From cd87c299dc1cb5d19bdb82dac438d4d08992f59b Mon Sep 17 00:00:00 2001
From: osaajani <pierre.lin@free.fr>
Date: Sun, 8 Dec 2019 01:50:18 +0100
Subject: [PATCH] add abstract daemon

---
 daemons/AbstractDaemon.php | 129 +++++++++++++++++++++++++++++++++++++
 1 file changed, 129 insertions(+)
 create mode 100644 daemons/AbstractDaemon.php

diff --git a/daemons/AbstractDaemon.php b/daemons/AbstractDaemon.php
new file mode 100644
index 0000000..1148b78
--- /dev/null
+++ b/daemons/AbstractDaemon.php
@@ -0,0 +1,129 @@
+<?php
+
+/**
+ * Class defining the global structur of a Linux Daemon
+ */
+abstract class AbstractDaemon
+{
+	protected $name;
+	private $is_running = true;
+	private $signals = array (
+        SIGTERM,
+        SIGINT,
+        SIGCHLD,
+        SIGHUP 
+    );
+
+	/**
+	 * Class used to handle POSIX signals and fork from the current process
+	 *
+	 * @param string $name : The name of the class
+	 * @param array $signals :An array containing additional POSIX signals to handle [optionel]
+	 */
+    protected function __construct (string $name, array $signals = [])
+    {
+		$this->name = $name;
+        $this->signals = array_merge($this->signals, $signals);
+
+        //Allow script to run indefinitly
+        set_time_limit(0);
+
+        //Register signals
+		$this->register_signals();
+    }
+
+
+	/**
+	 * Used to register POSIX signals
+	 */
+    private function register_signals()
+    {
+        //Enable a tick at every 1 instruction, allowing us to run a function frequently, for exemple looking at signal status
+        declare(ticks = 1);
+
+        foreach ($this->signals as $signal)
+        {
+            //For each signal define the method handle_signal of the current class as the way to handle it
+            @pcntl_signal($signal, [
+                    'self',
+					'handle_signal' 
+            ]);
+		}
+    }
+
+	/**
+	 * Used to handle properly SIGINT, SIGTERM, SIGCHLD and SIGHUP
+	 *
+     * @param int $signal
+     * @param mixed $signinfo
+	 */
+    protected function handle_signal(int $signal, $signinfo)
+    {
+        if ($signal == SIGTERM || $signal == SIGINT) //Stop the daemon
+        {
+			$this->is_running = false;
+        }
+        else if ($signal == SIGHUP) //Restart the daemon
+        {
+			$this->on_stop();
+			$this->on_start();
+        }
+        else if ($signal == SIGCHLD) //On daemon child stopping
+        {
+			pcntl_waitpid(-1, $status, WNOHANG);
+        }
+        else //All the other signals
+        {
+			$this->handle_other_signals($signal);
+		}
+    }
+
+
+	/**
+	 * Launch the infinite loop executing the "run" abstract method
+	 */
+    protected function start ()
+    {
+		$this->on_start();
+        while ($this->is_running)
+        {
+			pcntl_signal_dispatch(); //Call dispatcher for signals
+			$this->run();
+		}
+		$this->on_stop();
+    }
+
+
+	/**
+	 * True if the daemon is running
+	 */
+    public function is_running()
+    {
+		return $this->is_running;
+    }
+
+	/**
+	 * Override to implement the code that run infinetly (actually, it run one time but repeat the operation infinetly
+	 */
+    protected abstract function run();
+
+
+	/**
+	 * Override to execute code before the ''run'' method on daemon start
+	 */
+    protected abstract function on_start();
+
+
+	/**
+	 * Override to execute code after the ''run'' method on daemon shutdown
+	 */
+	protected abstract function on_stop();
+    
+    
+    /**
+	 * Override to handle additional POSIX signals
+	 *
+	 * @param int $signal : Signal sent by interrupt
+	 */
+	protected abstract function handle_other_signals(int $signal);
+}