Writing Linux Plugins

From L33TSig Wiki

Since version 0.8.4, L33TSig Linux supports plugins. These plugins can be written using any language, including scripting languages such as Perl and PHP. Please note that if you write a plugin using a scripting language the end user will require that particular interpreter to use your plugin.

Important: Plugins must be set executable (chmod a+x filename) for L33TSig to be able to execute them.

Creating a plugin

When a plugin is loaded into L33TSig, it executes the plugin twice, with 2 command line options:

./plugin --desc
This returns a description which will appear in the Plugins page on the user interface.

./plugin --shortdesc
This is a short description which will appear as the Line Type in the Edit Line dialog.

Linux plugins don't have a "GetLine" method, instead, they use the following:

./plugin
When the plugin is executed with no command line options it is expected to return the results of the plugin in a single line of text.

All 3 functions must end with a linefeed character (ASCII code 10 or "\n" in various scripting languages).

Example plugins

Perl

#!/usr/bin/perl
$desc = "My Perl test plugin 0.0.1 (c)2006 Matthew Hipkin\n";
$shortdesc = "Test Perl plugin\n";
if($#ARGV > -1) {
  if($ARGV[0] eq "--desc") { print $desc; }
  elsif($ARGV[0] eq "--shortdesc") { print $shortdesc; }
}
else {
  print "This is a Perl plugin!\n";
}

C

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, char *argv[])
{
  // Check for a required command line option
  if(argc > 1) {
    // Write description
    if(strstr(argv[1],"--desc")) {
      puts("My test C plugin 0.0.1 (c)2006 Matthew Hipkin");
    }
    // Write short description
    if(strstr(argv[1],"--shortdesc")) {
      puts("Test C plugin");
    }
  }
  else {
    // This is the text L33TSig Linux will pick up
    puts("This is a C plugin!");
  }
  return EXIT_SUCCESS;
}

PHP

#!/usr/bin/php -q
<?php
  // Set the description and short description variables
  $desc = "My test PHP plugin 0.0.1 (c)2006 Matthew Hipkin\n";
  $shortdesc = "Test PHP plugin\n";
  // Check for a required command line option
  if(count($argv) > 1) {
    if($argv[1] == "--desc") die($desc);
    elseif($argv[1] == "--shortdesc") die($shortdesc);
  }
  // No command line option was given so we are free to continue
  echo "This is a PHP plugin!\n"; // This is the text L33TSig Linux will pick up
?>