Tweaked callbacks to prevent race condition (https://github.com/libevent/libevent/issues/104)

This commit is contained in:
John Ohl 2014-01-27 14:54:55 -05:00
parent 40830f1644
commit 2ea15ed0f6

34
event.c
View File

@ -1454,6 +1454,10 @@ done:
static inline void static inline void
event_persist_closure(struct event_base *base, struct event *ev) event_persist_closure(struct event_base *base, struct event *ev)
{ {
// Define our callback, we use this to store our callback before it's executed
void (*evcb_callback)(evutil_socket_t, short, void *);
/* reschedule the persistent event if we have a timeout. */ /* reschedule the persistent event if we have a timeout. */
if (ev->ev_io_timeout.tv_sec || ev->ev_io_timeout.tv_usec) { if (ev->ev_io_timeout.tv_sec || ev->ev_io_timeout.tv_usec) {
/* If there was a timeout, we want it to run at an interval of /* If there was a timeout, we want it to run at an interval of
@ -1496,8 +1500,8 @@ event_persist_closure(struct event_base *base, struct event *ev)
event_add_nolock_(ev, &run_at, 1); event_add_nolock_(ev, &run_at, 1);
} }
// Get our callback before we release the lock // Save our callback before we release the lock
void (*evcb_callback)(evutil_socket_t, short, void *) = *ev->ev_callback; evcb_callback = *ev->ev_callback;
// Release the lock // Release the lock
EVBASE_RELEASE_LOCK(base, th_base_lock); EVBASE_RELEASE_LOCK(base, th_base_lock);
@ -1564,33 +1568,39 @@ event_process_active_single_queue(struct event_base *base,
EVUTIL_ASSERT(ev != NULL); EVUTIL_ASSERT(ev != NULL);
event_persist_closure(base, ev); event_persist_closure(base, ev);
break; break;
case EV_CLOSURE_EVENT: case EV_CLOSURE_EVENT: {
void (*evcb_callback)(evutil_socket_t, short, void *) = *ev->ev_callback;
EVUTIL_ASSERT(ev != NULL); EVUTIL_ASSERT(ev != NULL);
EVBASE_RELEASE_LOCK(base, th_base_lock); EVBASE_RELEASE_LOCK(base, th_base_lock);
(*ev->ev_callback)( evcb_callback(ev->ev_fd, ev->ev_res, ev->ev_arg);
ev->ev_fd, ev->ev_res, ev->ev_arg); }
break; break;
case EV_CLOSURE_CB_SELF: case EV_CLOSURE_CB_SELF: {
void (*evcb_selfcb)(struct event_callback *, void *) = evcb->evcb_cb_union.evcb_selfcb;
EVBASE_RELEASE_LOCK(base, th_base_lock); EVBASE_RELEASE_LOCK(base, th_base_lock);
evcb->evcb_cb_union.evcb_selfcb(evcb, evcb->evcb_arg); evcb_selfcb(evcb, evcb->evcb_arg);
}
break; break;
case EV_CLOSURE_EVENT_FINALIZE: case EV_CLOSURE_EVENT_FINALIZE:
case EV_CLOSURE_EVENT_FINALIZE_FREE: case EV_CLOSURE_EVENT_FINALIZE_FREE: {
void (*evcb_evfinalize)(struct event *, void *) = ev->ev_evcallback.evcb_cb_union.evcb_evfinalize;
base->current_event = NULL; base->current_event = NULL;
EVUTIL_ASSERT(ev != NULL); EVUTIL_ASSERT(ev != NULL);
EVUTIL_ASSERT((evcb->evcb_flags & EVLIST_FINALIZING)); EVUTIL_ASSERT((evcb->evcb_flags & EVLIST_FINALIZING));
EVBASE_RELEASE_LOCK(base, th_base_lock); EVBASE_RELEASE_LOCK(base, th_base_lock);
ev->ev_evcallback.evcb_cb_union.evcb_evfinalize(ev, ev->ev_arg); evcb_evfinalize(ev, ev->ev_arg);
event_debug_note_teardown_(ev); event_debug_note_teardown_(ev);
if (evcb->evcb_closure == EV_CLOSURE_EVENT_FINALIZE_FREE) if (evcb->evcb_closure == EV_CLOSURE_EVENT_FINALIZE_FREE)
mm_free(ev); mm_free(ev);
}
break; break;
case EV_CLOSURE_CB_FINALIZE: case EV_CLOSURE_CB_FINALIZE: {
void (*evcb_cbfinalize)(struct event_callback *, void *) = evcb->evcb_cb_union.evcb_cbfinalize;
base->current_event = NULL; base->current_event = NULL;
EVUTIL_ASSERT((evcb->evcb_flags & EVLIST_FINALIZING)); EVUTIL_ASSERT((evcb->evcb_flags & EVLIST_FINALIZING));
EVBASE_RELEASE_LOCK(base, th_base_lock); EVBASE_RELEASE_LOCK(base, th_base_lock);
base->current_event = NULL; evcb_cbfinalize(evcb, evcb->evcb_arg);
evcb->evcb_cb_union.evcb_cbfinalize(evcb, evcb->evcb_arg); }
break; break;
default: default:
EVUTIL_ASSERT(0); EVUTIL_ASSERT(0);