... of /)
| | | |
var usr adm <etc> (Note: these directories are picked up even if they are separate mounted filesystems.)
|
read-only
(Note: no it doesn't get cyclic at this point)
When a user logs in, instead of running a shell such as /sbin/sh in the password file, readonlyshell which has suid privileges runs. It changes the root directory for the user to "/var/read-only", sets a couple of shell variables and changes directory to the "/" directory, now "/var/read-only". Lastly it runs a bash shell.