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From: Markus Armbruster <armbru@redhat.com>
References: <1410092666-17405-1-git-send-email-zifeitong@gmail.com>
Date: Tue, 16 Sep 2014 08:06:36 +0200
In-Reply-To: <1410092666-17405-1-git-send-email-zifeitong@gmail.com> (Zifei
	Tong's message of "Sun, 7 Sep 2014 20:24:26 +0800")
Message-ID: <874mw8yu8j.fsf@blackfin.pond.sub.org>
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Subject: Re: [Qemu-devel] [PATCH] qemu-char: Do not disconnect when there's
	data for reading
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To: Zifei Tong <zifeitong@gmail.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>, Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>, qemu-devel@nongnu.org, Anthony Liguori <aliguori@amazon.com>, Kirill Batuzov <batuzovk@ispras.ru>

Cc'ing Gerd for additional chardev expertise.

Zifei Tong <zifeitong@gmail.com> writes:

> After commit 812c1057f6175ac9a9829fa2920a2b5783814193 (Handle G_IO_HUP
> in tcp_chr_read for tcp chardev), the connection is disconnected when in
> G_IO_HUP condition.
>
> However, it's possible that the channel is in G_IO_IN condition at the
> same time, meaning there is data for reading. In that case, the
> remaining data is not handled.
>
> I saw a related bug when running socat in write-only mode, with
>
>   $ echo "quit" | socat -u - UNIX-CONNECT:qemu-monitor
>
> the monitor won't not run the 'quit' command.

Reproduced.

Is this a regression caused by command 812c105?

> CC: Kirill Batuzov <batuzovk@ispras.ru>
> CC: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>
> CC: Anthony Liguori <aliguori@amazon.com>
> Signed-off-by: Zifei Tong <zifeitong@gmail.com>
> ---
>  qemu-char.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/qemu-char.c b/qemu-char.c
> index 1a8d9aa..5018c3a 100644
> --- a/qemu-char.c
> +++ b/qemu-char.c
> @@ -2706,7 +2706,7 @@ static gboolean tcp_chr_read(GIOChannel *chan, GIOCondition cond, void *opaque)
>      uint8_t buf[READ_BUF_LEN];
>      int len, size;
>  
> -    if (cond & G_IO_HUP) {
> +    if (!(cond & G_IO_IN) && (cond & G_IO_HUP)) {
>          /* connection closed */
>          tcp_chr_disconnect(chr);
>          return TRUE;

Kirill, you added the code being changed.  Could you review the patch?