proposal: add moby/sys/devices

[kolyshkin]

There is a set of functions (DeviceFromPath, HostDevices, GetDevices) which are copied across a few repos, in some cases with minor changes:

• https://github.com/opencontainers/runc/blob/main/libcontainer/devices/device_unix.go (not used by runc itself, used by containers/common, containers/buildah, cri-o, microsoft/hcsshim);
• https://github.com/containerd/containerd/blob/main/pkg/oci/utils_unix.go (used mostly from containerd and moby)
• https://github.com/containers/podman/blob/main/pkg/util/utils_linux.go (used from containers/*)

So, main users are moby/moby, cri-o/cri-o, containerd, faasd, microsoft/hcsshim, containers/*, etc.

I propose to create moby/sys/devices, figure out the implementation which will suit all the users, and add it there.

[thaJeztah]

No objections from my side; I think being able to collaborate on such things and reduce duplicating the work can benefit all those projects, and small modules tend to be easier to use and maintain.

We're actually in the process of untangling some of the packages in moby/moby (move things internal that shouldn't have been external, splitting packages, and looking at packages that could live as separate module).

@dmcgowan is currently working on some bits around pkg/archive and idtools, and also looking at the moby/sys/user package which was migrated from runc, but we found that some types there are effectively a copy of types in OCI runtime-spec, but ever-so-subtly different, so perhaps some changes are coming related to that.

@dmcgowan any thoughts on this? Who else should we involve in deciding on this?

[kolyshkin]

An initial release: https://github.com/moby/sys/releases/tag/devices%2Fv0.1.0