Daniel P. Berrangé a2458b6f69 io: return 0 for EOF in TLS session read after shutdown ... GNUTLS takes a paranoid approach when seeing 0 bytes returned by the underlying OS read() function. It will consider this an error and return GNUTLS_E_PREMATURE_TERMINATION instead of propagating the 0 return value. It expects apps to arrange for clean termination at the protocol level and not rely on seeing EOF from a read call to detect shutdown. This is to harden apps against a malicious 3rd party causing termination of the sockets layer. This is unhelpful for the QEMU NBD code which does have a clean protocol level shutdown, but still relies on seeing 0 from the I/O channel read in the coroutine handling incoming replies. The upshot is that when using a plain NBD connection shutdown is silent, but when using TLS, the client spams the console with Cannot read from TLS channel: Broken pipe The NBD connection has, however, called qio_channel_shutdown() at this point to indicate that it is done with I/O. This gives the opportunity to optimize the code such that when the channel has been shutdown in the read direction, the error code GNUTLS_E_PREMATURE_TERMINATION gets turned into a '0' return instead of an error. Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Message-Id: <20181119134228.11031-1-berrange@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>		2018-11-19 11:16:46 -06:00
..
channel-buffer.h	Clean up ill-advised or unusual header guards	2016-07-12 16:20:46 +02:00
channel-command.h	Clean up ill-advised or unusual header guards	2016-07-12 16:20:46 +02:00
channel-file.h	io: Fix QIOChannelFile when creating and opening read-write	2018-02-15 16:54:57 +00:00
channel-socket.h	qio: non-default context for async conn	2018-03-06 10:19:06 +00:00
channel-tls.h	io: return 0 for EOF in TLS session read after shutdown	2018-11-19 11:16:46 -06:00
channel-util.h	Clean up ill-advised or unusual header guards	2016-07-12 16:20:46 +02:00
channel-watch.h	Clean up ill-advised or unusual header guards	2016-07-12 16:20:46 +02:00
channel-websock.h	io: get rid of bounce buffering in websock write path	2017-10-16 16:57:08 +01:00
channel.h	io: return 0 for EOF in TLS session read after shutdown	2018-11-19 11:16:46 -06:00
dns-resolver.h	Include less of the generated modular QAPI headers	2018-03-02 13:45:50 -06:00
net-listener.h	qio: store gsources for net listeners	2018-03-06 10:19:05 +00:00
task.h	qio: non-default context for threaded qtask	2018-03-06 10:19:05 +00:00