usr/src/sys/kern/kern_time.c

/*
 * Copyright (c) 1982, 1986, 1989 Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 *
 *	@(#)kern_time.c	7.15 (Berkeley) %G%
 */

#include "param.h"
#include "resourcevar.h"
#include "kernel.h"
#include "proc.h"


/*
 * Time of day and interval timer support.
 *
 * These routines provide the kernel entry points to get and set
 * the time-of-day and per-process interval timers.  Subroutines
 * here provide support for adding and subtracting timeval structures
 * and decrementing interval timers, optionally reloading the interval
 * timers when they expire.
 */

/* ARGSUSED */
gettimeofday(p, uap, retval)
	struct proc *p;
	register struct args {
		struct	timeval *tp;
		struct	timezone *tzp;
	} *uap;
	int *retval;
{
	struct timeval atv;
	int error = 0;

	if (uap->tp) {
		microtime(&atv);
		if (error = copyout((caddr_t)&atv, (caddr_t)uap->tp,
		    sizeof (atv)))
			return (error);
	}
	if (uap->tzp)
		error = copyout((caddr_t)&tz, (caddr_t)uap->tzp,
		    sizeof (tz));
	return (error);
}

/* ARGSUSED */
settimeofday(p, uap, retval)
	struct proc *p;
	struct args {
		struct	timeval *tv;
		struct	timezone *tzp;
	} *uap;
	int *retval;
{
	struct timeval atv;
	struct timezone atz;
	int error, s;

	if (error = suser(p->p_ucred, &p->p_acflag))
		return (error);
	if (uap->tv) {
		if (error = copyin((caddr_t)uap->tv, (caddr_t)&atv,
		    sizeof (struct timeval)))
			return (error);
		/* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */
		boottime.tv_sec += atv.tv_sec - time.tv_sec;
		s = splhigh(); time = atv; splx(s);
		resettodr();
	}
	if (uap->tzp && (error = copyin((caddr_t)uap->tzp, (caddr_t)&atz,
	    sizeof (atz))) == 0)
		tz = atz;
	return (error);
}

extern	int tickadj;			/* "standard" clock skew, us./tick */
int	tickdelta;			/* current clock skew, us. per tick */
long	timedelta;			/* unapplied time correction, us. */
long	bigadj = 1000000;		/* use 10x skew above bigadj us. */

/* ARGSUSED */
adjtime(p, uap, retval)
	struct proc *p;
	register struct args {
		struct timeval *delta;
		struct timeval *olddelta;
	} *uap;
	int *retval;
{
	struct timeval atv, oatv;
	register long ndelta;
	int s, error;

	if (error = suser(p->p_ucred, &p->p_acflag))
		return (error);
	if (error =
	    copyin((caddr_t)uap->delta, (caddr_t)&atv, sizeof (struct timeval)))
		return (error);
	ndelta = atv.tv_sec * 1000000 + atv.tv_usec;
	if (timedelta == 0)
		if (ndelta > bigadj)
			tickdelta = 10 * tickadj;
		else
			tickdelta = tickadj;
	if (ndelta % tickdelta)
		ndelta = ndelta / tickadj * tickadj;

	s = splclock();
	if (uap->olddelta) {
		oatv.tv_sec = timedelta / 1000000;
		oatv.tv_usec = timedelta % 1000000;
	}
	timedelta = ndelta;
	splx(s);

	if (uap->olddelta)
		(void) copyout((caddr_t)&oatv, (caddr_t)uap->olddelta,
			sizeof (struct timeval));
	return (0);
}

/*
 * Get value of an interval timer.  The process virtual and
 * profiling virtual time timers are kept in the p_stats area, since
 * they can be swapped out.  These are kept internally in the
 * way they are specified externally: in time until they expire.
 *
 * The real time interval timer is kept in the process table slot
 * for the process, and its value (it_value) is kept as an
 * absolute time rather than as a delta, so that it is easy to keep
 * periodic real-time signals from drifting.
 *
 * Virtual time timers are processed in the hardclock() routine of
 * kern_clock.c.  The real time timer is processed by a timeout
 * routine, called from the softclock() routine.  Since a callout
 * may be delayed in real time due to interrupt processing in the system,
 * it is possible for the real time timeout routine (realitexpire, given below),
 * to be delayed in real time past when it is supposed to occur.  It
 * does not suffice, therefore, to reload the real timer .it_value from the
 * real time timers .it_interval.  Rather, we compute the next time in
 * absolute time the timer should go off.
 */
/* ARGSUSED */
getitimer(p, uap, retval)
	struct proc *p;
	register struct args {
		u_int	which;
		struct	itimerval *itv;
	} *uap;
	int *retval;
{
	struct itimerval aitv;
	int s;

