Bug 117024

The jail rc script now complains when trying to mount filesystems inside
the jail if any of the parent directories of the mountpoint are a
symlink.

The handbook (chapter 15.6.1.3) contains the following text:

jail_enable="YES"
jail_set_hostname_allow="NO"
jail_list="ns mail www"
jail_ns_hostname="ns.example.org"
jail_ns_ip="192.168.3.17"
jail_ns_rootdir="/home/j/ns"
jail_ns_devfs_enable="YES"
jail_mail_hostname="mail.example.org"
jail_mail_ip="192.168.3.18"
jail_mail_rootdir="/home/j/mail"
jail_mail_devfs_enable="YES"
jail_www_hostname="www.example.org"
jail_www_ip="62.123.43.14"
jail_www_rootdir="/home/j/www"
jail_www_devfs_enable="YES"

By default /home is a symlink to /usr/home and therefor devfs will not
be mounted in the jails.  In fact, they refuse to start.

I've attached a patch which changes the rootdir to not contain a
symlink.  This is my first patch to any of the documentation so please
let me know if I did anything wrong, I'll be glad to do what I can to
fix it up.

A brief discussion about this can be found at:
http://lists.freebsd.org/pipermail/freebsd-doc/2007-June/012671.html

I still maintain that the text quoted in that thread is not sufficient
given the examples and the behavior displayed.

How-To-Repeat: wxs@ack ~ % grep ^jail /etc/rc.conf
jail_enable="YES"
jail_interface="bge0"
jail_list="test"
jail_test_hostname="test"
jail_test_ip="192.168.1.222"
jail_test_rootdir="/home/wxs/test"
jail_test_devfs_enable="YES"
wxs@ack ~ % sudo /etc/rc.d/jail start
Configuring jails:.
Starting jails:/etc/rc.d/jail: WARNING: /home/wxs/test/dev has symlink
as parent - not starting jail test
.
wxs@ack ~ %