/* $OpenBSD: kern_time.c,v 1.77 2013/03/28 16:55:25 deraadt Exp $ */ /* $NetBSD: kern_time.c,v 1.20 1996/02/18 11:57:06 fvdl Exp $ */ /* * 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 8.4 (Berkeley) 5/26/95 */ #include #include #include #include #include #include #include #include #include #include #include struct timeval adjtimedelta; /* unapplied time correction */ void itimerround(struct timeval *); /* * 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. */ /* This function is used by clock_settime and settimeofday */ int settime(struct timespec *ts) { struct timespec now; /* * Adjtime in progress is meaningless or harmful after * setting the clock. Cancel adjtime and then set new time. */ adjtimedelta.tv_usec = 0; adjtimedelta.tv_sec = 0; /* * Don't allow the time to be set forward so far it will wrap * and become negative, thus allowing an attacker to bypass * the next check below. The cutoff is 1 year before rollover * occurs, so even if the attacker uses adjtime(2) to move * the time past the cutoff, it will take a very long time * to get to the wrap point. * * XXX: we check against INT_MAX since on 64-bit * platforms, sizeof(int) != sizeof(long) and * time_t is 32 bits even when atv.tv_sec is 64 bits. */ if (ts->tv_sec > INT_MAX - 365*24*60*60) { printf("denied attempt to set clock forward to %ld\n", ts->tv_sec); return (EPERM); } /* * If the system is secure, we do not allow the time to be * set to an earlier value (it may be slowed using adjtime, * but not set back). This feature prevent interlopers from * setting arbitrary time stamps on files. */ nanotime(&now); if (securelevel > 1 && timespeccmp(ts, &now, <)) { printf("denied attempt to set clock back %ld seconds\n", now.tv_sec - ts->tv_sec); return (EPERM); } tc_setrealtimeclock(ts); resettodr(); return (0); } int clock_gettime(struct proc *p, clockid_t clock_id, struct timespec *tp) { struct timeval tv; switch (clock_id) { case CLOCK_REALTIME: nanotime(tp); break; case CLOCK_MONOTONIC: nanouptime(tp); break; case CLOCK_PROF: microuptime(&tv); timersub(&tv, &curcpu()->ci_schedstate.spc_runtime, &tv); timeradd(&tv, &p->p_rtime, &tv); tp->tv_sec = tv.tv_sec; tp->tv_nsec = tv.tv_usec * 1000; break; default: return (EINVAL); } return (0); } /* ARGSUSED */ int sys_clock_gettime(struct proc *p, void *v, register_t *retval) { struct sys_clock_gettime_args /* { syscallarg(clockid_t) clock_id; syscallarg(struct timespec *) tp; } */ *uap = v; struct timespec ats; int error; if ((error = clock_gettime(p, SCARG(uap, clock_id), &ats)) != 0) return (error); error = copyout(&ats, SCARG(uap, tp), sizeof(ats)); #ifdef KTRACE if (error == 0 && KTRPOINT(p, KTR_STRUCT)) { KERNEL_LOCK(); ktrabstimespec(p, &ats); KERNEL_UNLOCK(); } #endif return (error); } /* ARGSUSED */ int sys_clock_settime(struct proc *p, void *v, register_t *retval) { struct sys_clock_settime_args /* { syscallarg(clockid_t) clock_id; syscallarg(const struct timespec *) tp; } */ *uap = v; struct timespec ats; clockid_t clock_id; int error; if ((error = suser(p, 0)) != 0) return (error); if ((error = copyin(SCARG(uap, tp), &ats, sizeof(ats))) != 0) return (error); clock_id = SCARG(uap, clock_id); switch (clock_id) { case CLOCK_REALTIME: if ((error = settime(&ats)) != 0) return (error); break; default: /* Other clocks are read-only */ return (EINVAL); } return (0); } int