text: /*-
   * SPDX-License-Identifier: BSD-3-Clause
   *
   * 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. 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
   */
  
  #include <sys/cdefs.h>
  __FBSDID("$FreeBSD$");
  
  #include "opt_ktrace.h"
  
  #include <sys/param.h>
  #include <sys/systm.h>
  #include <sys/limits.h>
  #include <sys/clock.h>
  #include <sys/lock.h>
  #include <sys/mutex.h>
  #include <sys/sysproto.h>
  #include <sys/eventhandler.h>
  #include <sys/resourcevar.h>
  #include <sys/signalvar.h>
  #include <sys/kernel.h>
  #include <sys/sleepqueue.h>
  #include <sys/syscallsubr.h>
  #include <sys/sysctl.h>
  #include <sys/sysent.h>
  #include <sys/priv.h>
  #include <sys/proc.h>
  #include <sys/posix4.h>
  #include <sys/time.h>
  #include <sys/timers.h>
  #include <sys/timetc.h>
  #include <sys/vnode.h>
  #ifdef KTRACE
  #include <sys/ktrace.h>
  #endif
  
  #include <vm/vm.h>
  #include <vm/vm_extern.h>
  
  #define MAX_CLOCKS 	(CLOCK_MONOTONIC+1)
  #define CPUCLOCK_BIT		0x80000000
  #define CPUCLOCK_PROCESS_BIT	0x40000000
  #define CPUCLOCK_ID_MASK	(~(CPUCLOCK_BIT|CPUCLOCK_PROCESS_BIT))
  #define MAKE_THREAD_CPUCLOCK(tid)	(CPUCLOCK_BIT|(tid))
  #define MAKE_PROCESS_CPUCLOCK(pid)	\
  	(CPUCLOCK_BIT|CPUCLOCK_PROCESS_BIT|(pid))
  
  static struct kclock	posix_clocks[MAX_CLOCKS];
  static uma_zone_t	itimer_zone = NULL;
  
  /*
   * 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	settime(struct thread *, struct timeval *);
  static void	timevalfix(struct timeval *);
  static int	user_clock_nanosleep(struct thread *td, clockid_t clock_id,
  		    int flags, const struct timespec *ua_rqtp,
  		    struct timespec *ua_rmtp);
  
  static void	itimer_start(void);
  static int	itimer_init(void *, int, int);
  static void	itimer_fini(void *, int);
  static void	itimer_enter(struct itimer *);
  static void	itimer_leave(struct itimer *);
  static struct itimer *itimer_find(struct proc *, int);
  static void	itimers_alloc(struct proc *);
  static void	itimers_event_hook_exec(void *arg, struct proc *p, struct image_params *imgp);
  static void	itimers_event_hook_exit(void *arg, struct proc *p);
  static int	realtimer_create(struct itimer *);
  static int	realtimer_gettime(struct itimer *, struct itimerspec *);
  static int	realtimer_settime(struct itimer *, int,
  			struct itimerspec *, struct itimerspec *);
  static int	realtimer_delete(struct itimer *);
  static void	realtimer_clocktime(clockid_t, struct timespec *);
  static void	realtimer_expire(void *);
  
  int		register_posix_clock(int, struct kclock *);
  void		itimer_fire(struct itimer *it);
  int		itimespecfix(struct timespec *ts);
  
  #define CLOCK_CALL(clock, call, arglist)		\
  	((*posix_clocks[clock].call) arglist)
  
  SYSINIT(posix_timer, SI_SUB_P1003_1B, SI_ORDER_FIRST+4, itimer_start, NULL);
  
  static int
  settime(struct thread *td, struct timeval *tv)
  {
  	struct timeval delta, tv1, tv2;
  	static struct timeval maxtime, laststep;
  	struct timespec ts;
  
  	microtime(&tv1);
  	delta = *tv;
  	timevalsub(&delta, &tv1);
  
  	/*
  	 * If the system is secure, we do not allow the time to be 
  	 * set to a value earlier than 1 second less than the highest
  	 * time we have yet seen. The worst a miscreant can do in
  	 * this circumstance is "freeze" time. He couldn't go
  	 * back to the past.
  	 *
  	 * We similarly do not allow the clock to be stepped more
  	 * than one second, nor more than once per second. This allows
  	 * a miscreant to make the clock march double-time, but no worse.
  	 */
  	if (securelevel_gt(td->td_ucred, 1) != 0) {
  		if (delta.tv_sec < 0 || delta.tv_usec < 0) {
  			/*
  			 * Update maxtime to latest time we've seen.
  			 */
  			if (tv1.tv_sec > maxtime.tv_sec)
  				maxtime = tv1;
  			tv2 = *tv;
  			timevalsub(&tv2, &maxtime);
  			if (tv2.tv_sec < -1) {
  				tv->tv_sec = maxtime.tv_sec - 1;
  				printf("Time adjustment clamped to -1 second\n");
  			}
  		} else {
  			if (tv1.tv_sec == laststep.tv_sec)
  				return (EPERM);
  			if (delta.tv_sec > 1) {
  				tv->tv_sec = tv1.tv_sec + 1;
  				printf("Time adjustment clamped to +1 second\n");
  			}
  			laststep = *tv;
  		}
  	}
  
  	ts.tv_sec = tv->tv_sec;
  	ts.tv_nsec = tv->tv_usec * 1000;
  	tc_setclock(&ts);
  	resettodr();
  	return (0);
  }
  
  #ifndef _SYS_SYSPROTO_H_
  struct clock_getcpuclockid2_args {
  	id_t id;
  	int which,
  	clockid_t *clock_id;
  };
  #endif
  /* ARGSUSED */
  int
  sys_clock_getcpuclockid2(struct thread *td, struct clock_getcpuclockid2_args *uap)
  {
  	clockid_t clk_id;
  	int error;
  
  	error = kern_clock_getcpuclockid2(td, uap->id, uap->which, &clk_id);
  	if (error == 0)
  		error = copyout(&clk_id, uap->clock_id, sizeof(clockid_t));
  	return (error);
  }
  
  int
  kern_clock_getcpuclockid2(struct thread *td, id_t id, int which,
      clockid_t *clk_id)
  {
  	struct proc *p;
  	pid_t pid;
  	lwpid_t tid;
  	int error;
  
  	switch (which) {
  	case CPUCLOCK_WHICH_PID:
  		if (id != 0) {
  			error = pget(id, PGET_CANSEE | PGET_NOTID, &p);
  			if (error != 0)
  				return (error);
  			PROC_UNLOCK(p);
  			pid = id;
  		} else {
  			pid = td->td_proc->p_pid;
  		}
  		*clk_id = MAKE_PROCESS_CPUCLOCK(pid);
  		return (0);
  	case CPUCLOCK_WHICH_TID:
  		tid = id == 0 ? td->td_tid : id;
  		*clk_id = MAKE_THREAD_CPUCLOCK(tid);
  		return (0);
  	default:
  		return (EINVAL);
  	}
  }
  
