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 * 4. 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 */
31
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD: releng/6.4/sys/kern/kern_time.c 153802 2005-12-28 19:30:41Z ps $");
34
35 #include "opt_mac.h"
36
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/lock.h>
40 #include <sys/mutex.h>
41 #include <sys/sysproto.h>
42 #include <sys/resourcevar.h>
43 #include <sys/signalvar.h>
44 #include <sys/kernel.h>
45 #include <sys/mac.h>
46 #include <sys/syscallsubr.h>
47 #include <sys/sysent.h>
48 #include <sys/proc.h>
49 #include <sys/time.h>
50 #include <sys/timetc.h>
51 #include <sys/vnode.h>
52
53 #include <vm/vm.h>
54 #include <vm/vm_extern.h>
55
56 int tz_minuteswest;
57 int tz_dsttime;
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
69 static int settime(struct thread *, struct timeval *);
70 static void timevalfix(struct timeval *);
71 static void no_lease_updatetime(int);
72
73 static void
74 no_lease_updatetime(deltat)
75 int deltat;
76 {
77 }
78
79 void (*lease_updatetime)(int) = no_lease_updatetime;
80
81 static int
82 settime(struct thread *td, struct timeval *tv)
83 {
84 struct timeval delta, tv1, tv2;
85 static struct timeval maxtime, laststep;
86 struct timespec ts;
87 int s;
88
89 s = splclock();
90 microtime(&tv1);
91 delta = *tv;
92 timevalsub(&delta, &tv1);
93
94 /*
95 * If the system is secure, we do not allow the time to be
96 * set to a value earlier than 1 second less than the highest
97 * time we have yet seen. The worst a miscreant can do in
98 * this circumstance is "freeze" time. He couldn't go
99 * back to the past.
100 *
101 * We similarly do not allow the clock to be stepped more
102 * than one second, nor more than once per second. This allows
103 * a miscreant to make the clock march double-time, but no worse.
104 */
105 if (securelevel_gt(td->td_ucred, 1) != 0) {
106 if (delta.tv_sec < 0 || delta.tv_usec < 0) {
107 /*
108 * Update maxtime to latest time we've seen.
109 */
110 if (tv1.tv_sec > maxtime.tv_sec)
111 maxtime = tv1;
112 tv2 = *tv;
113 timevalsub(&tv2, &maxtime);
114 if (tv2.tv_sec < -1) {
115 tv->tv_sec = maxtime.tv_sec - 1;
116 printf("Time adjustment clamped to -1 second\n");
117 }
118 } else {
119 if (tv1.tv_sec == laststep.tv_sec) {
120 splx(s);
121 return (EPERM);
122 }
123 if (delta.tv_sec > 1) {
124 tv->tv_sec = tv1.tv_sec + 1;
125 printf("Time adjustment clamped to +1 second\n");
126 }
127 laststep = *tv;
128 }
129 }
130
131 ts.tv_sec = tv->tv_sec;
132 ts.tv_nsec = tv->tv_usec * 1000;
133 mtx_lock(&Giant);
134 tc_setclock(&ts);
135 (void) splsoftclock();
136 lease_updatetime(delta.tv_sec);
137 splx(s);
138 resettodr();
139 mtx_unlock(&Giant);
140 return (0);
141 }
142
143 #ifndef _SYS_SYSPROTO_H_
144 struct clock_gettime_args {
145 clockid_t clock_id;
146 struct timespec *tp;
147 };
148 #endif
149
150 /*