	if (uap->which > ITIMER_PROF)
		return (EINVAL);
	s = splclock();
	if (uap->which == ITIMER_REAL) {
		/*
		 * Convert from absoulte to relative time in .it_value
		 * part of real time timer.  If time for real time timer
		 * has passed return 0, else return difference between
		 * current time and time for the timer to go off.
		 */
		aitv = p->p_realtimer;
		if (timerisset(&aitv.it_value))
			if (timercmp(&aitv.it_value, &time, <))
				timerclear(&aitv.it_value);
			else
				timevalsub(&aitv.it_value, &time);
	} else
		aitv = p->p_stats->p_timer[uap->which];
	splx(s);
	return (copyout((caddr_t)&aitv, (caddr_t)uap->itv,
	    sizeof (struct itimerval)));
}

/* ARGSUSED */
setitimer(p, uap, retval)
	struct proc *p;
	register struct args {
		u_int	which;
		struct	itimerval *itv, *oitv;
	} *uap;
	int *retval;
{
	struct itimerval aitv;
	register struct itimerval *itvp;
	int s, error;

	if (uap->which > ITIMER_PROF)
		return (EINVAL);
	itvp = uap->itv;
	if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv,
	    sizeof(struct itimerval))))
		return (error);
	if ((uap->itv = uap->oitv) && (error = getitimer(p, uap, retval)))
		return (error);
	if (itvp == 0)
		return (0);
	if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval))
		return (EINVAL);
	s = splclock();
	if (uap->which == ITIMER_REAL) {
		untimeout(realitexpire, (caddr_t)p);
		if (timerisset(&aitv.it_value)) {
			timevaladd(&aitv.it_value, &time);
			timeout(realitexpire, (caddr_t)p, hzto(&aitv.it_value));
		}
		p->p_realtimer = aitv;
	} else
		p->p_stats->p_timer[uap->which] = aitv;
	splx(s);
	return (0);
}

/*
 * Real interval timer expired:
 * send process whose timer expired an alarm signal.
 * If time is not set up to reload, then just return.
 * Else compute next time timer should go off which is > current time.
 * This is where delay in processing this timeout causes multiple
 * SIGALRM calls to be compressed into one.
 */
realitexpire(p)
	register struct proc *p;
{
	int s;

	psignal(p, SIGALRM);
	if (!timerisset(&p->p_realtimer.it_interval)) {
		timerclear(&p->p_realtimer.it_value);
		return;
	}
	for (;;) {
		s = splclock();
		timevaladd(&p->p_realtimer.it_value,
		    &p->p_realtimer.it_interval);
		if (timercmp(&p->p_realtimer.it_value, &time, >)) {
			timeout(realitexpire, (caddr_t)p,
			    hzto(&p->p_realtimer.it_value));
			splx(s);
			return;
		}
		splx(s);
	}
}

/*
 * Check that a proposed value to load into the .it_value or
 * .it_interval part of an interval timer is acceptable, and
 * fix it to have at least minimal value (i.e. if it is less
 * than the resolution of the clock, round it up.)
 */
itimerfix(tv)
	struct timeval *tv;
{

	if (tv->tv_sec < 0 || tv->tv_sec > 100000000 ||
	    tv->tv_usec < 0 || tv->tv_usec >= 1000000)
		return (EINVAL);
	if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick)
		tv->tv_usec = tick;
	return (0);
}

/*
 * Decrement an interval timer by a specified number
 * of microseconds, which must be less than a second,
 * i.e. < 1000000.  If the timer expires, then reload
 * it.  In this case, carry over (usec - old value) to
 * reducint the value reloaded into the timer so that
 * the timer does not drift.  This routine assumes
 * that it is called in a context where the timers
 * on which it is operating cannot change in value.
 */
itimerdecr(itp, usec)
	register struct itimerval *itp;
	int usec;
{

	if (itp->it_value.tv_usec < usec) {
		if (itp->it_value.tv_sec == 0) {
			/* expired, and already in next interval */
			usec -= itp->it_value.tv_usec;
			goto expire;
		}
		itp->it_value.tv_usec += 1000000;
		itp->it_value.tv_sec--;
	}
	itp->it_value.tv_usec -= usec;
	usec = 0;
	if (timerisset(&itp->it_value))
		return (1);
	/* expired, exactly at end of interval */
expire:
	if (timerisset(&itp->it_interval)) {
		itp->it_value = itp->it_interval;
		itp->it_value.tv_usec -= usec;
		if (itp->it_value.tv_usec < 0) {
			itp->it_value.tv_usec += 1000000;
			itp->it_value.tv_sec--;
		}
	} else
		itp->it_value.tv_usec = 0;		/* sec is already 0 */
	return (0);
}

