xnu-3789.60.24.tar.gz

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

/*
 * Copyright (c) 2000-2008 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The 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, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_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
 */
/*
 * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
 * support for mandatory and extensible security protections.  This notice
 * is included in support of clause 2.2 (b) of the Apple Public License,
 * Version 2.0.
 */

#include <sys/param.h>
#include <sys/resourcevar.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/proc_internal.h>
#include <sys/kauth.h>
#include <sys/vnode.h>
#include <sys/time.h>
#include <sys/priv.h>

#include <sys/mount_internal.h>
#include <sys/sysproto.h>
#include <sys/signalvar.h>
#include <sys/protosw.h> /* for net_uptime2timeval() */

#include <kern/clock.h>
#include <kern/task.h>
#include <kern/thread_call.h>
#if CONFIG_MACF
#include <security/mac_framework.h>
#endif

#define HZ      100     /* XXX */

/* simple lock used to access timezone, tz structure */
lck_spin_t * tz_slock;
lck_grp_t * tz_slock_grp;
lck_attr_t * tz_slock_attr;
lck_grp_attr_t  *tz_slock_grp_attr;

static void             setthetime(
                                        struct timeval  *tv);

void time_zone_slock_init(void);

/*
 * 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(
                        struct proc     *p,
                        struct gettimeofday_args *uap,
                        __unused int32_t *retval)
{
        int error = 0;
        struct timezone ltz; /* local copy */
        clock_sec_t secs;
        clock_usec_t usecs;
        uint64_t mach_time;

        if (uap->tp || uap->mach_absolute_time) {
                clock_gettimeofday_and_absolute_time(&secs, &usecs, &mach_time);
        }

        if (uap->tp) {
                /* Casting secs through a uint32_t to match arm64 commpage */
                if (IS_64BIT_PROCESS(p)) {
                        struct user64_timeval user_atv = {};
                        user_atv.tv_sec = (uint32_t)secs;
                        user_atv.tv_usec = usecs;
                        error = copyout(&user_atv, uap->tp, sizeof(user_atv));
                } else {
                        struct user32_timeval user_atv = {};
                        user_atv.tv_sec = (uint32_t)secs;
                        user_atv.tv_usec = usecs;
                        error = copyout(&user_atv, uap->tp, sizeof(user_atv));
                }
                if (error) {
                        return error;
                }
        }

        if (uap->tzp) {
                lck_spin_lock(tz_slock);
                ltz = tz;
                lck_spin_unlock(tz_slock);

                error = copyout((caddr_t)&ltz, CAST_USER_ADDR_T(uap->tzp), sizeof(tz));
        }

        if (error == 0 && uap->mach_absolute_time) {
                error = copyout(&mach_time, uap->mach_absolute_time, sizeof(mach_time));
        }

        return error;
}

/*
 * XXX Y2038 bug because of setthetime() argument
 */
/* ARGSUSED */
int
settimeofday(__unused struct proc *p, struct settimeofday_args  *uap, __unused int32_t *retval)
{
        struct timeval atv;
        struct timezone atz;
        int error;

        bzero(&atv, sizeof(atv));

#if CONFIG_MACF
        error = mac_system_check_settime(kauth_cred_get());
        if (error)
                return (error);
#endif
        if ((error = suser(kauth_cred_get(), &p->p_acflag)))
                return (error);
        /* Verify all parameters before changing time */
        if (uap->tv) {
                if (IS_64BIT_PROCESS(p)) {
                        struct user64_timeval user_atv;
                        error = copyin(uap->tv, &user_atv, sizeof(user_atv));
                        atv.tv_sec = user_atv.tv_sec;
                        atv.tv_usec = user_atv.tv_usec;
                } else {
                        struct user32_timeval user_atv;
                        error = copyin(uap->tv, &user_atv, sizeof(user_atv));
                        atv.tv_sec = user_atv.tv_sec;
                        atv.tv_usec = user_atv.tv_usec;
                }
                if (error)
                        return (error);
        }
        if (uap->tzp && (error = copyin(uap->tzp, (caddr_t)&atz, sizeof(atz))))
                return (error);
        if (uap->tv) {
                timevalfix(&atv);
                if (atv.tv_sec < 0 || (atv.tv_sec == 0 && atv.tv_usec < 0))
                        return (EPERM);
                setthetime(&atv);
        }
        if (uap->tzp) {
                lck_spin_lock(tz_slock);
                tz = atz;
                lck_spin_unlock(tz_slock);
        }
        return (0);
}

