In recent discussions it became clear that having the ability to go from pidfd to namespace file descriptor is desirable. Not just because it is already possible to use pidfds with setns() to switch namespaces atomically but also because it makes it possible to interact with namespaces without having procfs mounted solely relying on the pidfd. This adds support from deriving a namespace file descriptor from a pidfd for all namespace types. Thanks! Christian --- --- base-commit: 2a79498f76350570427af72da04b1c7d0e24149e change-id: 20240627-work-pidfs-fd415f4d3cd1
