PRoot

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 use PRoot as a generic Linux process instrumentation engine thanks to its extension mechanism, see CARE for an example. Technically PRoot relies on ptrace, an unprivileged system-call available in every Linux kernel. The new root file-system, a.k.a guest rootfs, typically contains a Linux distribution. By default PRoot confines the execution of programs to the guest rootfs only, however, users can use the built-in mount/bind mechanism to access files and directories from the actual root file-system, a.k.a host rootfs, just as if they were part of the guest rootfs.