static void
setthetime(
        struct timeval  *tv)
{
        clock_set_calendar_microtime(tv->tv_sec, tv->tv_usec);
}

/*
 * XXX Y2038 bug because of clock_adjtime() first argument
 */
/* ARGSUSED */
int
adjtime(struct proc *p, struct adjtime_args *uap, __unused int32_t *retval)
{
        struct timeval atv;
        int error;

#if CONFIG_MACF
        error = mac_system_check_settime(kauth_cred_get());
        if (error)
                return (error);
#endif
        if ((error = priv_check_cred(kauth_cred_get(), PRIV_ADJTIME, 0)))
                return (error);
        if (IS_64BIT_PROCESS(p)) {
                struct user64_timeval user_atv;
                error = copyin(uap->delta, &user_atv, sizeof(user_atv));
                atv.tv_sec = user_atv.tv_sec;
                atv.tv_usec = user_atv.tv_usec;
        } else {
                struct user32_timeval user_atv;
                error = copyin(uap->delta, &user_atv, sizeof(user_atv));
                atv.tv_sec = user_atv.tv_sec;
                atv.tv_usec = user_atv.tv_usec;
        }
        if (error)
                return (error);
                
        /*
         * Compute the total correction and the rate at which to apply it.
         */
        clock_adjtime(&atv.tv_sec, &atv.tv_usec);

        if (uap->olddelta) {
                if (IS_64BIT_PROCESS(p)) {
                        struct user64_timeval user_atv;
                        user_atv.tv_sec = atv.tv_sec;
                        user_atv.tv_usec = atv.tv_usec;
                        error = copyout(&user_atv, uap->olddelta, sizeof(user_atv));
                } else {
                        struct user32_timeval user_atv;
                        user_atv.tv_sec = atv.tv_sec;
                        user_atv.tv_usec = atv.tv_usec;
                        error = copyout(&user_atv, uap->olddelta, sizeof(user_atv));
                }
        }

        return (0);
}

/*
 *      Verify the calendar value.  If negative,
 *      reset to zero (the epoch).
 */
void
inittodr(
        __unused time_t base)
{
        struct timeval  tv;

        /*
         * Assertion:
         * The calendar has already been
         * set up from the platform clock.
         *
         * The value returned by microtime()
         * is gotten from the calendar.
         */
        microtime(&tv);

        if (tv.tv_sec < 0 || tv.tv_usec < 0) {
                printf ("WARNING: preposterous time in Real Time Clock");
                tv.tv_sec = 0;          /* the UNIX epoch */
                tv.tv_usec = 0;
                setthetime(&tv);
                printf(" -- CHECK AND RESET THE DATE!\n");
        }
}

time_t
boottime_sec(void)
{
        clock_sec_t             secs;
        clock_nsec_t    nanosecs;

        clock_get_boottime_nanotime(&secs, &nanosecs);
        return (secs);
}

void
boottime_timeval(struct timeval *tv)
{
        clock_sec_t             secs;
        clock_usec_t    microsecs;

        clock_get_boottime_microtime(&secs, &microsecs);

