From 2835eafd1207dfed90a140778323f94bd10e4e29 Mon Sep 17 00:00:00 2001
From: Dominique Fournier <dominique@fournier38.fr>
Date: Fri, 22 Dec 2017 14:03:29 +0000
Subject: [PATCH] Add daemon support

git-svn-id: https://svn.fournier38.fr/svn/ProgSVN/trunk@4009 bf3deb0d-5f1a-0410-827f-c0cc1f45334c
---
 daemon.php | 148 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 148 insertions(+)
 create mode 100644 daemon.php

diff --git a/daemon.php b/daemon.php
new file mode 100644
index 0000000..a73613e
--- /dev/null
+++ b/daemon.php
@@ -0,0 +1,148 @@
+<?php
+require_once ("domframework/fork.php");
+require_once ("domframework/file.php");
+
+/** Manage a daemon.
+  * Allow to start, stop, get status of a callable method
+  */
+class daemon
+{
+  /** Set the directory to store the PID of the daemon
+    */
+  private $runDir = "/var/run";
+
+  /** The constructor check if /proc is mounted
+    */
+  public function __construct ()
+  {
+    if (! file_exists ("/proc"))
+      throw new \Exception ("Can't manage daemon: /proc doesn't exists", 500);
+  }
+
+  /** Get/set the directory to store the PID of the daemon
+    * @param string|null $val The directory
+    */
+  public function runDir ($val = null)
+  {
+    if ($val === null)
+      return $this->runDir;
+    if (! is_string ($val))
+      throw new \Exception ("Can not set daemon runDir: not a string", 500);
+    $this->runDir = "$val";
+  }
+
+  /** Start the callable method. The terminal is closed. All the displayed
+    * messages from the child are silently dropped.
+    * If some parameters are provided, the called child method will receive them
+    * This function fork and return the child PID
+    * @param string $name The name of daemon to start.
+    * @param callable $callable The callback method to use in child
+    * @param mixed|null $params The params to provide to child method
+    * @return The child PID
+    */
+  public function start ($name, $callable, $params = array ())
+  {
+    $file = new \file ();
+    if (! $file->is_writeable ($this->runDir))
+      throw new \Exception (sprintf ("Run Directory '%s' is not writeable",
+        $this->runDir), 500);
+    if (! $file->is_readable ($this->runDir))
+      throw new \Exception (sprintf ("Run Directory '%s' is not readable",
+        $this->runDir), 500);
+    if ($file->file_exists ($this->runDir."/$name.pid"))
+    {
+      $pid = $file->file_get_contents ($this->runDir."/$name.pid");
+      if (file_exists ("/proc/$pid"))
+        throw new \Exception (sprintf (
+          "Can't start the daemon: already running with PID %d", $pid), 500);
+    }
+    $fork = new \fork ();
+    $pid = $fork->startDetachedChild ($name, $callable, $params);
+    file_put_contents ($this->runDir."/$name.pid", $pid);
+    return $pid;
+  }
+
+  /** Stop a $name daemon
+    * @param string $name The name of daemon to stop. The name must be the same
+    * as the name used in the start method
+    * @param integer $maxWaitStop The waiting maximum time after SIGTERM before
+    * sending SIGKILL
+    * @param integer $maxWaitKill The waiting maximum time after SIGKILL before
+    * raising an error
+    */
+  public function stop ($name, $maxWaitStop = 3, $maxWaitKill = 3)
+  {
+    $file = new \file ();
+    if (! $file->is_writeable ($this->runDir))
+      throw new \Exception (sprintf ("Run Directory '%s' is not writeable",
+        $this->runDir), 500);
+    if (! $file->is_readable ($this->runDir))
+      throw new \Exception (sprintf ("Run Directory '%s' is not readable",
+        $this->runDir), 500);
+    if (! $file->file_exists ($this->runDir."/$name.pid"))
+      throw new \Exception (sprintf (
+        "PID file %s not found : can't stop the daemon",
+        $this->runDir."/$name.pid"), 500);
+    $pid = $file->file_get_contents ($this->runDir."/$name.pid");
+    if (! file_exists ("/proc/$pid"))
+    {
+      $file->unlink ($this->runDir."/$name.pid");
+      throw new \Exception (
+        "Can't stop daemon $name. There is no process with the PID $pid",
+        500);
+    }
+    posix_kill ($pid, SIGTERM);
+    usleep (10000);
+    $startWait = time ();
+    while (time () < $startWait + $maxWaitStop)
+    {
+      // If the child is zombie and is connected to me, pcntl_waitpid allow it
+      // to be destroyed to close correctely the parent
+      pcntl_waitpid ($pid, $status, WNOHANG);
+      if (! file_exists ("/proc/$pid"))
+      {
+        $file->unlink ($this->runDir."/$name.pid");
+        return true;
+      }
+      usleep (100000);
+      echo ".";
+    }
+    posix_kill ($pid, SIGKILL);
+    $startWait = time ();
+    while (time () < $startWait + $maxWaitKill)
+    {
+      if (! file_exists ("/proc/$pid"))
+      {
+        $file->unlink ($this->runDir."/$name.pid");
+        return true;
+      }
+      usleep (100000);
+      echo "X";
+    }
+    throw new \Exception ("Can't stop and can't kill the process $pid", 500);
+  }
+
+  /** Status of a daemon
+    * @param string $name The name of daemon to have status. The name must be
+    * the same as the name used in the start method
+    */
+  public function status ($name)
+  {
+    $file = new \file ();
+    if (! $file->is_writeable ($this->runDir))
+      throw new \Exception (sprintf ("Run Directory '%s' is not writeable",
+        $this->runDir), 500);
+    if (! $file->is_readable ($this->runDir))
+      throw new \Exception (sprintf ("Run Directory '%s' is not readable",
+        $this->runDir), 500);
+    if (! $file->file_exists ($this->runDir."/$name.pid"))
+      return "The daemon is be stopped";
+    $pid = $file->file_get_contents ($this->runDir."/$name.pid");
+    if (! file_exists ("/proc/$pid"))
+    {
+      $file->unlink ($this->runDir."/$name.pid");
+      return "The daemon is stopped, but the PID file was remaining. Delete";
+    }
+    return "The daemon is running on PID $pid\n";
+  }
+}