Re: [Qemu-devel] Guest-sync-delimited and sentinel issue

[Eric Blake]

On 03/16/2012 06:47 AM, Michal Privoznik wrote:
> Hi guys,
> 
> I was just implementing support for guest-sync-delimited into libvirt. My 
> intent is to issue this command prior any other command to determine if GA is 
> available or not. The big advantage is - it doesn't change the state of the 
> guest so from libvirt POV it's harmless. The other big advantage is this 
> sentinel byte 0xFF which is supposed to flush all unprocessed (and possibly 
> stale) data from previous unsuccessful tries.
> 
> As written in documentation, this command will output sentinel byte to the 
> guest agent socket. This works perfectly. However, it is advised in the very 
> same documentation to prepend this command with the sentinel as well allowing 
> GA parser flush. But this doesn't work for me completely. All I can get is:
> 
> $ echo -e "\xFF{\"execute\":\"guest-sync-delimited\", 
> \"arguments\":{\"id\":1234}}" | nc -U /tmp/ga.sock | hexdump -C

side note - echo -e is non-portable; I would have written this as:

printf '\xff{"execute":"guest-sync-delimited", "arguments":{"id":1234}}'

-- 
Eric Blake   address@hidden    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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