151 * MPSAFE
152 */
153 /* ARGSUSED */
154 int
155 clock_gettime(struct thread *td, struct clock_gettime_args *uap)
156 {
157 struct timespec ats;
158 int error;
159
160 error = kern_clock_gettime(td, uap->clock_id, &ats);
161 if (error == 0)
162 error = copyout(&ats, uap->tp, sizeof(ats));
163
164 return (error);
165 }
166
167 int
168 kern_clock_gettime(struct thread *td, clockid_t clock_id, struct timespec *ats)
169 {
170 struct timeval sys, user;
171 struct proc *p;
172
173 p = td->td_proc;
174 switch (clock_id) {
175 case CLOCK_REALTIME:
176 nanotime(ats);
177 break;
178 case CLOCK_VIRTUAL:
179 PROC_LOCK(p);
180 calcru(p, &user, &sys);
181 PROC_UNLOCK(p);
182 TIMEVAL_TO_TIMESPEC(&user, ats);
183 break;
184 case CLOCK_PROF:
185 PROC_LOCK(p);
186 calcru(p, &user, &sys);
187 PROC_UNLOCK(p);
188 timevaladd(&user, &sys);
189 TIMEVAL_TO_TIMESPEC(&user, ats);
190 break;
191 case CLOCK_MONOTONIC:
192 nanouptime(ats);
193 break;
194 default:
195 return (EINVAL);
196 }
197 return (0);
198 }
199
200 #ifndef _SYS_SYSPROTO_H_
201 struct clock_settime_args {
202 clockid_t clock_id;
203 const struct timespec *tp;
204 };
205 #endif
206
207 /*
208 * MPSAFE
209 */
210 /* ARGSUSED */
211 int
212 clock_settime(struct thread *td, struct clock_settime_args *uap)
213 {
214 struct timespec ats;
215 int error;
216
217 if ((error = copyin(uap->tp, &ats, sizeof(ats))) != 0)
218 return (error);
219 return (kern_clock_settime(td, uap->clock_id, &ats));
220 }
221
222 int
223 kern_clock_settime(struct thread *td, clockid_t clock_id, struct timespec *ats)
224 {
225 struct timeval atv;
226 int error;
227
228 #ifdef MAC
229 error = mac_check_system_settime(td->td_ucred);
230 if (error)
231 return (error);
232 #endif
233 if ((error = suser(td)) != 0)
234 return (error);
235 if (clock_id != CLOCK_REALTIME)
236 return (EINVAL);
237 if (ats->tv_nsec < 0 || ats->tv_nsec >= 1000000000)
238 return (EINVAL);
239 /* XXX Don't convert nsec->usec and back */
240 TIMESPEC_TO_TIMEVAL(&atv, ats);
241 error = settime(td, &atv);
242 return (error);
243 }
244
245 #ifndef _SYS_SYSPROTO_H_
246 struct clock_getres_args {
247 clockid_t clock_id;
248 struct timespec *tp;
249 };
250 #endif
251
252 int
253 clock_getres(struct thread *td, struct clock_getres_args *uap)
254 {
255 struct timespec ts;
256 int error;
257
258 if (uap->tp == NULL)
259 return (0);
260
261 error = kern_clock_getres(td, uap->clock_id, &ts);
262 if (error == 0)
263 error = copyout(&ts, uap->tp, sizeof(ts));
264 return (error);
265 }
266
267 int
268 kern_clock_getres(struct thread *td, clockid_t clock_id, struct timespec *ts)
269 {
270
271 ts->tv_sec = 0;
272 switch (clock_id) {
273 case CLOCK_REALTIME:
274 case CLOCK_MONOTONIC:
275 /*
276 * Round up the result of the division cheaply by adding 1.
277 * Rounding up is especially important if rounding down
278 * would give 0. Perfect rounding is unimportant.
