ScreenSaver/dialog/medr-screensaver-dialog.py

#!/usr/bin/env python2.7
# -*- coding: utf-8 -*-
"""
Author: Zhang Yueqian zhangyueqian@antiy.cn
Date: 2022-10-31 11:32:24
LastEditors: Zhang Yueqian zhangyueqian@antiy.cn
LastEditTime: 2022-10-31 11:34:16
FilePath: /screensaver/dialog/medr-screensaver-dialog.py
Description: 屏保程序 for MEDR项目. 本文件为负责锁屏的部分.

提供实际锁屏功能, 支持三个参数: --lock 、--session-idle 和 --screensaver
    锁屏包括两个含义: 熄灭屏幕 & 触发lightdm锁定
    --lock: 直接锁定lightdm
    --session-idle: 根据系统设置进入session-idle模式
                    如果设置为空闲时激活屏保但不锁定, 那么关闭屏幕
                    如果设置了空闲激活屏保且锁定, 那么执行锁定, 通知lighdm执行黑屏
                    如果未设置空闲屏保但设置了锁定, 那么执行锁定, 不通知lightdm黑屏
    --screensaver:  首先熄灭屏幕, 然后锁定屏幕

本应用为单例模式, 启动后当前用户只允许一个实例
实现机制: 
    首先获取sock文件的锁
    如果获取失败, 表明已经运行一个了, 那么执行后将命令通过socket发送给当前活跃进程后退出.
    如果获取成功, 说明是新运行, 那么启动server监听socket,并且执行命令
"""

from argparse import ArgumentParser
import fcntl
from multiprocessing.managers import BaseManager
import os, socket
import atexit
from time import sleep
import gi

gi.require_version("Gtk", "3.0")
from gi.repository import GObject, Gio

MEDR_LOCK = "/tmp/medr-screensaver.lock"
TIMEOUT_FILE = "/var/run/medr-lightdm"
LOCK_FILE = "/var/run/medr-lightdm-lock"


def parse_args():
    """解析命令行参数

    Returns:
        (ArgumentParser.Namespace, str): 解析后的命令行参数及帮助信息
    """
    argparser = ArgumentParser(add_help=False)

    argparser.add_argument("-h", "--help", dest="help", action="store_true", help="Show this message and exit.")
    argparser.add_argument("-l", "--lock", dest="lock", action="store_true", help="Locks the screen.")
    argparser.add_argument(
        "--session-idle", dest="session_idle", action="store_true", help="Activated by session idle signal."
    )
    argparser.add_argument(
        "--screensaver",
        dest="screensaver",
        action="store_true",
        help="Locks the screen and shows screensaver immediatelly.",
    )

    return argparser.parse_args(), argparser.format_help()


def check_singleton():
    """检查是否是单例运行"""
    if not os.path.exists(MEDR_LOCK):
        open(MEDR_LOCK, "w").close()

    fd = open(MEDR_LOCK, "w")
    try:
        fcntl.flock(fd.fileno(), fcntl.LOCK_EX | fcntl.LOCK_NB)
    except IOError:
        fd.close()
        return False

    atexit.register(lambda: fd.close())
    return True


def write_lightdm(cmd):
    try:
        with open(LOCK_FILE, "w") as fp:
            fp.write(cmd)
    except Exception:
        return


def action(args, help):
    """执行命令

    Args:
        args (ArgumentParser.Namespace): ArgumentParser解析后的参数
        help (str): 帮助信息
    """
    first_run = check_singleton()
    if not first_run:
        print("Already running")
        return

    if args.help:
        print(help)
        return

    if args.lock:
        os.system("dm-tool lock")
        return

    if args.session_idle:
        # 从Gio获取gsettings设置
        # 1 判断是否设置了 /org/ukui/screensaver/idle-activation-enabled (空闲时是否激活屏保)
        screensaver = Gio.Settings("org.ukui.screensaver")
        idle_activation = screensaver.get_value("idle-activation-enabled").get_boolean()
        # 2 判断是否设置了 /org/ukui/screensaver/lock-enabled (空闲时是否锁定屏幕)
        lock_enabled = screensaver.get_value("lock-enabled").get_boolean()

        # idle_activation 0   0   1      1
        # lock_enabled    0   1   0      1
        # 动作            无  锁  黑不锁   黑锁

        if not idle_activation:
            if not lock_enabled:
                # 既不黑屏,也不锁定
                return
            else:
                # 只锁定不黑屏
                os.system("dm-tool lock")
        else:
            if not lock_enabled:
                # 黑屏, 不锁定
                os.system("xset dpms force off")
            else:
                # 黑屏且锁定
                os.system("xset dpms force off")
                sleep(1)
                write_lightdm("blank")
                os.system("dm-tool lock")

        return

    if args.screensaver:
        write_lightdm("blank")
        os.system("dm-tool lock")
        return

    print(help)


if __name__ == "__main__":
    args, msg = parse_args()
    action(args, msg)