        tv->tv_sec = secs;
        tv->tv_usec = microsecs;
}

/*
 * Get value of an interval timer.  The process virtual and
 * profiling virtual time timers are kept internally in the
 * way they are specified externally: in time until they expire.
 *
 * The real time interval timer expiration time (p_rtime)
 * is kept as an absolute time rather than as a delta, so that
 * it is easy to keep periodic real-time signals from drifting.
 *
 * The real time timer is processed by a callout routine.
 * Since a callout may be delayed in real time due to
 * other processing in the system, it is possible for the real
 * time callout 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 time .it_value from the
 * real time .it_interval.  Rather, we compute the next time in
 * absolute time when the timer should go off.
 *
 * Returns:     0                       Success
 *              EINVAL                  Invalid argument
 *      copyout:EFAULT                  Bad address
 */
/* ARGSUSED */
int
getitimer(struct proc *p, struct getitimer_args *uap, __unused int32_t *retval)
{
        struct itimerval aitv;

        if (uap->which > ITIMER_PROF)
                return(EINVAL);

        bzero(&aitv, sizeof(aitv));

        proc_spinlock(p);
        switch (uap->which) {

        case ITIMER_REAL:
                /*
                 * 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(&p->p_rtime)) {
                        struct timeval          now;

                        microuptime(&now);
                        if (timercmp(&p->p_rtime, &now, <))
                                timerclear(&aitv.it_value);
                        else {
                                aitv.it_value = p->p_rtime;
                                timevalsub(&aitv.it_value, &now);
                        }
                }
                else
                        timerclear(&aitv.it_value);
                break;

        case ITIMER_VIRTUAL:
                aitv = p->p_vtimer_user;
                break;

        case ITIMER_PROF:
                aitv = p->p_vtimer_prof;
                break;
        }

        proc_spinunlock(p);

        if (IS_64BIT_PROCESS(p)) {
                struct user64_itimerval user_itv;
                bzero(&user_itv, sizeof (user_itv));
                user_itv.it_interval.tv_sec = aitv.it_interval.tv_sec;
                user_itv.it_interval.tv_usec = aitv.it_interval.tv_usec;
                user_itv.it_value.tv_sec = aitv.it_value.tv_sec;
                user_itv.it_value.tv_usec = aitv.it_value.tv_usec;
                return (copyout((caddr_t)&user_itv, uap->itv, sizeof (user_itv)));
        } else {
                struct user32_itimerval user_itv;
                bzero(&user_itv, sizeof (user_itv));            
                user_itv.it_interval.tv_sec = aitv.it_interval.tv_sec;
                user_itv.it_interval.tv_usec = aitv.it_interval.tv_usec;
                user_itv.it_value.tv_sec = aitv.it_value.tv_sec;
                user_itv.it_value.tv_usec = aitv.it_value.tv_usec;
                return (copyout((caddr_t)&user_itv, uap->itv, sizeof (user_itv)));
        }
}

/*
 * Returns:     0                       Success
 *              EINVAL                  Invalid argument
 *      copyin:EFAULT                   Bad address
 *      getitimer:EINVAL                Invalid argument
 *      getitimer:EFAULT                Bad address
 */
/* ARGSUSED */
int
setitimer(struct proc *p, struct setitimer_args *uap, int32_t *retval)
{
        struct itimerval aitv;
        user_addr_t itvp;
        int error;

        bzero(&aitv, sizeof(aitv));

        if (uap->which > ITIMER_PROF)
                return (EINVAL);
        if ((itvp = uap->itv)) {
                if (IS_64BIT_PROCESS(p)) {
                        struct user64_itimerval user_itv;
                        if ((error = copyin(itvp, (caddr_t)&user_itv, sizeof (user_itv))))
                                return (error);
                        aitv.it_interval.tv_sec = user_itv.it_interval.tv_sec;
                        aitv.it_interval.tv_usec = user_itv.it_interval.tv_usec;
                        aitv.it_value.tv_sec = user_itv.it_value.tv_sec;
                        aitv.it_value.tv_usec = user_itv.it_value.tv_usec;
                } else { 
                        struct user32_itimerval user_itv;
                        if ((error = copyin(itvp, (caddr_t)&user_itv, sizeof (user_itv))))
                                return (error);
                        aitv.it_interval.tv_sec = user_itv.it_interval.tv_sec;
                        aitv.it_interval.tv_usec = user_itv.it_interval.tv_usec;
                        aitv.it_value.tv_sec = user_itv.it_value.tv_sec;
                        aitv.it_value.tv_usec = user_itv.it_value.tv_usec;
                }
        }
        if ((uap->itv = uap->oitv) && (error = getitimer(p, (struct getitimer_args *)uap, retval)))
                return (error);
        if (itvp == 0)
                return (0);
        if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval))
                return (EINVAL);

