insert dummy DNS entries for the domains specified in LeechBlock for Firefox

leechblock-dnsmasq.rb

#!/usr/bin/env ruby

# insert dummy DNS entries for the domains specified in LeechBlock for Firefox

# usage: use this as a cron job

USAGE = <<"EOD"
usage: #{$0} [-f leechblock_exported_file]
EOD

require 'optparse'

OPT = Struct.
  new(:file,  :id, :sentinel, :unreachable, :dnsmasq, :verbose).
  new(ENV['HOME']+'/.myconf/leechblock.txt', '1', 'leechblock-sentinel-a.localhost', '192.0.2.1', '/usr/sbin/dnsmasq', false)
OptionParser.new do |opts|
  opts.on('--file STR', String) do |v|
    OPT.file = v
  end
  opts.on('--[no-]verbose') do |v|
    OPT.verbose = v
  end
end.parse!

require 'resolv'
kvs = {}
open(OPT.file) do |io|
  io.each_line do |line|
    line.strip!
    k,v = line.split(/=/)
    kvs[k] = v
  end
end

duras = kvs['times'+OPT.id]
sites = kvs['sites'+OPT.id].split(/\s+/)

block_enabled = false
msg = Resolv::DNS.new.getresources('localhost.', Resolv::DNS::Resource::IN::TXT)
if msg.length > 0 and msg[0].strings.any?{|x| x == OPT.sentinel} then
  block_enabled = true
end
block_written = false

time = Time.new.hour * 100 + Time.new.min
duras.split(/,/).each do |pair|
  min,max = pair.split(/\-/).map{|x| x.to_i}
  if min <= time and time < max then
    block_written = true
  end
end

if OPT.verbose then
  def system_verbose(*x)
    puts x.join(' ')
    system *x
  end
else
  alias :system_verbose :system
end

if block_written and !block_enabled then
  args = sites.map do |x|
    x.sub!(/^\*/,'')
    "--address=/#{x}/#{OPT.unreachable}"
  end
  system_verbose "pkill dnsmasq && " + "#{OPT.dnsmasq} --txt-record=localhost,#{OPT.sentinel} #{args.join(' ')}"
end
if !block_written and block_enabled then
  system_verbose "pkill dnsmasq && #{OPT.dnsmasq}"
end