279 */
280 ts->tv_nsec = 1000000000 / tc_getfrequency() + 1;
281 break;
282 case CLOCK_VIRTUAL:
283 case CLOCK_PROF:
284 /* Accurately round up here because we can do so cheaply. */
285 ts->tv_nsec = (1000000000 + hz - 1) / hz;
286 break;
287 default:
288 return (EINVAL);
289 }
290 return (0);
291 }
292
293 static int nanowait;
294
295 int
296 kern_nanosleep(struct thread *td, struct timespec *rqt, struct timespec *rmt)
297 {
298 struct timespec ts, ts2, ts3;
299 struct timeval tv;
300 int error;
301
302 if (rqt->tv_nsec < 0 || rqt->tv_nsec >= 1000000000)
303 return (EINVAL);
304 if (rqt->tv_sec < 0 || (rqt->tv_sec == 0 && rqt->tv_nsec == 0))
305 return (0);
306 getnanouptime(&ts);
307 timespecadd(&ts, rqt);
308 TIMESPEC_TO_TIMEVAL(&tv, rqt);
309 for (;;) {
310 error = tsleep(&nanowait, PWAIT | PCATCH, "nanslp",
311 tvtohz(&tv));
312 getnanouptime(&ts2);
313 if (error != EWOULDBLOCK) {
314 if (error == ERESTART)
315 error = EINTR;
316 if (rmt != NULL) {
317 timespecsub(&ts, &ts2);
318 if (ts.tv_sec < 0)
319 timespecclear(&ts);
320 *rmt = ts;
321 }
322 return (error);
323 }
324 if (timespeccmp(&ts2, &ts, >=))
325 return (0);
326 ts3 = ts;
327 timespecsub(&ts3, &ts2);
328 TIMESPEC_TO_TIMEVAL(&tv, &ts3);
329 }
330 }
331
332 #ifndef _SYS_SYSPROTO_H_
333 struct nanosleep_args {
334 struct timespec *rqtp;
335 struct timespec *rmtp;
336 };
337 #endif
338
339 /*
340 * MPSAFE
341 */
342 /* ARGSUSED */
343 int
344 nanosleep(struct thread *td, struct nanosleep_args *uap)
345 {
346 struct timespec rmt, rqt;
347 int error;
348
349 error = copyin(uap->rqtp, &rqt, sizeof(rqt));
350 if (error)
351 return (error);
352
353 if (uap->rmtp &&
354 !useracc((caddr_t)uap->rmtp, sizeof(rmt), VM_PROT_WRITE))
355 return (EFAULT);
356 error = kern_nanosleep(td, &rqt, &rmt);
357 if (error && uap->rmtp) {
358 int error2;
359
360 error2 = copyout(&rmt, uap->rmtp, sizeof(rmt));
361 if (error2)
362 error = error2;
363 }
364 return (error);
365 }
366
367 #ifndef _SYS_SYSPROTO_H_
368 struct gettimeofday_args {
369 struct timeval *tp;
370 struct timezone *tzp;
371 };
372 #endif
373 /*
374 * MPSAFE
375 */
376 /* ARGSUSED */
377 int
378 gettimeofday(struct thread *td, struct gettimeofday_args *uap)
379 {
380 struct timeval atv;
381 struct timezone rtz;
382 int error = 0;
383
384 if (uap->tp) {
385 microtime(&atv);
386 error = copyout(&atv, uap->tp, sizeof (atv));
387 }
388 if (error == 0 && uap->tzp != NULL) {
389 rtz.tz_minuteswest = tz_minuteswest;
390 rtz.tz_dsttime = tz_dsttime;
391 error = copyout(&rtz, uap->tzp, sizeof (rtz));
392 }
393 return (error);
394 }
395
396 #ifndef _SYS_SYSPROTO_H_
397 struct settimeofday_args {
398 struct timeval *tv;
399 struct timezone *tzp;
400 };
401 #endif
402 /*
403 * MPSAFE
404 */
405 /* ARGSUSED */
406 int
407 settimeofday(struct thread *td, struct settimeofday_args *uap)
408 {
409 struct timeval atv, *tvp;
410 struct timezone atz, *tzp;
411 int error;
412
413 if (uap->tv) {
414 error = copyin(uap->tv, &atv, sizeof(atv));
415 if (error)
416 return (error);
417 tvp = &atv;
418 } else
419 tvp = NULL;
420 if (uap->tzp) {
421 error = copyin(uap->tzp, &atz, sizeof(atz));
422 if (error)
423 return (error);
424 tzp = &atz;
425 } else
426 tzp = NULL;
427 return (kern_settimeofday(td, tvp, tzp));
428 }
429
430 int
431 kern_settimeofday(struct thread *td, struct timeval *tv, struct timezone *tzp)
432 {
433 int error;
434
435 #ifdef MAC
436 error = mac_check_system_settime(td->td_ucred);
437 if (error)
438 return (error);
439 #endif
440 error = suser(td);
441 if (error)
442 return (error);
443 /* Verify all parameters before changing time. */
444 if (tv) {
445 if (tv->tv_usec < 0 || tv->tv_usec >= 1000000)
446 return (EINVAL);
447 error = settime(td, tv);
448 }
449 if (tzp && error == 0) {
450 tz_minuteswest = tzp->tz_minuteswest;
451 tz_dsttime = tzp->tz_dsttime;
452 }
453 return (error);
454 }
455
456 /*
457 * Get value of an interval timer. The process virtual and
458 * profiling virtual time timers are kept in the p_stats area, since
459 * they can be swapped out. These are kept internally in the
460 * way they are specified externally: in time until they expire.
