/* signal handling */
static int
kq_sig_add(struct event_base *base, int nsignal, short old, short events, void *p)
{
struct kqop *kqop = base->evbase;
struct kevent kev;
struct timespec timeout = { 0, 0 };
(void)p;
EVUTIL_ASSERT(nsignal >= 0 && nsignal < NSIG);
memset(&kev, 0, sizeof(kev));
kev.ident = nsignal;
kev.filter = EVFILT_SIGNAL;
kev.flags = EV_ADD;
/* Be ready for the signal if it is sent any
* time between now and the next call to
* kq_dispatch. */
if (kevent(kqop->kq, &kev, 1, NULL, 0, &timeout) == -1)
return (-1);
/* We can set the handler for most signals to SIG_IGN and
* still have them reported to us in the queue. However,
* if the handler for SIGCHLD is SIG_IGN, the system reaps
* zombie processes for us, and we don't get any notification.
* This appears to be the only signal with this quirk. */
if (evsig_set_handler_(base, nsignal,
nsignal == SIGCHLD ? SIG_DFL : SIG_IGN) == -1)
return (-1);
return (0);
}
static int
evsig_add(struct event_base *base, evutil_socket_t evsignal, short old, short events, void *p)
{
struct evsig_info *sig = &base->sig;
(void)p;
EVUTIL_ASSERT(evsignal >= 0 && evsignal < NSIG);
/* catch signals if they happen quickly */
EVSIGBASE_LOCK();
if (evsig_base != base && evsig_base_n_signals_added) {
event_warnx("Added a signal to event base %p with signals "
"already added to event_base %p. Only one can have "
"signals at a time with the %s backend. The base with "
"the most recently added signal or the most recent "
"event_base_loop() call gets preference; do "
"not rely on this behavior in future Libevent versions.",
base, evsig_base, base->evsel->name);
}
evsig_base = base;
evsig_base_n_signals_added = ++sig->ev_n_signals_added;
evsig_base_fd = base->sig.ev_signal_pair[1];
EVSIGBASE_UNLOCK();
event_debug(("%s: %d: changing signal handler", __func__, (int)evsignal));
if (evsig_set_handler_(base, (int)evsignal, evsig_handler) == -1) {
goto err;
}
if (!sig->ev_signal_added) {
if (event_add(&sig->ev_signal, NULL))
goto err;
sig->ev_signal_added = 1;
}
return (0);
err:
EVSIGBASE_LOCK();
--evsig_base_n_signals_added;
--sig->ev_n_signals_added;
EVSIGBASE_UNLOCK();
return (-1);
}