Bug#932103: RFP: fuidshift -- remap a filesystem tree to shift one set of UID/GID ranges to another

[Nicholas D Steeves <nsteeves@gmail.com>]

Package: wnpp
Severity: wishlist

Package name    : fuidshift
Version         : 3.0
Upstream Author : Name <somebody@example.org>
URL             : https://github.com/lxc/lxd/tree/master/fuidshift
License         : Apache 2.0
Programming Lang: Go
Description     : remap a filesystem tree to shift one set of UID/GID ranges to another

Fuidshift is useful for converting privileged containers to
unprivileged ones, and also to adapt a container master to multiple
users' authorised subuid and subguid ranges.  It also sounds like it
might be useful for fixing up cases where --numeric-owner should have
been used, but where it would be too labour-intensive to manually chown.

I learned about this tool via the following document:
  https://github.com/BenSartor/unprivileged-lxc-containers

Here is the upstream description:

  This tool lets you remap a filesystem tree, switching it from one
  set of UID/GID ranges to another.
  This is mostly useful when retrieving a wrongly shifted filesystem tree
  from a backup or broken system and having to remap everything either to
  the host UID/GID range (uid/gid 0 is root) or to an existing container's
  range.
  A range is represented as <u|b|g>:<first_container_id>:<first_host_id>:<size>.
  Where "u" means shift uid, "g" means shift gid and "b" means shift uid and gid.

https://github.com/lxc/lxd/blob/81b81b9ace3064c8065319f4e984378244587d80/fuidshift/main_shift.go#L26-L36

It's part of the LXD project, but I'm not sure if it's as difficult to
package as LXD itself, which is one reason why I've CCed the Go team.
I also wonder if the best way to get this into Debian would be a
src:lxd that produces bin:fuidshift.


Regards,
Nicholas