  #ifndef _SYS_SYSPROTO_H_
  struct clock_gettime_args {
  	clockid_t clock_id;
  	struct	timespec *tp;
  };
  #endif
  /* ARGSUSED */
  int
  sys_clock_gettime(struct thread *td, struct clock_gettime_args *uap)
  {
  	struct timespec ats;
  	int error;
  
  	error = kern_clock_gettime(td, uap->clock_id, &ats);
  	if (error == 0)
  		error = copyout(&ats, uap->tp, sizeof(ats));
  
  	return (error);
  }
  
  static inline void
  cputick2timespec(uint64_t runtime, struct timespec *ats)
  {
  	runtime = cputick2usec(runtime);
  	ats->tv_sec = runtime / 1000000;
  	ats->tv_nsec = runtime % 1000000 * 1000;
  }
  
  void
  kern_thread_cputime(struct thread *targettd, struct timespec *ats)
  {
  	uint64_t runtime, curtime, switchtime;
  
  	if (targettd == NULL) { /* current thread */
  		critical_enter();
  		switchtime = PCPU_GET(switchtime);
  		curtime = cpu_ticks();
  		runtime = curthread->td_runtime;
  		critical_exit();
  		runtime += curtime - switchtime;
  	} else {
  		PROC_LOCK_ASSERT(targettd->td_proc, MA_OWNED);
  		thread_lock(targettd);
  		runtime = targettd->td_runtime;
  		thread_unlock(targettd);
  	}
  	cputick2timespec(runtime, ats);
  }
  
  void
  kern_process_cputime(struct proc *targetp, struct timespec *ats)
  {
  	uint64_t runtime;
  	struct rusage ru;
  
  	PROC_LOCK_ASSERT(targetp, MA_OWNED);
  	PROC_STATLOCK(targetp);
  	rufetch(targetp, &ru);
  	runtime = targetp->p_rux.rux_runtime;
  	if (curthread->td_proc == targetp)
  		runtime += cpu_ticks() - PCPU_GET(switchtime);
  	PROC_STATUNLOCK(targetp);
  	cputick2timespec(runtime, ats);
  }
  
  static int
  get_cputime(struct thread *td, clockid_t clock_id, struct timespec *ats)
  {
  	struct proc *p, *p2;
  	struct thread *td2;
  	lwpid_t tid;
  	pid_t pid;
  	int error;
  
  	p = td->td_proc;
  	if ((clock_id & CPUCLOCK_PROCESS_BIT) == 0) {
  		tid = clock_id & CPUCLOCK_ID_MASK;
  		td2 = tdfind(tid, p->p_pid);
  		if (td2 == NULL)
  			return (EINVAL);
  		kern_thread_cputime(td2, ats);
  		PROC_UNLOCK(td2->td_proc);
  	} else {
  		pid = clock_id & CPUCLOCK_ID_MASK;
  		error = pget(pid, PGET_CANSEE, &p2);
  		if (error != 0)
  			return (EINVAL);
  		kern_process_cputime(p2, ats);
  		PROC_UNLOCK(p2);
  	}
  	return (0);
  }
  
  int
  kern_clock_gettime(struct thread *td, clockid_t clock_id, struct timespec *ats)
  {
  	struct timeval sys, user;
  	struct proc *p;
  
  	p = td->td_proc;
  	switch (clock_id) {
  	case CLOCK_REALTIME:		/* Default to precise. */
  	case CLOCK_REALTIME_PRECISE:
  		nanotime(ats);
  		break;
  	case CLOCK_REALTIME_FAST:
  		getnanotime(ats);
  		break;
  	case CLOCK_VIRTUAL:
  		PROC_LOCK(p);
  		PROC_STATLOCK(p);
  		calcru(p, &user, &sys);
  		PROC_STATUNLOCK(p);
  		PROC_UNLOCK(p);
  		TIMEVAL_TO_TIMESPEC(&user, ats);
  		break;
  	case CLOCK_PROF:
  		PROC_LOCK(p);
  		PROC_STATLOCK(p);
  		calcru(p, &user, &sys);
  		PROC_STATUNLOCK(p);
  		PROC_UNLOCK(p);
  		timevaladd(&user, &sys);
  		TIMEVAL_TO_TIMESPEC(&user, ats);
  		break;
  	case CLOCK_MONOTONIC:		/* Default to precise. */
  	case CLOCK_MONOTONIC_PRECISE:
  	case CLOCK_UPTIME:
  	case CLOCK_UPTIME_PRECISE:
  		nanouptime(ats);
  		break;
  	case CLOCK_UPTIME_FAST:
  	case CLOCK_MONOTONIC_FAST:
  		getnanouptime(ats);
  		break;
  	case CLOCK_SECOND:
  		ats->tv_sec = time_second;
  		ats->tv_nsec = 0;
  		break;
  	case CLOCK_THREAD_CPUTIME_ID:
  		kern_thread_cputime(NULL, ats);
  		break;
  	case CLOCK_PROCESS_CPUTIME_ID:
  		PROC_LOCK(p);
  		kern_process_cputime(p, ats);
  		PROC_UNLOCK(p);
  		break;
  	default:
  		if ((int)clock_id >= 0)
  			return (EINVAL);
  		return (get_cputime(td, clock_id, ats));
  	}
  	return (0);
  }
  
  #ifndef _SYS_SYSPROTO_H_
  struct clock_settime_args {
  	clockid_t clock_id;
  	const struct	timespec *tp;
  };
  #endif
  /* ARGSUSED */
  int
  sys_clock_settime(struct thread *td, struct clock_settime_args *uap)
  {
  	struct timespec ats;
  	int error;
  
  	if ((error = copyin(uap->tp, &ats, sizeof(ats))) != 0)
  		return (error);
  	return (kern_clock_settime(td, uap->clock_id, &ats));
  }
  
  static int allow_insane_settime = 0;
  SYSCTL_INT(_debug, OID_AUTO, allow_insane_settime, CTLFLAG_RWTUN,
      &allow_insane_settime, 0,
      "do not perform possibly restrictive checks on settime(2) args");
  
  int
  kern_clock_settime(struct thread *td, clockid_t clock_id, struct timespec *ats)
  {
  	struct timeval atv;
  	int error;
  
  	if ((error = priv_check(td, PRIV_CLOCK_SETTIME)) != 0)
  		return (error);
  	if (clock_id != CLOCK_REALTIME)
  		return (EINVAL);
  	if (ats->tv_nsec < 0 || ats->tv_nsec >= 1000000000 ||
  	    ats->tv_sec < 0)
  		return (EINVAL);
  	if (!allow_insane_settime &&
  	    (ats->tv_sec > 8000ULL * 365 * 24 * 60 * 60 ||
  	    ats->tv_sec < utc_offset()))
  		return (EINVAL);
  	/* XXX Don't convert nsec->usec and back */
  	TIMESPEC_TO_TIMEVAL(&atv, ats);
  	error = settime(td, &atv);
  	return (error);
  }
  
