守护进程删除smarty的缓存文件(注释版)

原文: 鸭嘴的Blog

偶参阅了网上资料加了注释.

 

<?php
 
define("PID_PATH", "/tmp/delSmartyCache.pid");

global $argv;
$cmd = $argv[1];
 
switch($cmd) {
    case 'start' :
        do_work();
        break;
    case 'stop' :
        do_stop();
        break;
    case 'status' :
        show_status();
        break;
    default :
        show_usage();
        break;
}

function do_work()
{
    // 创建子进程(守护进程)
    $newid = pcntl_fork();
    if ($newid == -1) {
        echo "pcntl_fork error\n";
        exit;
    }
    if ($newid) { // 返回值大于0, 表示创建成功, 提示信息并结束父进程
        echo "process delSmartyCache start successfully\n";
        exit;
    } else { // 返回值为0, 表示父进程结束后进入子进程的运行阶段
        // 取当前进程(子进程)的PID, 并写至进程文件
        $pid = posix_getpid();
        $fp = fopen(PID_PATH, "w");
        fwrite($fp, $pid);
        fclose($fp);
        while (true) {
            $cmd = "rm -rf /elink/bbs_data/smarty/tmpl_c/*";
            $re = popen("$cmd", "r"); // 打开一个指向删除进程的管道
            $ret = fread($re, 1024);
            if ($ret != "") {
                // 将执行情况写入日志
                $fp = fopen("/home/dexin/run_delSmartyCache.log","a+");
                fwrite($fp, $ret);
                fclose($fp);
            }
            // 延时6秒
            sleep(6);
        }
    }
}

// 停止守护进程
function do_stop()
{
    if (file_exists(PID_PATH)) {
        // 读取守护进程PID
        $fp = fopen(PID_PATH, "r");
        $pid = fread($fp, 10);
        // 退出守护进程
        $ret = posix_kill($pid, SIGQUIT);
        if ($ret === true) {
            echo "process delSmartyCache stopped successfully\n";
        } else {
            echo "fail stop process delSmartyCache\n";
        }
    } else {
        echo "process delSmartyCache not found\n";
    }
}

// 使用说明
function show_usage()
{
    print
<<<EOF
Usage:
    php delSmartyCache.php <option>

Options:
    start - Start the daemon
    stop - Stop daemon
    status - show the delSmartyCache daemon
    help - Show help
EOF;
}

// 显示状态
function show_status()
{
    if (file_exists(PID_PATH)) {
        $fp = fopen(PID_PATH, 'r');
        $pid = fread($fp, 10);
        $ret = posix_kill($pid, 0); // 发送信号判断进程是否存活
        if($ret === true) {
            echo "process delSmartyCache is alive\n";
            exit;
        } else {
            echo "process delSmartyCache is down\nplease start the process\n";
            exit;
        }
    } else {
        echo "pid file not exists\n";
        exit;
    }
}