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<?php
/**
* @package Joomla.Platform
* @subpackage Application
*
* @copyright Copyright (C) 2005 - 2012 Open Source Matters, Inc. All rights reserved.
* @license GNU General Public License version 2 or later; see LICENSE
*/
defined('JPATH_PLATFORM') or die;
jimport('joomla.filesystem.folder');
/**
* Class to turn JCli applications into daemons. It requires CLI and PCNTL support built into PHP.
*
* @package Joomla.Platform
* @subpackage Application
* @see http://www.php.net/manual/en/book.pcntl.php
* @see http://php.net/manual/en/features.commandline.php
* @since 11.1
*/
class JApplicationDaemon extends JApplicationCli
{
/**
* @var array The available POSIX signals to be caught by default.
* @see http://php.net/manual/pcntl.constants.php
* @since 11.1
*/
protected static $signals = array(
'SIGHUP',
'SIGINT',
'SIGQUIT',
'SIGILL',
'SIGTRAP',
'SIGABRT',
'SIGIOT',
'SIGBUS',
'SIGFPE',
'SIGUSR1',
'SIGSEGV',
'SIGUSR2',
'SIGPIPE',
'SIGALRM',
'SIGTERM',
'SIGSTKFLT',
'SIGCLD',
'SIGCHLD',
'SIGCONT',
'SIGTSTP',
'SIGTTIN',
'SIGTTOU',
'SIGURG',
'SIGXCPU',
'SIGXFSZ',
'SIGVTALRM',
'SIGPROF',
'SIGWINCH',
'SIGPOLL',
'SIGIO',
'SIGPWR',
'SIGSYS',
'SIGBABY',
'SIG_BLOCK',
'SIG_UNBLOCK',
'SIG_SETMASK'
);
/**
* @var boolean True if the daemon is in the process of exiting.
* @since 11.1
*/
protected $exiting = false;
/**
* @var integer The process id of the daemon.
* @since 11.1
*/
protected $processId = 0;
/**
* @var boolean True if the daemon is currently running.
* @since 11.1
*/
protected $running = false;
/**
* Class constructor.
*
* @param mixed $input An optional argument to provide dependency injection for the application's
* input object. If the argument is a JInputCli object that object will become
* the application's input object, otherwise a default input object is created.
* @param mixed $config An optional argument to provide dependency injection for the application's
* config object. If the argument is a JRegistry object that object will become
* the application's config object, otherwise a default config object is created.
* @param mixed $dispatcher An optional argument to provide dependency injection for the application's
* event dispatcher. If the argument is a JDispatcher object that object will become
* the application's event dispatcher, if it is null then the default event dispatcher
* will be created based on the application's loadDispatcher() method.
*
* @since 11.1
* @throws RuntimeException
*/
public function __construct(JInputCli $input = null, JRegistry $config = null, JDispatcher $dispatcher = null)
{
// Verify that the process control extension for PHP is available.
// @codeCoverageIgnoreStart
if (!defined('SIGHUP'))
{
JLog::add('The PCNTL extension for PHP is not available.', JLog::ERROR);
throw new RuntimeException('The PCNTL extension for PHP is not available.');
}
// Verify that POSIX support for PHP is available.
if (!function_exists('posix_getpid'))
{
JLog::add('The POSIX extension for PHP is not available.', JLog::ERROR);
throw new RuntimeException('The POSIX extension for PHP is not available.');
}
// @codeCoverageIgnoreEnd
// Call the parent constructor.
parent::__construct($input, $config, $dispatcher);
// Set some system limits.
@set_time_limit($this->config->get('max_execution_time', 0));
if ($this->config->get('max_memory_limit') !== null)
{
ini_set('memory_limit', $this->config->get('max_memory_limit', '256M'));
}
// Flush content immediately.
ob_implicit_flush();
}
/**
* Method to handle POSIX signals.
*
* @param integer $signal The received POSIX signal.
*
* @return void
*
* @since 11.1
* @see pcntl_signal()
* @throws RuntimeException
*/
public static function signal($signal)
{
// Log all signals sent to the daemon.