/*
 * Add and subtract routines for timevals.
 * N.B.: subtract routine doesn't deal with
 * results which are before the beginning,
 * it just gets very confused in this case.
 * Caveat emptor.
 */
timevaladd(t1, t2)
	struct timeval *t1, *t2;
{

	t1->tv_sec += t2->tv_sec;
	t1->tv_usec += t2->tv_usec;
	timevalfix(t1);
}

timevalsub(t1, t2)
	struct timeval *t1, *t2;
{

	t1->tv_sec -= t2->tv_sec;
	t1->tv_usec -= t2->tv_usec;
	timevalfix(t1);
}

timevalfix(t1)
	struct timeval *t1;
{

	if (t1->tv_usec < 0) {
		t1->tv_sec--;
		t1->tv_usec += 1000000;
	}
	if (t1->tv_usec >= 1000000) {
		t1->tv_sec++;
		t1->tv_usec -= 1000000;
	}
}
Commit	Line	Data
	1	/*
	2	* Copyright (c) 1982, 1986, 1989 Regents of the University of California.
	3	* All rights reserved.
	4	*
	5	* %sccs.include.redist.c%
	6	*
	7	* @(#)kern_time.c 7.15 (Berkeley) %G%
	8	*/
	9
	10	#include "param.h"
	11	#include "resourcevar.h"
	12	#include "kernel.h"
	13	#include "proc.h"
	14
	15
	16	/*
	17	* Time of day and interval timer support.
	18	*
	19	* These routines provide the kernel entry points to get and set
	20	* the time-of-day and per-process interval timers. Subroutines
	21	* here provide support for adding and subtracting timeval structures
	22	* and decrementing interval timers, optionally reloading the interval
	23	* timers when they expire.
	24	*/
	25
	26	/* ARGSUSED */
	27	gettimeofday(p, uap, retval)
	28	struct proc *p;
	29	register struct args {
	30	struct timeval *tp;
	31	struct timezone *tzp;
	32	} *uap;
	33	int *retval;
	34	{
	35	struct timeval atv;
	36	int error = 0;
	37
	38	if (uap->tp) {
	39	microtime(&atv);
	40	if (error = copyout((caddr_t)&atv, (caddr_t)uap->tp,
	41	sizeof (atv)))
	42	return (error);
	43	}
	44	if (uap->tzp)
	45	error = copyout((caddr_t)&tz, (caddr_t)uap->tzp,
	46	sizeof (tz));
	47	return (error);
	48	}
	49
	50	/* ARGSUSED */
	51	settimeofday(p, uap, retval)
	52	struct proc *p;
	53	struct args {
	54	struct timeval *tv;
	55	struct timezone *tzp;
	56	} *uap;
	57	int *retval;
	58	{
	59	struct timeval atv;
	60	struct timezone atz;
	61	int error, s;
	62
	63	if (error = suser(p->p_ucred, &p->p_acflag))
	64	return (error);
	65	if (uap->tv) {
	66	if (error = copyin((caddr_t)uap->tv, (caddr_t)&atv,
	67	sizeof (struct timeval)))
	68	return (error);
	69	/* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */
	70	boottime.tv_sec += atv.tv_sec - time.tv_sec;
	71	s = splhigh(); time = atv; splx(s);
	72	resettodr();
	73	}
	74	if (uap->tzp && (error = copyin((caddr_t)uap->tzp, (caddr_t)&atz,
	75	sizeof (atz))) == 0)
	76	tz = atz;
	77	return (error);
	78	}
	79
	80	extern int tickadj; /* "standard" clock skew, us./tick */
	81	int tickdelta; /* current clock skew, us. per tick */
	82	long timedelta; /* unapplied time correction, us. */
	83	long bigadj = 1000000; /* use 10x skew above bigadj us. */
	84
	85	/* ARGSUSED */
	86	adjtime(p, uap, retval)
	87	struct proc *p;
	88	register struct args {
	89	struct timeval *delta;
	90	struct timeval *olddelta;
	91	} *uap;
	92	int *retval;
	93	{
	94	struct timeval atv, oatv;
	95	register long ndelta;
	96	int s, error;
	97
	98	if (error = suser(p->p_ucred, &p->p_acflag))
	99	return (error);
	100	if (error =
	101	copyin((caddr_t)uap->delta, (caddr_t)&atv, sizeof (struct timeval)))
	102	return (error);
	103	ndelta = atv.tv_sec * 1000000 + atv.tv_usec;
	104	if (timedelta == 0)
	105	if (ndelta > bigadj)
	106	tickdelta = 10 * tickadj;
	107	else
	108	tickdelta = tickadj;
	109	if (ndelta % tickdelta)
	110	ndelta = ndelta / tickadj * tickadj;
	111
	112	s = splclock();
