCTL_INT(_kern, OID_AUTO, gettimeofday_quick, CTLFLAG_RW,
87 &gettimeofday_quick, 0, "")
88
89 static int
90 settime(struct timeval *tv)
91 {
92 struct timeval delta, tv1, tv2;
93 static struct timeval maxtime, laststep;
94 struct timespec ts;
95 int origcpu;
96
97 if ((origcpu = mycpu->gd_cpuid) != 0)
98 lwkt_setcpu_self(globaldata_find(0));
99
100 crit_enter();
101 microtime(&tv1);
102 delta = *tv;
103 timevalsub(&delta, &tv1);
104
105 /*
106 * If the system is secure, we do not allow the time to be
107 * set to a value earlier than 1 second less than the highest
108 * time we have yet seen. The worst a miscreant can do in
109 * this circumstance is "freeze" time. He couldn't go
110 * back to the past.
111 *
112 * We similarly do not allow the clock to be stepped more
113 * than one second, nor more than once per second. This allows
114 * a miscreant to make the clock march double-time, but no worse.
115 */
116 if (securelevel > 1) {
117 if (delta.tv_sec < 0 || delta.tv_usec < 0) {
118 /*
119 * Update maxtime to latest time we've seen.
120 */
121 if (tv1.tv_sec > maxtime.tv_sec)
122 maxtime = tv1;
123 tv2 = *tv;
124 timevalsub(&tv2, &maxtime);
125 if (tv2.tv_sec < -1) {
126 tv->tv_sec = maxtime.tv_sec - 1;
127 kprintf("Time adjustment clamped to -1 second\n");
128 }
129 } else {
130 if (tv1.tv_sec == laststep.tv_sec) {
131 crit_exit();
132 return (EPERM);
133 }
134 if (delta.tv_sec > 1) {
135 tv->tv_sec = tv1.tv_sec + 1;
136 kprintf("Time adjustment clamped to +1 second\n");
137 }
138 laststep = *tv;
139 }
140 }
141
142 ts.tv_sec = tv->tv_sec;
143 ts.tv_nsec = tv->tv_usec * 1000;
144 set_timeofday(&ts);
145 crit_exit();
146
147 if (origcpu != 0)
148 lwkt_setcpu_self(globaldata_find(origcpu));
149
150 resettodr();
151 return (0);
152 }
153
154 static void
155 get_curthread_cputime(struct timespec *ats)
156 {
157 struct thread *td = curthread;
158
159 crit_enter();
160 /*
161 * These are 64-bit fields but the actual values should never reach
162 * the limit. We don't care about overflows.
163 */
164 ats->tv_sec = td->td_uticks / 1000000;
165 ats->tv_sec += td->td_sticks / 1000000;
166 ats->tv_sec += td->td_iticks / 1000000;
167 ats->tv_nsec = (td->td_uticks % 1000000) * 1000;
168 ats->tv_nsec += (td->td_sticks % 1000000) * 1000;
169 ats->tv_nsec += (td->td_iticks % 1000000) * 1000;
170 crit_exit();
171 }
172
173 /*
174 * MPSAFE
175 */
176 int
177 kern_clock_gettime(clockid_t clock_id, struct timespec *ats)
178 {
179 int error = 0;
180 struct proc *p;
181
182 switch(clock_id) {
183 case CLOCK_REALTIME:
184 case CLOCK_REALTIME_PRECISE:
185 nanotime(ats);
186 break;
187 case CLOCK_REALTIME_FAST:
188 getnanotime(ats);
189 break;
190 case CLOCK_MONOTONIC:
191 case CLOCK_MONOTONIC_PRECISE:
192 case CLOCK_UPTIME:
193 case CLOCK_UPTIME_PRECISE:
194 nanouptime(ats);
195 break;
196 case CLOCK_MONOTONIC_FAST:
197 case CLOCK_UPTIME_FAST:
198 getnanouptime(ats);
199 break;
200 case CLOCK_VIRTUAL:
201 p = curproc;
202 ats->tv_sec = p->p_timer[ITIMER_VIRTUAL].it_value.tv_sec;
203 ats->tv_nsec = p->p_timer[ITIMER_VIRTUAL].it_value.tv_usec *
204 1000;
205 break;
206 case CLOCK_PROF:
