Extending Uliska Scanner

Main uliska.pl script only initializes and executes commands at the top level, based on OS kernel name, kernel major and minor versions.

Rest is delegated to modules deeper in the cfg and lib/Uliska sub-trees.

Uliska can be extended to cover more OS'es -- making the name-space tree 'wider', or going 'deeper' in the name-space tree covering more specific details of the distribution or environment.

Adding new OS (going wider)

At the top level of the scanner tree add files accordingly to kernel name and versions of UNIX system. For HP-UX 11i additional files should be something like:

lib/Uliska/HP-UX.pm
lib/Uliska/HP-UX/11.pm
cfg/HP-UX.cfg
cfg/HP-UX/11.cfg

Top level files are similar to the ones describe in the following section.

Adding new sub-trees (going deeper)

System specific scans are based on loading and executing nested list of commands and Perl modules. For example, for Linux sub-trees of .cfg and .pm files can be following:

./cfg/Linux.cfg
./cfg/Linux/Debian.cfg
./cfg/Linux/Debian/5.cfg
./cfg/Linux/Debian/5/4.cfg
./cfg/Linux/Debian/5/5.cfg
./cfg/Linux/Debian/6.cfg
./cfg/Linux/RedHat/5.cfg
./cfg/Linux/RedHat/5/4.cfg
./cfg/Linux/RedHat/5/5.cfg
./cfg/Linux/RedHat/6.cfg

./lib/Uliska.pm
./lib/Uliska/Linux.pm
./lib/Uliska/Linux/Debian.pm
./lib/Uliska/Linux/Debian/5.pm
./lib/Uliska/Linux/Debian/5/4.pm
./lib/Uliska/Linux/Debian/6.pm
./lib/Uliska/Linux/RedHat.pm
./lib/Uliska/Linux/RedHat/5.pm
./lib/Uliska/Linux/RedHat/5/1.pm
./lib/Uliska/Linux/RedHat/5/2.pm
./lib/Uliska/Linux/RedHat/5/3.pm
./lib/Uliska/Linux/RedHat/5/4.pm
./lib/Uliska/Linux/RedHat/5/5.pm
./lib/Uliska/Linux/RedHat/6.pm

Modules are loaded and executed on demand. I.e. for RedHat Linux 5.4 modules will be tried and loaded in the following order:

   ./lib/Uliska/Linux.pm
   ./lib/Uliska/Linux/RedHat.pm
   ./lib/Uliska/Linux/RedHat/5.pm
   ./lib/Uliska/Linux/RedHat/5/4.pm

Accordingly lists of commands will be executed from files in the similar order:

    ./cfg/Linux.cfg
    ./cfg/Linux/RedHat.cfg
    ./cfg/Linux/RedHat/5.cfg
    ./cfg/Linux/RedHat/5/4.cfg

All these files are not required to exist. In both cases (modules and commands) files are loaded only if they present, if file is not present this is logged to output file under WARNINGS branch (see LOGGING (TODO)).

Additional granularity can be added based on DNS or NIS domain-names, hostnames, hardware types, etc.

Adding your own modules

This example is based on Linux.pm module. In this module we can detect Linux distribution name, execute commands and load modules specific for the distribution.

• detect your distribution:

    $distro = 'RedHat' if -f '/etc/redhat-release';
    $distro = 'Debian' if -f '/etc/debian_version';

• add files in cfg directory and execute commands

This will execute commands from files Uliska/Linux/RedHat.cfg or Uliska/Linux/Debian.cfg:

     main::executeList(main::read_commands("Linux/$distro"));

• initialize and execute more nested modules

This will try to load and execute module Uliska::Linux::RedHat or Uliska::Linux::Debian. Module will be executed only if load is successful:

my $module = Uliska->init("Linux/$result->{distro}");
$module->run() if defined $module;

Nesting modules can go arbitrary number of levels deep.

Example

Full text of module Linux.pm

use strict;

package Uliska::Linux;


sub new {
  my $self = shift;
  return $self;
}

sub run  {
  my $result = \%main::result;
  $result->{'distro'} = &detect_distro();
  main::executeList(main::read_commands("Linux/".$result->{distro}));

  Uliska->init("Linux/$result->{distro}")->run();
};

sub detect_distro {
  return 'RedHat' if -f '/etc/redhat-release';
  return 'Debian' if -f '/etc/debian_version';
  'unknown';
}
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