3 files changed, 1242 insertions, 0 deletions
diff --git a/phpBB/phpbb/filesystem/exception/filesystem_exception.php b/phpBB/phpbb/filesystem/exception/filesystem_exception.php
new file mode 100644
index 0000000000..d68fa9adf3
--- /dev/null
+++ b/phpBB/phpbb/filesystem/exception/filesystem_exception.php
@@ -0,0 +1,42 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\filesystem\exception;
+
+class filesystem_exception extends \phpbb\exception\runtime_exception
+{
+	/**
+	 * Constructor
+	 *
+	 * @param string		$message	The Exception message to throw (must be a language variable).
+	 * @param string		$filename	The file that caused the error.
+	 * @param array			$parameters	The parameters to use with the language var.
+	 * @param \Exception	$previous	The previous runtime_exception used for the runtime_exception chaining.
+	 * @param integer		$code		The Exception code.
+	 */
+	public function __construct($message = "", $filename = '', $parameters = array(), \Exception $previous = null, $code = 0)
+	{
+		parent::__construct($message, array_merge(array('filename' => $filename), $parameters), $previous, $code);
+	}
+
+	/**
+	 * Returns the filename that triggered the error
+	 *
+	 * @return string
+	 */
+	public function get_filename()
+	{
+		$parameters = parent::get_parameters();
+		return $parameters['filename'];
+	}
+}
diff --git a/phpBB/phpbb/filesystem/filesystem.php b/phpBB/phpbb/filesystem/filesystem.php
new file mode 100644
index 0000000000..2112882d1d
--- /dev/null
+++ b/phpBB/phpbb/filesystem/filesystem.php
@@ -0,0 +1,916 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\filesystem;
+
+use phpbb\filesystem\exception\filesystem_exception;
+
+/**
+ * A class with various functions that are related to paths, files and the filesystem
+ */
+class filesystem implements filesystem_interface
+{
+	/**
+	 * Store some information about file ownership for phpBB's chmod function
+	 *
+	 * @var array
+	 */
+	protected $chmod_info;
+
+	/**
+	 * Stores current working directory
+	 *
+	 * @var string|bool		current working directory or false if it cannot be recovered
+	 */
+	protected $working_directory;
+
+	/**
+	 * Symfony's Filesystem component
+	 *
+	 * @var \Symfony\Component\Filesystem\Filesystem
+	 */
+	protected $symfony_filesystem;
+
+	/**
+	 * Constructor
+	 */
+	public function __construct()
+	{
+		$this->chmod_info			= array();
+		$this->symfony_filesystem	= new \Symfony\Component\Filesystem\Filesystem();
+		$this->working_directory	= null;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function chgrp($files, $group, $recursive = false)
+	{
+		try
+		{
+			$this->symfony_filesystem->chgrp($files, $group, $recursive);
+		}
+		catch (\Symfony\Component\Filesystem\Exception\IOException $e)
+		{
+			// Try to recover filename
+			// By the time this is written that is at the end of the message
+			$error = trim($e->getMessage());
+			$file = substr($error, strrpos($error, ' '));
+
+			throw new filesystem_exception('CANNOT_CHANGE_FILE_GROUP', $file, array(), $e);
+		}
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function chmod($files, $perms = null, $recursive = false, $force_chmod_link = false)
+	{
+		if (is_null($perms))
+		{
+			// Default to read permission for compatibility reasons
+			$perms = self::CHMOD_READ;
+		}
+
+		// Check if we got a permission flag
+		if ($perms > self::CHMOD_ALL)
+		{
+			$file_perm = $perms;
+
+			// Extract permissions
+			//$owner = ($file_perm >> 6) & 7; // This will be ignored
+			$group = ($file_perm >> 3) & 7;
+			$other = ($file_perm >> 0) & 7;
+
+			// Does any permissions provided? if so we add execute bit for directories
+			$group = ($group !== 0) ? ($group | self::CHMOD_EXECUTE) : $group;
+			$other = ($other !== 0) ? ($other | self::CHMOD_EXECUTE) : $other;
+
+			// Compute directory permissions
+			$dir_perm = (self::CHMOD_ALL << 6) + ($group << 3) + ($other << 3);
+		}
