VAdmind's Init.pm plugin
By Urivan Saaib <saaib@ciberlinux.net>
Oct 16, 2004

                      P   L   A   N   N   I   N   G
                      -----------------------------

Here we'll define all the technical detail and requirements in order to develop
the Init.pm plugin succesfully within a short period of time. The order will
follow the one defined in the Concept phase.

First, we'll define some information that is important for all the functions
that the plugin will provide. This is in order to understand how and what it
will read, write, create and modify in order to execute.

The configuration file used by Linux at boot to execute the proper sequence of
processes at the system initialization is /etc/inittab. The format of this file
is the following:

              id:runlevels:action:process

where:
      id:         4 char string
      runlevels:  One or more runlevels
      action:     What action to take
      process:    What process to execute

Valid runlevels: 0,1,2,3,4,5,6
Valid actions: respawn, wait, once, boot, bootwait, off, ondemand, initdefault,
               sysinit, powerwait, powerfail, powerokwait, powerfailnow,
               ctrlaltdel, kbrequest.

The directories where the bootup scripts are stored is /etc/rc.d/init.d
The directories where the specific runlevel bootup scripts refeer are
/etc/rc.d/rc?.d



A) runlevel_list
   Get the runlevels available in the system.
   We can either take them from /etc/inittab or scann for the directories in
   /etc/rc.d/rc?.d   Our first approach will be to scan the dirs.
   Input: none
   Return:
   <runlevels>0,1,2,3,4,5,6</runlevels>

B) runlevel_service_list
   Get the list of services that are on and off in a runlevel
   Input: 
   <runlevel>0-6</runlevel>
   Return: 
   <services>
      <service name="servicename">
         <start>56</start>
         <stop>24</stop>
      <service>
   </services>

C) service_add
   Adds a service entry to /etc/rc.d/init.d
   Input:
   <service>servicename</service>
   <description>The Servicename description goes here</description>
   <start>/somepath/to/script</strat>
   <stop>/something/to/execute</stop>
   Return: 0: Failure, 1: Success
   
D) service_del
   Deletes a service script from /etc/rc.d/init.d and its corresponding
   runlevel entries in /etc/rc.d/rc?.d/[SK0-90-9]servicename.
   Input:
   <service>servicename</service>
   Return: 0: Failure, 1: Success

E) service_runlevel_enable
   Enables a service in a runlevel.
   Input:
   <service>servicename</service>
   <runlevel>0-6</runlevel>
   <start>56</start>    # S56servicename
   <stop>24</stop>      # K24srevicename
   Return: 0: Failure, 1: Success

F) service_runlevel_disable
   Disables a service in a runlevel.
   Input:
   <service>servicename</service>
   <runlevel>0-6</runlevel>
   Return: 0: Failure, 1: Success
   
G) service_start
   Runs the service script with the "start" argument.
   Input:
   <service>servicename</service>
   Return: 0: Failure, 1: Success

H) service_stop
   Runs the service script with the "stop" argument.
   Input:
   <service>servicename</service>
   Return: 0: Failure, 1: Success

I) runlevel_current
   Get the current runlevel configured in the system for the bootup process.
   Input: none
   Return:

J) runlevel_set
   Set the bootup runlevel to the one specified.
   Input:
   <runlevel>0-6</runlevel>
   Return: 0: Failure, 1: Success

K) reboot
   Reboots the system.
   Input: none
   Return: 0: Failure, 1: Success

L) shutdown
   Shutdowns the system.
   Input: none
   Return: 0: Failure, 1: Success