Re: [PATCH 0/3] kobject: support namespace aware udev

[Michael J Coss <michael.coss@alcatel-lucent.com>]

On 9/8/2015 11:54 PM, Greg KH wrote:
> On Tue, Sep 08, 2015 at 10:10:27PM -0400, Michael J. Coss wrote:
>> Currently when a uevent occurs, the event is replicated and sent to every
>> listener on the kernel netlink socket, ignoring network namespaces boundaries,
>> forwarding events to every listener in every network namespace.
>>
>> With the expanded use of containers, it would be useful to be able to
>> regulate this flow of events to specific containers.  By restricting
>> the events to only the host network namespace, it allows for a userspace
>> program to provide a system wide policy on which events are routed where.
> Interesting, but why do you need a container to get a uevent at all?
> What uevents do a container care about?
>
> thanks,
>
> greg k-h
>
In our use case, we run a full desktop inside the container, including
X.  We run the Xserver in headless mode, and forward a uevent to the
container to allow binding/unbinding of remote keyboard, mice, and
displays.   So I want the add/del keyboard events, add/del mouse events,
and add/del display events. This is just one use case, I could image
others.  The bottom line is that the current behavior is to broadcast to
everyone all uevents, and I don't see that as correct as it crosses the
network namespace boundaries.  It seems to me that you would want to
provide controls as to  where you want to forward those uevents, and
that is not a policy that I believe should be in the kernel but rather
in user space.

-- 
---Michael J Coss