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/*
* clock.c - Fast-lookup 1Hz clock
*/
/***********************************************************************
* Copyright © 2006 Rémi Denis-Courmont. *
* This program is free software; you can redistribute and/or modify *
* it under the terms of the GNU General Public License as published *
* by the Free Software Foundation; version 2 of the license, or (at *
* your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. *
* See the GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, you can get it from: *
* http://www.gnu.org/copyleft/gpl.html *
***********************************************************************/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <time.h>
#include <signal.h>
#include <stdbool.h>
#include <string.h>
#include <limits.h> // DELAYTIMER_MAX
#include <sys/types.h>
#include <sys/time.h>
#include <unistd.h> // _POSIX_*
#include <pthread.h>
#include "clock.h"
#include "debug.h"
#ifdef HAVE_TIMER_CREATE
typedef struct clock_data_t
{
timer_t handle;
teredo_clock_t value;
bool active;
} clock_data_t;
static void clock_tick (union sigval val)
{
clock_data_t *context = (clock_data_t *)(val.sival_ptr);
int orun = timer_getoverrun (context->handle);
context->value += 1 + orun;
#ifdef DELAYTIMER_MAX
if (orun == DELAYTIMER_MAX)
/* We have a big problem, let next caller fix it */
context->active = false;
#endif
if (!context->active)
{
struct itimerspec it =
{
.it_value = { .tv_sec = 0, .tv_nsec = 0 },
};
timer_settime (context->handle, 0, &it, NULL);
}
context->active = false;
}
unsigned long teredo_clock (void)
{
static clock_data_t clk =
{
.value = 0,
.active = false
};
static struct
{
pthread_mutex_t lock;
clockid_t id;
bool present;
} priv = { PTHREAD_MUTEX_INITIALIZER, CLOCK_REALTIME, false };
teredo_clock_t value;
pthread_mutex_lock (&priv.lock);
if (!priv.present)
{
struct sigevent ev;
memset (&ev, 0, sizeof (ev));
ev.sigev_notify = SIGEV_THREAD;
ev.sigev_value.sival_ptr = &clk;
ev.sigev_notify_function = clock_tick;
#if (_POSIX_CLOCK_SELECTION - 0 >= 0) && (_POSIX_MONOTONIC_CLOCK - 0 >= 0)
/* Run-time POSIX monotonic clock detection */
struct timespec res;
if (clock_getres (CLOCK_MONOTONIC, &res) == 0)
priv.id = CLOCK_MONOTONIC;
#endif
if (timer_create (priv.id, &ev, &clk.handle) == 0)
priv.present = true;
}
if (!clk.active)
{
struct itimerspec it;
clock_gettime (priv.id, &it.it_value);
clk.value = it.it_value.tv_sec;
if (priv.present)
{
it.it_value.tv_sec++;
it.it_value.tv_nsec = 0;
it.it_interval.tv_sec = 1;
it.it_interval.tv_nsec = 0;
clk.active = true;
timer_settime (clk.handle, TIMER_ABSTIME, &it, NULL);
}
}
value = clk.value;
pthread_mutex_unlock (&priv.lock);
return value;
}
#else
unsigned long teredo_clock (void)
{
struct timespec ts;
clock_gettime (CLOCK_REALTIME, &ts);
return ts.tv_sec;
}
#endif
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