What you describe can be accomplished on linux using mount namespaces. It gives a namespaced view of the filesystem which the parent process can control via pic

What you describe can be accomplished on linux using mount namespaces. It gives a namespaced view of the filesystem which the parent process can control via picking its root location and what is bindmounted where. You've basically described a container where the filesystem is virtualized to a safe location on disk. Disallowing reading/writing data entirely is pretty easy with seccomp or ptrace, though that's not required with namespacing.