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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 $
35 * $DragonFly: src/sys/kern/kern_time.c,v 1.2 2003/06/17 04:28:41 dillon Exp $
38 #include <sys/param.h>
39 #include <sys/systm.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>
49 #include <sys/vnode.h>
51 #include <vm/vm_extern.h>
56 * Time of day and interval timer support.
58 * These routines provide the kernel entry points to get and set
59 * the time-of-day and per-process interval timers. Subroutines
60 * here provide support for adding and subtracting timeval structures
61 * and decrementing interval timers, optionally reloading the interval
62 * timers when they expire.
65 static int nanosleep1 __P((struct proc *p, struct timespec *rqt,
66 struct timespec *rmt));
67 static int settime __P((struct timeval *));
68 static void timevalfix __P((struct timeval *));
69 static void no_lease_updatetime __P((int));
72 no_lease_updatetime(deltat)
77 void (*lease_updatetime) __P((int)) = no_lease_updatetime;
83 struct timeval delta, tv1, tv2;
84 static struct timeval maxtime, laststep;
91 timevalsub(&delta, &tv1);
94 * If the system is secure, we do not allow the time to be
95 * set to a value earlier than 1 second less than the highest
96 * time we have yet seen. The worst a miscreant can do in
97 * this circumstance is "freeze" time. He couldn't go
100 * We similarly do not allow the clock to be stepped more
101 * than one second, nor more than once per second. This allows
102 * a miscreant to make the clock march double-time, but no worse.
104 if (securelevel > 1) {
105 if (delta.tv_sec < 0 || delta.tv_usec < 0) {
107 * Update maxtime to latest time we've seen.
109 if (tv1.tv_sec > maxtime.tv_sec)
112 timevalsub(&tv2, &maxtime);
113 if (tv2.tv_sec < -1) {
114 tv->tv_sec = maxtime.tv_sec - 1;
115 printf("Time adjustment clamped to -1 second\n");
118 if (tv1.tv_sec == laststep.tv_sec) {
122 if (delta.tv_sec > 1) {
123 tv->tv_sec = tv1.tv_sec + 1;
124 printf("Time adjustment clamped to +1 second\n");
130 ts.tv_sec = tv->tv_sec;
131 ts.tv_nsec = tv->tv_usec * 1000;
132 set_timecounter(&ts);
133 (void) splsoftclock();
134 lease_updatetime(delta.tv_sec);
140 #ifndef _SYS_SYSPROTO_H_
141 struct clock_gettime_args {
149 clock_gettime(p, uap)
151 struct clock_gettime_args *uap;
155 if (SCARG(uap, clock_id) != CLOCK_REALTIME)
158 return (copyout(&ats, SCARG(uap, tp), sizeof(ats)));
161 #ifndef _SYS_SYSPROTO_H_
162 struct clock_settime_args {
164 const struct timespec *tp;
170 clock_settime(p, uap)
172 struct clock_settime_args *uap;
178 if ((error = suser(p)) != 0)
180 if (SCARG(uap, clock_id) != CLOCK_REALTIME)
182 if ((error = copyin(SCARG(uap, tp), &ats, sizeof(ats))) != 0)
184 if (ats.tv_nsec < 0 || ats.tv_nsec >= 1000000000)
186 /* XXX Don't convert nsec->usec and back */
187 TIMESPEC_TO_TIMEVAL(&atv, &ats);
188 if ((error = settime(&atv)))
193 #ifndef _SYS_SYSPROTO_H_
194 struct clock_getres_args {
203 struct clock_getres_args *uap;
208 if (SCARG(uap, clock_id) != CLOCK_REALTIME)
211 if (SCARG(uap, tp)) {
214 * Round up the result of the division cheaply by adding 1.
215 * Rounding up is especially important if rounding down
216 * would give 0. Perfect rounding is unimportant.
