Re: [PATCH v2 2/7] libxl: add new hotplug interface support to hotplug script callers

["Roger Pau Monné" <roger.pau@citrix.com>]

On 16/04/13 14:06, Ian Campbell wrote:
> On Tue, 2013-04-16 at 12:30 +0100, Roger Pau Monne wrote:
>> On 11/04/13 18:25, Ian Jackson wrote:
>>> Roger Pau Monne writes ("[Xen-devel] [PATCH v2 2/7] libxl: add new hotplug interface support to hotplug script callers"):
>>>> +The hotplug script should take special care in not storing arbitrary
>>>> +values in the following entries:
>>>> +
>>>> +HOTPLUG_PATH/version
>>>> +HOTPLUG_PATH/pdev
>>>
>>> Do we want to allow any scope for introducing new toolstack-reserved
>>> entries later ?
>>
>> Would you agree to say that the script is not able to use entries
>> beginning with libxl_*, so we can reserve that for later use?
> 
> Doesn't the toolstack have its own prefix, under which it could
> duplicate HOTPLUG_PATH if it wanted?
> 
> Or maybe there is more benefit to having all the hotplug info about a
> device in the same place to having things be nicely separated?

One solution would be to say that the hotplug script can only write to
the following entries:

HOTPLUG_PATH/version
HOTPLUG_PATH/pdev

And then provide the script with another path that could be used to
store whatever private entries the hotplug script needs:

PRIVATE_PATH

This would solve the problem of adding new toolstack-reserved entries
later in HOTPLUG_PATH.

The private path could for example be:

/local/domain/<local_domid>/libxl/private/vbd/<guest_domid>/<device_id>

Which is basically the same as HOTPLUG_PATH replacing "hotplug" with
"private".

>>
>> Also, if you could take a look at the rest of the series, I would like
>> to try to respin the series before the end of the week.
>>
>>> "... take special care not to store ..." would be correct grammar.
>>>
>>> Thanks,
>>> Ian.
>>>
>>
> 
>