461 *
462 * The real time interval timer is kept in the process table slot
463 * for the process, and its value (it_value) is kept as an
464 * absolute time rather than as a delta, so that it is easy to keep
465 * periodic real-time signals from drifting.
466 *
467 * Virtual time timers are processed in the hardclock() routine of
468 * kern_clock.c. The real time timer is processed by a timeout
469 * routine, called from the softclock() routine. Since a callout
470 * may be delayed in real time due to interrupt processing in the system,
471 * it is possible for the real time timeout routine (realitexpire, given below),
472 * to be delayed in real time past when it is supposed to occur. It
473 * does not suffice, therefore, to reload the real timer .it_value from the
474 * real time timers .it_interval. Rather, we compute the next time in
475 * absolute time the timer should go off.
476 */
477 #ifndef _SYS_SYSPROTO_H_
478 struct getitimer_args {
479 u_int which;
480 struct itimerval *itv;
481 };
482 #endif
483 /*
484 * MPSAFE
485 */
486 int
487 getitimer(struct thread *td, struct getitimer_args *uap)
488 {
489 struct itimerval aitv;
490 int error;
491
492 error = kern_getitimer(td, uap->which, &aitv);
493 if (error != 0)
494 return (error);
495 return (copyout(&aitv, uap->itv, sizeof (struct itimerval)));
496 }
497
498 int
499 kern_getitimer(struct thread *td, u_int which, struct itimerval *aitv)
500 {
501 struct proc *p = td->td_proc;
502 struct timeval ctv;
503
504 if (which > ITIMER_PROF)
505 return (EINVAL);
506
507 if (which == ITIMER_REAL) {
508 /*
509 * Convert from absolute to relative time in .it_value
510 * part of real time timer. If time for real time timer
511 * has passed return 0, else return difference between
512 * current time and time for the timer to go off.
513 */
514 PROC_LOCK(p);
515 *aitv = p->p_realtimer;
516 PROC_UNLOCK(p);
517 if (timevalisset(&aitv->it_value)) {
518 getmicrouptime(&ctv);
519 if (timevalcmp(&aitv->it_value, &ctv, <))
520 timevalclear(&aitv->it_value);
521 else
522 timevalsub(&aitv->it_value, &ctv);
523 }
524 } else {
525 mtx_lock_spin(&sched_lock);
526 *aitv = p->p_stats->p_timer[which];
527 mtx_unlock_spin(&sched_lock);
528 }
529 return (0);
530 }
531
532 #ifndef _SYS_SYSPROTO_H_
533 struct setitimer_args {
534 u_int which;
535 struct itimerval *itv, *oitv;
536 };
537 #endif
538
539 /*
540 * MPSAFE
541 */
542 int
543 setitimer(struct thread *td, struct setitimer_args *uap)
544 {
545 struct itimerval aitv, oitv;
546 int error;
547
548 if (uap->itv == NULL) {
549 uap->itv = uap->oitv;
550 return (getitimer(td, (struct getitimer_args *)uap));
551 }
552
553 if ((error = copyin(uap->itv, &aitv, sizeof(struct itimerval))))
554 return (error);
555 error = kern_setitimer(td, uap->which, &aitv, &oitv);
556 if (error != 0 || uap->oitv == NULL)
557 return (error);
558 return (copyout(&oitv, uap->oitv, sizeof(struct itimerval)));
559 }
560
561 int
562 kern_setitimer(struct thread *td, u_int which, struct itimerval *aitv,
563 struct itimerval *oitv)
564 {
565 struct proc *p = td->td_proc;
566 struct timeval ctv;
567
568 if (aitv == NULL)
569 return (kern_getitimer(td, which, oitv));
570
571 if (which > ITIMER_PROF)
572 return (EINVAL);
573 if (itimerfix(&aitv->it_value))
574 return (EINVAL);