207 case CLOCK_PROCESS_CPUTIME_ID:
208 p = curproc;
209 ats->tv_sec = p->p_timer[ITIMER_PROF].it_value.tv_sec;
210 ats->tv_nsec = p->p_timer[ITIMER_PROF].it_value.tv_usec *
211 1000;
212 break;
213 case CLOCK_SECOND:
214 ats->tv_sec = time_second;
215 ats->tv_nsec = 0;
216 break;
217 case CLOCK_THREAD_CPUTIME_ID:
218 get_curthread_cputime(ats);
219 break;
220 default:
221 error = EINVAL;
222 break;
223 }
224 return (error);
225 }
226
227 /*
228 * MPSAFE
229 */
230 int
231 sys_clock_gettime(struct clock_gettime_args *uap)
232 {
233 struct timespec ats;
234 int error;
235
236 error = kern_clock_gettime(uap->clock_id, &ats);
237 if (error == 0)
238 error = copyout(&ats, uap->tp, sizeof(ats));
239
240 return (error);
241 }
242
243 int
244 kern_clock_settime(clockid_t clock_id, struct timespec *ats)
245 {
246 struct thread *td = curthread;
247 struct timeval atv;
248 int error;
249
250 if ((error = priv_check(td, PRIV_CLOCK_SETTIME)) != 0)
251 return (error);
252 if (clock_id != CLOCK_REALTIME)
253 return (EINVAL);
254 if (ats->tv_nsec < 0 || ats->tv_nsec >= 1000000000)
255 return (EINVAL);
256
257 TIMESPEC_TO_TIMEVAL(&atv, ats);
258 error = settime(&atv);
259 return (error);
260 }
261
262 /*
263 * MPALMOSTSAFE
264 */
265 int
266 sys_clock_settime(struct clock_settime_args *uap)
267 {
268 struct timespec ats;
269 int error;
270
271 if ((error = copyin(uap->tp, &ats, sizeof(ats))) != 0)
272 return (error);
273
274 get_mplock();
275 error = kern_clock_settime(uap->clock_id, &ats);
276 rel_mplock();
277 return (error);
278 }
279
280 /*
281 * MPSAFE
282 */
283 int
284 kern_clock_getres(clockid_t clock_id, struct timespec *ts)
285 {
286 int error;
287
288 switch(clock_id) {
289 case CLOCK_REALTIME:
290 case CLOCK_REALTIME_FAST:
291 case CLOCK_REALTIME_PRECISE:
292 case CLOCK_MONOTONIC:
293 case CLOCK_MONOTONIC_FAST:
294 case CLOCK_MONOTONIC_PRECISE:
295 case CLOCK_UPTIME:
296 case CLOCK_UPTIME_FAST:
297 case CLOCK_UPTIME_PRECISE:
298 case CLOCK_THREAD_CPUTIME_ID:
299 case CLOCK_PROCESS_CPUTIME_ID:
300 /*
301 * Round up the result of the division cheaply
302 * by adding 1. Rounding up is especially important
303 * if rounding down would give 0. Perfect rounding
304 * is unimportant.
305 */
306 ts->tv_sec = 0;
307 ts->tv_nsec = 1000000000 / sys_cputimer->freq + 1;
308 error = 0;
309 break;
310 case CLOCK_VIRTUAL:
311 case CLOCK_PROF:
312 /* Accurately round up here because we can do so cheaply. */
313 ts->tv_sec = 0;
314 ts->tv_nsec = (1000000000 + hz - 1) / hz;
315 error = 0;
316 break;
317 case CLOCK_SECOND:
318 ts->tv_sec = 1;
319 ts->tv_nsec = 0;
320 error = 0;
321 break;
322 default:
323 error = EINVAL;
324 break;
325 }
326
327 return(error);
328 }
329
330 /*
331 * MPSAFE
332 */
333 int
334 sys_clock_getres(struct clock_getres_args *uap)
335 {
336 int error;
337 struct timespec ts;
338
339 error = kern_clock_getres(uap->clock_id, &ts);
340 if (error == 0)
341 error = copyout(&ts, uap->tp, sizeof(ts));
342
343 return (error);
344 }
345
346 /*
347 * nanosleep1()
348 *
349 * This is a general helper function for nanosleep() (aka sleep() aka
350 * usleep()).