JLog::add('Received signal: ' . $signal, JLog::DEBUG);
// Let's make sure we have an application instance.
if (!is_subclass_of(static::$instance, 'JApplicationDaemon'))
{
JLog::add('Cannot find the application instance.', JLog::EMERGENCY);
throw new RuntimeException('Cannot find the application instance.');
}
// Fire the onReceiveSignal event.
static::$instance->triggerEvent('onReceiveSignal', array($signal));
switch ($signal)
{
case SIGTERM:
// Handle shutdown tasks
if (static::$instance->running && static::$instance->isActive())
{
static::$instance->shutdown();
}
else
{
static::$instance->close();
}
break;
case SIGHUP:
// Handle restart tasks
if (static::$instance->running && static::$instance->isActive())
{
static::$instance->shutdown(true);
}
else
{
static::$instance->close();
}
break;
case SIGCHLD:
// A child process has died
while (static::$instance->pcntlWait($signal, WNOHANG or WUNTRACED) > 0)
{
usleep(1000);
}
break;
case SIGCLD:
while (static::$instance->pcntlWait($signal, WNOHANG) > 0)
{
$signal = static::$instance->pcntlChildExitStatus($signal);
}
break;
default:
break;
}
}
/**
* Check to see if the daemon is active. This does not assume that $this daemon is active, but
* only if an instance of the application is active as a daemon.
*
* @return boolean True if daemon is active.
*
* @since 11.1
*/
public function isActive()
{
// Get the process id file location for the application.
$pidFile = $this->config->get('application_pid_file');
// If the process id file doesn't exist then the daemon is obviously not running.
if (!is_file($pidFile))
{
return false;
}
// Read the contents of the process id file as an integer.
$fp = fopen($pidFile, 'r');
$pid = fread($fp, filesize($pidFile));
$pid = intval($pid);
fclose($fp);
// Check to make sure that the process id exists as a positive integer.
if (!$pid)
{
return false;
}
// Check to make sure the process is active by pinging it and ensure it responds.
if (!posix_kill($pid, 0))
{
// No response so remove the process id file and log the situation.
@ unlink($pidFile);
JLog::add('The process found based on PID file was unresponsive.', JLog::WARNING);
return false;
}
return true;
}
/**
* Load an object or array into the application configuration object.
*
* @param mixed $data Either an array or object to be loaded into the configuration object.
*
* @return JCli Instance of $this to allow chaining.
*
* @since 11.1
*/
public function loadConfiguration($data)
{
// Execute the parent load method.
parent::loadConfiguration($data);
/*
* Setup some application metadata options. This is useful if we ever want to write out startup scripts
* or just have some sort of information available to share about things.
*/
// The application author name. This string is used in generating startup scripts and has
// a maximum of 50 characters.
$tmp = (string) $this->config->get('author_name', 'Joomla Platform');
$this->config->set('author_name', (strlen($tmp) > 50) ? substr($tmp, 0, 50) : $tmp);
// The application author email. This string is used in generating startup scripts.
$tmp = (string) $this->config->get('author_email', 'admin@joomla.org');
$this->config->set('author_email', filter_var($tmp, FILTER_VALIDATE_EMAIL));
// The application name. This string is used in generating startup scripts.
$tmp = (string) $this->config->get('application_name', 'JApplicationDaemon');
$this->config->set('application_name', (string) preg_replace('/[^A-Z0-9_-]/i', '', $tmp));
// The application description. This string is used in generating startup scripts.
$tmp = (string) $this->config->get('application_description', 'A generic Joomla Platform application.');
$this->config->set('application_description', filter_var($tmp, FILTER_SANITIZE_STRING));
/*
* Setup the application path options. This defines the default executable name, executable directory,
* and also the path to the daemon process id file.
*/
// The application executable daemon. This string is used in generating startup scripts.
$tmp = (string) $this->config->get('application_executable', basename($this->input->executable));
$this->config->set('application_executable', $tmp);
// The home directory of the daemon.
$tmp = (string) $this->config->get('application_directory', dirname($this->input->executable));
$this->config->set('application_directory', $tmp);
// The pid file location. This defaults to a path inside the /tmp directory.
$name = $this->config->get('application_name');
$tmp = (string) $this->config->get('application_pid_file', strtolower('/tmp/' . $name . '/' . $name . '.pid'));
$this->config->set('application_pid_file', $tmp);
/*
* Setup the application identity options. It is important to remember if the default of 0 is set for
* either UID or GID then changing that setting will not be attempted as there is no real way to "change"
* the identity of a process from some user to root.
*/
// The user id under which to run the daemon.
$tmp = (int) $this->config->get('application_uid', 0);
$options = array('options' => array('min_range' => 0, 'max_range' => 65000));
$this->config->set('application_uid', filter_var($tmp, FILTER_VALIDATE_INT, $options));
// The group id under which to run the daemon.
