diff options
Diffstat (limited to 'sys/kern/kern_time.c')
| -rw-r--r-- | sys/kern/kern_time.c | 714 |
1 files changed, 714 insertions, 0 deletions
diff --git a/sys/kern/kern_time.c b/sys/kern/kern_time.c new file mode 100644 index 0000000..96ed21c --- /dev/null +++ b/sys/kern/kern_time.c @@ -0,0 +1,714 @@ +/* + * 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 8.1 (Berkeley) 6/10/93 + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#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/kernel.h> +#include <sys/mac.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 nanosleep1(struct thread *td, struct timespec *rqt, + struct timespec *rmt); +static int settime(struct thread *, struct timeval *); +static void timevalfix(struct timeval *); +static void no_lease_updatetime(int); + +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; + + if (uap->clock_id == CLOCK_REALTIME) + nanotime(&ats); + else if (uap->clock_id == CLOCK_MONOTONIC) + nanouptime(&ats); + else + 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 ((error = suser(td)) != 0) + return (error); + 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; + int error; + + if (uap->clock_id != CLOCK_REALTIME) + return (EINVAL); + error = 0; + if (uap->tp) { + ts.tv_sec = 0; + /* + * 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; + error = copyout(&ts, uap->tp, sizeof(ts)); + } + return (error); +} + +static int nanowait; + +static int +nanosleep1(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 = nanosleep1(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; + struct timezone atz; + int error = 0; + +#ifdef MAC + error = mac_check_system_settime(td->td_ucred); + if (error) + return (error); +#endif + if ((error = suser(td))) + return (error); + /* Verify all parameters before changing time. */ + if (uap->tv) { + if ((error = copyin(uap->tv, &atv, sizeof(atv)))) + return (error); + if (atv.tv_usec < 0 || atv.tv_usec >= 1000000) + return (EINVAL); + } + if (uap->tzp && + (error = copyin(uap->tzp, &atz, sizeof(atz)))) + return (error); + + if (uap->tv && (error = settime(td, &atv))) + return (error); + if (uap->tzp) { + tz_minuteswest = atz.tz_minuteswest; + tz_dsttime = atz.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 proc *p = td->td_proc; + struct timeval ctv; + struct itimerval aitv; + + if (uap->which > ITIMER_PROF) + return (EINVAL); + + if (uap->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[uap->which]; + mtx_unlock_spin(&sched_lock); + } + return (copyout(&aitv, uap->itv, sizeof (struct itimerval))); +} + +#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 proc *p = td->td_proc; + struct itimerval aitv, oitv; + struct timeval ctv; + int error; + + if (uap->itv == NULL) { + uap->itv = uap->oitv; + return (getitimer(td, (struct getitimer_args *)uap)); + } + + if (uap->which > ITIMER_PROF) + return (EINVAL); + if ((error = copyin(uap->itv, &aitv, sizeof(struct itimerval)))) + return (error); + 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 (uap->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[uap->which]; + p->p_stats->p_timer[uap->which] = aitv; + mtx_unlock_spin(&sched_lock); + } + if (uap->oitv == NULL) + return (0); + return (copyout(&oitv, uap->oitv, sizeof(struct itimerval))); +} + +/* + * 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, 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); +} + +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); + } +} |
