systemu.rb

   1 # vim: ts=2:sw=2:sts=2:et:fdm=marker
   2 require 'tmpdir'
   3 require 'socket'
   4 require 'fileutils'
   5 require 'rbconfig'
   6 require 'thread'
   7 require 'yaml'
   8
   9 class Object
  10   def systemu(*a, &b) SystemUniversal.new(*a, &b).systemu end
  11 end
  12
  13 class SystemUniversal
  14 #
  15 # constants
  16 #
  17   SystemUniversal::VERSION = '1.2.0' unless defined?  SystemUniversal::VERSION
  18   def version() SystemUniversal::VERSION end
  19 #
  20 # class methods
  21 #
  22
  23   @host = Socket.gethostname
  24   @ppid = Process.ppid
  25   @pid = Process.pid
  26   @turd = ENV['SYSTEMU_TURD']
  27
  28   c = ::Config::CONFIG
  29   ruby = File.join(c['bindir'], c['ruby_install_name']) << c['EXEEXT']
  30   @ruby = if system('%s -e 42' % ruby)
  31     ruby
  32   else
  33     system('%s -e 42' % 'ruby') ? 'ruby' : warn('no ruby in PATH/CONFIG')
  34   end
  35
  36   class << self
  37     %w( host ppid pid ruby turd ).each{|a| attr_accessor a}
  38   end
  39
  40 #
  41 # instance methods
  42 #
  43
  44   def initialize argv, opts = {}, &block
  45     getopt = getopts opts
  46
  47     @argv = argv
  48     @block = block
  49
  50     @stdin = getopt[ ['stdin', 'in', '0', 0] ]
  51     @stdout = getopt[ ['stdout', 'out', '1', 1] ]
  52     @stderr = getopt[ ['stderr', 'err', '2', 2] ]
  53     @env = getopt[ 'env' ]
  54     @cwd = getopt[ 'cwd' ]
  55
  56     @host = getopt[ 'host', self.class.host ]
  57     @ppid = getopt[ 'ppid', self.class.ppid ]
  58     @pid = getopt[ 'pid', self.class.pid ]
  59     @ruby = getopt[ 'ruby', self.class.ruby ]
  60   end
  61
  62   def systemu
  63     tmpdir do |tmp|
  64       c = child_setup tmp
  65       status = nil
  66
  67       begin
  68         thread = nil
  69
  70         quietly{
  71           IO.popen "#{ @ruby } #{ c['program'] }", 'r+' do |pipe|
  72             line = pipe.gets
  73             case line
  74               when %r/^pid: \d+$/
  75                 cid = Integer line[%r/\d+/]
  76               else
  77                 begin
  78                   buf = pipe.read
  79                   buf = "#{ line }#{ buf }"
  80                   e = Marshal.load buf
  81                   raise unless Exception === e
  82                   raise e
  83                 rescue
  84                   raise "wtf?\n#{ buf }\n"
  85                 end
  86             end
  87             thread = new_thread cid, @block if @block
  88             pipe.read rescue nil
  89           end
  90         }
  91         status = $?
  92       ensure
  93         if thread
  94           begin
  95             class << status
  96               attr 'thread'
  97             end
  98             status.instance_eval{ @thread = thread }
  99           rescue
 100             42
 101           end
 102         end
 103       end
 104
 105       if @stdout or @stderr
 106         open(c['stdout']){|f| relay f => @stdout} if @stdout
 107         open(c['stderr']){|f| relay f => @stderr} if @stderr
 108         status
 109       else
 110         [status, IO.read(c['stdout']), IO.read(c['stderr'])]
 111       end
 112     end
 113   end
 114
 115   def new_thread cid, block
 116     q = Queue.new
 117     Thread.new(cid) do |cid|
 118       current = Thread.current
 119       current.abort_on_exception = true
 120       q.push current
 121       block.call cid
 122     end
 123     q.pop
 124   end
 125
 126   def child_setup tmp
 127     stdin = File.expand_path(File.join(tmp, 'stdin'))
 128     stdout = File.expand_path(File.join(tmp, 'stdout'))
 129     stderr = File.expand_path(File.join(tmp, 'stderr'))
 130     program = File.expand_path(File.join(tmp, 'program'))
 131     config = File.expand_path(File.join(tmp, 'config'))
 132
 133     if @stdin
 134       open(stdin, 'w'){|f| relay @stdin => f}
 135     else
 136       FileUtils.touch stdin