	113	if (uap->olddelta) {
	114	oatv.tv_sec = timedelta / 1000000;
	115	oatv.tv_usec = timedelta % 1000000;
	116	}
	117	timedelta = ndelta;
	118	splx(s);
	119
	120	if (uap->olddelta)
	121	(void) copyout((caddr_t)&oatv, (caddr_t)uap->olddelta,
	122	sizeof (struct timeval));
	123	return (0);
	124	}
	125
	126	/*
	127	* Get value of an interval timer. The process virtual and
	128	* profiling virtual time timers are kept in the p_stats area, since
	129	* they can be swapped out. These are kept internally in the
	130	* way they are specified externally: in time until they expire.
	131	*
	132	* The real time interval timer is kept in the process table slot
	133	* for the process, and its value (it_value) is kept as an
	134	* absolute time rather than as a delta, so that it is easy to keep
	135	* periodic real-time signals from drifting.
	136	*
	137	* Virtual time timers are processed in the hardclock() routine of
	138	* kern_clock.c. The real time timer is processed by a timeout
	139	* routine, called from the softclock() routine. Since a callout
	140	* may be delayed in real time due to interrupt processing in the system,
	141	* it is possible for the real time timeout routine (realitexpire, given below),
	142	* to be delayed in real time past when it is supposed to occur. It
	143	* does not suffice, therefore, to reload the real timer .it_value from the
	144	* real time timers .it_interval. Rather, we compute the next time in
	145	* absolute time the timer should go off.
	146	*/
	147	/* ARGSUSED */
	148	getitimer(p, uap, retval)
	149	struct proc *p;
	150	register struct args {
	151	u_int which;
	152	struct itimerval *itv;
	153	} *uap;
	154	int *retval;
	155	{
	156	struct itimerval aitv;
	157	int s;
	158
	159	if (uap->which > ITIMER_PROF)
	160	return (EINVAL);
	161	s = splclock();
	162	if (uap->which == ITIMER_REAL) {
	163	/*
	164	* Convert from absoulte to relative time in .it_value
	165	* part of real time timer. If time for real time timer
	166	* has passed return 0, else return difference between
	167	* current time and time for the timer to go off.
	168	*/
	169	aitv = p->p_realtimer;
	170	if (timerisset(&aitv.it_value))
	171	if (timercmp(&aitv.it_value, &time, <))
	172	timerclear(&aitv.it_value);
	173	else
	174	timevalsub(&aitv.it_value, &time);
	175	} else
	176	aitv = p->p_stats->p_timer[uap->which];
	177	splx(s);
	178	return (copyout((caddr_t)&aitv, (caddr_t)uap->itv,
	179	sizeof (struct itimerval)));
	180	}
	181
	182	/* ARGSUSED */
	183	setitimer(p, uap, retval)
	184	struct proc *p;
	185	register struct args {
	186	u_int which;
	187	struct itimerval itv, oitv;
	188	} *uap;
	189	int *retval;
	190	{
	191	struct itimerval aitv;
	192	register struct itimerval *itvp;
	193	int s, error;
	194
	195	if (uap->which > ITIMER_PROF)
	196	return (EINVAL);
	197	itvp = uap->itv;
	198	if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv,
	199	sizeof(struct itimerval))))
	200	return (error);
	201	if ((uap->itv = uap->oitv) && (error = getitimer(p, uap, retval)))
	202	return (error);
	203	if (itvp == 0)
	204	return (0);
	205	if (itimerfix(&aitv.it_value) \|\| itimerfix(&aitv.it_interval))
	206	return (EINVAL);
	207	s = splclock();
	208	if (uap->which == ITIMER_REAL) {
	209	untimeout(realitexpire, (caddr_t)p);
	210	if (timerisset(&aitv.it_value)) {
	211	timevaladd(&aitv.it_value, &time);
	212	timeout(realitexpire, (caddr_t)p, hzto(&aitv.it_value));
	213	}
	214	p->p_realtimer = aitv;
	215	} else
	216	p->p_stats->p_timer[uap->which] = aitv;
	217	splx(s);
	218	return (0);
	219	}
	220
	221	/*