351 *
352 * If there is less then one tick's worth of time left and
353 * we haven't done a yield, or the remaining microseconds is
354 * ridiculously low, do a yield. This avoids having
355 * to deal with systimer overheads when the system is under
356 * heavy loads. If we have done a yield already then use
357 * a systimer and an uninterruptable thread wait.
358 *
359 * If there is more then a tick's worth of time left,
360 * calculate the baseline ticks and use an interruptable
361 * tsleep, then handle the fine-grained delay on the next
362 * loop. This usually results in two sleeps occuring, a long one
363 * and a short one.
364 *
365 * MPSAFE
366 */
367 static void
368 ns1_systimer(systimer_t info, int in_ipi __unused,
369 struct intrframe *frame __unused)
370 {
371 lwkt_schedule(info->data);
372 }
373
374 int
375 nanosleep1(struct timespec *rqt, struct timespec *rmt)
376 {
377 static int nanowait;
378 struct timespec ts, ts2, ts3;
379 struct timeval tv;
380 int error;
381
382 if (rqt->tv_nsec < 0 || rqt->tv_nsec >= 1000000000)
383 return (EINVAL);
384 /* XXX: imho this should return EINVAL at least for tv_sec < 0 */
385 if (rqt->tv_sec < 0 || (rqt->tv_sec == 0 && rqt->tv_nsec == 0))
386 return (0);
387 nanouptime(&ts);
388 timespecadd(&ts, rqt); /* ts = target timestamp compare */
389 TIMESPEC_TO_TIMEVAL(&tv, rqt); /* tv = sleep interval */
390
391 for (;;) {
392 int ticks;
393 struct systimer info;
394
395 ticks = tv.tv_usec / ustick; /* approximate */
396
397 if (tv.tv_sec == 0 && ticks == 0) {
398 thread_t td = curthread;
399 if (tv.tv_usec > 0 && tv.tv_usec < nanosleep_min_us)
400 tv.tv_usec = nanosleep_min_us;
401 if (tv.tv_usec < nanosleep_hard_us) {
402 lwkt_user_yield();
403 cpu_pause();
404 } else {
405 crit_enter_quick(td);
406 systimer_init_oneshot(&info, ns1_systimer,
407 td, tv.tv_usec);
408 lwkt_deschedule_self(td);
409 crit_exit_quick(td);
410 lwkt_switch();
411 systimer_del(&info); /* make sure it's gone */
412 }
413 error = iscaught(td->td_lwp);
414 } else if (tv.tv_sec == 0) {
415 error = tsleep(&nanowait, PCATCH, "nanslp", ticks);
416 } else {
417 ticks = tvtohz_low(&tv); /* also handles overflow */
418 error = tsleep(&nanowait, PCATCH, "nanslp", ticks);
419 }
420 nanouptime(&ts2);
421 if (error && error != EWOULDBLOCK) {
422 if (error == ERESTART)
423 error = EINTR;
424 if (rmt != NULL) {
425 timespecsub(&ts, &ts2);
426 if (ts.tv_sec < 0)
427 timespecclear(&ts);
428 *rmt = ts;
429 }
430 return (error);
431 }
432 if (timespeccmp(&ts2, &ts, >=))
433 return (0);
434 ts3 = ts;
435 timespecsub(&ts3, &ts2);
436 TIMESPEC_TO_TIMEVAL(&tv, &ts3);
437 }
438 }
439
440 /*
441 * MPSAFE
442 */
443 int
444 sys_nanosleep(struct nanosleep_args *uap)
445 {
446 int error;
447 struct timespec rqt;
448 struct timespec rmt;
449
450 error = copyin(uap->rqtp, &rqt, sizeof(rqt));
451 if (error)
452 return (error);
453
454 error = nanosleep1(&rqt, &rmt);
455
456 /*
457 * copyout the residual if nanosleep was interrupted.