+		else
+		{
+			// Add execute bit to owner if execute bit is among perms
+			$owner_perm	= (self::CHMOD_READ | self::CHMOD_WRITE) | ($perms & self::CHMOD_EXECUTE);
+			$file_perm	= ($owner_perm << 6) + ($perms << 3) + ($perms << 0);
+
+			// Compute directory permissions
+			$perm = ($perms !== 0) ? ($perms | self::CHMOD_EXECUTE) : $perms;
+			$dir_perm = (($owner_perm | self::CHMOD_EXECUTE) << 6) + ($perm << 3) + ($perm << 0);
+		}
+
+		// Symfony's filesystem component does not support extra execution flags on directories
+		// so we need to implement it again
+		foreach ($this->to_iterator($files) as $file)
+		{
+			if ($recursive && is_dir($file) && !is_link($file))
+			{
+				$this->chmod(new \FilesystemIterator($file), $perms, true);
+			}
+
+			// Don't chmod links as mostly those require 0777 and that cannot be changed
+			if (is_dir($file) || (is_link($file) && $force_chmod_link))
+			{
+				if (true !== @chmod($file, $dir_perm))
+				{
+					throw new filesystem_exception('CANNOT_CHANGE_FILE_PERMISSIONS', $file,  array());
+				}
+			}
+			else if (is_file($file))
+			{
+				if (true !== @chmod($file, $file_perm))
+				{
+					throw new filesystem_exception('CANNOT_CHANGE_FILE_PERMISSIONS', $file,  array());
+				}
+			}
+		}
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function chown($files, $user, $recursive = false)
+	{
+		try
+		{
+			$this->symfony_filesystem->chown($files, $user, $recursive);
+		}
+		catch (\Symfony\Component\Filesystem\Exception\IOException $e)
+		{
+			// Try to recover filename
+			// By the time this is written that is at the end of the message
+			$error = trim($e->getMessage());
+			$file = substr($error, strrpos($error, ' '));
+
+			throw new filesystem_exception('CANNOT_CHANGE_FILE_GROUP', $file, array(), $e);
+		}
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function clean_path($path)
+	{
+		$exploded = explode('/', $path);
+		$filtered = array();
+		foreach ($exploded as $part)
+		{
+			if ($part === '.' && !empty($filtered))
+			{
+				continue;
+			}
+
+			if ($part === '..' && !empty($filtered) && $filtered[sizeof($filtered) - 1] !== '.' && $filtered[sizeof($filtered) - 1] !== '..')
+			{
+				array_pop($filtered);
+			}
+			else
+			{
+				$filtered[] = $part;
+			}
+		}
+		$path = implode('/', $filtered);
+		return $path;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function copy($origin_file, $target_file, $override = false)
+	{
+		try
+		{
+			$this->symfony_filesystem->copy($origin_file, $target_file, $override);
+		}
+		catch (\Symfony\Component\Filesystem\Exception\IOException $e)
+		{
+			throw new filesystem_exception('CANNOT_COPY_FILES', '', array(), $e);
+		}
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function dump_file($filename, $content)
+	{
+		try
+		{
+			$this->symfony_filesystem->dumpFile($filename, $content);
+		}
+		catch (\Symfony\Component\Filesystem\Exception\IOException $e)
+		{
+			throw new filesystem_exception('CANNOT_DUMP_FILE', $filename, array(), $e);
+		}
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function exists($files)
+	{
+		return $this->symfony_filesystem->exists($files);
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function is_absolute_path($path)
+	{
+		return (isset($path[0]) && $path[0] === '/' || preg_match('#^[a-z]:[/\\\]#i', $path)) ? true : false;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function is_readable($files, $recursive = false)
+	{
+		foreach ($this->to_iterator($files) as $file)
+		{
+			if ($recursive && is_dir($file) && !is_link($file))
+			{
+				if (!$this->is_readable(new \FilesystemIterator($file), true))
+				{
+					return false;
+				}
+			}
+
+			if (!is_readable($file))
+			{
+				return false;
+			}
+		}
+
+		return true;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function is_writable($files, $recursive = false)
+	{
