/**
* set next_timer to the next lowest enabled timer index
*/
void schedule_timer(void)
{
/* try to find *an active* timer */
next_timer = -1;
for (int i = 0; i < HWTIMER_MAXTIMERS; i++) {
if (native_hwtimer_isset[i] == 1) {
next_timer = i;
break;
}
}
if (next_timer == -1) {
DEBUG("schedule_timer(): no valid timer found - nothing to schedule\n");
struct itimerval null_timer;
null_timer.it_interval.tv_sec = 0;
null_timer.it_interval.tv_usec = 0;
null_timer.it_value.tv_sec = 0;
null_timer.it_value.tv_usec = 0;
if (real_setitimer(ITIMER_REAL, &null_timer, NULL) == -1) {
err(EXIT_FAILURE, "schedule_timer: setitimer");
}
return;
}
/* find the next pending timer (next_timer now points to *a* valid pending timer) */
for (int i = 0; i < HWTIMER_MAXTIMERS; i++) {
if (
(native_hwtimer_isset[i] == 1) &&
(tv2ticks(&(native_hwtimer[i].it_value)) < tv2ticks(&(native_hwtimer[next_timer].it_value)))
) {
/* timer in slot i is active and the timeout is more recent than next_timer */
next_timer = i;
}
}
/* next pending timer is in slot next_timer */
struct timeval now;
hwtimer_arch_now(); // update timer
ticks2tv(native_hwtimer_now, &now);
struct itimerval result;
memset(&result, 0, sizeof(result));
int retval = timeval_subtract(&result.it_value, &native_hwtimer[next_timer].it_value, &now);
if (retval || (tv2ticks(&result.it_value) < HWTIMERMINOFFSET)) {
DEBUG("\033[31mschedule_timer(): timer is already due (%i), mitigating.\033[0m\n", next_timer);
result.it_value.tv_sec = 0;
result.it_value.tv_usec = 1;
}
_native_syscall_enter();
if (real_setitimer(ITIMER_REAL, &result, NULL) == -1) {
err(EXIT_FAILURE, "schedule_timer: setitimer");
}
else {
DEBUG("schedule_timer(): set next timer (%i).\n", next_timer);
}
_native_syscall_leave();
}
/**
* set next_timer to the next lowest enabled timer index
*/
void schedule_timer(void)
{
int l = next_timer;
for (
int i = ((next_timer + 1) % ARCH_MAXTIMERS);
i != next_timer;
i = ((i + 1) % ARCH_MAXTIMERS)
) {
if (native_hwtimer_isset[l] != 1) {
/* make sure we dont compare to garbage in the following
* if condition */
l = i;
}
if (
(native_hwtimer_isset[i] == 1) &&
(tv2ticks(&(native_hwtimer[i].it_value)) < tv2ticks(&(native_hwtimer[l].it_value)))
) {
/* set l to the lowest active time */
l = i;
}
}
next_timer = l;
/* l could still point to some unused (garbage) timer if no timers
* are set at all */
if (native_hwtimer_isset[next_timer] == 1) {
if (setitimer(ITIMER_REAL, &native_hwtimer[next_timer], NULL) == -1) {
err(1, "schedule_timer");
}
else {
DEBUG("schedule_timer(): set next timer.\n");
}
}
else {
DEBUG("schedule_timer(): no next timer!? This looks suspicous.\n");
// TODO: unset timer.
}
}