458 */
459 if (error && uap->rmtp) {
460 int error2;
461
462 error2 = copyout(&rmt, uap->rmtp, sizeof(rmt));
463 if (error2)
464 error = error2;
465 }
466 return (error);
467 }
468
469 /*
470 * The gettimeofday() system call is supposed to return a fine-grained
471 * realtime stamp. However, acquiring a fine-grained stamp can create a
472 * bottleneck when multiple cpu cores are trying to accessing e.g. the
473 * HPET hardware timer all at the same time, so we have a sysctl that
474 * allows its behavior to be changed to a more coarse-grained timestamp
475 * which does not have to access a hardware timer.
476 */
477 int
478 sys_gettimeofday(struct gettimeofday_args *uap)
479 {
480 struct timeval atv;
481 int error = 0;
482
483 if (uap->tp) {
484 if (gettimeofday_quick)
485 getmicrotime(&atv);
486 else
487 microtime(&atv);
488 if ((error = copyout((caddr_t)&atv, (caddr_t)uap->tp,
489 sizeof (atv))))
490 return (error);
491 }
492 if (uap->tzp)
493 error = copyout((caddr_t)&tz, (caddr_t)uap->tzp,
494 sizeof (tz));
495 return (error);
496 }
497
498 /*
499 * MPALMOSTSAFE
500 */
501 int
502 sys_settimeofday(struct settimeofday_args *uap)
503 {
504 struct thread *td = curthread;
505 struct timeval atv;
506 struct timezone atz;
507 int error;
508
509 if ((error = priv_check(td, PRIV_SETTIMEOFDAY)))
510 return (error);
511 /*
512 * Verify all parameters before changing time.
513 *
514 * XXX: We do not allow the time to be set to 0.0, which also by
515 * happy coincidence works around a pkgsrc bulk build bug.
516 */
517 if (uap->tv) {
518 if ((error = copyin((caddr_t)uap->tv, (caddr_t)&atv,
519 sizeof(atv))))
520 return (error);
521 if (atv.tv_usec < 0 || atv.tv_usec >= 1000000)
522 return (EINVAL);
523 if (atv.tv_sec == 0 && atv.tv_usec == 0)
524 return (EINVAL);
525 }
526 if (uap->tzp &&
527 (error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, sizeof(atz))))
528 return (error);
529
530 get_mplock();
531 if (uap->tv && (error = settime(&atv))) {
532 rel_mplock();
533 return (error);
534 }
535 rel_mplock();
536 if (uap->tzp)
537 tz = atz;
538 return (0);
539 }
540
541 static void
542 kern_adjtime_common(void)
543 {
544 if ((ntp_delta >= 0 && ntp_delta < ntp_default_tick_delta) ||
545 (ntp_delta < 0 && ntp_delta > -ntp_default_tick_delta))
546 ntp_tick_delta = ntp_delta;
547 else if (ntp_delta > ntp_big_delta)
548 ntp_tick_delta = 10 * ntp_default_tick_delta;
549 else if (ntp_delta < -ntp_big_delta)
550 ntp_tick_delta = -10 * ntp_default_tick_delta;
551 else if (ntp_delta > 0)
552 ntp_tick_delta = ntp_default_tick_delta;
553 else
554 ntp_tick_delta = -ntp_default_tick_delta;
555 }
556
557 void
558 kern_adjtime(int64_t delta, int64_t *odelta)
559 {
560 int origcpu;
561
562 if ((origcpu = mycpu->gd_cpuid) != 0)
563 lwkt_setcpu_self(globaldata_find(0));
564
565 crit_enter();
566 *odelta = ntp_delta;
567 ntp_delta = delta;
568 kern_adjtime_common();
569 crit_exit();
570
571 if (origcpu != 0)
572 lwkt_setcpu_self(globaldata_find(origcpu));
573 }
574
575 static void
576 kern_get_ntp_delta(int64_t *delta)
577 {
578 int origcpu;
579
580 if ((origcpu = mycpu->gd_cpuid) != 0)
581 lwkt_setcpu_self(globaldata_find(0));
582
583 crit_enter();
584 *delta = ntp_delta;
585 crit_exit();
586
587 if (origcpu != 0)
588 lwkt_setcpu_self(globaldata_find(origcpu));
589 }
590
591 void
592 kern_reladjtime(int64_t delta)
593 {
594 int origcpu;
595
596 if ((origcpu = mycpu->gd_cpuid) != 0)
597 lwkt_setcpu_self(globaldata_find(0));
598
599 crit_enter();
600 ntp_delta += delta;
601 kern_adjtime_common();
602 crit_exit();
603
604 if (origcpu != 0)
605 lwkt_setcpu_self(globaldata_find(origcpu));
606 }
607
608 static void
609 kern_adjfreq(int64_t rate)
610 {
611 int origcpu;
612
613 if ((origcpu = mycpu->gd_cpuid) != 0)
614 lwkt_setcpu_self(globaldata_find(0));
615
616 crit_enter();
617 ntp_tick_permanent = rate;
618 crit_exit();
619
620 if (origcpu != 0)
621 lwkt_setcpu_self(globaldata_find(origcpu));
622 }
623
624 /*
625 * MPALMOSTSAFE
626 */
627 int
628 sys_adjtime(struct adjtime_args *uap)
629 {
630 struct thread *td = curthread;
631 struct timeval atv;
632 int64_t ndelta, odelta;
633 int error;
634
635 if ((error = priv_check(td, PRIV_ADJTIME)))
636 return (error);
637 error = copyin(uap->delta, &atv, sizeof(struct timeval));
638 if (error)
639 return (error);
640
641 /*
642 * Compute the total correction and the rate at which to apply it.