+		if (defined('PHP_WINDOWS_VERSION_MAJOR') || !function_exists('is_writable'))
+		{
+			foreach ($this->to_iterator($files) as $file)
+			{
+				if ($recursive && is_dir($file) && !is_link($file))
+				{
+					if (!$this->is_writable(new \FilesystemIterator($file), true))
+					{
+						return false;
+					}
+				}
+
+				if (!$this->phpbb_is_writable($file))
+				{
+					return false;
+				}
+			}
+		}
+		else
+		{
+			// use built in is_writable
+			foreach ($this->to_iterator($files) as $file)
+			{
+				if ($recursive && is_dir($file) && !is_link($file))
+				{
+					if (!$this->is_writable(new \FilesystemIterator($file), true))
+					{
+						return false;
+					}
+				}
+
+				if (!is_writable($file))
+				{
+					return false;
+				}
+			}
+		}
+
+		return true;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function make_path_relative($end_path, $start_path)
+	{
+		return $this->symfony_filesystem->makePathRelative($end_path, $start_path);
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function mirror($origin_dir, $target_dir, \Traversable $iterator = null, $options = array())
+	{
+		try
+		{
+			$this->symfony_filesystem->mirror($origin_dir, $target_dir, $iterator, $options);
+		}
+		catch (\Symfony\Component\Filesystem\Exception\IOException $e)
+		{
+			$msg = $e->getMessage();
+			$filename = substr($msg, strpos($msg, '"'), strrpos($msg, '"'));
+
+			throw new filesystem_exception('CANNOT_MIRROR_DIRECTORY', $filename, array(), $e);
+		}
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function mkdir($dirs, $mode = 0777)
+	{
+		try
+		{
+			$this->symfony_filesystem->mkdir($dirs, $mode);
+		}
+		catch (\Symfony\Component\Filesystem\Exception\IOException $e)
+		{
+			$msg = $e->getMessage();
+			$filename = substr($msg, strpos($msg, '"'), strrpos($msg, '"'));
+
+			throw new filesystem_exception('CANNOT_CREATE_DIRECTORY', $filename, array(), $e);
+		}
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function phpbb_chmod($files, $perms = null, $recursive = false, $force_chmod_link = false)
+	{
+		if (is_null($perms))
+		{
+			// Default to read permission for compatibility reasons
+			$perms = self::CHMOD_READ;
+		}
+
+		if (empty($this->chmod_info))
+		{
+			if (!function_exists('fileowner') || !function_exists('filegroup'))
+			{
+				$this->chmod_info['process'] = false;
+			}
+			else
+			{
+				$common_php_owner	= @fileowner(__FILE__);
+				$common_php_group	= @filegroup(__FILE__);
+
+				// And the owner and the groups PHP is running under.
+				$php_uid	= (function_exists('posic_getuid')) ? @posix_getuid() : false;
+				$php_gids	= (function_exists('posix_getgroups')) ? @posix_getgroups() : false;
+
+				// If we are unable to get owner/group, then do not try to set them by guessing
+				if (!$php_uid || empty($php_gids) || !$common_php_owner || !$common_php_group)
+				{
+					$this->chmod_info['process'] = false;
+				}
+				else
+				{
+					$this->chmod_info = array(
+						'process'		=> true,
+						'common_owner'	=> $common_php_owner,
+						'common_group'	=> $common_php_group,
+						'php_uid'		=> $php_uid,
+						'php_gids'		=> $php_gids,
+					);
+				}
+			}
+		}
+
+		if ($this->chmod_info['process'])
+		{
+			try
+			{
+				foreach ($this->to_iterator($files) as $file)
+				{
+					$file_uid = @fileowner($file);
+					$file_gid = @filegroup($file);
+
+					// Change owner
+					if ($file_uid !== $this->chmod_info['common_owner'])
+					{
+						$this->chown($file, $this->chmod_info['common_owner'], $recursive);
+					}
+
+					// Change group
+					if ($file_gid !== $this->chmod_info['common_group'])
+					{
+						$this->chgrp($file, $this->chmod_info['common_group'], $recursive);
+					}
+
+					clearstatcache();
+					$file_uid = @fileowner($file);
+					$file_gid = @filegroup($file);
+				}
+			}
+			catch (filesystem_exception $e)
+			{
+				$this->chmod_info['process'] = false;
+			}
+		}
+
+		// Still able to process?
