[apple/xnu.git] / bsd / kern / kern_time.c

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
/*
 * 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 <kern/cpu_number.h>

#include <kern/clock.h>

#define HZ      100     /* XXX */

struct timeval          time;

/* 
 * 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.
 */
struct gettimeofday_args{
        struct timeval *tp;
        struct timezone *tzp;
};
/* ARGSUSED */
int
gettimeofday(p, uap, retval)
        struct proc *p;
        register struct gettimeofday_args *uap;
        register_t *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);
}

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

        if (error = suser(p->p_ucred, &p->p_acflag))
                return (error);
        /* Verify all parameters before changing time. */
        if (uap->tv && (error = copyin((caddr_t)uap->tv,
            (caddr_t)&atv, sizeof(atv))))
                return (error);
        if (uap->tzp && (error = copyin((caddr_t)uap->tzp,
            (caddr_t)&atz, sizeof(atz))))
                return (error);
        if (uap->tv)
                setthetime(&atv);
        if (uap->tzp)
                tz = atz;
        return (0);
}

setthetime(tv)
        struct timeval *tv;
{
        mach_timespec_t now;
        long delta;
        int s;

        now.tv_sec = tv->tv_sec;
        now.tv_nsec = tv->tv_usec * NSEC_PER_USEC;

        clock_set_calendar_value(now);
        delta = tv->tv_sec - time.tv_sec;
        boottime.tv_sec += delta;
#if NFSCLIENT || NFSSERVER
        lease_updatetime(delta);
#endif
        s = splhigh();
        microtime(&time);
        splx(s);
}

int     tickadj = 240000 / (60 * HZ);   /* "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. */

struct adjtime_args {
        struct timeval *delta;
        struct timeval *olddelta;
};
/* ARGSUSED */
int
adjtime(p, uap, retval)
        struct proc *p;
        register struct adjtime_args *uap;
        register_t *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 / tickdelta * tickdelta;

        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);
}

#define SECDAY          ((unsigned)(24*60*60))          /* seconds per day */
#define SECYR           ((unsigned)(365*SECDAY))        /* per common year */
#define YRREF           70      /* UNIX time referenced to 1970 */

/*
 * Initialze the time of day register. 
 * Trust the RTC except for the case where it is set before 
 * the UNIX epoch. In that case use the the UNIX epoch.
 * The argument passed in is ignored.
 */
void
inittodr(base)
        time_t base;
{
        /*
         * Initialize the calendar by
         * reading the BBC, if not already set.
         */
        clock_initialize_calendar();

        /*
         * The value returned by microtime()
         * is gotten from the calendar.
         */
        microtime(&time);

        /*
         * This variable still exists to keep
         * 'w' happy.  It should only be considered
         * an approximation.
         */
        boottime.tv_sec = time.tv_sec;
        boottime.tv_usec = 0;

        /*
         * If the RTC does not have acceptable value, i.e. time before
         * the UNIX epoch, set it to the UNIX epoch
         */
        if (time.tv_sec < 0) {
                printf ("WARNING: preposterous time in Real Time Clock");
                time.tv_sec = 0;        /* the UNIX epoch */
                time.tv_usec = 0;
                setthetime(&time);
                boottime = time;
                printf(" -- CHECK AND RESET THE DATE!\n");
        }

        return;
}

/*
 * 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.
 */
 
struct getitimer_args {
        u_int   which;
        struct itimerval *itv;
}; 
/* ARGSUSED */
int
getitimer(p, uap, retval)
        struct proc *p;
        register struct getitimer_args *uap;
        register_t *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)));
}

struct setitimer_args {
        u_int   which;
        struct  itimerval *itv;
        struct  itimerval *oitv;
};
/* ARGSUSED */
int
setitimer(p, uap, retval)
        struct proc *p;
        register struct setitimer_args *uap;
        register_t *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); /* To insure good return value on success */
}

/*
 * 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;
        boolean_t       funnel_state;

        funnel_state = thread_funnel_set(kernel_flock,TRUE);

        p = (struct proc *)arg;
        psignal(p, SIGALRM);
        if (!timerisset(&p->p_realtimer.it_interval)) {
                timerclear(&p->p_realtimer.it_value);
                (void) thread_funnel_set(kernel_flock, FALSE);
                return;
        }
        
        /*
         * If the time's way off, don't try to compensate by getting
         * there incrementally.
         */
        s = splclock();
        if (p->p_realtimer.it_value.tv_sec < time.tv_sec - 10) {
                p->p_realtimer.it_value = time;
                timeout(realitexpire, (caddr_t)p,
                        hzto(&p->p_realtimer.it_value));
                splx(s);
                (void) thread_funnel_set(kernel_flock, FALSE);
                return;
                
        }
        splx(s);

        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);
                        (void) thread_funnel_set(kernel_flock, FALSE);
                        return;
                }
                splx(s);
        }
        
        (void) thread_funnel_set(kernel_flock, FALSE);
}

/*
 * 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
 * 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.
 */
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.
 */
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);
}
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;
        }
}

/*
 * Return the best possible estimate of the time in the timeval
 * to which tvp points.
 */
void
microtime(struct timeval * tvp)
{
        mach_timespec_t         now = clock_get_calendar_value();

        tvp->tv_sec = now.tv_sec;
        tvp->tv_usec = now.tv_nsec / NSEC_PER_USEC;
}