  #ifndef _SYS_SYSPROTO_H_
  struct clock_getres_args {
  	clockid_t clock_id;
  	struct	timespec *tp;
  };
  #endif
  int
  sys_clock_getres(struct thread *td, struct clock_getres_args *uap)
  {
  	struct timespec ts;
  	int error;
  
  	if (uap->tp == NULL)
  		return (0);
  
  	error = kern_clock_getres(td, uap->clock_id, &ts);
  	if (error == 0)
  		error = copyout(&ts, uap->tp, sizeof(ts));
  	return (error);
  }
  
  int
  kern_clock_getres(struct thread *td, clockid_t clock_id, struct timespec *ts)
  {
  
  	ts->tv_sec = 0;
  	switch (clock_id) {
  	case CLOCK_REALTIME:
  	case CLOCK_REALTIME_FAST:
  	case CLOCK_REALTIME_PRECISE:
  	case CLOCK_MONOTONIC:
  	case CLOCK_MONOTONIC_FAST:
  	case CLOCK_MONOTONIC_PRECISE:
  	case CLOCK_UPTIME:
  	case CLOCK_UPTIME_FAST:
  	case CLOCK_UPTIME_PRECISE:
  		/*
  		 * Round up the result of the division cheaply by adding 1.
  		 * Rounding up is especially important if rounding down
  		 * would give 0.  Perfect rounding is unimportant.
  		 */
  		ts->tv_nsec = 1000000000 / tc_getfrequency() + 1;
  		break;
  	case CLOCK_VIRTUAL:
  	case CLOCK_PROF:
  		/* Accurately round up here because we can do so cheaply. */
  		ts->tv_nsec = howmany(1000000000, hz);
  		break;
  	case CLOCK_SECOND:
  		ts->tv_sec = 1;
  		ts->tv_nsec = 0;
  		break;
  	case CLOCK_THREAD_CPUTIME_ID:
  	case CLOCK_PROCESS_CPUTIME_ID:
  	cputime:
  		/* sync with cputick2usec */
  		ts->tv_nsec = 1000000 / cpu_tickrate();
  		if (ts->tv_nsec == 0)
  			ts->tv_nsec = 1000;
  		break;
  	default:
  		if ((int)clock_id < 0)
  			goto cputime;
  		return (EINVAL);
  	}
  	return (0);
  }
  
  int
  kern_nanosleep(struct thread *td, struct timespec *rqt, struct timespec *rmt)
  {
  
  	return (kern_clock_nanosleep(td, CLOCK_REALTIME, TIMER_RELTIME, rqt,
  	    rmt));
  }
  
  static uint8_t nanowait[MAXCPU];
  
  int
  kern_clock_nanosleep(struct thread *td, clockid_t clock_id, int flags,
      const struct timespec *rqt, struct timespec *rmt)
  {
  	struct timespec ts, now;
  	sbintime_t sbt, sbtt, prec, tmp;
  	time_t over;
  	int error;
  	bool is_abs_real;
  
  	if (rqt->tv_nsec < 0 || rqt->tv_nsec >= 1000000000)
  		return (EINVAL);
  	if ((flags & ~TIMER_ABSTIME) != 0)
  		return (EINVAL);
  	switch (clock_id) {
  	case CLOCK_REALTIME:
  	case CLOCK_REALTIME_PRECISE:
  	case CLOCK_REALTIME_FAST:
  	case CLOCK_SECOND:
  		is_abs_real = (flags & TIMER_ABSTIME) != 0;
  		break;
  	case CLOCK_MONOTONIC:
  	case CLOCK_MONOTONIC_PRECISE:
  	case CLOCK_MONOTONIC_FAST:
  	case CLOCK_UPTIME:
  	case CLOCK_UPTIME_PRECISE:
  	case CLOCK_UPTIME_FAST:
  		is_abs_real = false;
  		break;
  	case CLOCK_VIRTUAL:
  	case CLOCK_PROF:
  	case CLOCK_PROCESS_CPUTIME_ID:
  		return (ENOTSUP);
  	case CLOCK_THREAD_CPUTIME_ID:
  	default:
  		return (EINVAL);
  	}
  	do {
  		ts = *rqt;
  		if ((flags & TIMER_ABSTIME) != 0) {
  			if (is_abs_real)
  				td->td_rtcgen =
  				    atomic_load_acq_int(&rtc_generation);
  			error = kern_clock_gettime(td, clock_id, &now);
  			KASSERT(error == 0, ("kern_clock_gettime: %d", error));
  			timespecsub(&ts, &now, &ts);
  		}
  		if (ts.tv_sec < 0 || (ts.tv_sec == 0 && ts.tv_nsec == 0)) {
  			error = EWOULDBLOCK;
  			break;
  		}
  		if (ts.tv_sec > INT32_MAX / 2) {
  			over = ts.tv_sec - INT32_MAX / 2;
  			ts.tv_sec -= over;
  		} else
  			over = 0;
  		tmp = tstosbt(ts);
  		prec = tmp;
  		prec >>= tc_precexp;
  		if (TIMESEL(&sbt, tmp))
  			sbt += tc_tick_sbt;
  		sbt += tmp;
  		error = tsleep_sbt(&nanowait[curcpu], PWAIT | PCATCH, "nanslp",
  		    sbt, prec, C_ABSOLUTE);
  	} while (error == 0 && is_abs_real && td->td_rtcgen == 0);
  	td->td_rtcgen = 0;
  	if (error != EWOULDBLOCK) {
  		if (TIMESEL(&sbtt, tmp))
  			sbtt += tc_tick_sbt;
  		if (sbtt >= sbt)
  			return (0);
  		if (error == ERESTART)
  			error = EINTR;
  		if ((flags & TIMER_ABSTIME) == 0 && rmt != NULL) {
  			ts = sbttots(sbt - sbtt);
  			ts.tv_sec += over;
  			if (ts.tv_sec < 0)
  				timespecclear(&ts);
  			*rmt = ts;
  		}
  		return (error);
  	}
  	return (0);
  }
  
  #ifndef _SYS_SYSPROTO_H_
  struct nanosleep_args {
  	struct	timespec *rqtp;
  	struct	timespec *rmtp;
  };
  #endif
  /* ARGSUSED */
  int
  sys_nanosleep(struct thread *td, struct nanosleep_args *uap)
  {
  
  	return (user_clock_nanosleep(td, CLOCK_REALTIME, TIMER_RELTIME,
  	    uap->rqtp, uap->rmtp));
  }
  