        switch (uap->which) {

        case ITIMER_REAL:
                proc_spinlock(p);
                if (timerisset(&aitv.it_value)) {
                        microuptime(&p->p_rtime);
                        timevaladd(&p->p_rtime, &aitv.it_value);
                        p->p_realtimer = aitv;
                        if (!thread_call_enter_delayed_with_leeway(p->p_rcall, NULL,
                                                 tvtoabstime(&p->p_rtime), 0, THREAD_CALL_DELAY_USER_NORMAL))
                                p->p_ractive++;
                } else  {
                        timerclear(&p->p_rtime);
                        p->p_realtimer = aitv;
                        if (thread_call_cancel(p->p_rcall))
                                p->p_ractive--;
                }
                proc_spinunlock(p);

                break;


        case ITIMER_VIRTUAL:
                if (timerisset(&aitv.it_value))
                        task_vtimer_set(p->task, TASK_VTIMER_USER);
        else
                        task_vtimer_clear(p->task, TASK_VTIMER_USER);

                proc_spinlock(p);
                p->p_vtimer_user = aitv;
                proc_spinunlock(p);
                break;

        case ITIMER_PROF:
                if (timerisset(&aitv.it_value))
                        task_vtimer_set(p->task, TASK_VTIMER_PROF);
                else
                        task_vtimer_clear(p->task, TASK_VTIMER_PROF);

                proc_spinlock(p);
                p->p_vtimer_prof = aitv;
                proc_spinunlock(p);
                break;
        }

        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(
        struct proc *p)
{
        struct proc *r;
        struct timeval t;

        r = proc_find(p->p_pid);

        proc_spinlock(p);

        assert(p->p_ractive > 0);

        if (--p->p_ractive > 0 || r != p) {
                /*
                 * bail, because either proc is exiting
                 * or there's another active thread call
                 */
                proc_spinunlock(p);

                if (r != NULL)
                        proc_rele(r);
                return;
        }

        if (!timerisset(&p->p_realtimer.it_interval)) {
                /*
                 * p_realtimer was cleared while this call was pending,
                 * send one last SIGALRM, but don't re-arm
                 */
                timerclear(&p->p_rtime);
                proc_spinunlock(p);

                psignal(p, SIGALRM);
                proc_rele(p);
                return;
        }

        proc_spinunlock(p);

        /*
         * Send the signal before re-arming the next thread call,
         * so in case psignal blocks, we won't create yet another thread call.
         */

        psignal(p, SIGALRM);

        proc_spinlock(p);

        /* Should we still re-arm the next thread call? */
        if (!timerisset(&p->p_realtimer.it_interval)) {
                timerclear(&p->p_rtime);
                proc_spinunlock(p);

                proc_rele(p);
                return;
        }

        microuptime(&t);
        timevaladd(&p->p_rtime, &p->p_realtimer.it_interval);

        if (timercmp(&p->p_rtime, &t, <=)) {
                if ((p->p_rtime.tv_sec + 2) >= t.tv_sec) {
                        for (;;) {
                                timevaladd(&p->p_rtime, &p->p_realtimer.it_interval);
                                if (timercmp(&p->p_rtime, &t, >))
                                        break;
                        }
                } else {
                        p->p_rtime = p->p_realtimer.it_interval;
                        timevaladd(&p->p_rtime, &t);
                }
        }

        assert(p->p_rcall != NULL);

