freebsd-dev/sys/kern/kern_time.c

646 lines
16 KiB
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 8.1 (Berkeley) 6/10/93
* $Id: kern_time.c,v 1.60 1999/01/27 21:49:56 dillon Exp $
*/
#include <sys/param.h>
#include <sys/buf.h>
#include <sys/sysproto.h>
#include <sys/resourcevar.h>
#include <sys/signalvar.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/sysent.h>
#include <sys/proc.h>
#include <sys/time.h>
#include <sys/vnode.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
struct timezone tz;
/*
* 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.
*/
static int nanosleep1 __P((struct proc *p, struct timespec *rqt,
struct timespec *rmt));
static int settime __P((struct timeval *));
static void timevalfix __P((struct timeval *));
static void no_lease_updatetime __P((int));
static void
no_lease_updatetime(deltat)
int deltat;
{
}
void (*lease_updatetime) __P((int)) = no_lease_updatetime;
static int
settime(tv)
struct timeval *tv;
{
struct timeval delta, tv1;
struct timespec ts;
int s;
s = splclock();
microtime(&tv1);
delta = *tv;
timevalsub(&delta, &tv1);
/*
* 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 (delta.tv_sec < 0 && securelevel > 1) {
splx(s);
return (EPERM);
}
ts.tv_sec = tv->tv_sec;
ts.tv_nsec = tv->tv_usec * 1000;
set_timecounter(&ts);
(void) splsoftclock();
lease_updatetime(delta.tv_sec);
splx(s);
resettodr();
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct clock_gettime_args {
clockid_t clock_id;
struct timespec *tp;
};
#endif
/* ARGSUSED */
int
clock_gettime(p, uap)
struct proc *p;
struct clock_gettime_args *uap;
{
struct timespec ats;
if (SCARG(uap, clock_id) != CLOCK_REALTIME)
return (EINVAL);
nanotime(&ats);
return (copyout(&ats, SCARG(uap, tp), sizeof(ats)));
}
#ifndef _SYS_SYSPROTO_H_
struct clock_settime_args {
clockid_t clock_id;
const struct timespec *tp;
};
#endif
/* ARGSUSED */
int
clock_settime(p, uap)
struct proc *p;
struct clock_settime_args *uap;
{
struct timeval atv;
struct timespec ats;
int error;
if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
return (error);
if (SCARG(uap, clock_id) != CLOCK_REALTIME)
return (EINVAL);
if ((error = copyin(SCARG(uap, tp), &ats, sizeof(ats))) != 0)
return (error);
if (ats.tv_nsec < 0 || ats.tv_nsec >= 1000000000)
return (EINVAL);
/* XXX Don't convert nsec->usec and back */
TIMESPEC_TO_TIMEVAL(&atv, &ats);
if ((error = settime(&atv)))
return (error);
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct clock_getres_args {
clockid_t clock_id;
struct timespec *tp;
};
#endif
int
clock_getres(p, uap)
struct proc *p;
struct clock_getres_args *uap;
{
struct timespec ts;
int error;
if (SCARG(uap, clock_id) != CLOCK_REALTIME)
return (EINVAL);
error = 0;
if (SCARG(uap, tp)) {
ts.tv_sec = 0;
ts.tv_nsec = 1000000000 / timecounter->tc_frequency;
error = copyout(&ts, SCARG(uap, tp), sizeof(ts));
}
return (error);
}
static int nanowait;
static int
nanosleep1(p, rqt, rmt)
struct proc *p;
struct timespec *rqt, *rmt;
{
struct timespec ts, ts2, ts3;
struct timeval tv;
int error;
if (rqt->tv_nsec < 0 || rqt->tv_nsec >= 1000000000)
return (EINVAL);
if (rqt->tv_sec < 0 || (rqt->tv_sec == 0 && rqt->tv_nsec == 0))
return (0);
getnanouptime(&ts);
timespecadd(&ts, rqt);
TIMESPEC_TO_TIMEVAL(&tv, rqt);
for (;;) {
error = tsleep(&nanowait, PWAIT | PCATCH, "nanslp",
tvtohz(&tv));
getnanouptime(&ts2);
if (error != EWOULDBLOCK) {
if (error == ERESTART)
error = EINTR;
if (rmt != NULL) {
timespecsub(&ts, &ts2);
if (ts.tv_sec < 0)
timespecclear(&ts);
*rmt = ts;
}
return (error);
}
if (timespeccmp(&ts2, &ts, >=))
return (0);
ts3 = ts;
timespecsub(&ts3, &ts2);
TIMESPEC_TO_TIMEVAL(&tv, &ts3);
}
}
#ifndef _SYS_SYSPROTO_H_
struct nanosleep_args {
struct timespec *rqtp;
struct timespec *rmtp;
};
#endif
/* ARGSUSED */
int
nanosleep(p, uap)
struct proc *p;
struct nanosleep_args *uap;
{
struct timespec rmt, rqt;
int error, error2;
error = copyin(SCARG(uap, rqtp), &rqt, sizeof(rqt));
if (error)
return (error);
if (SCARG(uap, rmtp))
if (!useracc((caddr_t)SCARG(uap, rmtp), sizeof(rmt), B_WRITE))
return (EFAULT);
error = nanosleep1(p, &rqt, &rmt);
if (error && SCARG(uap, rmtp)) {
error2 = copyout(&rmt, SCARG(uap, rmtp), sizeof(rmt));
if (error2) /* XXX shouldn't happen, did useracc() above */
return (error2);
}
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct gettimeofday_args {
struct timeval *tp;
struct timezone *tzp;
};
#endif
/* ARGSUSED */
int
gettimeofday(p, uap)
struct proc *p;
register struct gettimeofday_args *uap;