  #ifndef _SYS_SYSPROTO_H_
  struct clock_nanosleep_args {
  	clockid_t clock_id;
  	int 	  flags;
  	struct	timespec *rqtp;
  	struct	timespec *rmtp;
  };
  #endif
  /* ARGSUSED */
  int
  sys_clock_nanosleep(struct thread *td, struct clock_nanosleep_args *uap)
  {
  	int error;
  
  	error = user_clock_nanosleep(td, uap->clock_id, uap->flags, uap->rqtp,
  	    uap->rmtp);
  	return (kern_posix_error(td, error));
  }
  
  static int
  user_clock_nanosleep(struct thread *td, clockid_t clock_id, int flags,
      const struct timespec *ua_rqtp, struct timespec *ua_rmtp)
  {
  	struct timespec rmt, rqt;
  	int error;
  
  	error = copyin(ua_rqtp, &rqt, sizeof(rqt));
  	if (error)
  		return (error);
  	if (ua_rmtp != NULL && (flags & TIMER_ABSTIME) == 0 &&
  	    !useracc(ua_rmtp, sizeof(rmt), VM_PROT_WRITE))
  		return (EFAULT);
  	error = kern_clock_nanosleep(td, clock_id, flags, &rqt, &rmt);
  	if (error == EINTR && ua_rmtp != NULL && (flags & TIMER_ABSTIME) == 0) {
  		int error2;
  
  		error2 = copyout(&rmt, ua_rmtp, sizeof(rmt));
  		if (error2)
  			error = error2;
  	}
  	return (error);
  }
  
  #ifndef _SYS_SYSPROTO_H_
  struct gettimeofday_args {
  	struct	timeval *tp;
  	struct	timezone *tzp;
  };
  #endif
  /* ARGSUSED */
  int
  sys_gettimeofday(struct thread *td, struct gettimeofday_args *uap)
  {
  	struct timeval atv;
  	struct timezone rtz;
  	int error = 0;
  
  	if (uap->tp) {
  		microtime(&atv);
  		error = copyout(&atv, uap->tp, sizeof (atv));
  	}
  	if (error == 0 && uap->tzp != NULL) {
  		rtz.tz_minuteswest = 0;
  		rtz.tz_dsttime = 0;
  		error = copyout(&rtz, uap->tzp, sizeof (rtz));
  	}
  	return (error);
  }
  
  #ifndef _SYS_SYSPROTO_H_
  struct settimeofday_args {
  	struct	timeval *tv;
  	struct	timezone *tzp;
  };
  #endif
  /* ARGSUSED */
  int
  sys_settimeofday(struct thread *td, struct settimeofday_args *uap)
  {
  	struct timeval atv, *tvp;
  	struct timezone atz, *tzp;
  	int error;
  
  	if (uap->tv) {
  		error = copyin(uap->tv, &atv, sizeof(atv));
  		if (error)
  			return (error);
  		tvp = &atv;
  	} else
  		tvp = NULL;
  	if (uap->tzp) {
  		error = copyin(uap->tzp, &atz, sizeof(atz));
  		if (error)
  			return (error);
  		tzp = &atz;
  	} else
  		tzp = NULL;
  	return (kern_settimeofday(td, tvp, tzp));
  }
  
  int
  kern_settimeofday(struct thread *td, struct timeval *tv, struct timezone *tzp)
  {
  	int error;
  
  	error = priv_check(td, PRIV_SETTIMEOFDAY);
  	if (error)
  		return (error);
  	/* Verify all parameters before changing time. */
  	if (tv) {
  		if (tv->tv_usec < 0 || tv->tv_usec >= 1000000 ||
  		    tv->tv_sec < 0)
  			return (EINVAL);
  		error = settime(td, tv);
  	}
  	return (error);
  }
  
  /*
   * 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
  int
  sys_getitimer(struct thread *td, struct getitimer_args *uap)
  {
  	struct itimerval aitv;
  	int error;
  
  	error = kern_getitimer(td, uap->which, &aitv);
  	if (error != 0)
  		return (error);
  	return (copyout(&aitv, uap->itv, sizeof (struct itimerval)));
  }
  
  int
  kern_getitimer(struct thread *td, u_int which, struct itimerval *aitv)
  {
  	struct proc *p = td->td_proc;
  	struct timeval ctv;
  
  	if (which > ITIMER_PROF)
  		return (EINVAL);
  
  	if (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.
  		 */
  		PROC_LOCK(p);
  		*aitv = p->p_realtimer;
  		PROC_UNLOCK(p);
  		if (timevalisset(&aitv->it_value)) {
  			microuptime(&ctv);
  			if (timevalcmp(&aitv->it_value, &ctv, <))
  				timevalclear(&aitv->it_value);
  			else
  				timevalsub(&aitv->it_value, &ctv);
  		}
  	} else {
  		PROC_ITIMLOCK(p);
  		*aitv = p->p_stats->p_timer[which];
  		PROC_ITIMUNLOCK(p);
  	}
  #ifdef KTRACE
  	if (KTRPOINT(td, KTR_STRUCT))
  		ktritimerval(aitv);
  #endif
  	return (0);
  }
  
  #ifndef _SYS_SYSPROTO_H_
  struct setitimer_args {
  	u_int	which;
  	struct	itimerval *itv, *oitv;
  };
  #endif
  int
  sys_setitimer(struct thread *td, struct setitimer_args *uap)
  {
  	struct itimerval aitv, oitv;
  	int error;
  
  	if (uap->itv == NULL) {
  		uap->itv = uap->oitv;
  		return (sys_getitimer(td, (struct getitimer_args *)uap));
  	}
  
  	if ((error = copyin(uap->itv, &aitv, sizeof(struct itimerval))))
  		return (error);
  	error = kern_setitimer(td, uap->which, &aitv, &oitv);
  	if (error != 0 || uap->oitv == NULL)
  		return (error);
  	return (copyout(&oitv, uap->oitv, sizeof(struct itimerval)));
  }
  
  int
  kern_setitimer(struct thread *td, u_int which, struct itimerval *aitv,
      struct itimerval *oitv)
  {
  	struct proc *p = td->td_proc;
  	struct timeval ctv;
  	sbintime_t sbt, pr;
  
  	if (aitv == NULL)
  		return (kern_getitimer(td, which, oitv));
  
  	if (which > ITIMER_PROF)
  		return (EINVAL);
  #ifdef KTRACE
  	if (KTRPOINT(td, KTR_STRUCT))
  		ktritimerval(aitv);
  #endif
  	if (itimerfix(&aitv->it_value) ||
  	    aitv->it_value.tv_sec > INT32_MAX / 2)
  		return (EINVAL);
  	if (!timevalisset(&aitv->it_value))
  		timevalclear(&aitv->it_interval);
  	else if (itimerfix(&aitv->it_interval) ||
  	    aitv->it_interval.tv_sec > INT32_MAX / 2)
  		return (EINVAL);
  