 137     end
 138     FileUtils.touch stdout
 139     FileUtils.touch stderr
 140
 141     c = {}
 142     c['argv'] = @argv
 143     c['env'] = @env
 144     c['cwd'] = @cwd
 145     c['stdin'] = stdin
 146     c['stdout'] = stdout
 147     c['stderr'] = stderr
 148     c['program'] = program
 149     open(config, 'w'){|f| YAML.dump c, f}
 150
 151     open(program, 'w'){|f| f.write child_program(config)}
 152
 153     c
 154   end
 155
 156   def quietly
 157     v = $VERBOSE
 158     $VERBOSE = nil
 159     yield
 160   ensure
 161     $VERBOSE = v
 162   end
 163
 164   def child_program config
 165     <<-program
 166       PIPE = STDOUT.dup
 167       begin
 168         require 'yaml'
 169
 170         config = YAML.load(IO.read('#{ config }'))
 171
 172         argv = config['argv']
 173         env = config['env']
 174         cwd = config['cwd']
 175         stdin = config['stdin']
 176         stdout = config['stdout']
 177         stderr = config['stderr']
 178
 179         Dir.chdir cwd if cwd
 180         env.each{|k,v| ENV[k.to_s] = v.to_s} if env
 181
 182         STDIN.reopen stdin
 183         STDOUT.reopen stdout
 184         STDERR.reopen stderr
 185
 186         PIPE.puts "pid: \#{ Process.pid }"
 187         PIPE.flush                        ### the process is ready yo!
 188         PIPE.close
 189
 190         exec *argv
 191       rescue Exception => e
 192         PIPE.write Marshal.dump(e) rescue nil
 193         exit 42
 194       end
 195     program
 196   end
 197
 198   def relay srcdst
 199     src, dst, ignored = srcdst.to_a.first
 200     if src.respond_to? 'read'
 201       while((buf = src.read(8192))); dst << buf; end
 202     else
 203       src.each{|buf| dst << buf}
 204     end
 205   end
 206
 207   def tmpdir d = Dir.tmpdir, max = 42, &b
 208     i = -1 and loop{
 209       i += 1
 210
 211       tmp = File.join d, "systemu_#{ @host }_#{ @ppid }_#{ @pid }_#{ rand }_#{ i += 1 }"
 212
 213       begin
 214         Dir.mkdir tmp
 215       rescue Errno::EEXIST
 216         raise if i >= max
 217         next
 218       end
 219
 220       break(
 221         if b
 222           begin
 223             b.call tmp
 224           ensure
 225             FileUtils.rm_rf tmp unless SystemU.turd
 226           end
 227         else
 228           tmp
 229         end
 230       )
 231     }
 232   end
 233
 234   def getopts opts = {}
 235     lambda do |*args|
 236       keys, default, ignored = args
 237       catch('opt') do
 238         [keys].flatten.each do |key|
 239           [key, key.to_s, key.to_s.intern].each do |key|
 240             throw 'opt', opts[key] if opts.has_key?(key)
 241           end
 242         end
 243         default
 244       end
 245     end
 246   end
 247 end
 248
 249 SystemU = SystemUniversal unless defined? SystemU
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263 if $0 == __FILE__
 264 #
 265 # date
 266 #
 267   date = %q( ruby -e"  t = Time.now; STDOUT.puts t; STDERR.puts t  " )
 268
 269   status, stdout, stderr = systemu date
 270   p [status, stdout, stderr]
 271
 272   status = systemu date, 1=>(stdout = '')
 273   p [status, stdout]
 274
 275   status = systemu date, 2=>(stderr = '')
 276   p [status, stderr]
 277 #
 278 # sleep
 279 #
 280   sleep = %q( ruby -e"  p(sleep(1))  " )
 281   status, stdout, stderr = systemu sleep
 282   p [status, stdout, stderr]
 283
 284   sleep = %q( ruby -e"  p(sleep(42))  " )
 285   status, stdout, stderr = systemu(sleep){|cid| Process.kill 9, cid}
 286   p [status, stdout, stderr]
 287 #
 288 # env
 289 #
 290   env = %q( ruby -e"  p ENV['A']  " )
 291   status, stdout, stderr = systemu env, :env => {'A' => 42}
 292   p [status, stdout, stderr]
 293 #
 294 # cwd
 295 #
 296   env = %q( ruby -e"  p Dir.pwd  " )
 297   status, stdout, stderr = systemu env, :cwd => Dir.tmpdir
 298   p [status, stdout, stderr]
 299 end