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BSD 4_3_Tahoe release
[unix-history] / 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;
}
}
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.