diff options
Diffstat (limited to 'sys/kern/kern_time.c')
| -rw-r--r-- | sys/kern/kern_time.c | 416 |
1 files changed, 416 insertions, 0 deletions
diff --git a/sys/kern/kern_time.c b/sys/kern/kern_time.c new file mode 100644 index 0000000..4dadcb8 --- /dev/null +++ b/sys/kern/kern_time.c @@ -0,0 +1,416 @@ +/* + * 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/param.h> +#include <sys/resourcevar.h> +#include <sys/kernel.h> +#include <sys/systm.h> +#include <sys/proc.h> +#include <sys/vnode.h> + +#include <machine/cpu.h> + +/* + * 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. + */ + +struct gettimeofday_args { + struct timeval *tp; + struct timezone *tzp; +}; +/* ARGSUSED */ +gettimeofday(p, uap, retval) + struct proc *p; + register struct gettimeofday_args *uap; + int *retval; +{ + struct timeval atv; + int error = 0; + + if (uap->tp) { + microtime(&atv); + if (error = copyout((caddr_t)&atv, (caddr_t)uap->tp, + sizeof (atv))) + return (error); + } + if (uap->tzp) + error = copyout((caddr_t)&tz, (caddr_t)uap->tzp, + sizeof (tz)); + return (error); +} + +struct settimeofday_args { + struct timeval *tv; + struct timezone *tzp; +}; +/* ARGSUSED */ +settimeofday(p, uap, retval) + struct proc *p; + struct settimeofday_args *uap; + int *retval; +{ + struct timeval atv, delta; + struct timezone atz; + int error, s; + + if (error = suser(p->p_ucred, &p->p_acflag)) + return (error); + /* Verify all parameters before changing time. */ + if (uap->tv && + (error = copyin((caddr_t)uap->tv, (caddr_t)&atv, sizeof(atv)))) + return (error); + if (uap->tzp && + (error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, sizeof(atz)))) + return (error); + if (uap->tv) { + /* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */ + s = splclock(); + /* nb. delta.tv_usec may be < 0, but this is OK here */ + delta.tv_sec = atv.tv_sec - time.tv_sec; + delta.tv_usec = atv.tv_usec - time.tv_usec; + time = atv; + (void) splsoftclock(); + timevaladd(&boottime, &delta); + timevalfix(&boottime); + timevaladd(&runtime, &delta); + timevalfix(&runtime); + LEASE_UPDATETIME(delta.tv_sec); + splx(s); + resettodr(); + } + if (uap->tzp) + tz = atz; + return (0); +} + +extern int tickadj; /* "standard" clock skew, us./tick */ +int tickdelta; /* current clock skew, us. per tick */ +long timedelta; /* unapplied time correction, us. */ +long bigadj = 1000000; /* use 10x skew above bigadj us. */ + +struct adjtime_args { + struct timeval *delta; + struct timeval *olddelta; +}; +/* ARGSUSED */ +adjtime(p, uap, retval) + struct proc *p; + register struct adjtime_args *uap; + int *retval; +{ + struct timeval atv; + register long ndelta, ntickdelta, odelta; + int s, error; + + if (error = suser(p->p_ucred, &p->p_acflag)) + return (error); + if (error = + copyin((caddr_t)uap->delta, (caddr_t)&atv, sizeof(struct timeval))) + return (error); + + /* + * Compute the total correction and the rate at which to apply it. + * Round the adjustment down to a whole multiple of the per-tick + * delta, so that after some number of incremental changes in + * hardclock(), tickdelta will become zero, lest the correction + * overshoot and start taking us away from the desired final time. + */ + ndelta = atv.tv_sec * 1000000 + atv.tv_usec; + if (ndelta > bigadj) + ntickdelta = 10 * tickadj; + else + ntickdelta = tickadj; + if (ndelta % ntickdelta) + ndelta = ndelta / ntickdelta * ntickdelta; + + /* + * To make hardclock()'s job easier, make the per-tick delta negative + * if we want time to run slower; then hardclock can simply compute + * tick + tickdelta, and subtract tickdelta from timedelta. + */ + if (ndelta < 0) + ntickdelta = -ntickdelta; + s = splclock(); + odelta = timedelta; + timedelta = ndelta; + tickdelta = ntickdelta; + splx(s); + + if (uap->olddelta) { + atv.tv_sec = odelta / 1000000; + atv.tv_usec = odelta % 1000000; + (void) copyout((caddr_t)&atv, (caddr_t)uap->olddelta, + sizeof(struct timeval)); + } + return (0); +} + +/* + * 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. + */ +struct getitimer_args { + u_int which; + struct itimerval *itv; +}; +/* ARGSUSED */ +getitimer(p, uap, retval) + struct proc *p; + register struct getitimer_args *uap; + int *retval; +{ + struct itimerval aitv; + int s; + + if (uap->which > ITIMER_PROF) + return (EINVAL); + s = splclock(); + if (uap->which == ITIMER_REAL) { + /* + * Convert from absoulte 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. + */ + aitv = p->p_realtimer; + if (timerisset(&aitv.it_value)) + if (timercmp(&aitv.it_value, &time, <)) + timerclear(&aitv.it_value); + else + timevalsub(&aitv.it_value, + (struct timeval *)&time); + } else + aitv = p->p_stats->p_timer[uap->which]; + splx(s); + return (copyout((caddr_t)&aitv, (caddr_t)uap->itv, + sizeof (struct itimerval))); +} + +struct setitimer_args { + u_int which; + struct itimerval *itv, *oitv; +}; +/* ARGSUSED */ +setitimer(p, uap, retval) + struct proc *p; + register struct setitimer_args *uap; + int *retval; +{ + struct itimerval aitv; + register struct itimerval *itvp; + int s, error; + + if (uap->which > ITIMER_PROF) + return (EINVAL); + itvp = uap->itv; + if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv, + sizeof(struct itimerval)))) + return (error); + if ((uap->itv = uap->oitv) && (error = getitimer(p, uap, retval))) + return (error); + if (itvp == 0) + return (0); + if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) + return (EINVAL); + s = splclock(); + if (uap->which == ITIMER_REAL) { + untimeout(realitexpire, (caddr_t)p); + if (timerisset(&aitv.it_value)) { + timevaladd(&aitv.it_value, (struct timeval *)&time); + timeout(realitexpire, (caddr_t)p, hzto(&aitv.it_value)); + } + p->p_realtimer = aitv; + } else + p->p_stats->p_timer[uap->which] = aitv; + 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(arg) + void *arg; +{ + register struct proc *p; + int s; + + p = (struct proc *)arg; + psignal(p, SIGALRM); + if (!timerisset(&p->p_realtimer.it_interval)) { + timerclear(&p->p_realtimer.it_value); + return; + } + for (;;) { + s = splclock(); + timevaladd(&p->p_realtimer.it_value, + &p->p_realtimer.it_interval); + if (timercmp(&p->p_realtimer.it_value, &time, >)) { + timeout(realitexpire, (caddr_t)p, + hzto(&p->p_realtimer.it_value)); + splx(s); + return; + } + splx(s); + } +} + +/* + * 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.) + */ +itimerfix(tv) + 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. + */ +itimerdecr(itp, usec) + register 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); +} + +/* + * 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. + */ +timevaladd(t1, t2) + struct timeval *t1, *t2; +{ + + t1->tv_sec += t2->tv_sec; + t1->tv_usec += t2->tv_usec; + timevalfix(t1); +} + +timevalsub(t1, t2) + struct timeval *t1, *t2; +{ + + t1->tv_sec -= t2->tv_sec; + t1->tv_usec -= t2->tv_usec; + timevalfix(t1); +} + +timevalfix(t1) + 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; + } +} |
