Our recently deceased guru compiled a version of openssh for Scientific Linux in 2012 that allows us to lock users into their home directories in a really cool way.For example, we make their home dir (like) /u/sftpdir/./username.  When they login, all they see is /username.  If we modify that to /u/sftpdir/username/./, upon sftp login they only see /.  They cannot go 'up' the tree from there; effectively, the dot is root. Now, I need to update our openssh, and I am not sure what he did to make that work.  We are not chrooting, and that would require way too much reconfiguration and many continual man-hours to convert to.  Any ideas?
Openssh home dir mods
linux;directory;sftp;openssh;account restrictions