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author | Edgar Kaziakhmedov <edgar.kaziakhmedov@virtuozzo.com> | 2018-01-10 18:39:24 +0300 |
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committer | Daniel P. Berrangé <berrange@redhat.com> | 2018-02-15 16:54:57 +0000 |
commit | a46ded1de5cf0edd6c780e071ddafb92601070b5 (patch) | |
tree | 7f538816906bd367ebd670932587d311ca573174 /io | |
parent | 28bb0a59f84c11c42117a7009646508256ed4475 (diff) | |
download | qemu-a46ded1de5cf0edd6c780e071ddafb92601070b5.zip qemu-a46ded1de5cf0edd6c780e071ddafb92601070b5.tar.gz qemu-a46ded1de5cf0edd6c780e071ddafb92601070b5.tar.bz2 |
io/channel-websock: handle continuous reads without any data
According to the current implementation of websocket protocol in QEMU,
qio_channel_websock_handshake_io tries to read handshake from the
channel to start communication over socket. But this approach
doesn't cover scenario when socket was closed while handshaking.
Therefore, if G_IO_IN is caught and qio_channel_read returns zero,
error has to be set and connection has to be done.
Such behaviour causes 100% CPU load in main QEMU loop, because main loop
poll continues to receive and handle G_IO_IN events from websocket.
Step to reproduce 100% CPU load:
1) start qemu with the simplest configuration
$ qemu -vnc [::1]:1,websocket=7500
2) open any vnc listener (which doesn't follow websocket
protocol)
$ vncviewer :7500
3) kill listener
4) qemu main thread eats 100% CPU
Signed-off-by: Edgar Kaziakhmedov <edgar.kaziakhmedov@virtuozzo.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Diffstat (limited to 'io')
-rw-r--r-- | io/channel-websock.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/io/channel-websock.c b/io/channel-websock.c index 7fd6bb6..ec48a30 100644 --- a/io/channel-websock.c +++ b/io/channel-websock.c @@ -499,9 +499,12 @@ static int qio_channel_websock_handshake_read(QIOChannelWebsock *ioc, error_setg(errp, "End of headers not found in first 4096 bytes"); return 1; - } else { - return 0; + } else if (ret == 0) { + error_setg(errp, + "End of headers not found before connection closed"); + return -1; } + return 0; } *handshake_end = '\0'; |