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implemented a fork-based ticker in case setitimer() isn't available

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hyunghwan.chung 2019-10-17 15:43:00 +00:00
parent c2458c61cb
commit d7203b3e83
1 changed files with 57 additions and 1 deletions
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58
moo/lib/std.c
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@ -3571,6 +3571,7 @@ static MOO_INLINE void start_ticker (void)
the following is a fallback which will get */ the following is a fallback which will get */
unset_signal_handler (SIGVTALRM); unset_signal_handler (SIGVTALRM);
#if defined(SIGALRM) && defined(ITIMER_REAL)
if (set_signal_handler(SIGALRM, swproc_all_moos, SA_RESTART) >= 0) if (set_signal_handler(SIGALRM, swproc_all_moos, SA_RESTART) >= 0)
{ {
/* i double the interval as ITIMER_REAL is against the wall clock. /* i double the interval as ITIMER_REAL is against the wall clock.
@ -3582,6 +3583,7 @@ static MOO_INLINE void start_ticker (void)
itv.it_value.tv_usec = MOO_TICKER_INTERVAL_USECS * 2; itv.it_value.tv_usec = MOO_TICKER_INTERVAL_USECS * 2;
setitimer(ITIMER_REAL, &itv, MOO_NULL); setitimer(ITIMER_REAL, &itv, MOO_NULL);
} }
#endif
} }
} }
} }
@ -3600,6 +3602,7 @@ static MOO_INLINE void stop_ticker (void)
setitimer (ITIMER_VIRTUAL, &itv, MOO_NULL); setitimer (ITIMER_VIRTUAL, &itv, MOO_NULL);
} }
#if defined(SIGALRM) && defined(ITIMER_REAL)
if (is_signal_handler_set(SIGALRM) && set_signal_handler(SIGALRM, SIG_IGN, 0) >= 0) if (is_signal_handler_set(SIGALRM) && set_signal_handler(SIGALRM, SIG_IGN, 0) >= 0)
{ {
struct itimerval itv; struct itimerval itv;
@ -3609,10 +3612,63 @@ static MOO_INLINE void stop_ticker (void)
itv.it_value.tv_usec = 0; itv.it_value.tv_usec = 0;
setitimer (ITIMER_REAL, &itv, MOO_NULL); setitimer (ITIMER_REAL, &itv, MOO_NULL);
} }
#endif
} }
#else #else
# error UNSUPPORTED
static pid_t ticker_pid = -1;
static MOO_INLINE void start_ticker (void)
{
if (set_signal_handler(SIGALRM, swproc_all_moos, SA_RESTART) >= 0)
{
ticker_pid = fork();
if (ticker_pid <= -1)
{
unset_signal_handler (SIGALRM);
}
else if (ticker_pid == 0)
{
/* child process - actual ticker */
while (1)
{
#if defined(HAVE_NANOSLEEP)
struct timespec ts;
ts.tv_sec = 0;
ts.tv_nsec = MOO_USEC_TO_NSEC(MOO_TICKER_INTERVAL_USECS) * 2;
nanosleep (&ts, MOO_NULL);
#elif defined(HAVE_USLEEP)
usleep (MOO_TICKER_INTERVAL_USECS * 2);
#else
# error UNDEFINED SLEEP
#endif
kill (getppid(), SIGALRM);
}
_exit (0);
}
/* parent just carries on. */
}
}
static MOO_INLINE void stop_ticker (void)
{
if (ticker_pid >= 0)
{
int wstatus;
kill (ticker_pid, SIGKILL);
while (waitpid(ticker_pid, &wstatus, 0) != ticker_pid);
ticker_pid = -1;
unset_signal_handler (SIGALRM);
}
}
#endif #endif
/* ========================================================================= */ /* ========================================================================= */