$tmp = (int) $this->config->get('application_gid', 0);
$options = array('options' => array('min_range' => 0, 'max_range' => 65000));
$this->config->set('application_gid', filter_var($tmp, FILTER_VALIDATE_INT, $options));
// Option to kill the daemon if it cannot switch to the chosen identity.
$tmp = (bool) $this->config->get('application_require_identity', 1);
$this->config->set('application_require_identity', $tmp);
/*
* Setup the application runtime options. By default our execution time limit is infinite obviously
* because a daemon should be constantly running unless told otherwise. The default limit for memory
* usage is 128M, which admittedly is a little high, but remember it is a "limit" and PHP's memory
* management leaves a bit to be desired :-)
*/
// The maximum execution time of the application in seconds. Zero is infinite.
$tmp = $this->config->get('max_execution_time');
if ($tmp !== null)
{
$this->config->set('max_execution_time', (int) $tmp);
}
// The maximum amount of memory the application can use.
$tmp = $this->config->get('max_memory_limit', '256M');
if ($tmp !== null)
{
$this->config->set('max_memory_limit', (string) $tmp);
}
return $this;
}
/**
* Restart daemon process.
*
* @return void
*
* @codeCoverageIgnore
* @since 11.1
*/
public function restart()
{
JLog::add('Stopping ' . $this->name, JLog::INFO);
$this->shutdown(true);
}
/**
* Spawn daemon process.
*
* @return void
*
* @since 11.1
*/
public function start()
{
// Enable basic garbage collection. Only available in PHP 5.3+
if (function_exists('gc_enable'))
{
gc_enable();
}
JLog::add('Starting ' . $this->name, JLog::INFO);
// Set off the process for becoming a daemon.
if ($this->daemonize())
{
// Declare ticks to start signal monitoring. When you declare ticks, PCNTL will monitor
// incoming signals after each tick and call the relevant signal handler automatically.
declare (ticks = 1);
// Start the main execution loop.
while (true)
{
// Perform basic garbage collection.
$this->gc();
// Don't completely overload the CPU.
usleep(1000);
// Execute the main application logic.
$this->doExecute();
}
}
// We were not able to daemonize the application so log the failure and die gracefully.
else
{
JLog::add('Starting ' . $this->name . ' failed', JLog::INFO);
}
}
/**
* Stop daemon process.
*
* @return void
*
* @codeCoverageIgnore
* @since 11.1
*/
public function stop()
{
JLog::add('Stopping ' . $this->name, JLog::INFO);
$this->shutdown();
}
/**
* Method to change the identity of the daemon process and resources.
*
* @return boolean True if identity successfully changed
*
* @since 11.1
* @see posix_setuid()
*/
protected function changeIdentity()
{
// Get the group and user ids to set for the daemon.
$uid = (int) $this->config->get('application_uid', 0);
$gid = (int) $this->config->get('application_gid', 0);
// Get the application process id file path.
$file = $this->config->get('application_pid_file');
// Change the user id for the process id file if necessary.
if ($uid && (fileowner($file) != $uid) && (!@ chown($file, $uid)))
{
JLog::add('Unable to change user ownership of the process id file.', JLog::ERROR);
return false;
}
// Change the group id for the process id file if necessary.
if ($gid && (filegroup($file) != $gid) && (!@ chgrp($file, $gid)))
{
JLog::add('Unable to change group ownership of the process id file.', JLog::ERROR);
return false;
}
// Set the correct home directory for the process.
if ($uid && ($info = posix_getpwuid($uid)) && is_dir($info['dir']))
{
system('export HOME="' . $info['dir'] . '"');
}
// Change the user id for the process necessary.
if ($uid && (posix_getuid($file) != $uid) && (!@ posix_setuid($uid)))
{
JLog::add('Unable to change user ownership of the proccess.', JLog::ERROR);
return false;
}
// Change the group id for the process necessary.
if ($gid && (posix_getgid($file) != $gid) && (!@ posix_setgid($gid)))
{
JLog::add('Unable to change group ownership of the proccess.', JLog::ERROR);
return false;
}
// Get the user and group information based on uid and gid.
$user = posix_getpwuid($uid);
$group = posix_getgrgid($gid);
JLog::add('Changed daemon identity to ' . $user['name'] . ':' . $group['name'], JLog::INFO);
return true;
}
/**
* Method to put the application into the background.