+		if ($this->chmod_info['process'])
+		{
+			if ($file_uid === $this->chmod_info['php_uid'])
+			{
+				$php = 'owner';
+			}
+			else if (in_array($file_gid, $this->chmod_info['php_gids']))
+			{
+				$php = 'group';
+			}
+			else
+			{
+				// Since we are setting the everyone bit anyway, no need to do expensive operations
+				$this->chmod_info['process'] = false;
+			}
+		}
+
+		// We are not able to determine or change something
+		if (!$this->chmod_info['process'])
+		{
+			$php = 'other';
+		}
+
+		switch ($php)
+		{
+			case 'owner':
+				try
+				{
+					$this->chmod($files, $perms, $recursive, $force_chmod_link);
+					clearstatcache();
+					if ($this->is_readable($files) && $this->is_writable($files))
+					{
+						break;
+					}
+				}
+				catch (filesystem_exception $e)
+				{
+					// Do nothing
+				}
+			case 'group':
+				try
+				{
+					$this->chmod($files, $perms, $recursive, $force_chmod_link);
+					clearstatcache();
+					if ((!($perms & self::CHMOD_READ) || $this->is_readable($files, $recursive)) && (!($perms & self::CHMOD_WRITE) || $this->is_writable($files, $recursive)))
+					{
+						break;
+					}
+				}
+				catch (filesystem_exception $e)
+				{
+					// Do nothing
+				}
+			case 'other':
+			default:
+				$this->chmod($files, $perms, $recursive, $force_chmod_link);
+			break;
+		}
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function realpath($path)
+	{
+		if (!function_exists('realpath'))
+		{
+			return $this->phpbb_own_realpath($path);
+		}
+
+		$realpath = realpath($path);
+
+		// Strangely there are provider not disabling realpath but returning strange values. :o
+		// We at least try to cope with them.
+		if ((!$this->is_absolute_path($path) && $realpath === $path) || $realpath === false)
+		{
+			return $this->phpbb_own_realpath($path);
+		}
+
+		// Check for DIRECTORY_SEPARATOR at the end (and remove it!)
+		if (substr($realpath, -1) === DIRECTORY_SEPARATOR)
+		{
+			$realpath = substr($realpath, 0, -1);
+		}
+
+		return $realpath;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function remove($files)
+	{
+		try
+		{
+			$this->symfony_filesystem->remove($files);
+		}
+		catch (\Symfony\Component\Filesystem\Exception\IOException $e)
+		{
+			// Try to recover filename
+			// By the time this is written that is at the end of the message
+			$error = trim($e->getMessage());
+			$file = substr($error, strrpos($error, ' '));
+
+			throw new filesystem_exception('CANNOT_DELETE_FILES', $file, array(), $e);
+		}
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function rename($origin, $target, $overwrite = false)
+	{
+		try
+		{
+			$this->symfony_filesystem->rename($origin, $target, $overwrite);
+		}
+		catch (\Symfony\Component\Filesystem\Exception\IOException $e)
+		{
+			$msg = $e->getMessage();
+			$filename = substr($msg, strpos($msg, '"'), strrpos($msg, '"'));
+
+			throw new filesystem_exception('CANNOT_RENAME_FILE', $filename, array(), $e);
+		}
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function symlink($origin_dir, $target_dir, $copy_on_windows = false)
+	{
+		try
+		{
+			$this->symfony_filesystem->symlink($origin_dir, $target_dir, $copy_on_windows);
+		}
+		catch (\Symfony\Component\Filesystem\Exception\IOException $e)
+		{
+			throw new filesystem_exception('CANNOT_CREATE_SYMLINK', $origin_dir, array(), $e);
+		}
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function touch($files, $time = null, $access_time = null)
+	{
+		try
+		{
+			$this->symfony_filesystem->touch($files, $time, $access_time);
+		}
+		catch (\Symfony\Component\Filesystem\Exception\IOException $e)
+		{
+			// Try to recover filename
+			// By the time this is written that is at the end of the message
+			$error = trim($e->getMessage());
+			$file = substr($error, strrpos($error, ' '));
+