        if (!thread_call_enter_delayed_with_leeway(p->p_rcall, NULL, tvtoabstime(&p->p_rtime), 0,
                                                   THREAD_CALL_DELAY_USER_NORMAL)) {
                p->p_ractive++;
        }

        proc_spinunlock(p);

        proc_rele(p);
}

/*
 * Called once in proc_exit to clean up after an armed or pending realitexpire
 *
 * This will only be called after the proc refcount is drained,
 * so realitexpire cannot be currently holding a proc ref.
 * i.e. it will/has gotten PROC_NULL from proc_find.
 */
void
proc_free_realitimer(proc_t p)
{
        proc_spinlock(p);

        assert(p->p_rcall != NULL);
        assert(p->p_refcount == 0);

        timerclear(&p->p_realtimer.it_interval);

        if (thread_call_cancel(p->p_rcall)) {
                assert(p->p_ractive > 0);
                p->p_ractive--;
        }

        while (p->p_ractive > 0) {
                proc_spinunlock(p);

                delay(1);

                proc_spinlock(p);
        }

        thread_call_t call = p->p_rcall;
        p->p_rcall = NULL;

        proc_spinunlock(p);

        thread_call_free(call);
}

/*
 * Check that a proposed value to load into the .it_value or
 * .it_interval part of an interval timer is acceptable.
 */
int
itimerfix(
        struct timeval *tv)
{

        if (tv->tv_sec < 0 || tv->tv_sec > 100000000 ||
            tv->tv_usec < 0 || tv->tv_usec >= 1000000)
                return (EINVAL);
        return (0);
}

int
timespec_is_valid(const struct timespec *ts)
{
        /* The INT32_MAX limit ensures the timespec is safe for clock_*() functions
         * which accept 32-bit ints. */
        if (ts->tv_sec < 0 || ts->tv_sec > INT32_MAX ||
                        ts->tv_nsec < 0 || (unsigned long long)ts->tv_nsec > NSEC_PER_SEC) {
                return 0;
        }
        return 1;
}

/*
 * 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(proc_t p,
        struct itimerval *itp, int usec)
{

        proc_spinlock(p);
        
        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)) {
                proc_spinunlock(p);
                return (1);
        }
        /* expired, exactly at end of interval */
expire:
        if (timerisset(&itp->it_interval)) {
                itp->it_value = itp->it_interval;
                if (itp->it_value.tv_sec > 0) {
                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 */
        proc_spinunlock(p);
        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(
        struct timeval *t1,
        struct timeval *t2)
{

        t1->tv_sec += t2->tv_sec;
        t1->tv_usec += t2->tv_usec;
        timevalfix(t1);
}
void
timevalsub(
        struct timeval *t1,
        struct timeval *t2)
{

        t1->tv_sec -= t2->tv_sec;
        t1->tv_usec -= t2->tv_usec;
        timevalfix(t1);
}
void
timevalfix(
        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)
{
        clock_sec_t             tv_sec;
        clock_usec_t    tv_usec;

        clock_get_calendar_microtime(&tv_sec, &tv_usec);

        tvp->tv_sec = tv_sec;
        tvp->tv_usec = tv_usec;
}

void
microtime_with_abstime(
        struct timeval  *tvp, uint64_t *abstime)
{
        clock_sec_t             tv_sec;
        clock_usec_t    tv_usec;

        clock_get_calendar_absolute_and_microtime(&tv_sec, &tv_usec, abstime);

        tvp->tv_sec = tv_sec;
        tvp->tv_usec = tv_usec;
}

void
microuptime(
        struct timeval  *tvp)
{
        clock_sec_t             tv_sec;
        clock_usec_t    tv_usec;

        clock_get_system_microtime(&tv_sec, &tv_usec);

        tvp->tv_sec = tv_sec;
        tvp->tv_usec = tv_usec;
}

/*
 * Ditto for timespec.
 */
void
nanotime(
        struct timespec *tsp)
{
        clock_sec_t             tv_sec;
        clock_nsec_t    tv_nsec;

