lib/aids.rb

   1 # Copyright (C) 2012  Steven McDonald <steven@steven-mcdonald.id.au>
   2 #
   3 # This program is free software. It comes without any warranty, to the
   4 # extent permitted by applicable law. You can redistribute it and/or
   5 # modify it under the terms of the Do What The Fuck You Want To Public
   6 # License, Version 2, as published by Sam Hocevar. See the file COPYING
   7 # in the root of this program's source distribution for details, or:
   8 #
   9 #   http://sam.zoy.org/wtfpl/COPYING
  10
  11 module AIDS
  12         RUNLEVEL_SINGLE          = :'S'
  13         RUNLEVEL_MULTI_TO_SINGLE = :'1'
  14         RUNLEVEL_MULTI           = :'2'
  15         RUNLEVEL_MULTI_ALL       = [:'2',:'3',:'4',:'5']
  16         RUNLEVEL_HALT            = :'0'
  17         RUNLEVEL_REBOOT          = :'6'
  18         RUNLEVEL_ALL             = [:'0',:'1',:'2',:'3',:'4',:'5',:'6',:'S']
  19
  20         class Service
  21                 attr_reader :name
  22
  23                 def initialize(name)
  24                         if name.nil? or name.empty? or not name.is_a?(String)
  25                                 raise AIDS::Infection.new("Service name must be a non-empty string, got #{name.inspect}.")
  26                         end
  27                         name = $1 if name =~ %r{^/etc/init\.d/(.+)$}
  28                         if name =~ /[^[:alnum:]\-.]/
  29                                 raise AIDS::Infection.new("Invalid init script name: #{name}.")
  30                         end
  31                         unless File.exist?("/etc/init.d/#{name}")
  32                                 raise AIDS::Infection.new("Unknown service: #{name}.")
  33                         end
  34                         @name = name
  35                 end
  36
  37                 def enable!
  38                         start_on_runlevels!(RUNLEVEL_MULTI_ALL)
  39                 end
  40
  41                 def disable!
  42                         stop_on_runlevels!(RUNLEVEL_MULTI_ALL)
  43                 end
  44
  45                 def enabled?
  46                         started_on_runlevel?(RUNLEVEL_MULTI)
  47                 end
  48
  49                 def status
  50                         status = {}
  51                         RUNLEVEL_ALL.each do |r|
  52                                 if started_on_runlevel?(r)
  53                                         status[r] = :start
  54                                 elsif stopped_on_runlevel?(r)
  55                                         status[r] = :stop
  56                                 else
  57                                         status[r] = :none
  58                                 end
  59                         end
  60                         status
  61                 end
  62
  63                 private
  64
  65                 def started_on_runlevel?(runlevel)
  66                         AIDS.validate_runlevel(runlevel)
  67                         not Dir.glob("/etc/rc#{runlevel}.d/S[0-9][0-9]#{@name}").empty?
  68                 end
  69
  70                 def stopped_on_runlevel?(runlevel)
  71                         AIDS.validate_runlevel(runlevel)
  72                         not Dir.glob("/etc/rc#{runlevel}.d/K[0-9][0-9]#{@name}").empty?
  73                 end
  74
  75                 def start_on_runlevels!(runlevels)
  76                         [runlevels].flatten.each do |r|
  77                                 AIDS.validate_runlevel(r)
  78                                 next if started_on_runlevel?(r)
  79                                 updatercd(:enable, r)
  80                         end
  81                 end
  82
  83                 def stop_on_runlevels!(runlevels)
  84                         [runlevels].flatten.each do |r|
  85                                 AIDS.validate_runlevel(r)
  86                                 next if stopped_on_runlevel?(r)
  87                                 updatercd(:disable, r)
  88                         end
  89                 end
  90
  91                 def set_default_runlevels!
  92                         updatercd(:remove)
  93                         updatercd(:defaults)
  94                 end
  95
  96                 def updatercd(action, runlevel=nil)
  97                         unless [:enable, :disable, :remove, :defaults].include?(action)
  98                                 raise AIDS::Infection.new("Invalid action for updatercd: #{action}.")
  99                         end
 100                         AIDS.validate_runlevel(runlevel) if runlevel
 101                         # update-rc.d will baulk at being told to do anything with
 102                         # these runlevels.
 103                         if [:'0',:'1',:'6'].include?(runlevel)
 104                                 raise AIDS::Infection.new("Unable to comply: update-rc.d is balls.")
 105                         end
 106                         pid = Process.fork do
 107                                 $stdout.close
 108                                 $stderr.close
 109                                 Kernel.exec(
 110                                         '/usr/sbin/update-rc.d',
 111                                         @name,
 112                                         action.to_s,
 113                                         runlevel.to_s
 114                                 )
 115                         end
 116                         Process.wait(pid)
 117                         if (rc = $?.exitstatus) != 0
 118                                 raise AIDS::Infection.new("update-rc.d returned #{rc}")
 119                         end
 120                 end
 121         end
 122
 123         class Infection < Exception
 124         end
 125
 126         def self.get_all_services
 127                 Dir.glob("/etc/init.d/*").map do |f|
 128                         next unless File.executable?(f)
 129                         Service.new(f)
 130                 end.compact
 131         end
 132
 133         private
 134
 135         def self.validate_runlevel(runlevel)
 136                 unless RUNLEVEL_ALL.include?(runlevel)
 137                         raise AIDS::Infection.new("Invalid runlevel: #{runlevel}.")
 138                 end
 139         end
 140 end