Re: [Qemu-devel] [PATCH] qemu-char: Do not disconnect when there's data for reading

[Markus Armbruster]

Cc'ing Gerd for additional chardev expertise.

Zifei Tong <address@hidden> 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 <address@hidden>
> CC: Nikolay Nikolaev <address@hidden>
> CC: Anthony Liguori <address@hidden>
> Signed-off-by: Zifei Tong <address@hidden>
> ---
>  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?