Fix #106: Patch timer nsec handling

When using timers, a small window exists where they can end up in a non
running state.  This is caused by how the nsec value in struct timespec
is handled when restarting the timers.

When a timer is less than a second from expiring it is not restarted
correctly, resulting in timers that never expire.

Signed-off-by: Jonas Holmberg <jonas.holmberg@westermo.se>
Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

src/timer.c

@@ -58,10 +58,13 @@ static void set(struct timer *t, struct timespec *now)
 
 static int expired(struct timer *t, struct timespec *now)
 {
+ long round_nsec = now->tv_nsec + 250000000;
+ round_nsec = round_nsec > 999999999 ? 999999999 : round_nsec;
+
  if (t->timeout.tv_sec < now->tv_sec)
  return 1;
 
- if (t->timeout.tv_sec == now->tv_sec && t->timeout.tv_nsec <= now->tv_nsec)
+ if (t->timeout.tv_sec == now->tv_sec && t->timeout.tv_nsec <= round_nsec)
  return 1;
 
  return 0;
@@ -108,7 +111,7 @@ static int start(struct timespec *now)
 
  memset(&it, 0, sizeof(it));
  it.it_value.tv_sec = next->timeout.tv_sec - now->tv_sec;
- it.it_value.tv_nsec = 0;
+ it.it_value.tv_nsec = next->timeout.tv_nsec - now->tv_nsec;
  timer_settime(timer, 0, &it, NULL);
 
  return 0;