Re: [Qemu-devel] detecting seccomp sandbox capability via QMP

[Anthony Liguori <anthony@codemonkey.ws>]

"Daniel P. Berrange" <berrange@redhat.com> writes:

> On Tue, Dec 04, 2012 at 03:42:32PM +0100, Ján Tomko wrote:
>> On 12/04/12 12:46, Luiz Capitulino wrote:
>> > On Mon, 03 Dec 2012 16:55:35 +0100
>> > Ján Tomko <jtomko@redhat.com> wrote:
>> > 
>> >> Hello,
>> >>
>> >> is there a way to check if QEMU was compiled with --enable-seccomp via QMP?
>> > 
>> > Not that I'm aware of. Could you describe your use-case?
>> 
>> It's for libvirt. The detection is broken since the switch from parsing
>> -help output to QMP and I wanted to fix it.
>> 
>> Assuming it's supported if we do capabilities detection via QMP (since
>> libvirt 1.0.0 and QEMU 1.2) would work except for this case:
>> If seccomp sandbox was requested in /etc/libvirt/qemu.conf, but it was
>> compiled out from qemu, libvirt would try to run QEMU with -sandbox on
>> instead of printing an error earlier.
>
> In the absence of any way to detect it via QMP, libvirt should fallback
> to hardcoding it based on the version number. This presumes that QEMU was
> built with it enabled in configure, but we've no other option for current
> released 1.2/1.3 versions.

echo quit | qemu -machine none -S -monitor stdio -vnc none -sandbox on

A non-zero execute means QEMU doesn't support the option.  This will
work for any new command line option introduction and can be considered
a "supported" way of probing for whether options are supported.

Regards,

Anthony Liguori

>
> Daniel
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