usr/src/sys/sys/kern_time.c

/*
 * Copyright (c) 1982, 1986 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 *
 *	@(#)kern_time.c	7.5 (Berkeley) 7/21/87
 */

#include "param.h"
#include "dir.h"		/* XXX */
#include "user.h"
#include "kernel.h"
#include "proc.h"

#include "../machine/reg.h"
#include "../machine/cpu.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.
 */

gettimeofday()
{
	register struct a {
		struct	timeval *tp;
		struct	timezone *tzp;
	} *uap = (struct a *)u.u_ap;
	struct timeval atv;

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

settimeofday()
{
	register struct a {
		struct	timeval *tv;
		struct	timezone *tzp;
	} *uap = (struct a *)u.u_ap;
	struct timeval atv;
	struct timezone atz;

	if (uap->tv) {
		u.u_error = copyin((caddr_t)uap->tv, (caddr_t)&atv,
			sizeof (struct timeval));
		if (u.u_error)
			return;
		setthetime(&atv);
	}
	if (uap->tzp && suser()) {
		u.u_error = copyin((caddr_t)uap->tzp, (caddr_t)&atz,
			sizeof (atz));
		if (u.u_error == 0)
			tz = atz;
	}
}

setthetime(tv)
	struct timeval *tv;
{
	int s;

	if (!suser())
		return;
/* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */
	boottime.tv_sec += tv->tv_sec - time.tv_sec;
	s = splhigh(); time = *tv; splx(s);
	resettodr();
}

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. */

adjtime()
{
	register struct a {
		struct timeval *delta;
		struct timeval *olddelta;
	} *uap = (struct a *)u.u_ap;
	struct timeval atv, oatv;
	register long ndelta;
	int s;

	if (!suser())
		return;
	u.u_error = copyin((caddr_t)uap->delta, (caddr_t)&atv,
		sizeof (struct timeval));
	if (u.u_error)
		return;
	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));
}

/*
 * Get value of an interval timer.  The process virtual and
 * profiling virtual time timers are kept in the u. 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.
 */
getitimer()
{
	register struct a {
		u_int	which;
		struct	itimerval *itv;
	} *uap = (struct a *)u.u_ap;
	struct itimerval aitv;
	int s;

	if (uap->which > 2) {
		u.u_error = EINVAL;
		return;
	}
	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 = u.u_procp->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 = u.u_timer[uap->which];
	splx(s);
	u.u_error = copyout((caddr_t)&aitv, (caddr_t)uap->itv,
	    sizeof (struct itimerval));
}

setitimer()
{
	register struct a {
		u_int	which;
		struct	itimerval *itv, *oitv;
	} *uap = (struct a *)u.u_ap;
	struct itimerval aitv, *aitvp;
	int s;
	register struct proc *p = u.u_procp;

	if (uap->which > 2) {
		u.u_error = EINVAL;
		return;
	}
	aitvp = uap->itv;
	if (uap->oitv) {
		uap->itv = uap->oitv;
		getitimer();
	}
	if (aitvp == 0)
		return;
	u.u_error = copyin((caddr_t)aitvp, (caddr_t)&aitv,
	    sizeof (struct itimerval));
	if (u.u_error)
		return;
	if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) {
		u.u_error = EINVAL;
		return;
	}
	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
		u.u_timer[uap->which] = aitv;
	splx(s);
}

