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subr_time.c
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/
subr_time.c
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/* $NetBSD: subr_time.c,v 1.19 2017/01/05 23:29:14 pgoyette 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 <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_time.c,v 1.19 2017/01/05 23:29:14 pgoyette Exp $");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/kauth.h>
#include <sys/lwp.h>
#include <sys/timex.h>
#include <sys/time.h>
#include <sys/timetc.h>
#include <sys/intr.h>
#ifdef DEBUG_STICKS
#define DPRINTF(a) uprintf a
#else
#define DPRINTF(a)
#endif
/*
* 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);
}
static void
ticks2ts(uint64_t ticks, struct timespec *ts)
{
ts->tv_sec = ticks / hz;
uint64_t sticks = ticks - ts->tv_sec * hz;
if (sticks > BINTIME_SCALE_MS) /* floor(2^64 / 1000) */
ts->tv_nsec = sticks / hz * 1000000000LL;
else if (sticks > BINTIME_SCALE_US) /* floor(2^64 / 1000000) */
ts->tv_nsec = sticks * 1000LL / hz * 1000000LL;
else
ts->tv_nsec = sticks * 1000000000LL / hz;
DPRINTF(("%s: %ju/%ju -> %ju.%ju\n", __func__,
(uintmax_t)ticks, (uintmax_t)sticks,
(uintmax_t)ts->tv_sec, (uintmax_t)ts->tv_nsec));
}
int
clock_gettime1(clockid_t clock_id, struct timespec *ts)
{
int error;
uint64_t ticks;
struct proc *p;
#define CPUCLOCK_ID_MASK (~(CLOCK_THREAD_CPUTIME_ID|CLOCK_PROCESS_CPUTIME_ID))
if (clock_id & CLOCK_PROCESS_CPUTIME_ID) {
pid_t pid = clock_id & CPUCLOCK_ID_MASK;
mutex_enter(proc_lock);
p = pid == 0 ? curproc : proc_find(pid);
if (p == NULL) {
mutex_exit(proc_lock);
return ESRCH;
}
ticks = p->p_uticks + p->p_sticks + p->p_iticks;
DPRINTF(("%s: u=%ju, s=%ju, i=%ju\n", __func__,
(uintmax_t)p->p_uticks, (uintmax_t)p->p_sticks,
(uintmax_t)p->p_iticks));
mutex_exit(proc_lock);
// XXX: Perhaps create a special kauth type
error = kauth_authorize_process(curlwp->l_cred,
KAUTH_PROCESS_PTRACE, p,
KAUTH_ARG(KAUTH_REQ_PROCESS_CANSEE_ENTRY), NULL, NULL);
if (error)
return error;
} else if (clock_id & CLOCK_THREAD_CPUTIME_ID) {
struct lwp *l;
lwpid_t lid = clock_id & CPUCLOCK_ID_MASK;
p = curproc;
mutex_enter(p->p_lock);
l = lid == 0 ? curlwp : lwp_find(p, lid);
if (l == NULL) {
mutex_exit(p->p_lock);
return ESRCH;
}
ticks = l->l_rticksum + l->l_slpticksum;
DPRINTF(("%s: r=%ju, s=%ju\n", __func__,
(uintmax_t)l->l_rticksum, (uintmax_t)l->l_slpticksum));
mutex_exit(p->p_lock);
} else
ticks = (uint64_t)-1;
if (ticks != (uint64_t)-1) {
ticks2ts(ticks, ts);
return 0;
}
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;
}