643 * Round the adjustment down to a whole multiple of the per-tick
644 * delta, so that after some number of incremental changes in
645 * hardclock(), tickdelta will become zero, lest the correction
646 * overshoot and start taking us away from the desired final time.
647 */
648 ndelta = (int64_t)atv.tv_sec * 1000000000 + atv.tv_usec * 1000;
649 get_mplock();
650 kern_adjtime(ndelta, &odelta);
651 rel_mplock();
652
653 if (uap->olddelta) {
654 atv.tv_sec = odelta / 1000000000;
655 atv.tv_usec = odelta % 1000000000 / 1000;
656 copyout(&atv, uap->olddelta, sizeof(struct timeval));
657 }
658 return (0);
659 }
660
661 static int
662 sysctl_adjtime(SYSCTL_HANDLER_ARGS)
663 {
664 int64_t delta;
665 int error;
666
667 if (req->newptr != NULL) {
668 if (priv_check(curthread, PRIV_ROOT))
669 return (EPERM);
670 error = SYSCTL_IN(req, &delta, sizeof(delta));
671 if (error)
672 return (error);
673 kern_reladjtime(delta);
674 }
675
676 if (req->oldptr)
677 kern_get_ntp_delta(&delta);
678 error = SYSCTL_OUT(req, &delta, sizeof(delta));
679 return (error);
680 }
681
682 /*
683 * delta is in nanoseconds.
684 */
685 static int
686 sysctl_delta(SYSCTL_HANDLER_ARGS)
687 {
688 int64_t delta, old_delta;
689 int error;
690
691 if (req->newptr != NULL) {
692 if (priv_check(curthread, PRIV_ROOT))
693 return (EPERM);
694 error = SYSCTL_IN(req, &delta, sizeof(delta));
695 if (error)
696 return (error);
697 kern_adjtime(delta, &old_delta);
698 }
699
700 if (req->oldptr != NULL)
701 kern_get_ntp_delta(&old_delta);
702 error = SYSCTL_OUT(req, &old_delta, sizeof(old_delta));
703 return (error);
704 }
705
706 /*
707 * frequency is in nanoseconds per second shifted left 32.
708 * kern_adjfreq() needs it in nanoseconds per tick shifted left 32.