+			throw new filesystem_exception('CANNOT_TOUCH_FILES', $file, array(), $e);
+		}
+	}
+
+	/**
+	 * phpBB's implementation of is_writable
+	 *
+	 * @todo Investigate if is_writable is still buggy
+	 *
+	 * @param string	$file	file/directory to check if writable
+	 *
+	 * @return bool	true if the given path is writable
+	 */
+	protected function phpbb_is_writable($file)
+	{
+		if (file_exists($file))
+		{
+			// Canonicalise path to absolute path
+			$file = $this->realpath($file);
+
+			if (is_dir($file))
+			{
+				// Test directory by creating a file inside the directory
+				$result = @tempnam($file, 'i_w');
+
+				if (is_string($result) && file_exists($result))
+				{
+					unlink($result);
+
+					// Ensure the file is actually in the directory (returned realpathed)
+					return (strpos($result, $file) === 0) ? true : false;
+				}
+			}
+			else
+			{
+				$handle = @fopen($file, 'c');
+
+				if (is_resource($handle))
+				{
+					fclose($handle);
+					return true;
+				}
+			}
+		}
+		else
+		{
+			// file does not exist test if we can write to the directory
+			$dir = dirname($file);
+
+			if (file_exists($dir) && is_dir($dir) && $this->phpbb_is_writable($dir))
+			{
+				return true;
+			}
+		}
+
+		return false;
+	}
+
+	/**
+	 * Try to resolve real path when PHP's realpath failes to do so
+	 *
+	 * @param string	$path
+	 * @return bool|string
+	 */
+	protected function phpbb_own_realpath($path)
+	{
+		// Replace all directory separators with '/'
+		$path = str_replace(DIRECTORY_SEPARATOR, '/', $path);
+
+		$is_absolute_path = false;
+		$path_prefix = '';
+
+		if ($this->is_absolute_path($path))
+		{
+			$is_absolute_path = true;
+		}
+		else
+		{
+			// Resolve working directory and store it
+			if (is_null($this->working_directory))
+			{
+				if (function_exists('getcwd'))
+				{
+					$this->working_directory = str_replace(DIRECTORY_SEPARATOR, '/', getcwd());
+				}
+
+				//
+				// From this point on we really just guessing
+				// If chdir were called we screwed
+				//
+				else if (function_exists('debug_backtrace'))
+				{
+					$call_stack = debug_backtrace(0);
+					$this->working_directory = str_replace(DIRECTORY_SEPARATOR, '/', dirname($call_stack[sizeof($call_stack) - 1]['file']));
+				}
+				else
+				{
+					//
+					// Assuming that the working directory is phpBB root
+					// we could use this as a fallback, when phpBB will use controllers
+					// everywhere this will be a safe assumption
+					//
+					//$dir_parts = explode(DIRECTORY_SEPARATOR, __DIR__);
+					//$namespace_parts = explode('\\', trim(__NAMESPACE__, '\\'));
+
+					//$namespace_part_count = sizeof($namespace_parts);
+
+					// Check if we still loading from root
+					//if (array_slice($dir_parts, -$namespace_part_count) === $namespace_parts)
+					//{
+					//	$this->working_directory = implode('/', array_slice($dir_parts, 0, -$namespace_part_count));
+					//}
+					//else
+					//{
+					//	$this->working_directory = false;
+					//}
+
+					$this->working_directory = false;
+				}
+			}
+
+			if ($this->working_directory !== false)
+			{
+				$is_absolute_path = true;
+				$path = $this->working_directory . '/' . $path;
+			}
+		}
+
+		if ($is_absolute_path)
+		{
+			if (defined('PHP_WINDOWS_VERSION_MAJOR'))
+			{
+				$path_prefix = $path[0] . ':';
+				$path = substr($path, 2);
+			}
+			else
+			{
+				$path_prefix = '';
+			}
+		}
+
+		$resolved_path = $this->resolve_path($path, $path_prefix, $is_absolute_path);
+		if ($resolved_path === false)
+		{
+			return false;
+		}
+
+		if (!@file_exists($resolved_path) || (!@is_dir($resolved_path . '/') && !is_file($resolved_path)))
+		{
+			return false;
+		}
+
+		// Return OS specific directory separators
+		$resolved = str_replace('/', DIRECTORY_SEPARATOR, $resolved_path);
+
+		// Check for DIRECTORY_SEPARATOR at the end (and remove it!)