575 if (!timevalisset(&aitv->it_value))
576 timevalclear(&aitv->it_interval);
577 else if (itimerfix(&aitv->it_interval))
578 return (EINVAL);
579
580 if (which == ITIMER_REAL) {
581 PROC_LOCK(p);
582 if (timevalisset(&p->p_realtimer.it_value))
583 callout_stop(&p->p_itcallout);
584 getmicrouptime(&ctv);
585 if (timevalisset(&aitv->it_value)) {
586 callout_reset(&p->p_itcallout, tvtohz(&aitv->it_value),
587 realitexpire, p);
588 timevaladd(&aitv->it_value, &ctv);
589 }
590 *oitv = p->p_realtimer;
591 p->p_realtimer = *aitv;
592 PROC_UNLOCK(p);
593 if (timevalisset(&oitv->it_value)) {
594 if (timevalcmp(&oitv->it_value, &ctv, <))
595 timevalclear(&oitv->it_value);
596 else
597 timevalsub(&oitv->it_value, &ctv);
598 }
599 } else {
600 mtx_lock_spin(&sched_lock);
601 *oitv = p->p_stats->p_timer[which];
602 p->p_stats->p_timer[which] = *aitv;
603 mtx_unlock_spin(&sched_lock);
604 }
605 return (0);
606 }
607
608 /*
609 * Real interval timer expired:
610 * send process whose timer expired an alarm signal.
611 * If time is not set up to reload, then just return.
612 * Else compute next time timer should go off which is > current time.
613 * This is where delay in processing this timeout causes multiple
614 * SIGALRM calls to be compressed into one.
615 * tvtohz() always adds 1 to allow for the time until the next clock
616 * interrupt being strictly less than 1 clock tick, but we don't want
617 * that here since we want to appear to be in sync with the clock
618 * interrupt even when we're delayed.
619 */
620 void
621 realitexpire(void *arg)
622 {
623 struct proc *p;
624 struct timeval ctv, ntv;
625
626 p = (struct proc *)arg;
627 PROC_LOCK(p);
628 psignal(p, SIGALRM);
629 if (!timevalisset(&p->p_realtimer.it_interval)) {
630 timevalclear(&p->p_realtimer.it_value);
631 if (p->p_flag & P_WEXIT)
632 wakeup(&p->p_itcallout);
633 PROC_UNLOCK(p);
634 return;
635 }
636 for (;;) {
637 timevaladd(&p->p_realtimer.it_value,
638 &p->p_realtimer.it_interval);
639 getmicrouptime(&ctv);
640 if (timevalcmp(&p->p_realtimer.it_value, &ctv, >)) {
641 ntv = p->p_realtimer.it_value;
642 timevalsub(&ntv, &ctv);
643 callout_reset(&p->p_itcallout, tvtohz(&ntv) - 1,
644 realitexpire, p);
645 PROC_UNLOCK(p);
646 return;
647 }
648 }
649 /*NOTREACHED*/
650 }
651
652 /*
653 * Check that a proposed value to load into the .it_value or
654 * .it_interval part of an interval timer is acceptable, and
655 * fix it to have at least minimal value (i.e. if it is less
656 * than the resolution of the clock, round it up.)
657 */
658 int
659 itimerfix(struct timeval *tv)
660 {
661
662 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 ||
663 tv->tv_usec < 0 || tv->tv_usec >= 1000000)
664 return (EINVAL);
665 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick)
666 tv->tv_usec = tick;
667 return (0);
668 }
669
670 /*
671 * Decrement an interval timer by a specified number
672 * of microseconds, which must be less than a second,
673 * i.e. < 1000000. If the timer expires, then reload
674 * it. In this case, carry over (usec - old value) to
675 * reduce the value reloaded into the timer so that
676 * the timer does not drift. This routine assumes
677 * that it is called in a context where the timers
678 * on which it is operating cannot change in value.
