package main

import (
	"flag"
	"fmt"
	"os/exec"
	"runtime"
	"syscall"
)

func main() {
	kill := false
	flag.BoolVar(&kill, "death", false, "Set deathsig")
	flag.Parse()

	cmd := exec.Command("sleep", "1000")
	if kill == true {
		fmt.Println("Death is coming")
		cmd.SysProcAttr = &syscall.SysProcAttr{
			Setpgid:   true,
			Pdeathsig: syscall.SIGKILL,
		}
	}

	// force other goroutines to be spawned on a new thread
	runtime.LockOSThread()

	done := make(chan struct{})

	go func() {
		runtime.LockOSThread()
		err := cmd.Start()
		if err != nil {
			fmt.Println(err)
		}
		close(done)
		fmt.Println("Exit goroutine")
	}()

	<-done

	fmt.Println("Waiting")
	err := cmd.Wait()
	fmt.Println("Done", err)
}

package main

import (
	"fmt"
	"os/exec"
	"runtime"
	"syscall"
)

func main() {

	done := make(chan struct{})

	cmd := exec.Command("sleep", "1000")
	cmd.SysProcAttr = &syscall.SysProcAttr{
		Setpgid:   true,
		Pdeathsig: syscall.SIGKILL,
	}

	go func() {
		// On Linux, pdeathsig will kill the child process when the thread dies,
		// not when the process dies. runtime.LockOSThread ensures that as long
		// as this function is executing that OS thread will still be around
		runtime.LockOSThread()
		defer runtime.UnlockOSThread()

		err := cmd.Start()
		if err != nil {
			fmt.Println(err)
		}

		fmt.Println("Child is PID", cmd.Process.Pid)
		err = cmd.Wait()
		close(done)
		fmt.Println("Child exited:", err)
	}()

	fmt.Println("Waiting for child to exit")
	<-done
	fmt.Println("Parent exiting")
}