	222	* Real interval timer expired:
	223	* send process whose timer expired an alarm signal.
	224	* If time is not set up to reload, then just return.
	225	* Else compute next time timer should go off which is > current time.
	226	* This is where delay in processing this timeout causes multiple
	227	* SIGALRM calls to be compressed into one.
	228	*/
	229	realitexpire(p)
	230	register struct proc *p;
	231	{
	232	int s;
	233
	234	psignal(p, SIGALRM);
	235	if (!timerisset(&p->p_realtimer.it_interval)) {
	236	timerclear(&p->p_realtimer.it_value);
	237	return;
	238	}
	239	for (;;) {
	240	s = splclock();
	241	timevaladd(&p->p_realtimer.it_value,
	242	&p->p_realtimer.it_interval);
	243	if (timercmp(&p->p_realtimer.it_value, &time, >)) {
	244	timeout(realitexpire, (caddr_t)p,
	245	hzto(&p->p_realtimer.it_value));
	246	splx(s);
	247	return;
	248	}
	249	splx(s);
	250	}
	251	}
	252
	253	/*
	254	* Check that a proposed value to load into the .it_value or
	255	* .it_interval part of an interval timer is acceptable, and
	256	* fix it to have at least minimal value (i.e. if it is less
	257	* than the resolution of the clock, round it up.)
	258	*/
	259	itimerfix(tv)
	260	struct timeval *tv;
	261	{
	262
	263	if (tv->tv_sec < 0 \|\| tv->tv_sec > 100000000 \|\|
	264	tv->tv_usec < 0 \|\| tv->tv_usec >= 1000000)
	265	return (EINVAL);
	266	if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick)
	267	tv->tv_usec = tick;
	268	return (0);
	269	}
	270
	271	/*
	272	* Decrement an interval timer by a specified number
	273	* of microseconds, which must be less than a second,
	274	* i.e. < 1000000. If the timer expires, then reload
	275	* it. In this case, carry over (usec - old value) to
	276	* reducint the value reloaded into the timer so that
	277	* the timer does not drift. This routine assumes
	278	* that it is called in a context where the timers
	279	* on which it is operating cannot change in value.
	280	*/
	281	itimerdecr(itp, usec)
	282	register struct itimerval *itp;
	283	int usec;
	284	{
	285
	286	if (itp->it_value.tv_usec < usec) {
	287	if (itp->it_value.tv_sec == 0) {
	288	/* expired, and already in next interval */
	289	usec -= itp->it_value.tv_usec;
	290	goto expire;
	291	}
	292	itp->it_value.tv_usec += 1000000;
	293	itp->it_value.tv_sec--;
	294	}
	295	itp->it_value.tv_usec -= usec;
	296	usec = 0;
	297	if (timerisset(&itp->it_value))
	298	return (1);
	299	/* expired, exactly at end of interval */
	300	expire:
	301	if (timerisset(&itp->it_interval)) {
	302	itp->it_value = itp->it_interval;
	303	itp->it_value.tv_usec -= usec;
	304	if (itp->it_value.tv_usec < 0) {
	305	itp->it_value.tv_usec += 1000000;
	306	itp->it_value.tv_sec--;
	307	}
	308	} else
	309	itp->it_value.tv_usec = 0; /* sec is already 0 */
	310	return (0);
	311	}
	312
	313	/*
	314	* Add and subtract routines for timevals.
	315	* N.B.: subtract routine doesn't deal with
	316	* results which are before the beginning,
	317	* it just gets very confused in this case.
	318	* Caveat emptor.
	319	*/
	320	timevaladd(t1, t2)
	321	struct timeval t1, t2;
	322	{
	323
	324	t1->tv_sec += t2->tv_sec;
	325	t1->tv_usec += t2->tv_usec;
	326	timevalfix(t1);
	327	}
	328
	329	timevalsub(t1, t2)
	330	struct timeval t1, t2;
	331	{
	332
	333	t1->tv_sec -= t2->tv_sec;
	334	t1->tv_usec -= t2->tv_usec;
	335	timevalfix(t1);
	336	}
	337
	338	timevalfix(t1)
	339	struct timeval *t1;
	340	{
	341
	342	if (t1->tv_usec < 0) {
	343	t1->tv_sec--;
	344	t1->tv_usec += 1000000;
	345	}
	346	if (t1->tv_usec >= 1000000) {
	347	t1->tv_sec++;
	348	t1->tv_usec -= 1000000;
	349	}
	350	}