/*
 * 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 Regents of the University of California.
	3	* All rights reserved. The Berkeley software License Agreement
	4	* specifies the terms and conditions for redistribution.
	5	*
	6	* @(#)kern_time.c 7.5 (Berkeley) 7/21/87
	7	*/
	8
	9	#include "param.h"
	10	#include "dir.h" /* XXX */
	11	#include "user.h"
	12	#include "kernel.h"
	13	#include "proc.h"
	14
	15	#include "../machine/reg.h"
	16	#include "../machine/cpu.h"
	17
	18	/*
	19	* Time of day and interval timer support.
	20	*
	21	* These routines provide the kernel entry points to get and set
	22	* the time-of-day and per-process interval timers. Subroutines
	23	* here provide support for adding and subtracting timeval structures
	24	* and decrementing interval timers, optionally reloading the interval
	25	* timers when they expire.
	26	*/
	27
	28	gettimeofday()
	29	{
	30	register struct a {
	31	struct timeval *tp;
	32	struct timezone *tzp;
	33	} uap = (struct a )u.u_ap;
	34	struct timeval atv;
	35
	36	if (uap->tp) {
	37	microtime(&atv);
	38	u.u_error = copyout((caddr_t)&atv, (caddr_t)uap->tp,
	39	sizeof (atv));
	40	if (u.u_error)
	41	return;
	42	}
	43	if (uap->tzp)
	44	u.u_error = copyout((caddr_t)&tz, (caddr_t)uap->tzp,
	45	sizeof (tz));
	46	}
	47
	48	settimeofday()
	49	{
	50	register struct a {
	51	struct timeval *tv;
	52	struct timezone *tzp;
	53	} uap = (struct a )u.u_ap;
	54	struct timeval atv;
	55	struct timezone atz;
	56
	57	if (uap->tv) {
	58	u.u_error = copyin((caddr_t)uap->tv, (caddr_t)&atv,
	59	sizeof (struct timeval));
	60	if (u.u_error)
	61	return;
	62	setthetime(&atv);
	63	}
	64	if (uap->tzp && suser()) {
	65	u.u_error = copyin((caddr_t)uap->tzp, (caddr_t)&atz,
	66	sizeof (atz));
	67	if (u.u_error == 0)
	68	tz = atz;
	69	}
	70	}
	71
	72	setthetime(tv)
	73	struct timeval *tv;
	74	{
	75	int s;
	76
	77	if (!suser())
	78	return;
	79	/* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */
	80	boottime.tv_sec += tv->tv_sec - time.tv_sec;
	81	s = splhigh(); time = *tv; splx(s);
	82	resettodr();
	83	}
	84
	85	extern int tickadj; /* "standard" clock skew, us./tick */
	86	int tickdelta; /* current clock skew, us. per tick */
	87	long timedelta; /* unapplied time correction, us. */
	88	long bigadj = 1000000; /* use 10x skew above bigadj us. */
	89
	90	adjtime()
	91	{
	92	register struct a {
	93	struct timeval *delta;
	94	struct timeval *olddelta;
	95	} uap = (struct a )u.u_ap;
	96	struct timeval atv, oatv;
	97	register long ndelta;
	98	int s;
	99
	100	if (!suser())
	101	return;
	102	u.u_error = copyin((caddr_t)uap->delta, (caddr_t)&atv,
	103	sizeof (struct timeval));
	104	if (u.u_error)
	105	return;
	106	ndelta = atv.tv_sec * 1000000 + atv.tv_usec;
	107	if (timedelta == 0)
	108	if (ndelta > bigadj)
	109	tickdelta = 10 * tickadj;
	110	else
	111	tickdelta = tickadj;
	112	if (ndelta % tickdelta)
	113	ndelta = ndelta / tickadj * tickadj;
	114
	115	s = splclock();
	116	if (uap->olddelta) {
	117	oatv.tv_sec = timedelta / 1000000;
	118	oatv.tv_usec = timedelta % 1000000;
	119	}
	120	timedelta = ndelta;
	121	splx(s);
	122
	123	if (uap->olddelta)
	124	(void) copyout((caddr_t)&oatv, (caddr_t)uap->olddelta,
	125	sizeof (struct timeval));
	126	}
	127
	128	/*
	129	* Get value of an interval timer. The process virtual and