*
* @return boolean
*
* @since 11.1
* @throws RuntimeException
*/
protected function daemonize()
{
// Is there already an active daemon running?
if ($this->isActive())
{
JLog::add($this->name . ' daemon is still running. Exiting the application.', JLog::EMERGENCY);
return false;
}
// Reset Process Information
$this->safeMode = !!@ ini_get('safe_mode');
$this->processId = 0;
$this->running = false;
// Detach process!
try
{
$this->detach();
}
catch (RuntimeException $e)
{
JLog::add('Unable to fork.', JLog::EMERGENCY);
return false;
}
// Verify the process id is valid.
if ($this->processId < 1)
{
JLog::add('The process id is invalid; the fork failed.', JLog::EMERGENCY);
return false;
}
// Clear the umask.
@ umask(0);
// Write out the process id file for concurrency management.
if (!$this->writeProcessIdFile())
{
JLog::add('Unable to write the pid file at: ' . $this->config->get('application_pid_file'), JLog::EMERGENCY);
return false;
}
// Attempt to change the identity of user running the process.
if (!$this->changeIdentity())
{
// If the identity change was required then we need to return false.
if ($this->config->get('application_require_identity'))
{
JLog::add('Unable to change process owner.', JLog::CRITICAL);
return false;
}
else
{
JLog::add('Unable to change process owner.', JLog::WARNING);
}
}
// Setup the signal handlers for the daemon.
if (!$this->setupSignalHandlers())
{
return false;
}
// Change the current working directory to the application working directory.
@ chdir($this->config->get('application_directory'));
return true;
}
/**
* This is truly where the magic happens. This is where we fork the process and kill the parent
* process, which is essentially what turns the application into a daemon.
*
* @return void
*
* @since 12.1
* @throws RuntimeException
*/
protected function detach()
{
JLog::add('Detaching the ' . $this->name . ' daemon.', JLog::DEBUG);
// Attempt to fork the process.
$pid = $this->fork();
// If the pid is positive then we successfully forked, and can close this application.
if ($pid)
{
// Add the log entry for debugging purposes and exit gracefully.
JLog::add('Ending ' . $this->name . ' parent process', JLog::DEBUG);
$this->close();
}
// We are in the forked child process.
else
{
// Setup some protected values.
$this->exiting = false;
$this->running = true;
}
}
/**
* Method to fork the process.
*
* @return integer The child process id to the parent process, zero to the child process.
*
* @since 11.1
* @throws RuntimeException
*/
protected function fork()
{
// Attempt to fork the process.
$pid = $this->pcntlFork();
// If the fork failed, throw an exception.
if ($pid === -1)
{
throw new RuntimeException('The process could not be forked.');
}
// Update the process id for the child.
elseif ($pid === 0)
{
$this->processId = (int) posix_getpid();
}
// Log the fork in the parent.
else
{
// Log the fork.
JLog::add('Process forked ' . $pid, JLog::DEBUG);
}
// Trigger the onFork event.
$this->postFork();
return $pid;
}
/**
* Method to perform basic garbage collection and memory management in the sense of clearing the
* stat cache. We will probably call this method pretty regularly in our main loop.
*
* @return void
*
* @codeCoverageIgnore
* @since 11.1
*/
protected function gc()
{
// Perform generic garbage collection. Only available in PHP 5.3+
if (function_exists('gc_collect_cycles'))
{
gc_collect_cycles();
}
// Clear the stat cache so it doesn't blow up memory.
clearstatcache();
}
/**
* Method to attach the JApplicationDaemon signal handler to the known signals. Applications
* can override these handlers by using the pcntl_signal() function and attaching a different
* callback method.
*
* @return boolean
*
* @since 11.1
* @see pcntl_signal()
*/
protected function setupSignalHandlers()
{
// We add the error suppression for the loop because on some platforms some constants are not defined.
foreach (self::$signals as $signal)
{
// Ignore signals that are not defined.
if (!defined($signal) || !is_int(constant($signal)) || (constant($signal) === 0))
{
continue;
}
// Attach the signal handler for the signal.
if (!$this->pcntlSignal(constant($signal), array('JApplicationDaemon', 'signal')))
{
JLog::add(sprintf('Unable to reroute signal handler: %s', $signal), JLog::EMERGENCY);
return false;
}
}
return true;
}
/**
* Method to shut down the daemon and optionally restart it.