709 */
710 static int
711 sysctl_adjfreq(SYSCTL_HANDLER_ARGS)
712 {
713 int64_t freqdelta;
714 int error;
715
716 if (req->newptr != NULL) {
717 if (priv_check(curthread, PRIV_ROOT))
718 return (EPERM);
719 error = SYSCTL_IN(req, &freqdelta, sizeof(freqdelta));
720 if (error)
721 return (error);
722
723 freqdelta /= hz;
724 kern_adjfreq(freqdelta);
725 }
726
727 if (req->oldptr != NULL)
728 freqdelta = ntp_tick_permanent * hz;
729 error = SYSCTL_OUT(req, &freqdelta, sizeof(freqdelta));
730 if (error)
731 return (error);
732
733 return (0);
734 }
735
736 SYSCTL_NODE(_kern, OID_AUTO, ntp, CTLFLAG_RW, 0, "NTP related controls");
737 SYSCTL_PROC(_kern_ntp, OID_AUTO, permanent,
738 CTLTYPE_QUAD|CTLFLAG_RW, 0, 0,
739 sysctl_adjfreq, "Q", "permanent correction per second");
740 SYSCTL_PROC(_kern_ntp, OID_AUTO, delta,
741 CTLTYPE_QUAD|CTLFLAG_RW, 0, 0,
742 sysctl_delta, "Q", "one-time delta");
743 SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, big_delta, CTLFLAG_RD,
744 &ntp_big_delta, sizeof(ntp_big_delta), "Q",
745 "threshold for fast adjustment");
746 SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, tick_delta, CTLFLAG_RD,
747 &ntp_tick_delta, sizeof(ntp_tick_delta), "LU",
748 "per-tick adjustment");
749 SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, default_tick_delta, CTLFLAG_RD,
750 &ntp_default_tick_delta, sizeof(ntp_default_tick_delta), "LU",
751 "default per-tick adjustment");
752 SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, next_leap_second, CTLFLAG_RW,
753 &ntp_leap_second, sizeof(ntp_leap_second), "LU",
754 "next leap second");
755 SYSCTL_INT(_kern_ntp, OID_AUTO, insert_leap_second, CTLFLAG_RW,
756 &ntp_leap_insert, 0, "insert or remove leap second");
757 SYSCTL_PROC(_kern_ntp, OID_AUTO, adjust,
758 CTLTYPE_QUAD|CTLFLAG_RW, 0, 0,
759 sysctl_adjtime, "Q", "relative adjust for delta");
760
761 /*
762 * Get value of an interval timer. The process virtual and
763 * profiling virtual time timers are kept in the p_stats area, since
764 * they can be swapped out. These are kept internally in the
765 * way they are specified externally: in time until they expire.
766 *
767 * The real time interval timer is kept in the process table slot
768 * for the process, and its value (it_value) is kept as an
769 * absolute time rather than as a delta, so that it is easy to keep
770 * periodic real-time signals from drifting.
771 *
772 * Virtual time timers are processed in the hardclock() routine of
773 * kern_clock.c. The real time timer is processed by a timeout
774 * routine, called from the softclock() routine. Since a callout
775 * may be delayed in real time due to interrupt processing in the system,
776 * it is possible for the real time timeout routine (realitexpire, given below),
777 * to be delayed in real time past when it is supposed to occur. It
778 * does not suffice, therefore, to reload the real timer .it_value from the
779 * real time timers .it_interval. Rather, we compute the next time in
780 * absolute time the timer should go off.
781 *
782 * MPALMOSTSAFE
783 */
784 int
785 sys_getitimer(struct getitimer_args *uap)
786 {
787 struct proc *p = curproc;
788 struct timeval ctv;
789 struct itimerval aitv;
790
791 if (uap->which > ITIMER_PROF)
792 return (EINVAL);
793 lwkt_gettoken(&p->p_token);
794 if (uap->which == ITIMER_REAL) {
795 /*
796 * Convert from absolute to relative time in .it_value
797 * part of real time timer. If time for real time timer
798 * has passed return 0, else return difference between
799 * current time and time for the timer to go off.
