Re: [Qemu-devel] Patch Send Ctrl-C to stdio target.

[Anthony Liguori <anthony@codemonkey.ws>]

Krumme, Chris wrote:
> Hello Anthony,
>
> You were quite right, the ckmakeraw function was the direction to go.
>
> It turns out that the utility of that function had already been hard
> coded in vl.c, with one twist.  The ISIG attribute was controlled by the
> -nographic option.
>
> In my use I had written a script that backdoored -nographic by setting
> the various outputs to use stdio instead of VGA, but I had not used the
> -nographic option. This meant I had all of the functionality of
> -nographic except the ISIG attribute (and a banner message :-).  This
> lead me to want to get rid of the SIGINT.
>
> So now I have to ask: what is the connection between ISIG for Control-C
> handling and using the monitor, serial port, or parallel port on stdio.
> If any one of these uses stdio then I think the ISIG should be used
> without regard to the -nographic option.
>   

That would be a bit of a pain.  When you use -nographic, you get monitor 
multiplexing which means that you can kill the qemu process by doing 
'C-a x'.  If we unconditionally set ISIG when -serial stdio then it's 
impossible to kill the QEMU process from the same tty which is a bit 
annoying.

In the very least, it needs to be a non default option for stdio.  
However, I should ask, why are you not just using -nographic?

Regards,

Anthony Liguori

> Thanks
>
> Chris
>
> Here is a patch to affect this change:
> Index: vl.c
> ===================================================================
> --- vl.c	(revision 4995)
> +++ vl.c	(working copy)
> @@ -2368,8 +2368,7 @@
>      tty.c_oflag |= OPOST;
>      tty.c_lflag &= ~(ECHO|ECHONL|ICANON|IEXTEN);
>      /* if graphical mode, we allow Ctrl-C handling */
> -    if (nographic)
> -        tty.c_lflag &= ~ISIG;
> +    tty.c_lflag &= ~ISIG;
>      tty.c_cflag &= ~(CSIZE|PARENB);
>      tty.c_cflag |= CS8;
>      tty.c_cc[VMIN] = 1;
>
>
>
>
> -----Original Message-----
> From: qemu-devel-bounces+chris.krumme=windriver.com@nongnu.org
> [mailto:qemu-devel-bounces+chris.krumme=windriver.com@nongnu.org] On
> Behalf Of Anthony Liguori
> Sent: Monday, August 11, 2008 4:14 PM
> To: qemu-devel@nongnu.org
> Subject: Re: [Qemu-devel] Patch Send Ctrl-C to stdio target.
>
> Krumme, Chris wrote:
>   
>> Hello,
>>  
>> This patch will catch a SIGINT and pass it as a ctrl-c to the target 
>> when running with the target on stdio.
>>   
>>     
>
> Just catching SIGINT is kind of a hack.  What about SIGSTOP and SIGCONT?
>
> If we're going to go this route, we should do it properly by cfmakeraw()
> stdio instead of trapping individual signals.
>
> Regards,
>
> Anthony Liguori
>
>
>
>
>
>