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//
// Copyright 2016 Garrett D'Amore <garrett@damore.org>
//
// This software is supplied under the terms of the MIT License, a
// copy of which should be located in the distribution where this
// file was obtained (LICENSE.txt). A copy of the license may also be
// found online at https://opensource.org/licenses/MIT.
//
// POSIX clock stuff.
#include "core/nng_impl.h"
#ifdef PLATFORM_POSIX_CLOCK
#include <errno.h>
#include <string.h>
#include <time.h>
#ifndef NNG_USE_GETTIMEOFDAY
// Use POSIX realtime stuff
nni_time
nni_plat_clock(void)
{
struct timespec ts;
nni_time usec;
if (clock_gettime(NNG_USE_CLOCKID, &ts) != 0) {
/* This should never ever occur. */
nni_panic("clock_gettime failed: %s", strerror(errno));
}
usec = ts.tv_sec;
usec *= 1000000;
usec += (ts.tv_nsec / 1000);
return (usec);
}
void
nni_plat_usleep(nni_duration usec)
{
struct timespec ts;
ts.tv_sec = usec / 1000000;
ts.tv_nsec = (usec % 1000000) * 1000;
/* Do this in a loop, so that interrupts don't actually wake us. */
while (ts.tv_sec || ts.tv_nsec) {
if (nanosleep(&ts, &ts) == 0) {
break;
}
}
}
#else // NNG_USE_GETTIMEOFDAY
// If you're here, its because you don't have a modern clock_gettime with
// monotonic clocks, or the necessary pthread_condattr_settclock(). In
// this case, you should be advised that *bad* things can happen if your
// system clock changes time while programs using this library are running.
// (Basically, timeouts can take longer or shorter, leading to either hangs
// or apparent spurious errors. Eventually it should all sort itself out,
// but if you change the clock by a large amount you might wonder what the
// heck is happening until it does.)
#include <poll.h>
#include <pthread.h>
#include <sys/time.h>
nni_time
nni_plat_clock(void)
{
nni_time usec;
struct timeval tv;
if (gettimeofday(&tv, NULL) != 0) {
nni_panic("gettimeofday failed: %s", strerror(errno));
}
usec = tv.tv_sec;
usec *= 1000000;
usec += tv.tv_usec;
return (usec);
}
void
nni_plat_usleep(nni_duration usec)
{
// So probably there is no nanosleep. We could in theory use
// pthread condition variables, but that means doing memory
// allocation, or forcing the use of pthreads where the platform
// might be preferring the use of another threading package.
// Additionally, use of pthreads means that we cannot use
// relative times in a clock_settime safe manner.
// So we can use poll() instead, which is rather coarse, but
// pretty much guaranteed to work.
struct pollfd pfd;
nni_time now;
nni_time expire;
// Possibly we could pass NULL instead of pfd, but passing a valid
// pointer ensures that if the system dereferences the pointer it
// won't come back with EFAULT.
pfd.fd = -1;
pfd.events = 0;
now = nni_clock();
expire = now + usec;
while (now < expire) {
// In theory we could round up to a whole number of msec,
// but under the covers poll already does some rounding up,
// and the loop above guarantees that we will not bail out
// early. So this gives us a better chance to avoid adding
// nearly an extra unneeded millisecond to the wait.
(void) poll(&pfd, 0, (int) ((expire - now) / 1000));
now = nni_clock();
}
}
#endif // NNG_USE_GETTIMEOFDAY
#else
// Suppress empty symbols warnings in ranlib.
int nni_posix_clock_not_used = 0;
#endif // PLATFORM_POSIX_CLOCK
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