#!/usr/bin/env ruby

if ARGV.length < 3
	puts "Usage: #{$0} LOGFILE PIDFILE command arg..."
	exit 1
end

TIMEFORMAT = "%b %d %X"

logpath = File.expand_path(ARGV.shift)
log = File.open(logpath, 'a')

pidpath = File.expand_path(ARGV.shift)

name = File.basename(ARGV.first)
prog = ARGV.shift
if prog[0] == '.'[0]
	prog = File.expand_path(prog)
end
cmd = ([prog] + ARGV).join(' ')

# IO.daemonize
	exit! 0 if fork
	Process.setsid
	exit! 0 if fork
	Dir.chdir('/')
	File.umask(0)
	STDIN.reopen  '/dev/null', 'r'
	STDOUT.reopen logpath, 'a'
	STDERR.reopen logpath, 'a'

File.open(pidpath, 'w') {|f| f.puts(Process.pid) }
log.puts "#{Time.now.strftime(TIMEFORMAT)} #{File.basename($0)}[#{Process.pid}]: #{cmd}"
log.flush

while true

	io = IO.popen("#{cmd} 2>&1", "r+") {|io|
		pid = io.pid
		File.open("#{pidpath}.child", "w") {|f| f.puts(pid)}

		#ch = Process.detach(pid)

		while line = io.gets
			log.puts "#{Time.now.strftime(TIMEFORMAT)} #{name}[#{pid}]: #{line}"
			log.flush
		end

		Process.waitpid(pid)
		#ch.join
	}

	log.puts "#{Time.now.strftime(TIMEFORMAT)} --- restart ----"
	log.flush

	sleep 2

end