Jailkit is a set of utilities to limit user accounts to specific files
using chroot() and or specific commands. Setting up a chroot shell,
a shell limited to some specific command, or a daemon inside a chroot
jail is a lot easier using these utilities.
Jailkit has been in use for a while on CVS servers (in a chroot and
limited to cvs), sftp/scp servers (both in a chroot and limited to
sftp/scp as well as not in a chroot but only limited to sftp/scp),
and also on general servers with accounts where the shell accounts
are in a chroot.