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/*-* 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.* 4. Neither the name of the University nor the names of its contributors* may be used to endorse or promote products derived from this software* without specific prior written permission.** THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF* SUCH DAMAGE.** @(#)kern_time.c 8.1 (Berkeley) 6/10/93*/#include <sys/cdefs.h>__FBSDID("$FreeBSD: src/sys/kern/kern_time.c,v 1.116 2005/03/31 22:51:18 jhb Exp $");#include "opt_mac.h"#include <sys/param.h>#include <sys/systm.h>#include <sys/lock.h>#include <sys/mutex.h>#include <sys/sysproto.h>#include <sys/resourcevar.h>#include <sys/signalvar.h>#include <sys/jail.h>#include <sys/kernel.h>#include <sys/mac.h>#include <sys/syscallsubr.h>#include <sys/sysctl.h>#include <sys/sysent.h>#include <sys/proc.h>#include <sys/time.h>#include <sys/timetc.h>#include <sys/vnode.h>#include <vm/vm.h>#include <vm/vm_extern.h>int tz_minuteswest;int tz_dsttime;/** 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 void no_lease_updatetime(int);static int cf_usersettime;static int cf_jailsettime;SYSCTL_INT(_kern, OID_AUTO, usersettime, CTLFLAG_RW, &cf_usersettime, 0,"Non-root is allowed to change system time");SYSCTL_INT(_kern, OID_AUTO, jailsettime, CTLFLAG_RW, &cf_jailsettime, 0,"System time is allowed to be changed from jail");static voidno_lease_updatetime(deltat)int deltat;{}void (*lease_updatetime)(int) = no_lease_updatetime;static intsettime(struct thread *td, struct timeval *tv){struct timeval delta, tv1, tv2;static struct timeval maxtime, laststep;struct timespec ts;int s;s = splclock();microtime(&tv1);delta = *tv;timevalsub(&delta, &tv1);/** If the system is secure, we do not allow the time to be* set to 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) {splx(s);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;mtx_lock(&Giant);tc_setclock(&ts);(void) splsoftclock();lease_updatetime(delta.tv_sec);splx(s);resettodr();mtx_unlock(&Giant);return (0);}#ifndef _SYS_SYSPROTO_H_struct clock_gettime_args {clockid_t clock_id;struct timespec *tp;};#endif/** MPSAFE*//* ARGSUSED */intclock_gettime(struct thread *td, struct clock_gettime_args *uap){struct timespec ats;struct timeval sys, user;struct proc *p;p = td->td_proc;switch (uap->clock_id) {case CLOCK_REALTIME:nanotime(&ats);break;case CLOCK_VIRTUAL:PROC_LOCK(p);calcru(p, &user, &sys);PROC_UNLOCK(p);TIMEVAL_TO_TIMESPEC(&user, &ats);break;case CLOCK_PROF:PROC_LOCK(p);calcru(p, &user, &sys);PROC_UNLOCK(p);timevaladd(&user, &sys);TIMEVAL_TO_TIMESPEC(&user, &ats);break;case CLOCK_MONOTONIC:nanouptime(&ats);break;default:return (EINVAL);}return (copyout(&ats, uap->tp, sizeof(ats)));}#ifndef _SYS_SYSPROTO_H_struct clock_settime_args {clockid_t clock_id;const struct timespec *tp;};#endif/** MPSAFE*//* ARGSUSED */intclock_settime(struct thread *td, struct clock_settime_args *uap){struct timeval atv;struct timespec ats;int error;#ifdef MACerror = mac_check_system_settime(td->td_ucred);if (error)return (error);#endifif (!cf_jailsettime && jailed(td->td_ucred))return (EPERM);if (!cf_usersettime && (error = suser_cred(td->td_ucred, SUSER_ALLOWJAIL)) != 0)return (error); /* jail is already checked */if (uap->clock_id != CLOCK_REALTIME)return (EINVAL);if ((error = copyin(uap->tp, &ats, sizeof(ats))) != 0)return (error);if (ats.tv_nsec < 0 || ats.tv_nsec >= 1000000000)return (EINVAL);/* XXX Don't convert nsec->usec and back */TIMESPEC_TO_TIMEVAL(&atv, &ats);error = settime(td, &atv);return (error);}#ifndef _SYS_SYSPROTO_H_struct clock_getres_args {clockid_t clock_id;struct timespec *tp;};#endifintclock_getres(struct thread *td, struct clock_getres_args *uap){struct timespec ts;ts.tv_sec = 0;switch (uap->clock_id) {case CLOCK_REALTIME:case CLOCK_MONOTONIC:/** 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 = (1000000000 + hz - 1) / hz;break;default:return (EINVAL);}if (uap->tp == NULL)return (0);return (copyout(&ts, uap->tp, sizeof(ts)));}static int nanowait;intkern_nanosleep(struct thread *td, struct timespec *rqt, struct timespec *rmt){struct timespec ts, ts2, ts3;struct timeval tv;int error;if (rqt->tv_nsec < 0 || rqt->tv_nsec >= 1000000000)return (EINVAL);if (rqt->tv_sec < 0 || (rqt->tv_sec == 0 && rqt->tv_nsec == 0))return (0);getnanouptime(&ts);timespecadd(&ts, rqt);TIMESPEC_TO_TIMEVAL(&tv, rqt);for (;;) {error = tsleep(&nanowait, PWAIT | PCATCH, "nanslp",tvtohz(&tv));getnanouptime(&ts2);if (error != EWOULDBLOCK) {if (error == ERESTART)error = EINTR;if (rmt != NULL) {timespecsub(&ts, &ts2);if (ts.tv_sec < 0)timespecclear(&ts);*rmt = ts;}return (error);}if (timespeccmp(&ts2, &ts, >=))return (0);ts3 = ts;timespecsub(&ts3, &ts2);TIMESPEC_TO_TIMEVAL(&tv, &ts3);}}#ifndef _SYS_SYSPROTO_H_struct nanosleep_args {struct timespec *rqtp;struct timespec *rmtp;};#endif/** MPSAFE*//* ARGSUSED */intnanosleep(struct thread *td, struct nanosleep_args *uap){struct timespec rmt, rqt;int error;error = copyin(uap->rqtp, &rqt, sizeof(rqt));if (error)return (error);if (uap->rmtp &&!useracc((caddr_t)uap->rmtp, sizeof(rmt), VM_PROT_WRITE))return (EFAULT);error = kern_nanosleep(td, &rqt, &rmt);if (error && uap->rmtp) {int error2;error2 = copyout(&rmt, uap->rmtp, sizeof(rmt));if (error2)error = error2;}return (error);}#ifndef _SYS_SYSPROTO_H_struct gettimeofday_args {struct timeval *tp;struct timezone *tzp;};#endif/** MPSAFE*//* ARGSUSED */intgettimeofday(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 = tz_minuteswest;rtz.tz_dsttime = tz_dsttime;error = copyout(&rtz, uap->tzp, sizeof (rtz));}return (error);}#ifndef _SYS_SYSPROTO_H_struct settimeofday_args {struct timeval *tv;struct timezone *tzp;};#endif/** MPSAFE*//* ARGSUSED */intsettimeofday(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;} elsetvp = NULL;if (uap->tzp) {error = copyin(uap->tzp, &atz, sizeof(atz));if (error)return (error);tzp = &atz;} elsetzp = NULL;return (kern_settimeofday(td, tvp, tzp));}intkern_settimeofday(struct thread *td, struct timeval *tv, struct timezone *tzp){int error = 0;#ifdef MACerror = mac_check_system_settime(td->td_ucred);if (error)return (error);#endifif (!cf_jailsettime && jailed(td->td_ucred))return (EPERM);if (!cf_usersettime && (error = suser_cred(td->td_ucred, SUSER_ALLOWJAIL)) != 0)return (error); /* jail is already checked *//* Verify all parameters before changing time. */if (tv) {if (tv->tv_usec < 0 || tv->tv_usec >= 1000000)return (EINVAL);error = settime(td, tv);}if (tzp && error == 0) {tz_minuteswest = tzp->tz_minuteswest;tz_dsttime = tzp->tz_dsttime;}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/** MPSAFE*/intgetitimer(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)));}intkern_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)) {getmicrouptime(&ctv);if (timevalcmp(&aitv->it_value, &ctv, <))timevalclear(&aitv->it_value);elsetimevalsub(&aitv->it_value, &ctv);}} else {mtx_lock_spin(&sched_lock);*aitv = p->p_stats->p_timer[which];mtx_unlock_spin(&sched_lock);}return (0);}#ifndef _SYS_SYSPROTO_H_struct setitimer_args {u_int which;struct itimerval *itv, *oitv;};#endif/** MPSAFE*/intsetitimer(struct thread *td, struct setitimer_args *uap){struct itimerval aitv, oitv;int error;if (uap->itv == NULL) {uap->itv = uap->oitv;return (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)));}intkern_setitimer(struct thread *td, u_int which, struct itimerval *aitv,struct itimerval *oitv){struct proc *p = td->td_proc;struct timeval ctv;if (aitv == NULL)return (kern_getitimer(td, which, oitv));if (which > ITIMER_PROF)return (EINVAL);if (itimerfix(&aitv->it_value))return (EINVAL);if (!timevalisset(&aitv->it_value))timevalclear(&aitv->it_interval);else if (itimerfix(&aitv->it_interval))return (EINVAL);if (which == ITIMER_REAL) {PROC_LOCK(p);if (timevalisset(&p->p_realtimer.it_value))callout_stop(&p->p_itcallout);getmicrouptime(&ctv);if (timevalisset(&aitv->it_value)) {callout_reset(&p->p_itcallout, tvtohz(&aitv->it_value),realitexpire, p);timevaladd(&aitv->it_value, &ctv);}*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);elsetimevalsub(&oitv->it_value, &ctv);}} else {mtx_lock_spin(&sched_lock);*oitv = p->p_stats->p_timer[which];p->p_stats->p_timer[which] = *aitv;mtx_unlock_spin(&sched_lock);}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.*/voidrealitexpire(void *arg){struct proc *p;struct timeval ctv, ntv;p = (struct proc *)arg;PROC_LOCK(p);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);PROC_UNLOCK(p);return;}for (;;) {timevaladd(&p->p_realtimer.it_value,&p->p_realtimer.it_interval);getmicrouptime(&ctv);if (timevalcmp(&p->p_realtimer.it_value, &ctv, >)) {ntv = p->p_realtimer.it_value;timevalsub(&ntv, &ctv);callout_reset(&p->p_itcallout, tvtohz(&ntv) - 1,realitexpire, p);PROC_UNLOCK(p);return;}}/*NOTREACHED*/}/** 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.)*/intitimerfix(struct timeval *tv){if (tv->tv_sec < 0 || tv->tv_sec > 100000000 ||tv->tv_usec < 0 || tv->tv_usec >= 1000000)return (EINVAL);if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick)tv->tv_usec = tick;return (0);}/** Decrement an interval timer by a specified number* of microseconds, which must be less than a second,* i.e. < 1000000. If the timer expires, then reload* it. In this case, carry over (usec - old value) to* reduce the value reloaded into the timer so that* the timer does not drift. This routine assumes* that it is called in a context where the timers* on which it is operating cannot change in value.*/intitimerdecr(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--;}} elseitp->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.*/voidtimevaladd(struct timeval *t1, const struct timeval *t2){t1->tv_sec += t2->tv_sec;t1->tv_usec += t2->tv_usec;timevalfix(t1);}voidtimevalsub(struct timeval *t1, const struct timeval *t2){t1->tv_sec -= t2->tv_sec;t1->tv_usec -= t2->tv_usec;timevalfix(t1);}static voidtimevalfix(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.*/intratecheck(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.*/intppsratecheck(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);}}