271 lines
6.7 KiB
C
271 lines
6.7 KiB
C
/* $NetBSD: subr_time.c,v 1.17 2013/05/22 16:00:52 christos Exp $ */
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/*
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* Copyright (c) 1982, 1986, 1989, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)kern_clock.c 8.5 (Berkeley) 1/21/94
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* @(#)kern_time.c 8.4 (Berkeley) 5/26/95
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: subr_time.c,v 1.17 2013/05/22 16:00:52 christos Exp $");
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/timex.h>
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#include <sys/time.h>
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#include <sys/timetc.h>
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#include <sys/intr.h>
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/*
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* Compute number of hz until specified time. Used to compute second
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* argument to callout_reset() from an absolute time.
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*/
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int
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tvhzto(const struct timeval *tvp)
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{
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struct timeval now, tv;
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tv = *tvp; /* Don't modify original tvp. */
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getmicrotime(&now);
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timersub(&tv, &now, &tv);
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return tvtohz(&tv);
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}
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/*
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* Compute number of ticks in the specified amount of time.
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*/
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int
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tvtohz(const struct timeval *tv)
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{
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unsigned long ticks;
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long sec, usec;
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/*
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* If the number of usecs in the whole seconds part of the time
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* difference fits in a long, then the total number of usecs will
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* fit in an unsigned long. Compute the total and convert it to
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* ticks, rounding up and adding 1 to allow for the current tick
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* to expire. Rounding also depends on unsigned long arithmetic
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* to avoid overflow.
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*
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* Otherwise, if the number of ticks in the whole seconds part of
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* the time difference fits in a long, then convert the parts to
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* ticks separately and add, using similar rounding methods and
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* overflow avoidance. This method would work in the previous
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* case, but it is slightly slower and assumes that hz is integral.
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*
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* Otherwise, round the time difference down to the maximum
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* representable value.
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*
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* If ints are 32-bit, then the maximum value for any timeout in
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* 10ms ticks is 248 days.
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*/
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sec = tv->tv_sec;
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usec = tv->tv_usec;
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KASSERT(usec >= 0 && usec < 1000000);
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/* catch overflows in conversion time_t->int */
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if (tv->tv_sec > INT_MAX)
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return INT_MAX;
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if (tv->tv_sec < 0)
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return 0;
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if (sec < 0 || (sec == 0 && usec == 0)) {
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/*
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* Would expire now or in the past. Return 0 ticks.
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* This is different from the legacy tvhzto() interface,
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* and callers need to check for it.
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*/
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ticks = 0;
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} else if (sec <= (LONG_MAX / 1000000))
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ticks = (((sec * 1000000) + (unsigned long)usec + (tick - 1))
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/ tick) + 1;
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else if (sec <= (LONG_MAX / hz))
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ticks = (sec * hz) +
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(((unsigned long)usec + (tick - 1)) / tick) + 1;
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else
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ticks = LONG_MAX;
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if (ticks > INT_MAX)
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ticks = INT_MAX;
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return ((int)ticks);
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}
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int
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tshzto(const struct timespec *tsp)
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{
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struct timespec now, ts;
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ts = *tsp; /* Don't modify original tsp. */
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getnanotime(&now);
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timespecsub(&ts, &now, &ts);
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return tstohz(&ts);
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}
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int
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tshztoup(const struct timespec *tsp)
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{
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struct timespec now, ts;
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ts = *tsp; /* Don't modify original tsp. */
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getnanouptime(&now);
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timespecsub(&ts, &now, &ts);
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return tstohz(&ts);
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}
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/*
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* Compute number of ticks in the specified amount of time.
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*/
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int
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tstohz(const struct timespec *ts)
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{
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struct timeval tv;
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/*
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* usec has great enough resolution for hz, so convert to a
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* timeval and use tvtohz() above.
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*/
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TIMESPEC_TO_TIMEVAL(&tv, ts);
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return tvtohz(&tv);
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}
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/*
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* Check that a proposed value to load into the .it_value or
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* .it_interval part of an interval timer is acceptable, and
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* fix it to have at least minimal value (i.e. if it is less
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* than the resolution of the clock, round it up.). We don't
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* timeout the 0,0 value because this means to disable the
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* timer or the interval.
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*/
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int
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itimerfix(struct timeval *tv)
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{
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if (tv->tv_usec < 0 || tv->tv_usec >= 1000000)
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return EINVAL;
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if (tv->tv_sec < 0)
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return ETIMEDOUT;
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if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick)
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tv->tv_usec = tick;
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return 0;
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}
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int
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itimespecfix(struct timespec *ts)
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{
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if (ts->tv_nsec < 0 || ts->tv_nsec >= 1000000000)
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return EINVAL;
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if (ts->tv_sec < 0)
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return ETIMEDOUT;
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if (ts->tv_sec == 0 && ts->tv_nsec != 0 && ts->tv_nsec < tick * 1000)
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ts->tv_nsec = tick * 1000;
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return 0;
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}
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int
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inittimeleft(struct timespec *ts, struct timespec *sleepts)
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{
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if (itimespecfix(ts)) {
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return -1;
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}
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getnanouptime(sleepts);
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return 0;
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}
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int
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gettimeleft(struct timespec *ts, struct timespec *sleepts)
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{
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struct timespec sleptts;
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/*
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* Reduce ts by elapsed time based on monotonic time scale.
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*/
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getnanouptime(&sleptts);
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timespecadd(ts, sleepts, ts);
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timespecsub(ts, &sleptts, ts);
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*sleepts = sleptts;
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return tstohz(ts);
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}
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int
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clock_gettime1(clockid_t clock_id, struct timespec *ts)
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{
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switch (clock_id) {
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case CLOCK_REALTIME:
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nanotime(ts);
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break;
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case CLOCK_MONOTONIC:
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nanouptime(ts);
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break;
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default:
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return EINVAL;
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}
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return 0;
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}
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/*
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* Calculate delta and convert from struct timespec to the ticks.
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*/
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int
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ts2timo(clockid_t clock_id, int flags, struct timespec *ts,
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int *timo, struct timespec *start)
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{
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int error;
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struct timespec tsd;
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flags &= TIMER_ABSTIME;
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if (start == NULL)
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start = &tsd;
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if (flags || start != &tsd)
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if ((error = clock_gettime1(clock_id, start)) != 0)
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return error;
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if (flags)
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timespecsub(ts, start, ts);
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if ((error = itimespecfix(ts)) != 0)
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return error;
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if (ts->tv_sec == 0 && ts->tv_nsec == 0)
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return ETIMEDOUT;
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*timo = tstohz(ts);
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KASSERT(*timo > 0);
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return 0;
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}
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