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BSD 4_4_Lite2 release
[unix-history] / usr / src / sys / kern / kern_time.c
/*
* Copyright (c) 1982, 1986, 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)kern_time.c 8.4 (Berkeley) 5/26/95
*/
#include <sys/param.h>
#include <sys/resourcevar.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/syscallargs.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.
*/
/* ARGSUSED */
int
gettimeofday(p, uap, retval)
struct proc *p;
register struct gettimeofday_args /* {
syscallarg(struct timeval *) tp;
syscallarg(struct timezone *) tzp;
} */ *uap;
register_t *retval;
{
struct timeval atv;
int error = 0;
if (SCARG(uap, tp)) {
microtime(&atv);
if (error = copyout((caddr_t)&atv, (caddr_t)SCARG(uap, tp),
sizeof (atv)))
return (error);
}
if (SCARG(uap, tzp))
error = copyout((caddr_t)&tz, (caddr_t)SCARG(uap, tzp),
sizeof (tz));
return (error);
}
/* ARGSUSED */
int
settimeofday(p, uap, retval)
struct proc *p;
struct settimeofday_args /* {
syscallarg(struct timeval *) tv;
syscallarg(struct timezone *) tzp;
} */ *uap;
register_t *retval;
{
struct timeval atv, delta;
struct timezone atz;
int error, s;
if (error = suser(p->p_ucred, &p->p_acflag))
return (error);
/* Verify all parameters before changing time. */
if (SCARG(uap, tv) && (error = copyin((caddr_t)SCARG(uap, tv),
(caddr_t)&atv, sizeof(atv))))
return (error);
if (SCARG(uap, tzp) && (error = copyin((caddr_t)SCARG(uap, tzp),
(caddr_t)&atz, sizeof(atz))))
return (error);
if (SCARG(uap, tv)) {
/*
* If the system is secure, we do not allow the time to be
* set to an earlier value (it may be slowed using adjtime,
* but not set back). This feature prevent interlopers from
* setting arbitrary time stamps on files.
*/
if (securelevel > 0 && timercmp(&atv, &time, <))
return (EPERM);
/* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */
s = splclock();
/* nb. delta.tv_usec may be < 0, but this is OK here */
delta.tv_sec = atv.tv_sec - time.tv_sec;
delta.tv_usec = atv.tv_usec - time.tv_usec;
time = atv;
(void) splsoftclock();
timevaladd(&boottime, &delta);
timevalfix(&boottime);
timevaladd(&runtime, &delta);
timevalfix(&runtime);
# ifdef NFS
lease_updatetime(delta.tv_sec);
# endif
splx(s);
resettodr();
}
if (SCARG(uap, tzp))
tz = atz;
return (0);
}
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 */
int
adjtime(p, uap, retval)
struct proc *p;
register struct adjtime_args /* {
syscallarg(struct timeval *) delta;
syscallarg(struct timeval *) olddelta;
} */ *uap;
register_t *retval;
{
struct timeval atv;
register long ndelta, ntickdelta, odelta;
int s, error;
if (error = suser(p->p_ucred, &p->p_acflag))
return (error);
if (error = copyin((caddr_t)SCARG(uap, delta), (caddr_t)&atv,
sizeof(struct timeval)))
return (error);
/*
* Compute the total correction and the rate at which to apply it.
* Round the adjustment down to a whole multiple of the per-tick
* delta, so that after some number of incremental changes in
* hardclock(), tickdelta will become zero, lest the correction
* overshoot and start taking us away from the desired final time.
*/
ndelta = atv.tv_sec * 1000000 + atv.tv_usec;
if (ndelta > bigadj)
ntickdelta = 10 * tickadj;
else
ntickdelta = tickadj;
if (ndelta % ntickdelta)
ndelta = ndelta / ntickdelta * ntickdelta;
/*
* To make hardclock()'s job easier, make the per-tick delta negative
* if we want time to run slower; then hardclock can simply compute
* tick + tickdelta, and subtract tickdelta from timedelta.
*/
if (ndelta < 0)
ntickdelta = -ntickdelta;
s = splclock();
odelta = timedelta;
timedelta = ndelta;
tickdelta = ntickdelta;
splx(s);
if (SCARG(uap, olddelta)) {
atv.tv_sec = odelta / 1000000;
atv.tv_usec = odelta % 1000000;
(void) copyout((caddr_t)&atv, (caddr_t)SCARG(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 */
int
getitimer(p, uap, retval)
struct proc *p;
register struct getitimer_args /* {
syscallarg(u_int) which;
syscallarg(struct itimerval *) itv;
} */ *uap;
register_t *retval;
{
struct itimerval aitv;
int s;
if (SCARG(uap, which) > ITIMER_PROF)
return (EINVAL);
s = splclock();
if (SCARG(uap, which) == ITIMER_REAL) {
/*
* Convert from absolute 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,
(struct timeval *)&time);
} else
aitv = p->p_stats->p_timer[SCARG(uap, which)];
splx(s);
return (copyout((caddr_t)&aitv, (caddr_t)SCARG(uap, itv),
sizeof (struct itimerval)));
}
/* ARGSUSED */
int
setitimer(p, uap, retval)
struct proc *p;
register struct setitimer_args /* {
syscallarg(u_int) which;
syscallarg(struct itimerval *) itv;
syscallarg(struct itimerval *) oitv;
} */ *uap;
register_t *retval;
{
struct itimerval aitv;
register struct itimerval *itvp;
int s, error;
if (SCARG(uap, which) > ITIMER_PROF)
return (EINVAL);
itvp = SCARG(uap, itv);
if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv,
sizeof(struct itimerval))))
return (error);
if ((SCARG(uap, itv) = SCARG(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 (SCARG(uap, which) == ITIMER_REAL) {
untimeout(realitexpire, (caddr_t)p);
if (timerisset(&aitv.it_value)) {
timevaladd(&aitv.it_value, (struct timeval *)&time);
timeout(realitexpire, (caddr_t)p, hzto(&aitv.it_value));
}
p->p_realtimer = aitv;
} else
p->p_stats->p_timer[SCARG(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.
*/
void
realitexpire(arg)
void *arg;
{
register struct proc *p;
int s;
p = (struct proc *)arg;
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.)
*/
int
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
* reduce 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.
*/
int
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.