	130	* profiling virtual time timers are kept in the u. area, since
	131	* they can be swapped out. These are kept internally in the
	132	* way they are specified externally: in time until they expire.
	133	*
	134	* The real time interval timer is kept in the process table slot
	135	* for the process, and its value (it_value) is kept as an
	136	* absolute time rather than as a delta, so that it is easy to keep
	137	* periodic real-time signals from drifting.
	138	*
	139	* Virtual time timers are processed in the hardclock() routine of
	140	* kern_clock.c. The real time timer is processed by a timeout
	141	* routine, called from the softclock() routine. Since a callout
	142	* may be delayed in real time due to interrupt processing in the system,
	143	* it is possible for the real time timeout routine (realitexpire, given below),
	144	* to be delayed in real time past when it is supposed to occur. It
	145	* does not suffice, therefore, to reload the real timer .it_value from the
	146	* real time timers .it_interval. Rather, we compute the next time in
	147	* absolute time the timer should go off.
	148	*/
	149	getitimer()
	150	{
	151	register struct a {
	152	u_int which;
	153	struct itimerval *itv;
	154	} uap = (struct a )u.u_ap;
	155	struct itimerval aitv;
	156	int s;
	157
	158	if (uap->which > 2) {
	159	u.u_error = EINVAL;
	160	return;
	161	}
	162	s = splclock();
	163	if (uap->which == ITIMER_REAL) {
	164	/*
	165	* Convert from absoulte to relative time in .it_value
	166	* part of real time timer. If time for real time timer
	167	* has passed return 0, else return difference between
	168	* current time and time for the timer to go off.
	169	*/
	170	aitv = u.u_procp->p_realtimer;
	171	if (timerisset(&aitv.it_value))
	172	if (timercmp(&aitv.it_value, &time, <))
	173	timerclear(&aitv.it_value);
	174	else
	175	timevalsub(&aitv.it_value, &time);
	176	} else
	177	aitv = u.u_timer[uap->which];
	178	splx(s);
	179	u.u_error = copyout((caddr_t)&aitv, (caddr_t)uap->itv,
	180	sizeof (struct itimerval));
	181	}
	182
	183	setitimer()
	184	{
	185	register struct a {
	186	u_int which;
	187	struct itimerval itv, oitv;
	188	} uap = (struct a )u.u_ap;
	189	struct itimerval aitv, *aitvp;
	190	int s;
	191	register struct proc *p = u.u_procp;
	192
	193	if (uap->which > 2) {
	194	u.u_error = EINVAL;
	195	return;
	196	}
	197	aitvp = uap->itv;
	198	if (uap->oitv) {
	199	uap->itv = uap->oitv;
	200	getitimer();
	201	}
	202	if (aitvp == 0)
	203	return;
	204	u.u_error = copyin((caddr_t)aitvp, (caddr_t)&aitv,
	205	sizeof (struct itimerval));
	206	if (u.u_error)
	207	return;
	208	if (itimerfix(&aitv.it_value) \|\| itimerfix(&aitv.it_interval)) {
	209	u.u_error = EINVAL;
	210	return;
	211	}
	212	s = splclock();
	213	if (uap->which == ITIMER_REAL) {
	214	untimeout(realitexpire, (caddr_t)p);
	215	if (timerisset(&aitv.it_value)) {
	216	timevaladd(&aitv.it_value, &time);
	217	timeout(realitexpire, (caddr_t)p, hzto(&aitv.it_value));
	218	}
	219	p->p_realtimer = aitv;
	220	} else
	221	u.u_timer[uap->which] = aitv;
	222	splx(s);
	223	}
	224
	225	/*
	226	* Real interval timer expired:
	227	* send process whose timer expired an alarm signal.
	228	* If time is not set up to reload, then just return.
	229	* Else compute next time timer should go off which is > current time.