679 */
680 int
681 itimerdecr(struct itimerval *itp, int usec)
682 {
683
684 if (itp->it_value.tv_usec < usec) {
685 if (itp->it_value.tv_sec == 0) {
686 /* expired, and already in next interval */
687 usec -= itp->it_value.tv_usec;
688 goto expire;
689 }
690 itp->it_value.tv_usec += 1000000;
691 itp->it_value.tv_sec--;
692 }
693 itp->it_value.tv_usec -= usec;
694 usec = 0;
695 if (timevalisset(&itp->it_value))
696 return (1);
697 /* expired, exactly at end of interval */
698 expire:
699 if (timevalisset(&itp->it_interval)) {
700 itp->it_value = itp->it_interval;
701 itp->it_value.tv_usec -= usec;
702 if (itp->it_value.tv_usec < 0) {
703 itp->it_value.tv_usec += 1000000;
704 itp->it_value.tv_sec--;
705 }
706 } else
707 itp->it_value.tv_usec = 0; /* sec is already 0 */
708 return (0);
709 }
710
711 /*
712 * Add and subtract routines for timevals.
713 * N.B.: subtract routine doesn't deal with
714 * results which are before the beginning,
715 * it just gets very confused in this case.
716 * Caveat emptor.
717 */
718 void
719 timevaladd(struct timeval *t1, const struct timeval *t2)
720 {
721
722 t1->tv_sec += t2->tv_sec;
723 t1->tv_usec += t2->tv_usec;
724 timevalfix(t1);
725 }
726
727 void
728 timevalsub(struct timeval *t1, const struct timeval *t2)
729 {
730
731 t1->tv_sec -= t2->tv_sec;
732 t1->tv_usec -= t2->tv_usec;
733 timevalfix(t1);
734 }
735
736 static void
737 timevalfix(struct timeval *t1)
738 {
739
740 if (t1->tv_usec < 0) {
741 t1->tv_sec--;
742 t1->tv_usec += 1000000;
743 }
744 if (t1->tv_usec >= 1000000) {
745 t1->tv_sec++;
746 t1->tv_usec -= 1000000;
747 }
748 }
749
750 /*
751 * ratecheck(): simple time-based rate-limit checking.
752 */
753 int
754 ratecheck(struct timeval *lasttime, const struct timeval *mininterval)
755 {
756 struct timeval tv, delta;
757 int rv = 0;
758
759 getmicrouptime(&tv); /* NB: 10ms precision */
760 delta = tv;
761 timevalsub(&delta, lasttime);
762
763 /*
764 * check for 0,0 is so that the message will be seen at least once,
765 * even if interval is huge.
766 */
767 if (timevalcmp(&delta, mininterval, >=) ||
768 (lasttime->tv_sec == 0 && lasttime->tv_usec == 0)) {
769 *lasttime = tv;
770 rv = 1;
771 }
772
773 return (rv);
774 }
775
776 /*
777 * ppsratecheck(): packets (or events) per second limitation.
778 *
779 * Return 0 if the limit is to be enforced (e.g. the caller
780 * should drop a packet because of the rate limitation).
781 *
782 * maxpps of 0 always causes zero to be returned. maxpps of -1
783 * always causes 1 to be returned; this effectively defeats rate
784 * limiting.
785 *
786 * Note that we maintain the struct timeval for compatibility
787 * with other bsd systems. We reuse the storage and just monitor
788 * clock ticks for minimal overhead.
789 */
790 int
791 ppsratecheck(struct timeval *lasttime, int *curpps, int maxpps)
792 {
793 int now;
794
795 /*
796 * Reset the last time and counter if this is the first call
797 * or more than a second has passed since the last update of
798 * lasttime.
799 */
800 now = ticks;
801 if (lasttime->tv_sec == 0 || (u_int)(now - lasttime->tv_sec) >= hz) {
802 lasttime->tv_sec = now;
803 *curpps = 1;
804 return (maxpps != 0);
805 } else {
806 (*curpps)++; /* NB: ignore potential overflow */
807 return (maxpps < 0 || *curpps < maxpps);
808 }
809 }
Cache object: 3553e84760cea08432bcf12366fb295b
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