  	if (which == ITIMER_REAL) {
  		PROC_LOCK(p);
  		if (timevalisset(&p->p_realtimer.it_value))
  			callout_stop(&p->p_itcallout);
  		microuptime(&ctv);
  		if (timevalisset(&aitv->it_value)) {
  			pr = tvtosbt(aitv->it_value) >> tc_precexp;
  			timevaladd(&aitv->it_value, &ctv);
  			sbt = tvtosbt(aitv->it_value);
  			callout_reset_sbt(&p->p_itcallout, sbt, pr,
  			    realitexpire, p, C_ABSOLUTE);
  		}
  		*oitv = p->p_realtimer;
  		p->p_realtimer = *aitv;
  		PROC_UNLOCK(p);
  		if (timevalisset(&oitv->it_value)) {
  			if (timevalcmp(&oitv->it_value, &ctv, <))
  				timevalclear(&oitv->it_value);
  			else
  				timevalsub(&oitv->it_value, &ctv);
  		}
  	} else {
  		if (aitv->it_interval.tv_sec == 0 &&
  		    aitv->it_interval.tv_usec != 0 &&
  		    aitv->it_interval.tv_usec < tick)
  			aitv->it_interval.tv_usec = tick;
  		if (aitv->it_value.tv_sec == 0 &&
  		    aitv->it_value.tv_usec != 0 &&
  		    aitv->it_value.tv_usec < tick)
  			aitv->it_value.tv_usec = tick;
  		PROC_ITIMLOCK(p);
  		*oitv = p->p_stats->p_timer[which];
  		p->p_stats->p_timer[which] = *aitv;
  		PROC_ITIMUNLOCK(p);
  	}
  #ifdef KTRACE
  	if (KTRPOINT(td, KTR_STRUCT))
  		ktritimerval(oitv);
  #endif
  	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(void *arg)
  {
  	struct proc *p;
  	struct timeval ctv;
  	sbintime_t isbt;
  
  	p = (struct proc *)arg;
  	kern_psignal(p, SIGALRM);
  	if (!timevalisset(&p->p_realtimer.it_interval)) {
  		timevalclear(&p->p_realtimer.it_value);
  		if (p->p_flag & P_WEXIT)
  			wakeup(&p->p_itcallout);
  		return;
  	}
  	isbt = tvtosbt(p->p_realtimer.it_interval);
  	if (isbt >= sbt_timethreshold)
  		getmicrouptime(&ctv);
  	else
  		microuptime(&ctv);
  	do {
  		timevaladd(&p->p_realtimer.it_value,
  		    &p->p_realtimer.it_interval);
  	} while (timevalcmp(&p->p_realtimer.it_value, &ctv, <=));
  	callout_reset_sbt(&p->p_itcallout, tvtosbt(p->p_realtimer.it_value),
  	    isbt >> tc_precexp, realitexpire, p, C_ABSOLUTE);
  }
  
  /*
   * 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(struct timeval *tv)
  {
  
  	if (tv->tv_sec < 0 || tv->tv_usec < 0 || tv->tv_usec >= 1000000)
  		return (EINVAL);
  	if (tv->tv_sec == 0 && tv->tv_usec != 0 &&
  	    tv->tv_usec < (u_int)tick / 16)
  		tv->tv_usec = (u_int)tick / 16;
  	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(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(struct timeval *t1, const struct timeval *t2)
  {
  
  	t1->tv_sec += t2->tv_sec;
  	t1->tv_usec += t2->tv_usec;
  	timevalfix(t1);
  }
  
  void
  timevalsub(struct timeval *t1, const struct timeval *t2)
  {
  
  	t1->tv_sec -= t2->tv_sec;
  	t1->tv_usec -= t2->tv_usec;
  	timevalfix(t1);
  }
  
  static 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;
  	}
  }
  
  /*
   * ratecheck(): simple time-based rate-limit checking.
   */
  int
  ratecheck(struct timeval *lasttime, const struct timeval *mininterval)
  {
  	struct timeval tv, delta;
  	int rv = 0;
  
  	getmicrouptime(&tv);		/* NB: 10ms precision */
  	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.
   *
   * Return 0 if the limit is to be enforced (e.g. the caller
   * should drop a packet because of the rate limitation).
   *
   * maxpps of 0 always causes zero to be returned.  maxpps of -1
   * always causes 1 to be returned; this effectively defeats rate
   * limiting.
   *
   * Note that we maintain the struct timeval for compatibility
   * with other bsd systems.  We reuse the storage and just monitor
   * clock ticks for minimal overhead.  
   */
  int
  ppsratecheck(struct timeval *lasttime, int *curpps, int maxpps)
  {
  	int now;
  
  	/*
  	 * Reset the last time and counter if this is the first call
  	 * or more than a second has passed since the last update of
  	 * lasttime.
  	 */
  	now = ticks;
  	if (lasttime->tv_sec == 0 || (u_int)(now - lasttime->tv_sec) >= hz) {
  		lasttime->tv_sec = now;
  		*curpps = 1;
  		return (maxpps != 0);
  	} else {
  		(*curpps)++;		/* NB: ignore potential overflow */
  		return (maxpps < 0 || *curpps <= maxpps);
  	}
  }
  
  static void
  itimer_start(void)
  {
  	struct kclock rt_clock = {
  		.timer_create  = realtimer_create,
  		.timer_delete  = realtimer_delete,
  		.timer_settime = realtimer_settime,
  		.timer_gettime = realtimer_gettime,
  		.event_hook    = NULL
  	};
  
  	itimer_zone = uma_zcreate("itimer", sizeof(struct itimer),
  		NULL, NULL, itimer_init, itimer_fini, UMA_ALIGN_PTR, 0);
  	register_posix_clock(CLOCK_REALTIME,  &rt_clock);
  	register_posix_clock(CLOCK_MONOTONIC, &rt_clock);
  	p31b_setcfg(CTL_P1003_1B_TIMERS, 200112L);
  	p31b_setcfg(CTL_P1003_1B_DELAYTIMER_MAX, INT_MAX);
  	p31b_setcfg(CTL_P1003_1B_TIMER_MAX, TIMER_MAX);
  	EVENTHANDLER_REGISTER(process_exit, itimers_event_hook_exit,
  		(void *)ITIMER_EV_EXIT, EVENTHANDLER_PRI_ANY);
  	EVENTHANDLER_REGISTER(process_exec, itimers_event_hook_exec,
  		(void *)ITIMER_EV_EXEC, EVENTHANDLER_PRI_ANY);
  }
  
  int
  register_posix_clock(int clockid, struct kclock *clk)
  {
  	if ((unsigned)clockid >= MAX_CLOCKS) {
  		printf("%s: invalid clockid\n", __func__);
  		return (0);
  	}
  	posix_clocks[clockid] = *clk;
  	return (1);
  }
  
  static int
  itimer_init(void *mem, int size, int flags)
  {
  	struct itimer *it;
  
  	it = (struct itimer *)mem;
  	mtx_init(&it->it_mtx, "itimer lock", NULL, MTX_DEF);
  	return (0);
  }
  
  static void
  itimer_fini(void *mem, int size)
  {
  	struct itimer *it;
  
  	it = (struct itimer *)mem;
  	mtx_destroy(&it->it_mtx);
  }
  
  static void
  itimer_enter(struct itimer *it)
  {
  
  	mtx_assert(&it->it_mtx, MA_OWNED);
  	it->it_usecount++;
  }
  
  static void
  itimer_leave(struct itimer *it)
  {
  
  	mtx_assert(&it->it_mtx, MA_OWNED);
  	KASSERT(it->it_usecount > 0, ("invalid it_usecount"));
  
  	if (--it->it_usecount == 0 && (it->it_flags & ITF_WANTED) != 0)
  		wakeup(it);
  }
  