	230	* This is where delay in processing this timeout causes multiple
	231	* SIGALRM calls to be compressed into one.
	232	*/
	233	realitexpire(p)
	234	register struct proc *p;
	235	{
	236	int s;
	237
	238	psignal(p, SIGALRM);
	239	if (!timerisset(&p->p_realtimer.it_interval)) {
	240	timerclear(&p->p_realtimer.it_value);
	241	return;
	242	}
	243	for (;;) {
	244	s = splclock();
	245	timevaladd(&p->p_realtimer.it_value,
	246	&p->p_realtimer.it_interval);
	247	if (timercmp(&p->p_realtimer.it_value, &time, >)) {
	248	timeout(realitexpire, (caddr_t)p,
	249	hzto(&p->p_realtimer.it_value));
	250	splx(s);
	251	return;
	252	}
	253	splx(s);
	254	}
	255	}
	256
	257	/*
	258	* Check that a proposed value to load into the .it_value or
	259	* .it_interval part of an interval timer is acceptable, and
	260	* fix it to have at least minimal value (i.e. if it is less
	261	* than the resolution of the clock, round it up.)
	262	*/
	263	itimerfix(tv)
	264	struct timeval *tv;
	265	{
	266
	267	if (tv->tv_sec < 0 \|\| tv->tv_sec > 100000000 \|\|
	268	tv->tv_usec < 0 \|\| tv->tv_usec >= 1000000)
	269	return (EINVAL);
	270	if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick)
	271	tv->tv_usec = tick;
	272	return (0);
	273	}
	274
	275	/*
	276	* Decrement an interval timer by a specified number
	277	* of microseconds, which must be less than a second,
	278	* i.e. < 1000000. If the timer expires, then reload
	279	* it. In this case, carry over (usec - old value) to
	280	* reducint the value reloaded into the timer so that
	281	* the timer does not drift. This routine assumes
	282	* that it is called in a context where the timers
	283	* on which it is operating cannot change in value.
	284	*/
	285	itimerdecr(itp, usec)
	286	register struct itimerval *itp;
	287	int usec;
	288	{
	289
	290	if (itp->it_value.tv_usec < usec) {
	291	if (itp->it_value.tv_sec == 0) {
	292	/* expired, and already in next interval */
	293	usec -= itp->it_value.tv_usec;
	294	goto expire;
	295	}
	296	itp->it_value.tv_usec += 1000000;
	297	itp->it_value.tv_sec--;
	298	}
	299	itp->it_value.tv_usec -= usec;
	300	usec = 0;
	301	if (timerisset(&itp->it_value))
	302	return (1);
	303	/* expired, exactly at end of interval */
	304	expire:
	305	if (timerisset(&itp->it_interval)) {
	306	itp->it_value = itp->it_interval;
	307	itp->it_value.tv_usec -= usec;
	308	if (itp->it_value.tv_usec < 0) {
	309	itp->it_value.tv_usec += 1000000;
	310	itp->it_value.tv_sec--;
	311	}
	312	} else
	313	itp->it_value.tv_usec = 0; /* sec is already 0 */
	314	return (0);
	315	}
	316
	317	/*
	318	* Add and subtract routines for timevals.
	319	* N.B.: subtract routine doesn't deal with
	320	* results which are before the beginning,
	321	* it just gets very confused in this case.
	322	* Caveat emptor.
	323	*/
	324	timevaladd(t1, t2)
	325	struct timeval t1, t2;
	326	{
	327
	328	t1->tv_sec += t2->tv_sec;
	329	t1->tv_usec += t2->tv_usec;
	330	timevalfix(t1);
	331	}
	332
	333	timevalsub(t1, t2)
	334	struct timeval t1, t2;
	335	{
	336
	337	t1->tv_sec -= t2->tv_sec;
	338	t1->tv_usec -= t2->tv_usec;
	339	timevalfix(t1);
	340	}
	341
	342	timevalfix(t1)
	343	struct timeval *t1;
	344	{
	345
	346	if (t1->tv_usec < 0) {
	347	t1->tv_sec--;
	348	t1->tv_usec += 1000000;
	349	}
	350	if (t1->tv_usec >= 1000000) {
	351	t1->tv_sec++;
	352	t1->tv_usec -= 1000000;
	353	}
	354	}