init.go

func startReapingChildren() {
	sigchld := make(chan os.Signal, 1)
	signal.Notify(sigchld, syscall.SIGCHLD)
	log.Println("starting to reap children")
	go func() {
		for _ = range sigchld {
			reapChildren()
		}
	}()
}

func reapChildren() {
	var stat syscall.WaitStatus
	var rusage syscall.Rusage
	for {
		// {_,ECHILD} means that there are no children.
		// {0,nil} means that there are children, but none have changed state (died)
		// {_,any other error} means something kinda serious happened.
		pid, err := syscall.Wait4(0, &stat, syscall.WNOHANG, &rusage)
		if err != nil {
			if err == syscall.ECHILD {
				break
			}
			reportErrorAndDie("Unexpected error reaping children: ", err) // EINVAL
		}
		if pid == 0 {
			break
		}
		if pid == AppPid {
			fmt.Printf("App rusage: %#v\n", rusage)
			log.Println("App died")
			AppDead <- stat.ExitStatus()
		}
	}
}