0,0 → 1,791 |
/*- |
* 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 void |
no_lease_updatetime(deltat) |
int deltat; |
{ |
} |
|
void (*lease_updatetime)(int) = no_lease_updatetime; |
|
static int |
settime(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 */ |
int |
clock_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 */ |
int |
clock_settime(struct thread *td, struct clock_settime_args *uap) |
{ |
struct timeval atv; |
struct timespec ats; |
int error; |
|
#ifdef MAC |
error = mac_check_system_settime(td->td_ucred); |
if (error) |
return (error); |
#endif |
if (!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; |
}; |
#endif |
|
int |
clock_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; |
|
int |
kern_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 */ |
int |
nanosleep(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 */ |
int |
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 = 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 */ |
int |
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 = 0; |
|
#ifdef MAC |
error = mac_check_system_settime(td->td_ucred); |
if (error) |
return (error); |
#endif |
if (!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 |
*/ |
int |
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)) { |
getmicrouptime(&ctv); |
if (timevalcmp(&aitv->it_value, &ctv, <)) |
timevalclear(&aitv->it_value); |
else |
timevalsub(&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 |
*/ |
int |
setitimer(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))); |
} |
|
int |
kern_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); |
else |
timevalsub(&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. |
*/ |
void |
realitexpire(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.) |
*/ |
int |
itimerfix(struct timeval *tv) |
{ |
|
if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || |
tv->tv_usec < 0 || tv->tv_usec >= 1000000) |
return (EINVAL); |
if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) |
tv->tv_usec = tick; |
return (0); |
} |
|
/* |
* Decrement an interval timer by a specified number |
* of microseconds, which must be less than a second, |
* i.e. < 1000000. If the timer expires, then reload |
* it. In this case, carry over (usec - old value) to |
* reduce the value reloaded into the timer so that |
* the timer does not drift. This routine assumes |
* that it is called in a context where the timers |
* on which it is operating cannot change in value. |
*/ |
int |
itimerdecr(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); |
} |
} |