+		if (substr($resolved, -1) === DIRECTORY_SEPARATOR)
+		{
+			return substr($resolved, 0, -1);
+		}
+
+		return $resolved;
+	}
+
+	/**
+	 * Convert file(s) to \Traversable object
+	 *
+	 * This is the same function as Symfony's toIterator, but that is private
+	 * so we cannot use it.
+	 *
+	 * @param string|array|\Traversable	$files	filename/list of filenames
+	 * @return \Traversable
+	 */
+	protected function to_iterator($files)
+	{
+		if (!$files instanceof \Traversable)
+		{
+			$files = new \ArrayObject(is_array($files) ? $files : array($files));
+		}
+
+		return $files;
+	}
+
+	/**
+	 * Try to resolve symlinks in path
+	 *
+	 * @param string	$path			The path to resolve
+	 * @param string	$prefix			The path prefix (on windows the drive letter)
+	 * @param bool 		$absolute		Whether or not the path is absolute
+	 * @param bool		$return_array	Whether or not to return path parts
+	 *
+	 * @return string|array|bool	returns the resolved path or an array of parts of the path if $return_array is true
+	 * 								or false if path cannot be resolved
+	 */
+	protected function resolve_path($path, $prefix = '', $absolute = false, $return_array = false)
+	{
+		if ($return_array)
+		{
+			$path = str_replace(DIRECTORY_SEPARATOR, '/', $path);
+		}
+
+		trim ($path, '/');
+		$path_parts = explode('/', $path);
+		$resolved = array();
+		$resolved_path = $prefix;
+		$file_found = false;
+
+		foreach ($path_parts as $path_part)
+		{
+			if ($file_found)
+			{
+				return false;
+			}
+
+			if (empty($path_part) || ($path_part === '.' && ($absolute || !empty($resolved))))
+			{
+				continue;
+			}
+			else if ($absolute && $path_part === '..')
+			{
+				if (empty($resolved))
+				{
+					// No directories above root
+					return false;
+				}
+
+				array_pop($resolved);
+				$resolved_path = false;
+			}
+			else if ($path_part === '..' && !empty($resolved) && !in_array($resolved[sizeof($resolved) - 1], array('.', '..')))
+			{
+				array_pop($resolved);
+				$resolved_path = false;
+			}
+			else
+			{
+				if ($resolved_path === false)
+				{
+					if (empty($resolved))
+					{
+						$resolved_path = ($absolute) ? $prefix . '/' . $path_part : $path_part;
+					}
+					else
+					{
+						$tmp_array = $resolved;
+						if ($absolute)
+						{
+							array_unshift($tmp_array, $prefix);
+						}
+
+						$resolved_path = implode('/', $tmp_array);
+					}
+				}
+
+				$current_path = $resolved_path . '/' . $path_part;
+
+				// Resolve symlinks
+				if (is_link($current_path))
+				{
+					if (!function_exists('readlink'))
+					{
+						return false;
+					}
+
+					$link = readlink($current_path);
+
+					// Is link has an absolute path in it?
+					if ($this->is_absolute_path($link))
+					{
+						if (defined('PHP_WINDOWS_VERSION_MAJOR'))
+						{
+							$prefix = $link[0] . ':';
+							$link = substr($link, 2);
+						}
+						else
+						{
+							$prefix = '';
+						}
+
+						$resolved = $this->resolve_path($link, $prefix, true, true);
+						$absolute = true;
+					}
+					else
+					{
+						$resolved = $this->resolve_path($resolved_path . '/' . $link, $prefix, $absolute, true);
+					}
+
+					if (!$resolved)
+					{
+						return false;
+					}
+
+					$resolved_path = false;
+				}
+				else if (is_dir($current_path . '/'))
+				{
+					$resolved[] = $path_part;
+					$resolved_path = $current_path;
+				}
+				else if (is_file($current_path))
+				{
+					$resolved[] = $path_part;
+					$resolved_path = $current_path;
+					$file_found = true;
+				}
+				else
+				{
+					return false;
+				}
+			}
+		}
+
+		// If at the end of the path there were a .. or .
