better process killing

vendor/github.com/jesseduffield/kill/kill_default_platform.go

@@ -0,0 +1,33 @@
+//go:build !windows
+// +build !windows
+
+package kill
+
+import (
+	"os/exec"
+	"syscall"
+)
+
+// Kill kills a process. If the process has Setpgid == true, then we have anticipated that it might spawn its own child processes, so we've given it a process group ID (PGID) equal to its process id (PID) and given its child processes will inherit the PGID, we can kill that group, rather than killing the process itself.
+func Kill(cmd *exec.Cmd) error {
+	if cmd.Process == nil {
+		// You can't kill a person with no body
+		return nil
+	}
+
+	if cmd.SysProcAttr != nil && cmd.SysProcAttr.Setpgid {
+		// minus sign means we're talking about a PGID as opposed to a PID
+		return syscall.Kill(-cmd.Process.Pid, syscall.SIGKILL)
+	}
+
+	return cmd.Process.Kill()
+}
+
+// PrepareForChildren ensures that child processes of this parent process will share the same group id
+// as the parent, meaning when the call Kill on the parent process, we'll kill
+// the whole group, parent and children both. Gruesome when you think about it.
+func PrepareForChildren(cmd *exec.Cmd) {
+	cmd.SysProcAttr = &syscall.SysProcAttr{
+		Setpgid: true,
+	}
+}