  #ifndef _SYS_SYSPROTO_H_
  struct ktimer_create_args {
  	clockid_t clock_id;
  	struct sigevent * evp;
  	int * timerid;
  };
  #endif
  int
  sys_ktimer_create(struct thread *td, struct ktimer_create_args *uap)
  {
  	struct sigevent *evp, ev;
  	int id;
  	int error;
  
  	if (uap->evp == NULL) {
  		evp = NULL;
  	} else {
  		error = copyin(uap->evp, &ev, sizeof(ev));
  		if (error != 0)
  			return (error);
  		evp = &ev;
  	}
  	error = kern_ktimer_create(td, uap->clock_id, evp, &id, -1);
  	if (error == 0) {
  		error = copyout(&id, uap->timerid, sizeof(int));
  		if (error != 0)
  			kern_ktimer_delete(td, id);
  	}
  	return (error);
  }
  
  int
  kern_ktimer_create(struct thread *td, clockid_t clock_id, struct sigevent *evp,
      int *timerid, int preset_id)
  {
  	struct proc *p = td->td_proc;
  	struct itimer *it;
  	int id;
  	int error;
  
  	if (clock_id < 0 || clock_id >= MAX_CLOCKS)
  		return (EINVAL);
  
  	if (posix_clocks[clock_id].timer_create == NULL)
  		return (EINVAL);
  
  	if (evp != NULL) {
  		if (evp->sigev_notify != SIGEV_NONE &&
  		    evp->sigev_notify != SIGEV_SIGNAL &&
  		    evp->sigev_notify != SIGEV_THREAD_ID)
  			return (EINVAL);
  		if ((evp->sigev_notify == SIGEV_SIGNAL ||
  		     evp->sigev_notify == SIGEV_THREAD_ID) &&
  			!_SIG_VALID(evp->sigev_signo))
  			return (EINVAL);
  	}
  	
  	if (p->p_itimers == NULL)
  		itimers_alloc(p);
  	
  	it = uma_zalloc(itimer_zone, M_WAITOK);
  	it->it_flags = 0;
  	it->it_usecount = 0;
  	it->it_active = 0;
  	timespecclear(&it->it_time.it_value);
  	timespecclear(&it->it_time.it_interval);
  	it->it_overrun = 0;
  	it->it_overrun_last = 0;
  	it->it_clockid = clock_id;
  	it->it_timerid = -1;
  	it->it_proc = p;
  	ksiginfo_init(&it->it_ksi);
  	it->it_ksi.ksi_flags |= KSI_INS | KSI_EXT;
  	error = CLOCK_CALL(clock_id, timer_create, (it));
  	if (error != 0)
  		goto out;
  
  	PROC_LOCK(p);
  	if (preset_id != -1) {
  		KASSERT(preset_id >= 0 && preset_id < 3, ("invalid preset_id"));
  		id = preset_id;
  		if (p->p_itimers->its_timers[id] != NULL) {
  			PROC_UNLOCK(p);
  			error = 0;
  			goto out;
  		}
  	} else {
  		/*
  		 * Find a free timer slot, skipping those reserved
  		 * for setitimer().
  		 */
  		for (id = 3; id < TIMER_MAX; id++)
  			if (p->p_itimers->its_timers[id] == NULL)
  				break;
  		if (id == TIMER_MAX) {
  			PROC_UNLOCK(p);
  			error = EAGAIN;
  			goto out;
  		}
  	}
  	it->it_timerid = id;
  	p->p_itimers->its_timers[id] = it;
  	if (evp != NULL)
  		it->it_sigev = *evp;
  	else {
  		it->it_sigev.sigev_notify = SIGEV_SIGNAL;
  		switch (clock_id) {
  		default:
  		case CLOCK_REALTIME:
  			it->it_sigev.sigev_signo = SIGALRM;
  			break;
  		case CLOCK_VIRTUAL:
   			it->it_sigev.sigev_signo = SIGVTALRM;
  			break;
  		case CLOCK_PROF:
  			it->it_sigev.sigev_signo = SIGPROF;
  			break;
  		}
  		it->it_sigev.sigev_value.sival_int = id;
  	}
  
  	if (it->it_sigev.sigev_notify == SIGEV_SIGNAL ||
  	    it->it_sigev.sigev_notify == SIGEV_THREAD_ID) {
  		it->it_ksi.ksi_signo = it->it_sigev.sigev_signo;
  		it->it_ksi.ksi_code = SI_TIMER;
  		it->it_ksi.ksi_value = it->it_sigev.sigev_value;
  		it->it_ksi.ksi_timerid = id;
  	}
  	PROC_UNLOCK(p);
  	*timerid = id;
  	return (0);
  
  out:
  	ITIMER_LOCK(it);
  	CLOCK_CALL(it->it_clockid, timer_delete, (it));
  	ITIMER_UNLOCK(it);
  	uma_zfree(itimer_zone, it);
  	return (error);
  }
  
  #ifndef _SYS_SYSPROTO_H_
  struct ktimer_delete_args {
  	int timerid;
  };
  #endif
  int
  sys_ktimer_delete(struct thread *td, struct ktimer_delete_args *uap)
  {
  
  	return (kern_ktimer_delete(td, uap->timerid));
  }
  
  static struct itimer *
  itimer_find(struct proc *p, int timerid)
  {
  	struct itimer *it;
  
  	PROC_LOCK_ASSERT(p, MA_OWNED);
  	if ((p->p_itimers == NULL) ||
  	    (timerid < 0) || (timerid >= TIMER_MAX) ||
  	    (it = p->p_itimers->its_timers[timerid]) == NULL) {
  		return (NULL);
  	}
  	ITIMER_LOCK(it);
  	if ((it->it_flags & ITF_DELETING) != 0) {
  		ITIMER_UNLOCK(it);
  		it = NULL;
  	}
  	return (it);
  }
  
  int
  kern_ktimer_delete(struct thread *td, int timerid)
  {
  	struct proc *p = td->td_proc;
  	struct itimer *it;
  
  	PROC_LOCK(p);
  	it = itimer_find(p, timerid);
  	if (it == NULL) {
  		PROC_UNLOCK(p);
  		return (EINVAL);
  	}
  	PROC_UNLOCK(p);
  
  	it->it_flags |= ITF_DELETING;
  	while (it->it_usecount > 0) {
  		it->it_flags |= ITF_WANTED;
  		msleep(it, &it->it_mtx, PPAUSE, "itimer", 0);
  	}
  	it->it_flags &= ~ITF_WANTED;
  	CLOCK_CALL(it->it_clockid, timer_delete, (it));
  	ITIMER_UNLOCK(it);
  