*
* @param boolean $restart True to restart the daemon on exit.
*
* @return void
*
* @since 11.1
*/
protected function shutdown($restart = false)
{
// If we are already exiting, chill.
if ($this->exiting)
{
return;
}
// If not, now we are.
else
{
$this->exiting = true;
}
// If we aren't already daemonized then just kill the application.
if (!$this->running && !$this->isActive())
{
JLog::add('Process was not daemonized yet, just halting current process', JLog::INFO);
$this->close();
}
// Read the contents of the process id file as an integer.
$fp = fopen($this->config->get('application_pid_file'), 'r');
$pid = fread($fp, filesize($this->config->get('application_pid_file')));
$pid = intval($pid);
fclose($fp);
// Remove the process id file.
@ unlink($this->config->get('application_pid_file'));
// If we are supposed to restart the daemon we need to execute the same command.
if ($restart)
{
$this->close(exec(implode(' ', $GLOBALS['argv']) . ' > /dev/null &'));
}
// If we are not supposed to restart the daemon let's just kill -9.
else
{
passthru('kill -9 ' . $pid);
$this->close();
}
}
/**
* Method to write the process id file out to disk.
*
* @return boolean
*
* @since 11.1
*/
protected function writeProcessIdFile()
{
// Verify the process id is valid.
if ($this->processId < 1)
{
JLog::add('The process id is invalid.', JLog::EMERGENCY);
return false;
}
// Get the application process id file path.
$file = $this->config->get('application_pid_file');
if (empty($file))
{
JLog::add('The process id file path is empty.', JLog::ERROR);
return false;
}
// Make sure that the folder where we are writing the process id file exists.
$folder = dirname($file);
if (!is_dir($folder) && !JFolder::create($folder))
{
JLog::add('Unable to create directory: ' . $folder, JLog::ERROR);
return false;
}
// Write the process id file out to disk.
if (!file_put_contents($file, $this->processId))
{
JLog::add('Unable to write proccess id file: ' . $file, JLog::ERROR);
return false;
}
// Make sure the permissions for the proccess id file are accurate.
if (!chmod($file, 0644))
{
JLog::add('Unable to adjust permissions for the proccess id file: ' . $file, JLog::ERROR);
return false;
}
return true;
}
/**
* Method to handle post-fork triggering of the onFork event.
*
* @return void
*
* @since 12.1
*/
protected function postFork()
{
// Trigger the onFork event.
$this->triggerEvent('onFork');
}
/**
* Method to return the exit code of a terminated child process.
*
* @param integer $status The status parameter is the status parameter supplied to a successful call to pcntl_waitpid().
*
* @return integer The child process exit code.
*
* @codeCoverageIgnore
* @see pcntl_wexitstatus()
* @since 11.3
*/
protected function pcntlChildExitStatus($status)
{
return pcntl_wexitstatus($status);
}
/**
* Method to return the exit code of a terminated child process.
*
* @return integer On success, the PID of the child process is returned in the parent's thread
* of execution, and a 0 is returned in the child's thread of execution. On
* failure, a -1 will be returned in the parent's context, no child process
* will be created, and a PHP error is raised.
*
* @codeCoverageIgnore
* @see pcntl_fork()
* @since 11.3
*/
protected function pcntlFork()
{
return pcntl_fork();
}
/**
* Method to install a signal handler.
*
* @param integer $signal The signal number.
* @param callback $handler The signal handler which may be the name of a user created function,
* or method, or either of the two global constants SIG_IGN or SIG_DFL.
* @param boolean $restart Specifies whether system call restarting should be used when this
* signal arrives.
*
* @return boolean True on success.
*
* @codeCoverageIgnore
* @see pcntl_signal()
* @since 11.3
*/
protected function pcntlSignal($signal , $handler, $restart = true)
{
return pcntl_signal($signal, $handler, $restart);
}
/**
* Method to wait on or return the status of a forked child.
*
* @param integer &$status Status information.
* @param integer $options If wait3 is available on your system (mostly BSD-style systems),
* you can provide the optional options parameter.
*
* @return integer The process ID of the child which exited, -1 on error or zero if WNOHANG
* was provided as an option (on wait3-available systems) and no child was available.
*
* @codeCoverageIgnore
* @see pcntl_wait()
* @since 11.3
*/
protected function pcntlWait(&$status, $options = 0)
{
return pcntl_wait($status, $options);
}
}