        clock_get_calendar_nanotime(&tv_sec, &tv_nsec);

        tsp->tv_sec = tv_sec;
        tsp->tv_nsec = tv_nsec;
}

void
nanouptime(
        struct timespec *tsp)
{
        clock_sec_t             tv_sec;
        clock_nsec_t    tv_nsec;

        clock_get_system_nanotime(&tv_sec, &tv_nsec);

        tsp->tv_sec = tv_sec;
        tsp->tv_nsec = tv_nsec;
}

uint64_t
tvtoabstime(
        struct timeval  *tvp)
{
        uint64_t        result, usresult;

        clock_interval_to_absolutetime_interval(
                                                tvp->tv_sec, NSEC_PER_SEC, &result);
        clock_interval_to_absolutetime_interval(
                                                tvp->tv_usec, NSEC_PER_USEC, &usresult);

        return (result + usresult);
}

uint64_t
tstoabstime(struct timespec *ts)
{
        uint64_t abstime_s, abstime_ns;
        clock_interval_to_absolutetime_interval(ts->tv_sec, NSEC_PER_SEC, &abstime_s);
        clock_interval_to_absolutetime_interval(ts->tv_nsec, 1, &abstime_ns);
        return abstime_s + abstime_ns;
}

#if NETWORKING
/*
 * ratecheck(): simple time-based rate-limit checking.
 */
int
ratecheck(struct timeval *lasttime, const struct timeval *mininterval)
{
        struct timeval tv, delta;
        int rv = 0;

        net_uptime2timeval(&tv);
        delta = tv;
        timevalsub(&delta, lasttime);

        /*
         * check for 0,0 is so that the message will be seen at least once,
         * even if interval is huge.
         */
        if (timevalcmp(&delta, mininterval, >=) ||
            (lasttime->tv_sec == 0 && lasttime->tv_usec == 0)) {
                *lasttime = tv;
                rv = 1;
        }

        return (rv);
}

/*
 * ppsratecheck(): packets (or events) per second limitation.
 */
int
ppsratecheck(struct timeval *lasttime, int *curpps, int maxpps)
{
        struct timeval tv, delta;
        int rv;

        net_uptime2timeval(&tv);

        timersub(&tv, lasttime, &delta);

        /*
         * Check for 0,0 so that the message will be seen at least once.
         * If more than one second has passed since the last update of
         * lasttime, reset the counter.
         *
         * we do increment *curpps even in *curpps < maxpps case, as some may
         * try to use *curpps for stat purposes as well.
         */
        if ((lasttime->tv_sec == 0 && lasttime->tv_usec == 0) ||
            delta.tv_sec >= 1) {
                *lasttime = tv;
                *curpps = 0;
                rv = 1;
        } else if (maxpps < 0)
                rv = 1;
        else if (*curpps < maxpps)
                rv = 1;
        else
                rv = 0;

#if 1 /* DIAGNOSTIC? */
        /* be careful about wrap-around */
        if (*curpps + 1 > 0)
                *curpps = *curpps + 1;
#else
        /*
         * assume that there's not too many calls to this function.
         * not sure if the assumption holds, as it depends on *caller's*
         * behavior, not the behavior of this function.
         * IMHO it is wrong to make assumption on the caller's behavior,
         * so the above #if is #if 1, not #ifdef DIAGNOSTIC.
         */
        *curpps = *curpps + 1;
#endif

        return (rv);
}
#endif /* NETWORKING */

void
time_zone_slock_init(void)
{
        /* allocate lock group attribute and group */
        tz_slock_grp_attr = lck_grp_attr_alloc_init();

        tz_slock_grp =  lck_grp_alloc_init("tzlock", tz_slock_grp_attr);

        /* Allocate lock attribute */
        tz_slock_attr = lck_attr_alloc_init();

        /* Allocate the spin lock */
        tz_slock = lck_spin_alloc_init(tz_slock_grp, tz_slock_attr);
}