FreeBSD: fix read write kevent #1186
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Otherwise code such as webui which does "if (tcp_socket_dead(...))" fails since we were returning EIO if there is nothing to read, but nothing to immediately read is not the same as EOF on FreeBSD. Since what occurs is the async tcp connect returns EINPROGRESS, the socket has no bytes to read, so is immediately disconnected.
The kevent does not take a bitmask. So if you register for READ|WRITE then it only registers READ since READ=-1 and WRITE=-2. This means that with an async socket connect then you do not get a callback on connect. So we need to register these separately.
perexg
reviewed
Oct 16, 2018
| @@ -458,7 +458,7 @@ tcp_socket_dead(int fd) | |||
| if (err < 0) | |||
| return -errno; | |||
| else if (err == 0) | |||
| return -EIO; | |||
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It looks like that 3895c92 should be reverted ?
|
I applied kevent fix and reverted 3895c92 . |
|
Thanks. You're right, that earlier change should be reverted. |
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On FreeBSD, the kevent EVFILT_READ=-1 and EVFILT_WRITE=-2 (rather than 1 and 2), so when they are ORed together you get -1, so we only end up registering READ in tvhpoll.
This means that on an async tcp connect we eventually timeout since we are not registered for WRITE.
So we now delete the special logic and use the existing separate read/write registration logic.
Also no longer return EIO for FreeBSD on tcp_socket_dead for zero bytes available to read, otherwise streaming fails to my tablet since we get no bytes to read so immediately disconnect the client, but no bytes on async socket is not same as eof.