{
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);
}
#ifndef _SYS_SYSPROTO_H_
struct settimeofday_args {
struct timeval *tv;
struct timezone *tzp;
};
#endif
/* ARGSUSED */
int
settimeofday(p, uap)
struct proc *p;
struct settimeofday_args *uap;
{
struct timeval atv;
struct timezone atz;
int error;
if ((error = suser(p->p_ucred, &p->p_acflag)))
return (error);
/* Verify all parameters before changing time. */
if (uap->tv) {
if ((error = copyin((caddr_t)uap->tv, (caddr_t)&atv,
sizeof(atv))))
return (error);
if (atv.tv_usec < 0 || atv.tv_usec >= 1000000)
return (EINVAL);
}
if (uap->tzp &&
(error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, sizeof(atz))))
return (error);
if (uap->tv && (error = settime(&atv)))
return (error);
if (uap->tzp)
tz = atz;
return (0);
}
int tickdelta; /* current clock skew, us. per tick */
long timedelta; /* unapplied time correction, us. */
static long bigadj = 1000000; /* use 10x skew above bigadj us. */
#ifndef _SYS_SYSPROTO_H_
struct adjtime_args {
struct timeval *delta;
struct timeval *olddelta;
};
#endif
/* ARGSUSED */
int
adjtime(p, uap)
struct proc *p;
register struct adjtime_args *uap;
{
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)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 || 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 (uap->olddelta) {
atv.tv_sec = odelta / 1000000;
atv.tv_usec = odelta % 1000000;
(void) copyout((caddr_t)&atv, (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.
*/
#ifndef _SYS_SYSPROTO_H_
struct getitimer_args {
u_int which;
struct itimerval *itv;
};
#endif
/* ARGSUSED */
int
getitimer(p, uap)
struct proc *p;
register struct getitimer_args *uap;
{
struct timeval ctv;
struct itimerval aitv;
int s;
if (uap->which > ITIMER_PROF)
return (EINVAL);
s = splclock(); /* XXX still needed ? */
if (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 (timevalisset(&aitv.it_value)) {
getmicrouptime(&ctv);
if (timevalcmp(&aitv.it_value, &ctv, <))
timevalclear(&aitv.it_value);
else
timevalsub(&aitv.it_value, &ctv);
}
} else
aitv = p->p_stats->p_timer[uap->which];
splx(s);
return (copyout((caddr_t)&aitv, (caddr_t)uap->itv,
sizeof (struct itimerval)));
}
#ifndef _SYS_SYSPROTO_H_
struct setitimer_args {
u_int which;
struct itimerval *itv, *oitv;
};
#endif
/* ARGSUSED */
int
setitimer(p, uap)
struct proc *p;
register struct setitimer_args *uap;
{
struct itimerval aitv;
struct timeval ctv;
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, (struct getitimer_args *)uap)))
return (error);
if (itvp == 0)
return (0);
if (itimerfix(&aitv.it_value))
return (EINVAL);
if (!timevalisset(&aitv.it_value))
timevalclear(&aitv.it_interval);
else if (itimerfix(&aitv.it_interval))
return (EINVAL);
s = splclock(); /* XXX: still needed ? */
if (uap->which == ITIMER_REAL) {
if (timevalisset(&p->p_realtimer.it_value))
untimeout(realitexpire, (caddr_t)p, p->p_ithandle);
if (timevalisset(&aitv.it_value))
p->p_ithandle = timeout(realitexpire, (caddr_t)p,
tvtohz(&aitv.it_value));
getmicrouptime(&ctv);
timevaladd(&aitv.it_value, &ctv);
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.
* tvtohz() always adds 1 to allow for the time until the next clock
* interrupt being strictly less than 1 clock tick, but we don't want
* that here since we want to appear to be in sync with the clock
* interrupt even when we're delayed.
*/
void
realitexpire(arg)
void *arg;
{
register struct proc *p;
struct timeval ctv, ntv;
int s;
p = (struct proc *)arg;
psignal(p, SIGALRM);
if (!timevalisset(&p->p_realtimer.it_interval)) {
timevalclear(&p->p_realtimer.it_value);
return;
}
for (;;) {
s = splclock(); /* XXX: still neeeded ? */
timevaladd(&p->p_realtimer.it_value,
&p->p_realtimer.it_interval);
getmicrouptime(&ctv);
if (timevalcmp(&p->p_realtimer.it_value, &ctv, >)) {
ntv = p->p_realtimer.it_value;
timevalsub(&ntv, &ctv);
p->p_ithandle = timeout(realitexpire, (caddr_t)p,
tvtohz(&ntv) - 1);
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 (timevalisset(&itp->it_value))
return (1);
/* expired, exactly at end of interval */
expire:
if (timevalisset(&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.
*/
void
timevaladd(t1, t2)
struct timeval *t1, *t2;
{
t1->tv_sec += t2->tv_sec;
t1->tv_usec += t2->tv_usec;
timevalfix(t1);
}
void
timevalsub(t1, t2)
struct timeval *t1, *t2;
{
t1->tv_sec -= t2->tv_sec;
t1->tv_usec -= t2->tv_usec;
timevalfix(t1);
}
static void
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;
}
}