lib/aids.rb

   1 module AIDS
   2         RUNLEVEL_SINGLE          = 'S'
   3         RUNLEVEL_MULTI_TO_SINGLE = '1'
   4         RUNLEVEL_MULTI           = '2'
   5         RUNLEVEL_HALT            = '0'
   6         RUNLEVEL_REBOOT          = '6'
   7
   8         class Service
   9                 attr_reader :name
  10
  11                 def initialize(name)
  12                         if name.nil? or name.empty? or not name.is_a?(String)
  13                                 raise Exception.new("Service name must be a non-empty string, got #{name.inspect}.")
  14                         end
  15                         name = $1 if name =~ %r{^/etc/init\.d/(.+)$}
  16                         if name =~ /[^[:alnum:]\-.]/
  17                                 raise Exception.new("Invalid init script name: #{name}.")
  18                         end
  19                         unless File.exist?("/etc/init.d/#{name}")
  20                                 raise Exception.new("Unknown service: #{name}.")
  21                         end
  22                         @name = name
  23                 end
  24
  25                 def enable!
  26                         start_on_runlevel!(RUNLEVEL_MULTI)
  27                 end
  28
  29                 def disable!
  30                         stop_on_runlevel!(RUNLEVEL_MULTI)
  31                 end
  32
  33                 def enabled?
  34                         started_on_runlevel?(RUNLEVEL_MULTI)
  35                 end
  36
  37                 def status
  38                         if started_on_runlevel?(RUNLEVEL_MULTI)
  39                                 :enabled
  40                         elsif stopped_on_runlevel?(RUNLEVEL_MULTI)
  41                                 :disabled
  42                         else
  43                                 :unknown
  44                         end
  45                 end
  46
  47                 private
  48
  49                 def started_on_runlevel?(runlevel)
  50                         AIDS.validate_runlevel(runlevel)
  51                         not Dir.glob("/etc/rc#{runlevel}.d/S[0-9][0-9]#{@name}").empty?
  52                 end
  53
  54                 def stopped_on_runlevel?(runlevel)
  55                         AIDS.validate_runlevel(runlevel)
  56                         not Dir.glob("/etc/rc#{runlevel}.d/K[0-9][0-9]#{@name}").empty?
  57                 end
  58
  59                 def start_on_runlevel!(runlevel)
  60                         AIDS.validate_runlevel(runlevel)
  61                         return true if started_on_runlevel?(runlevel)
  62                         updatercd(:enable, runlevel)
  63                 end
  64
  65                 def stop_on_runlevel!(runlevel)
  66                         AIDS.validate_runlevel(runlevel)
  67                         return true if stopped_on_runlevel?(runlevel)
  68                         updatercd(:disable, runlevel)
  69                 end
  70
  71                 def set_default_runlevels!
  72                         updatercd(:remove)
  73                         updatercd(:defaults)
  74                 end
  75
  76                 def updatercd(action, runlevel=nil)
  77                         unless [:enable, :disable, :remove, :defaults].include?(action)
  78                                 raise Exception.new("Invalid action for updatercd: #{action}.")
  79                         end
  80                         AIDS.validate_runlevel(runlevel) if runlevel
  81                         # update-rc.d will baulk at being told to do anything with
  82                         # these runlevels.
  83                         if ['0', '1', '6'].include?(runlevel.to_s)
  84                                 raise Exception.new("Unable to comply: update-rc.d is balls.")
  85                         end
  86                         pid = Process.fork do
  87                                 $stdout.close
  88                                 $stderr.close
  89                                 Kernel.exec(
  90                                         '/usr/sbin/update-rc.d',
  91                                         @name,
  92                                         action.to_s,
  93                                         runlevel.to_s
  94                                 )
  95                         end
  96                         Process.wait(pid)
  97                         if (rc = $?.exitstatus) != 0
  98                                 raise Exception.new("update-rc.d returned #{rc}")
  99                         end
 100                 end
 101         end
 102
 103         def self.get_all_services
 104                 Dir.glob("/etc/init.d/*").map do |f|
 105                         next unless File.executable?(f)
 106                         Service.new(f)
 107                 end.compact
 108         end
 109
 110         def self.validate_runlevel(runlevel)
 111                 unless ['0', '1', '2', '3', '4', '5', '6', 'S'].include?(runlevel.to_s)
 112                         raise Exception.new("Invalid runlevel: #{runlevel}.")
 113                 end
 114         end
 115 end