/* * 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 * $FreeBSD$ */ #include "opt_mac.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include 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); if (timevalisset(&aitv.it_value)) callout_reset(&p->p_itcallout, tvtohz(&aitv.it_value), realitexpire, p); getmicrouptime(&ctv); 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); 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). * * 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 (1); } else { (*curpps)++; /* NB: ignore potential overflow */ return (maxpps < 0 || *curpps < maxpps); } }