  	PROC_LOCK(p);
  	if (KSI_ONQ(&it->it_ksi))
  		sigqueue_take(&it->it_ksi);
  	p->p_itimers->its_timers[timerid] = NULL;
  	PROC_UNLOCK(p);
  	uma_zfree(itimer_zone, it);
  	return (0);
  }
  
  #ifndef _SYS_SYSPROTO_H_
  struct ktimer_settime_args {
  	int timerid;
  	int flags;
  	const struct itimerspec * value;
  	struct itimerspec * ovalue;
  };
  #endif
  int
  sys_ktimer_settime(struct thread *td, struct ktimer_settime_args *uap)
  {
  	struct itimerspec val, oval, *ovalp;
  	int error;
  
  	error = copyin(uap->value, &val, sizeof(val));
  	if (error != 0)
  		return (error);
  	ovalp = uap->ovalue != NULL ? &oval : NULL;
  	error = kern_ktimer_settime(td, uap->timerid, uap->flags, &val, ovalp);
  	if (error == 0 && uap->ovalue != NULL)
  		error = copyout(ovalp, uap->ovalue, sizeof(*ovalp));
  	return (error);
  }
  
  int
  kern_ktimer_settime(struct thread *td, int timer_id, int flags,
      struct itimerspec *val, struct itimerspec *oval)
  {
  	struct proc *p;
  	struct itimer *it;
  	int error;
  
  	p = td->td_proc;
  	PROC_LOCK(p);
  	if (timer_id < 3 || (it = itimer_find(p, timer_id)) == NULL) {
  		PROC_UNLOCK(p);
  		error = EINVAL;
  	} else {
  		PROC_UNLOCK(p);
  		itimer_enter(it);
  		error = CLOCK_CALL(it->it_clockid, timer_settime, (it,
  		    flags, val, oval));
  		itimer_leave(it);
  		ITIMER_UNLOCK(it);
  	}
  	return (error);
  }
  
  #ifndef _SYS_SYSPROTO_H_
  struct ktimer_gettime_args {
  	int timerid;
  	struct itimerspec * value;
  };
  #endif
  int
  sys_ktimer_gettime(struct thread *td, struct ktimer_gettime_args *uap)
  {
  	struct itimerspec val;
  	int error;
  
  	error = kern_ktimer_gettime(td, uap->timerid, &val);
  	if (error == 0)
  		error = copyout(&val, uap->value, sizeof(val));
  	return (error);
  }
  
  int
  kern_ktimer_gettime(struct thread *td, int timer_id, struct itimerspec *val)
  {
  	struct proc *p;
  	struct itimer *it;
  	int error;
  
  	p = td->td_proc;
  	PROC_LOCK(p);
  	if (timer_id < 3 || (it = itimer_find(p, timer_id)) == NULL) {
  		PROC_UNLOCK(p);
  		error = EINVAL;
  	} else {
  		PROC_UNLOCK(p);
  		itimer_enter(it);
  		error = CLOCK_CALL(it->it_clockid, timer_gettime, (it, val));
  		itimer_leave(it);
  		ITIMER_UNLOCK(it);
  	}
  	return (error);
  }
  
  #ifndef _SYS_SYSPROTO_H_
  struct timer_getoverrun_args {
  	int timerid;
  };
  #endif
  int
  sys_ktimer_getoverrun(struct thread *td, struct ktimer_getoverrun_args *uap)
  {
  
  	return (kern_ktimer_getoverrun(td, uap->timerid));
  }
  
  int
  kern_ktimer_getoverrun(struct thread *td, int timer_id)
  {
  	struct proc *p = td->td_proc;
  	struct itimer *it;
  	int error ;
  
  	PROC_LOCK(p);
  	if (timer_id < 3 ||
  	    (it = itimer_find(p, timer_id)) == NULL) {
  		PROC_UNLOCK(p);
  		error = EINVAL;
  	} else {
  		td->td_retval[0] = it->it_overrun_last;
  		ITIMER_UNLOCK(it);
  		PROC_UNLOCK(p);
  		error = 0;
  	}
  	return (error);
  }
  
  static int
  realtimer_create(struct itimer *it)
  {
  	callout_init_mtx(&it->it_callout, &it->it_mtx, 0);
  	return (0);
  }
  
  static int
  realtimer_delete(struct itimer *it)
  {
  	mtx_assert(&it->it_mtx, MA_OWNED);
  	
  	/*
  	 * clear timer's value and interval to tell realtimer_expire
  	 * to not rearm the timer.
  	 */
  	timespecclear(&it->it_time.it_value);
  	timespecclear(&it->it_time.it_interval);
  	ITIMER_UNLOCK(it);
  	callout_drain(&it->it_callout);
  	ITIMER_LOCK(it);
  	return (0);
  }
  
  static int
  realtimer_gettime(struct itimer *it, struct itimerspec *ovalue)
  {
  	struct timespec cts;
  
  	mtx_assert(&it->it_mtx, MA_OWNED);
  
  	realtimer_clocktime(it->it_clockid, &cts);
  	*ovalue = it->it_time;
  	if (ovalue->it_value.tv_sec != 0 || ovalue->it_value.tv_nsec != 0) {
  		timespecsub(&ovalue->it_value, &cts, &ovalue->it_value);
  		if (ovalue->it_value.tv_sec < 0 ||
  		    (ovalue->it_value.tv_sec == 0 &&
  		     ovalue->it_value.tv_nsec == 0)) {
  			ovalue->it_value.tv_sec  = 0;
  			ovalue->it_value.tv_nsec = 1;
  		}
  	}
  	return (0);
  }
  
  static int
  realtimer_settime(struct itimer *it, int flags,
  	struct itimerspec *value, struct itimerspec *ovalue)
  {
  	struct timespec cts, ts;
  	struct timeval tv;
  	struct itimerspec val;
  
  	mtx_assert(&it->it_mtx, MA_OWNED);
  
  	val = *value;
  	if (itimespecfix(&val.it_value))
  		return (EINVAL);
  
  	if (timespecisset(&val.it_value)) {
  		if (itimespecfix(&val.it_interval))
  			return (EINVAL);
  	} else {
  		timespecclear(&val.it_interval);
  	}
  	
  	if (ovalue != NULL)
  		realtimer_gettime(it, ovalue);
  
  	it->it_time = val;
  	if (timespecisset(&val.it_value)) {
  		realtimer_clocktime(it->it_clockid, &cts);
  		ts = val.it_value;
  		if ((flags & TIMER_ABSTIME) == 0) {
  			/* Convert to absolute time. */
  			timespecadd(&it->it_time.it_value, &cts,
  				&it->it_time.it_value);
  		} else {
  			timespecsub(&ts, &cts, &ts);
  			/*
  			 * We don't care if ts is negative, tztohz will
  			 * fix it.
  			 */
  		}
  		TIMESPEC_TO_TIMEVAL(&tv, &ts);
  		callout_reset(&it->it_callout, tvtohz(&tv),
  			realtimer_expire, it);
  	} else {
  		callout_stop(&it->it_callout);
  	}
  
  	return (0);
  }
  
  static void
  realtimer_clocktime(clockid_t id, struct timespec *ts)
  {
  	if (id == CLOCK_REALTIME)
  		getnanotime(ts);
  	else	/* CLOCK_MONOTONIC */
  		getnanouptime(ts);
  }
  
  int
  itimer_accept(struct proc *p, int timerid, ksiginfo_t *ksi)
  {
  	struct itimer *it;
  