sys_clock_getres(struct proc *p, void *v, register_t *retval) { struct sys_clock_getres_args /* { syscallarg(clockid_t) clock_id; syscallarg(struct timespec *) tp; } */ *uap = v; clockid_t clock_id; struct timespec ts; int error = 0; clock_id = SCARG(uap, clock_id); switch (clock_id) { case CLOCK_REALTIME: case CLOCK_MONOTONIC: ts.tv_sec = 0; ts.tv_nsec = 1000000000 / hz; break; default: return (EINVAL); } if (SCARG(uap, tp)) { error = copyout(&ts, SCARG(uap, tp), sizeof (ts)); #ifdef KTRACE if (error == 0 && KTRPOINT(p, KTR_STRUCT)) { KERNEL_LOCK(); ktrreltimespec(p, &ts); KERNEL_UNLOCK(); } #endif } return error; } /* ARGSUSED */ int sys_nanosleep(struct proc *p, void *v, register_t *retval) { static int nanowait; struct sys_nanosleep_args/* { syscallarg(const struct timespec *) rqtp; syscallarg(struct timespec *) rmtp; } */ *uap = v; struct timespec rqt, rmt; struct timespec sts, ets; struct timespec *rmtp; struct timeval tv; int error, error1; rmtp = SCARG(uap, rmtp); error = copyin(SCARG(uap, rqtp), &rqt, sizeof(struct timespec)); if (error) return (error); #ifdef KTRACE if (KTRPOINT(p, KTR_STRUCT)) { KERNEL_LOCK(); ktrreltimespec(p, &rqt); KERNEL_UNLOCK(); } #endif TIMESPEC_TO_TIMEVAL(&tv, &rqt); if (itimerfix(&tv)) return (EINVAL); if (rmtp) getnanouptime(&sts); error = tsleep(&nanowait, PWAIT | PCATCH, "nanosleep", MAX(1, tvtohz(&tv))); if (error == ERESTART) error = EINTR; if (error == EWOULDBLOCK) error = 0; if (rmtp) { getnanouptime(&ets); timespecsub(&ets, &sts, &sts); timespecsub(&rqt, &sts, &rmt); if (rmt.tv_sec < 0) timespecclear(&rmt); error1 = copyout(&rmt, rmtp, sizeof(rmt)); if (error1 != 0) error = error1; #ifdef KTRACE if (error1 == 0 && KTRPOINT(p, KTR_STRUCT)) { KERNEL_LOCK(); ktrreltimespec(p, &rmt); KERNEL_UNLOCK(); } #endif } return error; } /* ARGSUSED */ int sys_gettimeofday(struct proc *p, void *v, register_t *retval) { struct sys_gettimeofday_args /* { syscallarg(struct timeval *) tp; syscallarg(struct timezone *) tzp; } */ *uap = v; struct timeval atv; struct timeval *tp; struct timezone *tzp; int error = 0; tp = SCARG(uap, tp); tzp = SCARG(uap, tzp); if (tp) { microtime(&atv); if ((error = copyout(&atv, tp, sizeof (atv)))) return (error); #ifdef KTRACE if (KTRPOINT(p, KTR_STRUCT)) { KERNEL_LOCK(); ktrabstimeval(p, &atv); KERNEL_UNLOCK(); } #endif } if (tzp) error = copyout(&tz, tzp, sizeof (tz)); return (error); } /* ARGSUSED */ int sys_settimeofday(struct proc *p, void *v, register_t *retval) { struct sys_settimeofday_args /* { syscallarg(const struct timeval *) tv; syscallarg(const struct timezone *) tzp; } */ *uap = v; struct timezone atz; struct timeval atv; const struct timeval *tv; const struct timezone *tzp; int error; tv = SCARG(uap, tv); tzp = SCARG(uap, tzp); if ((error = suser(p, 0))) return (error); /* Verify all parameters before changing time. */ if (tv && (error = copyin(tv, &atv, sizeof(atv)))) return (error); if (tzp && (error = copyin(tzp, &atz, sizeof(atz)))) return (error); if (tv) { struct timespec ts; TIMEVAL_TO_TIMESPEC(&atv, &ts); if ((error = settime(&ts)) != 0) return (error); } if (tzp) tz = atz; return (0); } /* ARGSUSED */ int sys_adjfreq(struct proc *p, void *v, register_t *retval) { struct sys_adjfreq_args /* { syscallarg(const int64_t *) freq; syscallarg(int64_t *) oldfreq; } */ *uap = v; int error; int64_t f; const int64_t *freq = SCARG(uap, freq); int64_t *oldfreq = SCARG(uap, oldfreq); if (oldfreq) { if ((error = tc_adjfreq(&f, NULL))) return (error); if ((error = copyout(&f, oldfreq, sizeof(f)))) return (error); } if (freq) { if ((error = suser(p, 0))) return (error); if ((error = copyin(freq, &f, sizeof(f)))) return (error); if ((error = tc_adjfreq(NULL, &f))) return (error); } return (0); } /* ARGSUSED */ int sys_adjtime(struct proc *p, void *v, register_t *retval) { struct sys_adjtime_args /* { syscallarg(const struct timeval *) delta; syscallarg(struct timeval *) olddelta; } */ *uap = v; const struct timeval *delta = SCARG(uap, delta); struct timeval *olddelta = SCARG(uap, olddelta); int error; if (olddelta) if ((error = copyout(&adjtimedelta, olddelta, sizeof(struct timeval)))) return (error); if (delta) { if ((error = suser(p, 0))) return (error); if ((error = copyin(delta, &adjtimedelta, sizeof(struct timeval)))) return (error); } /* Normalize the correction. */ while (adjtimedelta.tv_usec >= 1000000) { adjtimedelta.tv_usec -= 1000000; adjtimedelta.tv_sec += 1; } while (adjtimedelta.tv_usec < 0) { adjtimedelta.tv_usec += 1000000; adjtimedelta.tv_sec -= 1; } return (0); } /* * Get value of an interval timer. The process virtual and * profiling virtual time timers are kept internally in the * way they are specified externally: in time until they expire. * * The real time interval timer's it_value, in contast, 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. */ /* ARGSUSED */ int sys_getitimer(struct proc *p, void *v, register_t *retval) { struct sys_getitimer_args /* { syscallarg(int) which; syscallarg(struct itimerval *) itv; } */ *uap = v; struct itimerval aitv; int s; int which; which = SCARG(uap, which); if (which < ITIMER_REAL || which > ITIMER_PROF) return (EINVAL); s = splclock(); aitv = p->p_p->ps_timer[which]; if (which == ITIMER_REAL) { struct timeval now; getmicrouptime(&now); /* * 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. */ if (timerisset(&aitv.it_value)) { if (timercmp(&aitv.it_value, &now, <)) timerclear(&aitv.it_value); else timersub(&aitv.it_value, &now, &aitv.it_value); } } splx(s); return (copyout(&aitv, SCARG(uap, itv), sizeof (struct itimerval))); } /* ARGSUSED */ int sys_setitimer(struct proc *p, void *v, register_t *retval) { struct sys_setitimer_args /* { syscallarg(int) which; syscallarg(const struct itimerval *) itv; syscallarg(struct itimerval *) oitv; } */ *uap = v; struct sys_getitimer_args getargs; struct itimerval aitv; const struct itimerval *itvp; struct itimerval *oitv; struct process *pr = p->p_p; int error; int timo; int which; which = SCARG(uap, which); oitv = SCARG(uap, oitv); if (which < ITIMER_REAL || which > ITIMER_PROF) return (EINVAL); itvp = SCARG(uap, itv); if (itvp && (error = copyin((void *)itvp, (void *)&aitv, sizeof(struct itimerval)))) return (error); if (oitv != NULL) { SCARG(&getargs, which) = which; SCARG(&getargs, itv) = oitv; if ((error = sys_getitimer(p, &getargs, retval))) return (error); } if (itvp == 0) return (0); if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) return (EINVAL); if (which == ITIMER_REAL) { struct timeval ctv; timeout_del(&pr->ps_realit_to); getmicrouptime(&ctv); if (timerisset(&aitv.it_value)) { timo = tvtohz(&aitv.it_value); timeout_add(&pr->ps_realit_to, timo); timeradd(&aitv.it_value, &ctv, &aitv.it_value); } pr->ps_timer[ITIMER_REAL] = aitv; } else { int s; itimerround(&aitv.it_interval); s = splclock(); pr->ps_timer[which] = aitv; if (which == ITIMER_VIRTUAL) timeout_del(&pr->ps_virt_to); if (which == ITIMER_PROF) timeout_del(&pr->ps_prof_to); splx(s); } 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. */ void realitexpire(void *arg) { struct process *pr = arg; struct itimerval *tp = &pr->ps_timer[ITIMER_REAL]; psignal(pr->ps_mainproc, SIGALRM); if (!timerisset(&tp->it_interval)) { timerclear(&tp->it_value); return; } for (;;) { struct timeval ctv, ntv; int timo; timeradd(&tp->it_value, &tp->it_interval, &tp->it_value); getmicrouptime(&ctv); if (timercmp(&tp->it_value, &ctv, >)) { ntv = tp->it_value; timersub(&ntv, &ctv, &ntv); timo = tvtohz(&ntv) - 1; if (timo <= 0) timo = 1; if ((pr->ps_flags & PS_EXITING) == 0) timeout_add(&pr->ps_realit_to, timo); return; } } } /* * Check that a timespec value is legit */ int timespecfix(struct timespec *ts) { if (ts->tv_sec < 0 || ts->tv_sec > 100000000 || ts->tv_nsec < 0 || ts->tv_nsec >= 1000000000) return (EINVAL); return (0); } /* * Check that a proposed value to load into the .it_value or * .it_interval part of an interval timer is acceptable. */ 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); } /* * Nonzero timer interval smaller than the resolution of the * system clock are rounded up. */ void itimerround(struct timeval *tv) { if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) tv->tv_usec = tick; } /* * 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 (timerisset(&itp->it_value)) return (1); /* expired, exactly at end of interval */ expire: if (timerisset(&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); } /* * ratecheck(): simple time-based rate-limit checking. see ratecheck(9) * for usage and rationale. */ int ratecheck(struct timeval *lasttime, const struct timeval *mininterval) { struct timeval tv, delta; int rv = 0; getmicrouptime(&tv); timersub(&tv, lasttime, &delta); /* * check for 0,0 is so that the message will be seen at least once, * even if interval is huge. */ if (timercmp(&delta, mininterval, >=) || (lasttime->tv_sec == 0 && lasttime->tv_usec == 0)) { *lasttime = tv; rv = 1; } return (rv); } /* * ppsratecheck(): packets (or events) per second limitation. */ int ppsratecheck(struct timeval *lasttime, int *curpps, int maxpps) { struct timeval tv, delta; int rv; microuptime(&tv); timersub(&tv, lasttime, &delta); /* * check for 0,0 is so that the message will be seen at least once. * if more than one second have passed since the last update of * lasttime, reset the counter. * * we do increment *curpps even in *curpps < maxpps case, as some may * try to use *curpps for stat purposes as well. */ if (maxpps == 0) rv = 0; else if ((lasttime->tv_sec == 0 && lasttime->tv_usec == 0) || delta.tv_sec >= 1) { *lasttime = tv; *curpps = 0; rv = 1; } else if (maxpps < 0) rv = 1; else if (*curpps < maxpps) rv = 1; else rv = 0; #if 1 /*DIAGNOSTIC?*/ /* be careful about wrap-around */ if (*curpps + 1 > *curpps) *curpps = *curpps + 1; #else /* * assume that there's not too many calls to this function. * not sure if the assumption holds, as it depends on *caller's* * behavior, not the behavior of this function. * IMHO it is wrong to make assumption on the caller's behavior, * so the above #if is #if 1, not #ifdef DIAGNOSTIC. */ *curpps = *curpps + 1; #endif return (rv); }