218 ts.tv_nsec = 1000000000 / timecounter->tc_frequency + 1;
219 error = copyout(&ts, SCARG(uap, tp), sizeof(ts));
227 nanosleep1(p, rqt, rmt)
229 struct timespec *rqt, *rmt;
231 struct timespec ts, ts2, ts3;
235 if (rqt->tv_nsec < 0 || rqt->tv_nsec >= 1000000000)
237 if (rqt->tv_sec < 0 || (rqt->tv_sec == 0 && rqt->tv_nsec == 0))
240 timespecadd(&ts, rqt);
241 TIMESPEC_TO_TIMEVAL(&tv, rqt);
243 error = tsleep(&nanowait, PWAIT | PCATCH, "nanslp",
246 if (error != EWOULDBLOCK) {
247 if (error == ERESTART)
250 timespecsub(&ts, &ts2);
257 if (timespeccmp(&ts2, &ts, >=))
260 timespecsub(&ts3, &ts2);
261 TIMESPEC_TO_TIMEVAL(&tv, &ts3);
265 #ifndef _SYS_SYSPROTO_H_
266 struct nanosleep_args {
267 struct timespec *rqtp;
268 struct timespec *rmtp;
276 struct nanosleep_args *uap;
278 struct timespec rmt, rqt;
281 error = copyin(SCARG(uap, rqtp), &rqt, sizeof(rqt));
284 if (SCARG(uap, rmtp))
285 if (!useracc((caddr_t)SCARG(uap, rmtp), sizeof(rmt),
288 error = nanosleep1(p, &rqt, &rmt);
289 if (error && SCARG(uap, rmtp)) {
290 error2 = copyout(&rmt, SCARG(uap, rmtp), sizeof(rmt));
291 if (error2) /* XXX shouldn't happen, did useracc() above */
297 #ifndef _SYS_SYSPROTO_H_
298 struct gettimeofday_args {
300 struct timezone *tzp;
307 register struct gettimeofday_args *uap;
314 if ((error = copyout((caddr_t)&atv, (caddr_t)uap->tp,
319 error = copyout((caddr_t)&tz, (caddr_t)uap->tzp,
324 #ifndef _SYS_SYSPROTO_H_
325 struct settimeofday_args {
327 struct timezone *tzp;
334 struct settimeofday_args *uap;
340 if ((error = suser(p)))
342 /* Verify all parameters before changing time. */
344 if ((error = copyin((caddr_t)uap->tv, (caddr_t)&atv,
347 if (atv.tv_usec < 0 || atv.tv_usec >= 1000000)
351 (error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, sizeof(atz))))
353 if (uap->tv && (error = settime(&atv)))
360 int tickdelta; /* current clock skew, us. per tick */
361 long timedelta; /* unapplied time correction, us. */
362 static long bigadj = 1000000; /* use 10x skew above bigadj us. */
364 #ifndef _SYS_SYSPROTO_H_
365 struct adjtime_args {
366 struct timeval *delta;
367 struct timeval *olddelta;
374 register struct adjtime_args *uap;
377 register long ndelta, ntickdelta, odelta;
380 if ((error = suser(p)))
383 copyin((caddr_t)uap->delta, (caddr_t)&atv, sizeof(struct timeval))))
387 * Compute the total correction and the rate at which to apply it.
388 * Round the adjustment down to a whole multiple of the per-tick
389 * delta, so that after some number of incremental changes in
390 * hardclock(), tickdelta will become zero, lest the correction
391 * overshoot and start taking us away from the desired final time.
393 ndelta = atv.tv_sec * 1000000 + atv.tv_usec;
394 if (ndelta > bigadj || ndelta < -bigadj)
395 ntickdelta = 10 * tickadj;
397 ntickdelta = tickadj;
398 if (ndelta % ntickdelta)
399 ndelta = ndelta / ntickdelta * ntickdelta;
402 * To make hardclock()'s job easier, make the per-tick delta negative
403 * if we want time to run slower; then hardclock can simply compute
404 * tick + tickdelta, and subtract tickdelta from timedelta.
407 ntickdelta = -ntickdelta;
411 tickdelta = ntickdelta;
415 atv.tv_sec = odelta / 1000000;
416 atv.tv_usec = odelta % 1000000;
417 (void) copyout((caddr_t)&atv, (caddr_t)uap->olddelta,
418 sizeof(struct timeval));
424 * Get value of an interval timer. The process virtual and
425 * profiling virtual time timers are kept in the p_stats area, since
426 * they can be swapped out. These are kept internally in the
427 * way they are specified externally: in time until they expire.
429 * The real time interval timer is kept in the process table slot
430 * for the process, and its value (it_value) is kept as an
431 * absolute time rather than as a delta, so that it is easy to keep
432 * periodic real-time signals from drifting.
434 * Virtual time timers are processed in the hardclock() routine of
435 * kern_clock.c. The real time timer is processed by a timeout
436 * routine, called from the softclock() routine. Since a callout
437 * may be delayed in real time due to interrupt processing in the system,
438 * it is possible for the real time timeout routine (realitexpire, given below),
439 * to be delayed in real time past when it is supposed to occur. It
440 * does not suffice, therefore, to reload the real timer .it_value from the
441 * real time timers .it_interval. Rather, we compute the next time in
442 * absolute time the timer should go off.
444 #ifndef _SYS_SYSPROTO_H_
445 struct getitimer_args {
447 struct itimerval *itv;
454 register struct getitimer_args *uap;
457 struct itimerval aitv;
460 if (uap->which > ITIMER_PROF)
462 s = splclock(); /* XXX still needed ? */
463 if (uap->which == ITIMER_REAL) {
465 * Convert from absolute to relative time in .it_value
466 * part of real time timer. If time for real time timer
467 * has passed return 0, else return difference between
468 * current time and time for the timer to go off.
