linux 守护进程下载

import os
import sys
import time
import urllib.request

def daemonize():
    try:
        pid = os.fork()
        if pid > 0:
            # Exit first parent
            sys.exit(0)
    except OSError as e:
        sys.stderr.write(f"Fork #1 failed: {e.errno} ({e.strerror})\n")
        sys.exit(1)

    # Decouple from parent environment
    os.chdir("/")
    os.setsid()
    os.umask(0)

    # Do second fork
    try:
        pid = os.fork()
        if pid > 0:
            # Exit from second parent
            sys.exit(0)
    except OSError as e:
        sys.stderr.write(f"Fork #2 failed: {e.errno} ({e.strerror})\n")
        sys.exit(1)

    # Redirect standard file descriptors
    sys.stdout.flush()
    sys.stderr.flush()
    si = open(os.devnull, 'r')
    so = open(os.devnull, 'a+')
    se = open(os.devnull, 'a+')

    os.dup2(si.fileno(), sys.stdin.fileno())
    os.dup2(so.fileno(), sys.stdout.fileno())
    os.dup2(se.fileno(), sys.stderr.fileno())

def download_file(url, destination):
    try:
        urllib.request.urlretrieve(url, destination)
        print(f"Downloaded {url} to {destination}")
    except Exception as e:
        print(f"Failed to download {url}: {e}")

if __name__ == "__main__":
    daemonize()
    while True:
        download_file("http://example.com/file.zip", "/path/to/download/file.zip")
        time.sleep(3600)  # Sleep for 1 hour