PRoot is a user-space implementation of "chroot", "mount --bind", and "binfmt_misc". This means that users don't need any privileges or setup to do things like using an arbitrary directory as the new root filesystem, making files accessible somewhere else in the filesystem hierarchy, or executing programs built for another CPU architecture transparently through QEMU user mode. Also, developers can add their own features or use PRoot as a Linux process instrumentation engine thanks to its extension mechanism. Technically, PRoot relies on "ptrace", an unprivileged system call available in every Linux kernel.
