Prevent the running of multiple xmpp auth daemons at a time

doc/htconfig.md

@@ -19,6 +19,7 @@ Example: To set the directory value please add this line to your .htconfig.php:
 
 ## jabber ##
 * **debug** (Boolean) - Enable debug level for the jabber account synchronisation.
+* **lockpath** - Must be writable by the ejabberd process. if set then it will prevent the running of multiple processes.
 
 ## system ##
 

src/Util/ExAuth.php

@@ -45,6 +45,8 @@ require_once 'include/dba.php';
 class ExAuth
 {
 	private $bDebug;
+	private $host;
+	private $pidfile;
 
 	/**
 	 * @brief Create the class
@@ -133,6 +135,10 @@ class ExAuth
 			return;
 		}
 
+		// We only allow one process per hostname. So we set a lock file
+		// Problem: We get the firstname after the first auth - not before
+		$this->setHost($aCommand[2]);
+
 		// Now we check if the given user is valid
 		$sUser = str_replace(array('%20', '(a)'), array(' ', '@'), $aCommand[1]);
 
@@ -209,6 +215,10 @@ class ExAuth
 			return;
 		}
 
+		// We only allow one process per hostname. So we set a lock file
+		// Problem: We get the firstname after the first auth - not before
+		$this->setHost($aCommand[2]);
+
 		// We now check if the password match
 		$sUser = str_replace(array('%20', '(a)'), array(' ', '@'), $aCommand[1]);
 
@@ -281,6 +291,43 @@ class ExAuth
 		return $http_code == 200;
 	}
 
+	/**
+	 * @brief Set the hostname for this process
+	 *
+	 * @param string $host The hostname
+	 */
+	private function setHost($host)
+	{
+		if (!empty($this->host)) {
+			return;
+		}
+
+		$this->writeLog(LOG_INFO, 'Hostname for process ' . getmypid() . ' is ' . $host);
+
+		$this->host = $host;
+
+		$lockpath = Config::get('jabber', 'lockpath');
+		if (is_null($lockpath)) {
+			return;
+		}
+
+		$this->pidfile = new Pidfile($lockpath, $host);
+		if ($this->pidfile->isRunning()) {
+			$oldpid = $this->pidfile->pid();
+			$this->writeLog(LOG_INFO, 'Process ' . $oldpid . ' was running for ' . $this->pidfile->runningTime() . ' seconds and will now be killed');
+			$this->pidfile->kill();
+
+			// Wait until the other process is hopefully killed
+			sleep(2);
+
+			$this->pidfile = new Pidfile($lockpath, $host);
+			if ($oldpid == $this->pidfile->pid()) {
+				$this->writeLog(LOG_ERR, 'Process ' . $oldpid . "wasn't killed in time. We now quit our process.");
+				die();
+			}
+		}
+	}
+
 	/**
 	 * @brief write data to the syslog
 	 *

src/Util/Pidfile.php

@@ -11,6 +11,7 @@ class Pidfile
 {
 	private $file;
 	private $running;
+	private $pid;
 
 	/**
 	 * @param string $dir  path
@@ -19,18 +20,19 @@ class Pidfile
 	 */
 	public function __construct($dir, $name)
 	{
-		$this->_file = "$dir/$name.pid";
+		$this->file = "$dir/$name";
+		$this->running = false;
 
-		if (file_exists($this->_file)) {
-			$pid = trim(@file_get_contents($this->file));
-			if (($pid != "") && posix_kill($pid, 0)) {
+		if (file_exists($this->file)) {
+			$this->pid = trim(@file_get_contents($this->file));
+			if (($this->pid != "") && posix_kill($this->pid, 0)) {
 				$this->running = true;
 			}
 		}
 
 		if (!$this->running) {
-			$pid = getmypid();
-			file_put_contents($this->file, $pid);
+			$this->pid = getmypid();
+			file_put_contents($this->file, $this->pid);
 		}
 	}
 
@@ -39,34 +41,46 @@ class Pidfile
 	 */
 	public function __destruct()
 	{
-		if ((! $this->running) && file_exists($this->file)) {
+		if (!$this->running && file_exists($this->file)) {
 			@unlink($this->file);
 		}
 	}
 
 	/**
-	 * @return boolean
+	 * @brief Check if a process with this pid file is already running
+	 * @return boolean Is it running?
 	 */
-	public static function isRunning()
+	public function isRunning()
 	{
-		return self::$running;
+		return $this->running;
 	}
 
 	/**
-	 * @return object
+	 * @brief Return the pid of the process
+	 * @return boolean process id
 	 */
-	public static function runningTime()
+	public function pid()
 	{
-		return time() - @filectime(self::$file);
+		return $this->pid;
 	}
 
 	/**
+	 * @brief Returns the seconds that the old process was running
+	 * @return integer run time of the old process
+	 */
+	public function runningTime()
+	{
+		return time() - @filectime($this->file);
+	}
+
+	/**
+	 * @brief Kills the old process
 	 * @return boolean
 	 */
-	public static function kill()
+	public function kill()
 	{
-		if (file_exists(self::$file)) {
-			return posix_kill(file_get_contents(self::$file), SIGTERM);
+		if (!empty($this->pid)) {
+			return posix_kill($this->pid, SIGTERM);
 		}
 	}
 }