[CRIU] RFC: Add owner user namespace to tty_struct

[Pavel Emelyanov]

On 05/29/2017 01:00 PM, Cyrill Gorcunov wrote:
> On Mon, May 29, 2017 at 12:43:52PM +0300, Pavel Emelyanov wrote:
>>>
>>> Hi Matt! Currently we don't use fake input in criu so at moment it won't
>>> affect us anyhow, but in longterm I expect more owner_user_ns testing may
>>> appear. Thus we will need to know which owner tty belong to. I think we
>>> may extend tty_fops and use show_fdinfo method to print owner_user_ns.
>>
>> We have similar problem with net_device:net pairing and with userns:<any other ns>
>> one -- we need to know which object belongs to which. For the net_device:net case
>> there has appeared a netdev ioctl, that results in an opened namespace file, just
>> like if we did open("/proc/pid/ns/net"). I think the same API would be more convenient
>> for tty:userns. All the more so there's already plenty of ioctls for ttys :)
> 
> Mind to point which netdev ioctl it is?

It's SIOCGSKNS. And I've made a mistake when told it was netdev->netns, it's
socket->netns mapper. Still, it returns an open file :)

-- Pavel