SYNOPSIS

       jailer [ console-file ]

DESCRIPTION

       jailer  manages  the  startup  and shutdown of a jail from
       within the jail. It also  manages  the  jails  console  by
       linking /dev/console inside the jail to a log file.

       To use, replace the '/bin/sh /etc/rc' portion of your jail
       startup command with jailer. For example instead of:

        jail /jails/myjail host 10.0.1.1 /bin/sh /etc/rc

       use:

        jail /jails/myjail host 10.0.1.1 /usr/local/sbin/jailer


       jailer will start the jail by  running  /etc/rc  and  then
       remain  running  as  a  daemon inside the jail waiting for
       signals to perform shutdown or restarts.

       A shutdown is performed by first running /etc/rc.shutdown,
       and  then  killing  all  the  processes  still  running. A
       restart is a combination of the above.


       The following signals have special meaning to the jailer:

       HUP    Causes jailer to restart the jail. If the  jail  is
              not running at the time it is simply started.

       QUIT   Initiates  a jail shutdown.  jailer remains running
              after processing the request.

       TERM   Same as QUIT but also quits jailer.  No  more  pro-
              cesses will be left running inside the jail.

JAIL CONSOLE MANAGEMENT

       A  normal  jail  has  no console perse, and dmesg(8) reads
       straight from the  host  kernel  message  buffer.   jailer
       changes this to provide a virtual console for the jail.

       On  jailer startup the file /var/log/console is created or
       truncated.  /dev/console is then hard linked to  the  con-
       sole file.

       Along  with  the  jailer  distribution  you'll  find a new
       dmesg(8) which  just  reads  from  /dev/console.   Replace
       /sbin/dmesg(8) with this new executable and you're set.

OPTIONS

       console-file
              Overrides the default location of the  console  log
              file, usually /var/log/console

FILES

       /var/log/console
              Virtual console file.

BUGS

       shutdown(8) doesn't work with the halt and reboot scripts.

AUTHOR

       Stef Walter <stef@thewalter.net>

SEE ALSO

       jail(8), halt(8), reboot(8), dmesg(8)



Version 1.1.2                May 2002                   JAILER(8)