lib/aids.rb

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