800 */
801 aitv = p->p_realtimer;
802 if (timevalisset(&aitv.it_value)) {
803 getmicrouptime(&ctv);
804 if (timevalcmp(&aitv.it_value, &ctv, <))
805 timevalclear(&aitv.it_value);
806 else
807 timevalsub(&aitv.it_value, &ctv);
808 }
809 } else {
810 aitv = p->p_timer[uap->which];
811 }
812 lwkt_reltoken(&p->p_token);
813 return (copyout(&aitv, uap->itv, sizeof (struct itimerval)));
814 }
815
816 /*
817 * MPALMOSTSAFE
818 */
819 int
820 sys_setitimer(struct setitimer_args *uap)
821 {
822 struct itimerval aitv;
823 struct timeval ctv;
824 struct itimerval *itvp;
825 struct proc *p = curproc;
826 int error;
827
828 if (uap->which > ITIMER_PROF)
829 return (EINVAL);
830 itvp = uap->itv;
831 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv,
832 sizeof(struct itimerval))))
833 return (error);
834 if ((uap->itv = uap->oitv) &&
835 (error = sys_getitimer((struct getitimer_args *)uap)))
836 return (error);
837 if (itvp == NULL)
838 return (0);
839 if (itimerfix(&aitv.it_value))
840 return (EINVAL);
841 if (!timevalisset(&aitv.it_value))
842 timevalclear(&aitv.it_interval);
843 else if (itimerfix(&aitv.it_interval))
844 return (EINVAL);
845 lwkt_gettoken(&p->p_token);
846 if (uap->which == ITIMER_REAL) {
847 if (timevalisset(&p->p_realtimer.it_value))
848 callout_stop_sync(&p->p_ithandle);
849 if (timevalisset(&aitv.it_value))
850 callout_reset(&p->p_ithandle,
851 tvtohz_high(&aitv.it_value), realitexpire, p);
852 getmicrouptime(&ctv);
853 timevaladd(&aitv.it_value, &ctv);
854 p->p_realtimer = aitv;
855 } else {
856 p->p_timer[uap->which] = aitv;
857 switch(uap->which) {
858 case ITIMER_VIRTUAL:
859 p->p_flags &= ~P_SIGVTALRM;
860 break;
861 case ITIMER_PROF:
862 p->p_flags &= ~P_SIGPROF;
863 break;
864 }
865 }
866 lwkt_reltoken(&p->p_token);
867 return (0);
868 }
869
870 /*
871 * Real interval timer expired:
872 * send process whose timer expired an alarm signal.
873 * If time is not set up to reload, then just return.
874 * Else compute next time timer should go off which is > current time.
875 * This is where delay in processing this timeout causes multiple
876 * SIGALRM calls to be compressed into one.
877 * tvtohz_high() always adds 1 to allow for the time until the next clock
878 * interrupt being strictly less than 1 clock tick, but we don't want
879 * that here since we want to appear to be in sync with the clock
880 * interrupt even when we're delayed.
881 */
882 void
883 realitexpire(void *arg)
884 {
885 struct proc *p;
886 struct timeval ctv, ntv;
887
888 p = (struct proc *)arg;
889 PHOLD(p);
890 lwkt_gettoken(&p->p_token);
891 ksignal(p, SIGALRM);
892 if (!timevalisset(&p->p_realtimer.it_interval)) {
893 timevalclear(&p->p_realtimer.it_value);
894 goto done;
895 }
896 for (;;) {
897 timevaladd(&p->p_realtimer.it_value,
898 &p->p_realtimer.it_interval);
899 getmicrouptime(&ctv);
900 if (timevalcmp(&p->p_realtimer.it_value, &ctv, >)) {
901 ntv = p->p_realtimer.it_value;
902 timevalsub(&ntv, &ctv);
903 callout_reset(&p->p_ithandle, tvtohz_low(&ntv),
904 realitexpire, p);
905 goto done;
906 }
907 }
908 done:
909 lwkt_reltoken(&p->p_token);
910 PRELE(p);
911 }
912
913 /*
914 * Check that a proposed value to load into the .it_value or
915 * .it_interval part of an interval timer is acceptable, and
916 * fix it to have at least minimal value (i.e. if it is less
917 * than the resolution of the clock, round it up.)
918 *
919 * MPSAFE
920 */
921 int
922 itimerfix(struct timeval *tv)
923 {
924
925 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 ||
926 tv->tv_usec < 0 || tv->tv_usec >= 1000000)
927 return (EINVAL);
928 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < ustick)
929 tv->tv_usec = ustick;
930 return (0);
931 }
932
933 /*
934 * Decrement an interval timer by a specified number
935 * of microseconds, which must be less than a second,
936 * i.e. < 1000000. If the timer expires, then reload
937 * it. In this case, carry over (usec - old value) to
938 * reduce the value reloaded into the timer so that
939 * the timer does not drift. This routine assumes
940 * that it is called in a context where the timers
941 * on which it is operating cannot change in value.
