Re: [libvirt] [systemd-devel] Suspending access to opened/active /dev/nodes during application runtime

On 7 Mar 2014, at 20:09, Greg KH <gregkh(a)linuxfoundation.org&gt; wrote: > On Fri, Mar 07, 2014 at 07:46:44PM +0100, Lukasz Pawelczyk wrote: >> Problem: >> Has anyone thought about a mechanism to limit/remove an access to a >> device during an application runtime? Meaning we have an application >> that has an open file descriptor to some /dev/node and depending on >> *something* it gains or looses the access to it gracefully (with or >> without a notification, but without any fatal consequences). >> >> Example: >> LXC. Imagine we have 2 separate containers. Both running full operating >> systems. Specifically with 2 X servers. Both running concurrently of >> course. Both need the same input devices (e.g. we have just one mouse). > > Stop right there. > > If they "both" need an input device, then they should use the "shared" > input device stream, i.e. evdev. > > And it goes the same for every type of device the kernel is exposing to > userspace, if you want to "share" them, then you need to work on > changing the kernel to be able to handle shared devices. I think you might have misunderstood me. They are using a shared input stream (evdev in this case). The problem is I don’t want them to eavesdrop on each other. So it’s not about making it to work. It’s about making them to work „in turns”.