From eaefc3c5032506e89cceb6ad5fdd1c5955c4ea66 Mon Sep 17 00:00:00 2001 From: Olivier Houchard Date: Tue, 10 Dec 2019 18:22:55 +0100 Subject: [PATCH] BUG/MEDIUM: kqueue: Make sure we report read events even when no data. When we have a EVFILT_READ event, an optimization was made, and the FD was not reported as ready to receive if there were no data available. That way, if the socket was closed by our peer (the EV8EOF flag was set), and there were no remaining data to read, we would just close(), and avoid doing a recv(). However, it may be fine for TCP socket, but it is not for UDP. If we send data via UDP, and we receive an error, the only way to detect it is to attempt a recv(). However, in this case, kevent() will report a read event, but with no data, so we'd just ignore that read event, nothing would be done about it, and the poller would be woken up by it over and over. To fix this, report read events if either we have data, or the EV_EOF flag is not set. This should be backported to 2.1, 2.0, 1.9 and 1.8. --- src/ev_kqueue.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/ev_kqueue.c b/src/ev_kqueue.c index 8f0b7c907..98fac8520 100644 --- a/src/ev_kqueue.c +++ b/src/ev_kqueue.c @@ -197,7 +197,7 @@ REGPRM3 static void _do_poll(struct poller *p, int exp, int wake) } if (kev[count].filter == EVFILT_READ) { - if (kev[count].data) + if (kev[count].data || !(kev[count].flags & EV_EOF)) n |= FD_EV_READY_R; if (kev[count].flags & EV_EOF) n |= FD_EV_SHUT_R;