470 aitv = p->p_realtimer;
471 if (timevalisset(&aitv.it_value)) {
472 getmicrouptime(&ctv);
473 if (timevalcmp(&aitv.it_value, &ctv, <))
474 timevalclear(&aitv.it_value);
476 timevalsub(&aitv.it_value, &ctv);
479 aitv = p->p_stats->p_timer[uap->which];
481 return (copyout((caddr_t)&aitv, (caddr_t)uap->itv,
482 sizeof (struct itimerval)));
485 #ifndef _SYS_SYSPROTO_H_
486 struct setitimer_args {
488 struct itimerval *itv, *oitv;
495 register struct setitimer_args *uap;
497 struct itimerval aitv;
499 register struct itimerval *itvp;
502 if (uap->which > ITIMER_PROF)
505 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv,
506 sizeof(struct itimerval))))
508 if ((uap->itv = uap->oitv) &&
509 (error = getitimer(p, (struct getitimer_args *)uap)))
513 if (itimerfix(&aitv.it_value))
515 if (!timevalisset(&aitv.it_value))
516 timevalclear(&aitv.it_interval);
517 else if (itimerfix(&aitv.it_interval))
519 s = splclock(); /* XXX: still needed ? */
520 if (uap->which == ITIMER_REAL) {
521 if (timevalisset(&p->p_realtimer.it_value))
522 untimeout(realitexpire, (caddr_t)p, p->p_ithandle);
523 if (timevalisset(&aitv.it_value))
524 p->p_ithandle = timeout(realitexpire, (caddr_t)p,
525 tvtohz(&aitv.it_value));
526 getmicrouptime(&ctv);
527 timevaladd(&aitv.it_value, &ctv);
528 p->p_realtimer = aitv;
530 p->p_stats->p_timer[uap->which] = aitv;
536 * Real interval timer expired:
537 * send process whose timer expired an alarm signal.
538 * If time is not set up to reload, then just return.
539 * Else compute next time timer should go off which is > current time.
540 * This is where delay in processing this timeout causes multiple
541 * SIGALRM calls to be compressed into one.
542 * tvtohz() always adds 1 to allow for the time until the next clock
543 * interrupt being strictly less than 1 clock tick, but we don't want
544 * that here since we want to appear to be in sync with the clock
545 * interrupt even when we're delayed.
551 register struct proc *p;
552 struct timeval ctv, ntv;
555 p = (struct proc *)arg;
557 if (!timevalisset(&p->p_realtimer.it_interval)) {
558 timevalclear(&p->p_realtimer.it_value);
562 s = splclock(); /* XXX: still neeeded ? */
563 timevaladd(&p->p_realtimer.it_value,
564 &p->p_realtimer.it_interval);
565 getmicrouptime(&ctv);
566 if (timevalcmp(&p->p_realtimer.it_value, &ctv, >)) {
567 ntv = p->p_realtimer.it_value;
568 timevalsub(&ntv, &ctv);
569 p->p_ithandle = timeout(realitexpire, (caddr_t)p,
579 * Check that a proposed value to load into the .it_value or
580 * .it_interval part of an interval timer is acceptable, and
581 * fix it to have at least minimal value (i.e. if it is less
582 * than the resolution of the clock, round it up.)
589 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 ||
590 tv->tv_usec < 0 || tv->tv_usec >= 1000000)
592 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick)
598 * Decrement an interval timer by a specified number
599 * of microseconds, which must be less than a second,
600 * i.e. < 1000000. If the timer expires, then reload
601 * it. In this case, carry over (usec - old value) to
602 * reduce the value reloaded into the timer so that
603 * the timer does not drift. This routine assumes
604 * that it is called in a context where the timers
605 * on which it is operating cannot change in value.
608 itimerdecr(itp, usec)
609 register struct itimerval *itp;
613 if (itp->it_value.tv_usec < usec) {
614 if (itp->it_value.tv_sec == 0) {
615 /* expired, and already in next interval */
616 usec -= itp->it_value.tv_usec;
619 itp->it_value.tv_usec += 1000000;
620 itp->it_value.tv_sec--;
622 itp->it_value.tv_usec -= usec;
624 if (timevalisset(&itp->it_value))
626 /* expired, exactly at end of interval */
628 if (timevalisset(&itp->it_interval)) {
629 itp->it_value = itp->it_interval;
630 itp->it_value.tv_usec -= usec;
631 if (itp->it_value.tv_usec < 0) {
632 itp->it_value.tv_usec += 1000000;
633 itp->it_value.tv_sec--;
636 itp->it_value.tv_usec = 0; /* sec is already 0 */
641 * Add and subtract routines for timevals.
642 * N.B.: subtract routine doesn't deal with
643 * results which are before the beginning,
644 * it just gets very confused in this case.
649 struct timeval *t1, *t2;
652 t1->tv_sec += t2->tv_sec;
653 t1->tv_usec += t2->tv_usec;
659 struct timeval *t1, *t2;
662 t1->tv_sec -= t2->tv_sec;
663 t1->tv_usec -= t2->tv_usec;
672 if (t1->tv_usec < 0) {
674 t1->tv_usec += 1000000;
676 if (t1->tv_usec >= 1000000) {
678 t1->tv_usec -= 1000000;