942 */
943 int
944 itimerdecr(struct itimerval *itp, int usec)
945 {
946
947 if (itp->it_value.tv_usec < usec) {
948 if (itp->it_value.tv_sec == 0) {
949 /* expired, and already in next interval */
950 usec -= itp->it_value.tv_usec;
951 goto expire;
952 }
953 itp->it_value.tv_usec += 1000000;
954 itp->it_value.tv_sec--;
955 }
956 itp->it_value.tv_usec -= usec;
957 usec = 0;
958 if (timevalisset(&itp->it_value))
959 return (1);
960 /* expired, exactly at end of interval */
961 expire:
962 if (timevalisset(&itp->it_interval)) {
963 itp->it_value = itp->it_interval;
964 itp->it_value.tv_usec -= usec;
965 if (itp->it_value.tv_usec < 0) {
966 itp->it_value.tv_usec += 1000000;
967 itp->it_value.tv_sec--;
968 }
969 } else
970 itp->it_value.tv_usec = 0; /* sec is already 0 */
971 return (0);
972 }
973
974 /*
975 * Add and subtract routines for timevals.
976 * N.B.: subtract routine doesn't deal with
977 * results which are before the beginning,
978 * it just gets very confused in this case.
979 * Caveat emptor.
980 */
981 void
982 timevaladd(struct timeval *t1, const struct timeval *t2)
983 {
984
985 t1->tv_sec += t2->tv_sec;
986 t1->tv_usec += t2->tv_usec;
987 timevalfix(t1);
988 }
989
990 void
991 timevalsub(struct timeval *t1, const struct timeval *t2)
992 {
993
994 t1->tv_sec -= t2->tv_sec;
995 t1->tv_usec -= t2->tv_usec;
996 timevalfix(t1);
997 }
998
999 static void
1000 timevalfix(struct timeval *t1)
1001 {
1002
1003 if (t1->tv_usec < 0) {
1004 t1->tv_sec--;
1005 t1->tv_usec += 1000000;
1006 }
1007 if (t1->tv_usec >= 1000000) {
1008 t1->tv_sec++;
1009 t1->tv_usec -= 1000000;
1010 }
1011 }
1012
1013 /*
1014 * ratecheck(): simple time-based rate-limit checking.
1015 */
1016 int
1017 ratecheck(struct timeval *lasttime, const struct timeval *mininterval)
1018 {
1019 struct timeval tv, delta;
1020 int rv = 0;
1021
1022 getmicrouptime(&tv); /* NB: 10ms precision */
1023 delta = tv;
1024 timevalsub(&delta, lasttime);
1025
1026 /*
1027 * check for 0,0 is so that the message will be seen at least once,
1028 * even if interval is huge.
1029 */
1030 if (timevalcmp(&delta, mininterval, >=) ||
1031 (lasttime->tv_sec == 0 && lasttime->tv_usec == 0)) {
1032 *lasttime = tv;
1033 rv = 1;
1034 }
1035
1036 return (rv);
1037 }
1038
1039 /*
1040 * ppsratecheck(): packets (or events) per second limitation.
1041 *
1042 * Return 0 if the limit is to be enforced (e.g. the caller
1043 * should drop a packet because of the rate limitation).
1044 *
1045 * maxpps of 0 always causes zero to be returned. maxpps of -1
1046 * always causes 1 to be returned; this effectively defeats rate
1047 * limiting.
1048 *
1049 * Note that we maintain the struct timeval for compatibility
1050 * with other bsd systems. We reuse the storage and just monitor
1051 * clock ticks for minimal overhead.
1052 */
1053 int
1054 ppsratecheck(struct timeval *lasttime, int *curpps, int maxpps)
1055 {
1056 int now;
1057
1058 /*
1059 * Reset the last time and counter if this is the first call
1060 * or more than a second has passed since the last update of
1061 * lasttime.
1062 */
1063 now = ticks;
1064 if (lasttime->tv_sec == 0 || (u_int)(now - lasttime->tv_sec) >= hz) {
1065 lasttime->tv_sec = now;
1066 *curpps = 1;
1067 return (maxpps != 0);
1068 } else {
1069 (*curpps)++; /* NB: ignore potential overflow */
1070 return (maxpps < 0 || *curpps < maxpps);
1071 }
1072 }
Cache object: 9783c3365eeb3312cfb77e8b71c00670
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