lib/aids.rb

   1 module AIDS
   2         RUNLEVEL_SINGLE          = :'S'
   3         RUNLEVEL_MULTI_TO_SINGLE = :'1'
   4         RUNLEVEL_MULTI           = :'2'
   5         RUNLEVEL_MULTI_ALL       = [:'2',:'3',:'4',:'5']
   6         RUNLEVEL_HALT            = :'0'
   7         RUNLEVEL_REBOOT          = :'6'
   8         RUNLEVEL_ALL             = [:'0',:'1',:'2',:'3',:'4',:'5',:'6',:'S']
   9
  10         class Service
  11                 attr_reader :name
  12
  13                 def initialize(name)
  14                         if name.nil? or name.empty? or not name.is_a?(String)
  15                                 raise AIDS::Infection.new("Service name must be a non-empty string, got #{name.inspect}.")
  16                         end
  17                         name = $1 if name =~ %r{^/etc/init\.d/(.+)$}
  18                         if name =~ /[^[:alnum:]\-.]/
  19                                 raise AIDS::Infection.new("Invalid init script name: #{name}.")
  20                         end
  21                         unless File.exist?("/etc/init.d/#{name}")
  22                                 raise AIDS::Infection.new("Unknown service: #{name}.")
  23                         end
  24                         @name = name
  25                 end
  26
  27                 def enable!
  28                         start_on_runlevels!(RUNLEVEL_MULTI_ALL)
  29                 end
  30
  31                 def disable!
  32                         stop_on_runlevels!(RUNLEVEL_MULTI_ALL)
  33                 end
  34
  35                 def enabled?
  36                         started_on_runlevel?(RUNLEVEL_MULTI)
  37                 end
  38
  39                 def status
  40                         status = {}
  41                         RUNLEVEL_ALL.each do |r|
  42                                 if started_on_runlevel?(r)
  43                                         status[r] = :start
  44                                 elsif stopped_on_runlevel?(r)
  45                                         status[r] = :stop
  46                                 else
  47                                         status[r] = :none
  48                                 end
  49                         end
  50                         status
  51                 end
  52
  53                 private
  54
  55                 def started_on_runlevel?(runlevel)
  56                         AIDS.validate_runlevel(runlevel)
  57                         not Dir.glob("/etc/rc#{runlevel}.d/S[0-9][0-9]#{@name}").empty?
  58                 end
  59
  60                 def stopped_on_runlevel?(runlevel)
  61                         AIDS.validate_runlevel(runlevel)
  62                         not Dir.glob("/etc/rc#{runlevel}.d/K[0-9][0-9]#{@name}").empty?
  63                 end
  64
  65                 def start_on_runlevels!(runlevels)
  66                         [runlevels].flatten.each do |r|
  67                                 AIDS.validate_runlevel(r)
  68                                 next if started_on_runlevel?(r)
  69                                 updatercd(:enable, r)
  70                         end
  71                 end
  72
  73                 def stop_on_runlevels!(runlevels)
  74                         [runlevels].flatten.each do |r|
  75                                 AIDS.validate_runlevel(r)
  76                                 next if stopped_on_runlevel?(r)
  77                                 updatercd(:disable, r)
  78                         end
  79                 end
  80
  81                 def set_default_runlevels!
  82                         updatercd(:remove)
  83                         updatercd(:defaults)
  84                 end
  85
  86                 def updatercd(action, runlevel=nil)
  87                         unless [:enable, :disable, :remove, :defaults].include?(action)
  88                                 raise AIDS::Infection.new("Invalid action for updatercd: #{action}.")
  89                         end
  90                         AIDS.validate_runlevel(runlevel) if runlevel
  91                         # update-rc.d will baulk at being told to do anything with
  92                         # these runlevels.
  93                         if [:'0',:'1',:'6'].include?(runlevel)
  94                                 raise AIDS::Infection.new("Unable to comply: update-rc.d is balls.")
  95                         end
  96                         pid = Process.fork do
  97                                 $stdout.close
  98                                 $stderr.close
  99                                 Kernel.exec(
 100                                         '/usr/sbin/update-rc.d',
 101                                         @name,
 102                                         action.to_s,
 103                                         runlevel.to_s
 104                                 )
 105                         end
 106                         Process.wait(pid)
 107                         if (rc = $?.exitstatus) != 0
 108                                 raise AIDS::Infection.new("update-rc.d returned #{rc}")
 109                         end
 110                 end
 111         end
 112
 113         class Infection < Exception
 114         end
 115
 116         def self.get_all_services
 117                 Dir.glob("/etc/init.d/*").map do |f|
 118                         next unless File.executable?(f)
 119                         Service.new(f)
 120                 end.compact
 121         end
 122
 123         private
 124
 125         def self.validate_runlevel(runlevel)
 126                 unless RUNLEVEL_ALL.include?(runlevel)
 127                         raise AIDS::Infection.new("Invalid runlevel: #{runlevel}.")
 128                 end
 129         end
 130 end