  	PROC_LOCK_ASSERT(p, MA_OWNED);
  	it = itimer_find(p, timerid);
  	if (it != NULL) {
  		ksi->ksi_overrun = it->it_overrun;
  		it->it_overrun_last = it->it_overrun;
  		it->it_overrun = 0;
  		ITIMER_UNLOCK(it);
  		return (0);
  	}
  	return (EINVAL);
  }
  
  int
  itimespecfix(struct timespec *ts)
  {
  
  	if (ts->tv_sec < 0 || ts->tv_nsec < 0 || ts->tv_nsec >= 1000000000)
  		return (EINVAL);
  	if (ts->tv_sec == 0 && ts->tv_nsec != 0 && ts->tv_nsec < tick * 1000)
  		ts->tv_nsec = tick * 1000;
  	return (0);
  }
  
  /* Timeout callback for realtime timer */
  static void
  realtimer_expire(void *arg)
  {
  	struct timespec cts, ts;
  	struct timeval tv;
  	struct itimer *it;
  
  	it = (struct itimer *)arg;
  
  	realtimer_clocktime(it->it_clockid, &cts);
  	/* Only fire if time is reached. */
  	if (timespeccmp(&cts, &it->it_time.it_value, >=)) {
  		if (timespecisset(&it->it_time.it_interval)) {
  			timespecadd(&it->it_time.it_value,
  				    &it->it_time.it_interval,
  				    &it->it_time.it_value);
  			while (timespeccmp(&cts, &it->it_time.it_value, >=)) {
  				if (it->it_overrun < INT_MAX)
  					it->it_overrun++;
  				else
  					it->it_ksi.ksi_errno = ERANGE;
  				timespecadd(&it->it_time.it_value,
  					    &it->it_time.it_interval,
  					    &it->it_time.it_value);
  			}
  		} else {
  			/* single shot timer ? */
  			timespecclear(&it->it_time.it_value);
  		}
  		if (timespecisset(&it->it_time.it_value)) {
  			timespecsub(&it->it_time.it_value, &cts, &ts);
  			TIMESPEC_TO_TIMEVAL(&tv, &ts);
  			callout_reset(&it->it_callout, tvtohz(&tv),
  				 realtimer_expire, it);
  		}
  		itimer_enter(it);
  		ITIMER_UNLOCK(it);
  		itimer_fire(it);
  		ITIMER_LOCK(it);
  		itimer_leave(it);
  	} else if (timespecisset(&it->it_time.it_value)) {
  		ts = it->it_time.it_value;
  		timespecsub(&ts, &cts, &ts);
  		TIMESPEC_TO_TIMEVAL(&tv, &ts);
  		callout_reset(&it->it_callout, tvtohz(&tv), realtimer_expire,
   			it);
  	}
  }
  
  void
  itimer_fire(struct itimer *it)
  {
  	struct proc *p = it->it_proc;
  	struct thread *td;
  
  	if (it->it_sigev.sigev_notify == SIGEV_SIGNAL ||
  	    it->it_sigev.sigev_notify == SIGEV_THREAD_ID) {
  		if (sigev_findtd(p, &it->it_sigev, &td) != 0) {
  			ITIMER_LOCK(it);
  			timespecclear(&it->it_time.it_value);
  			timespecclear(&it->it_time.it_interval);
  			callout_stop(&it->it_callout);
  			ITIMER_UNLOCK(it);
  			return;
  		}
  		if (!KSI_ONQ(&it->it_ksi)) {
  			it->it_ksi.ksi_errno = 0;
  			ksiginfo_set_sigev(&it->it_ksi, &it->it_sigev);
  			tdsendsignal(p, td, it->it_ksi.ksi_signo, &it->it_ksi);
  		} else {
  			if (it->it_overrun < INT_MAX)
  				it->it_overrun++;
  			else
  				it->it_ksi.ksi_errno = ERANGE;
  		}
  		PROC_UNLOCK(p);
  	}
  }
  
  static void
  itimers_alloc(struct proc *p)
  {
  	struct itimers *its;
  	int i;
  
  	its = malloc(sizeof (struct itimers), M_SUBPROC, M_WAITOK | M_ZERO);
  	LIST_INIT(&its->its_virtual);
  	LIST_INIT(&its->its_prof);
  	TAILQ_INIT(&its->its_worklist);
  	for (i = 0; i < TIMER_MAX; i++)
  		its->its_timers[i] = NULL;
  	PROC_LOCK(p);
  	if (p->p_itimers == NULL) {
  		p->p_itimers = its;
  		PROC_UNLOCK(p);
  	}
  	else {
  		PROC_UNLOCK(p);
  		free(its, M_SUBPROC);
  	}
  }
  
  static void
  itimers_event_hook_exec(void *arg, struct proc *p, struct image_params *imgp __unused)
  {
  	itimers_event_hook_exit(arg, p);
  }
  
  /* Clean up timers when some process events are being triggered. */
  static void
  itimers_event_hook_exit(void *arg, struct proc *p)
  {
  	struct itimers *its;
  	struct itimer *it;
  	int event = (int)(intptr_t)arg;
  	int i;
  
  	if (p->p_itimers != NULL) {
  		its = p->p_itimers;
  		for (i = 0; i < MAX_CLOCKS; ++i) {
  			if (posix_clocks[i].event_hook != NULL)
  				CLOCK_CALL(i, event_hook, (p, i, event));
  		}
  		/*
  		 * According to susv3, XSI interval timers should be inherited
  		 * by new image.
  		 */
  		if (event == ITIMER_EV_EXEC)
  			i = 3;
  		else if (event == ITIMER_EV_EXIT)
  			i = 0;
  		else
  			panic("unhandled event");
  		for (; i < TIMER_MAX; ++i) {
  			if ((it = its->its_timers[i]) != NULL)
  				kern_ktimer_delete(curthread, i);
  		}
  		if (its->its_timers[0] == NULL &&
  		    its->its_timers[1] == NULL &&
  		    its->its_timers[2] == NULL) {
  			free(its, M_SUBPROC);
  			p->p_itimers = NULL;
  		}
  	}
  }
  