/* $NetBSD: subr_time.c,v 1.17 2013/05/22 16:00:52 christos 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_clock.c 8.5 (Berkeley) 1/21/94 * @(#)kern_time.c 8.4 (Berkeley) 5/26/95 */ #include __KERNEL_RCSID(0, "$NetBSD: subr_time.c,v 1.17 2013/05/22 16:00:52 christos Exp $"); #include #include #include #include #include #include /* * Compute number of hz until specified time. Used to compute second * argument to callout_reset() from an absolute time. */ int tvhzto(const struct timeval *tvp) { struct timeval now, tv; tv = *tvp; /* Don't modify original tvp. */ getmicrotime(&now); timersub(&tv, &now, &tv); return tvtohz(&tv); } /* * Compute number of ticks in the specified amount of time. */ int tvtohz(const struct timeval *tv) { unsigned long ticks; long sec, usec; /* * If the number of usecs in the whole seconds part of the time * difference fits in a long, then the total number of usecs will * fit in an unsigned long. Compute the total and convert it to * ticks, rounding up and adding 1 to allow for the current tick * to expire. Rounding also depends on unsigned long arithmetic * to avoid overflow. * * Otherwise, if the number of ticks in the whole seconds part of * the time difference fits in a long, then convert the parts to * ticks separately and add, using similar rounding methods and * overflow avoidance. This method would work in the previous * case, but it is slightly slower and assumes that hz is integral. * * Otherwise, round the time difference down to the maximum * representable value. * * If ints are 32-bit, then the maximum value for any timeout in * 10ms ticks is 248 days. */ sec = tv->tv_sec; usec = tv->tv_usec; KASSERT(usec >= 0 && usec < 1000000); /* catch overflows in conversion time_t->int */ if (tv->tv_sec > INT_MAX) return INT_MAX; if (tv->tv_sec < 0) return 0; if (sec < 0 || (sec == 0 && usec == 0)) { /* * Would expire now or in the past. Return 0 ticks. * This is different from the legacy tvhzto() interface, * and callers need to check for it. */ ticks = 0; } else if (sec <= (LONG_MAX / 1000000)) ticks = (((sec * 1000000) + (unsigned long)usec + (tick - 1)) / tick) + 1; else if (sec <= (LONG_MAX / hz)) ticks = (sec * hz) + (((unsigned long)usec + (tick - 1)) / tick) + 1; else ticks = LONG_MAX; if (ticks > INT_MAX) ticks = INT_MAX; return ((int)ticks); } int tshzto(const struct timespec *tsp) { struct timespec now, ts; ts = *tsp; /* Don't modify original tsp. */ getnanotime(&now); timespecsub(&ts, &now, &ts); return tstohz(&ts); } int tshztoup(const struct timespec *tsp) { struct timespec now, ts; ts = *tsp; /* Don't modify original tsp. */ getnanouptime(&now); timespecsub(&ts, &now, &ts); return tstohz(&ts); } /* * Compute number of ticks in the specified amount of time. */ int tstohz(const struct timespec *ts) { struct timeval tv; /* * usec has great enough resolution for hz, so convert to a * timeval and use tvtohz() above. */ TIMESPEC_TO_TIMEVAL(&tv, ts); return tvtohz(&tv); } /* * 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.). We don't * timeout the 0,0 value because this means to disable the * timer or the interval. */ int itimerfix(struct timeval *tv) { if (tv->tv_usec < 0 || tv->tv_usec >= 1000000) return EINVAL; if (tv->tv_sec < 0) return ETIMEDOUT; if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) tv->tv_usec = tick; return 0; } int itimespecfix(struct timespec *ts) { if (ts->tv_nsec < 0 || ts->tv_nsec >= 1000000000) return EINVAL; if (ts->tv_sec < 0) return ETIMEDOUT; if (ts->tv_sec == 0 && ts->tv_nsec != 0 && ts->tv_nsec < tick * 1000) ts->tv_nsec = tick * 1000; return 0; } int inittimeleft(struct timespec *ts, struct timespec *sleepts) { if (itimespecfix(ts)) { return -1; } getnanouptime(sleepts); return 0; } int gettimeleft(struct timespec *ts, struct timespec *sleepts) { struct timespec sleptts; /* * Reduce ts by elapsed time based on monotonic time scale. */ getnanouptime(&sleptts); timespecadd(ts, sleepts, ts); timespecsub(ts, &sleptts, ts); *sleepts = sleptts; return tstohz(ts); } int clock_gettime1(clockid_t clock_id, struct timespec *ts) { switch (clock_id) { case CLOCK_REALTIME: nanotime(ts); break; case CLOCK_MONOTONIC: nanouptime(ts); break; default: return EINVAL; } return 0; } /* * Calculate delta and convert from struct timespec to the ticks. */ int ts2timo(clockid_t clock_id, int flags, struct timespec *ts, int *timo, struct timespec *start) { int error; struct timespec tsd; flags &= TIMER_ABSTIME; if (start == NULL) start = &tsd; if (flags || start != &tsd) if ((error = clock_gettime1(clock_id, start)) != 0) return error; if (flags) timespecsub(ts, start, ts); if ((error = itimespecfix(ts)) != 0) return error; if (ts->tv_sec == 0 && ts->tv_nsec == 0) return ETIMEDOUT; *timo = tstohz(ts); KASSERT(*timo > 0); return 0; }