timer.c

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/* ************************************************************************** */
/*      ____    _    _____ ____     _    _   _   _____ _  _   ____  ____      */
/*     / ___|  / \  |  ___|  _ \   / \  | \ | | |_   _| || | |  _ \/ ___|     */
/*     \___ \ / _ \ | |_  | |_) | / _ \ |  \| |   | | | || |_| | | \___ \     */
/*      ___) / ___ \|  _| |  _ < / ___ \| |\  |   | | |__   _| |_| |___) |    */
/*     |____/_/   \_|_|   |_| \_/_/   \_|_| \_|   |_|    |_| |____/|____/     */
/*                                                                            */
/* ************************************************************************** */
 
#define _GNU_SOURCE
 
#include "o2s/timer.h"
 
#include "o2s/log.h"
 
#include <errno.h>  // errno
#include <iso646.h> // not
#include <signal.h> // sigaction
#include <string.h> // strerror
#include <time.h>   // timer_*
#include <unistd.h> // gettid

#define MS_IN_NS 1000000UL

#define MS_PER_S 1000

bool o2s_timer_setup_process(void (*handle)(int, siginfo_t*, void*))
{
    struct sigaction signal_action;
 
    sigemptyset(&signal_action.sa_mask);
    signal_action.sa_sigaction = handle;
    signal_action.sa_flags = SA_SIGINFO;
    if (sigaction(SIGALRM, &signal_action, NULL) == 0)
        return true;
    log_error("Unable to set signal action: %s", strerror(errno));
    return false;
}

o2s_timer_t o2s_timer_create()
{
    o2s_timer_t     timer;
    struct sigevent event = {
        .sigev_notify   = SIGEV_THREAD_ID,
        .sigev_signo    = SIGALRM,
#ifdef __USE_GNU
        ._sigev_un._tid = gettid(),
#else
        .sigev_notify_thread_id = gettid(),
#endif
    };
 
    timer.created = (timer_create(CLOCK_REALTIME, &event, &timer.timer_id) == 0);
    if (not timer.created)
        log_error("Unable to create a timer: %s", strerror(errno));
    return timer;
}

o2s_timer_t o2s_timer_start(o2s_timer_t timer, unsigned milliseconds)
{
    struct itimerspec duration = {
        .it_value.tv_nsec = MS_IN_NS * (milliseconds % MS_PER_S),
        .it_value.tv_sec  = milliseconds / MS_PER_S,
    };
 
    timer.armed = (timer_settime(timer.timer_id, 0, &duration, NULL) == 0);
    if (not timer.armed)
        log_error("Unable to arm timer: %s", strerror(errno));
    return timer;
}

void o2s_timer_stop(o2s_timer_t* timer)
{
    struct itimerspec duration = {0};
 
    if (not timer->armed)
    {
        log_debug("No need to disarm a disarmed timer");
        return;
    }
    if (timer_settime(timer->timer_id, 0, &duration, NULL) == 0)
        return;
    log_error("Unable to disarm timer: %s", strerror(errno));
}

void o2s_timer_delete(o2s_timer_t* timer)
{
    if (not timer->created)
    {
        log_debug("No need to delete a non-created timer");
        return;
    }
    if (timer_delete(timer->timer_id) == 0)
        return;
    log_error("Unable to delete timer: %s", strerror(errno));
}