如何通过发信号的方式杀死父进程及其子进程？

import multiprocessing
import os
import signal
import time

def child_process():
    while True:
        print("子进程运行中...")
        time.sleep(1)

def signal_handler(signum, frame):
    print(f"父进程收到信号 {signum}")
    #  添加必要的清理工作

if __name__ == "__main__":
    child = multiprocessing.Process(target=child_process)
    child.daemon = True  # 设置为守护进程，父进程退出时子进程也退出
    child.start()

    pgid = os.getpgid(0) # 获取当前进程组ID
    with open("./pidfile", "w") as f:
        f.write(str(pgid))

    signal.signal(signal.SIGTERM, signal_handler)

    print("父进程运行中... PID:", os.getpid(), "进程组ID:", pgid)
    try:
        while True:
            time.sleep(1)
    except KeyboardInterrupt:
        print("父进程收到中断信号，准备退出...")
    finally:
        #  可选：添加额外的清理操作
        if os.path.exists("./pidfile"):
            os.remove("./pidfile")

import os
import signal

try:
    with open("./pidfile", "r") as f:
        pgid = int(f.read())
        os.killpg(pgid, signal.SIGTERM)
        print(f"已向进程组 {pgid} 发送SIGTERM信号")
except FileNotFoundError:
    print("pidfile 未找到")
except Exception as e:
    print(f"发送信号失败: {e}")