Why Doesn\'t `Process.Signal` Kill Child Processes in Go?

Why Won't Go Kill a Child Process Using Process.Signal?

In the provided code snippet, the process is supposed to be killed using cmd.Process.Signal(syscall.SIGKILL) after a specified timeout. However, the timeout is not working correctly. Despite printing "It's dead Jim," the process continues to run, and "Done waiting" never prints.

The Issue

The issue here is related to the fact that cmd.Process.Signal does not kill child processes. Child processes have their own process groups and need to be killed separately.

Solution

To resolve this issue, a different approach can be taken by using syscall.Getpgid and syscall.Kill:

import "syscall"

cmd := exec.Command(some_command)
cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
cmd.Start()

pgid, err := syscall.Getpgid(cmd.Process.Pid)
if err == nil {
    syscall.Kill(-pgid, 15)  // note the minus sign
}

cmd.Wait()

By using SysProcAttr.Setpgid = true, a separate process group is created for the child process. Then, syscall.Getpgid retrieves the process group ID (pgid) of the child process. Finally, syscall.Kill(-pgid, 15) is called to send a SIGTERM signal to the entire process group, effectively killing both the child process and its child processes.

Caveats

This solution may not work across all platforms. It has been confirmed to work on macOS and Linux, but its behavior on other operating systems is uncertain.

The above is the detailed content of Why Doesn\'t `Process.Signal` Kill Child Processes in Go?. For more information, please follow other related articles on the PHP Chinese website!