+		// we need to build the path again.
+		// Only doing this when a string is expected in return
+		if ($resolved_path === false && $return_array === false)
+		{
+			if (empty($resolved))
+			{
+				$resolved_path = ($absolute) ? $prefix . '/' : './';
+			}
+			else
+			{
+				$tmp_array = $resolved;
+				if ($absolute)
+				{
+					array_unshift($tmp_array, $prefix);
+				}
+
+				$resolved_path = implode('/', $tmp_array);
+			}
+		}
+
+		return ($return_array) ? $resolved : $resolved_path;
+	}
+}
diff --git a/phpBB/phpbb/filesystem/filesystem_interface.php b/phpBB/phpbb/filesystem/filesystem_interface.php
new file mode 100644
index 0000000000..1093be2499
--- /dev/null
+++ b/phpBB/phpbb/filesystem/filesystem_interface.php
@@ -0,0 +1,284 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\filesystem;
+
+/**
+ * Interface for phpBB's filesystem service
+ */
+interface filesystem_interface
+{
+	/**
+	 * chmod all permissions flag
+	 *
+	 * @var int
+	 */
+	const CHMOD_ALL = 7;
+
+	/**
+	 * chmod read permissions flag
+	 *
+	 * @var int
+	 */
+	const CHMOD_READ = 4;
+
+	/**
+	 * chmod write permissions flag
+	 *
+	 * @var int
+	 */
+	const CHMOD_WRITE = 2;
+
+	/**
+	 * chmod execute permissions flag
+	 *
+	 * @var int
+	 */
+	const CHMOD_EXECUTE = 1;
+
+	/**
+	 * Change owner group of files/directories
+	 *
+	 * @param string|array|\Traversable	$files		The file(s)/directorie(s) to change group
+	 * @param string					$group		The group that should own the files/directories
+	 * @param bool 						$recursive	If the group should be changed recursively
+	 * @throws \phpbb\filesystem\exception\filesystem_exception	the filename which triggered the error can be
+	 * 															retrieved by filesystem_exception::get_filename()
+	 */
+	public function chgrp($files, $group, $recursive = false);
+
+	/**
+	 * Global function for chmodding directories and files for internal use
+	 *
+	 * The function accepts filesystem_interface::CHMOD_ flags in the permission argument
+	 * or the user can specify octal values (or any integer if it makes sense). All directories will have
+	 * an execution bit appended, if the user group (owner, group or other) has any bit specified.
+	 *
+	 * @param string|array|\Traversable	$files				The file/directory to be chmodded
+	 * @param int						$perms				Permissions to set
+	 * @param bool						$recursive			If the permissions should be changed recursively
+	 * @param bool						$force_chmod_link	Try to apply permissions to symlinks as well
+	 *
+	 * @throws \phpbb\filesystem\exception\filesystem_exception	the filename which triggered the error can be
+	 * 															retrieved by filesystem_exception::get_filename()
+	 */
+	public function chmod($files, $perms = null, $recursive = false, $force_chmod_link = false);
+
+	/**
+	 * Change owner group of files/directories
+	 *
+	 * @param string|array|\Traversable	$files		The file(s)/directorie(s) to change group
+	 * @param string					$user		The owner user name
+	 * @param bool 						$recursive	Whether change the owner recursively or not
+	 *
+	 * @throws \phpbb\filesystem\exception\filesystem_exception	the filename which triggered the error can be
+	 * 															retrieved by filesystem_exception::get_filename()
+	 */
+	public function chown($files, $user, $recursive = false);
+
+	/**
+	 * Eliminates useless . and .. components from specified path.
+	 *
+	 * @param string $path Path to clean
+	 *
+	 * @return string Cleaned path
+	 */
+	public function clean_path($path);
+
+	/**
+	 * Copies a file.
+	 *
+	 * This method only copies the file if the origin file is newer than the target file.
+	 *
+	 * By default, if the target already exists, it is not overridden.
+	 *
+	 * @param string	$origin_file	The original filename
+	 * @param string	$target_file	The target filename
+	 * @param bool		$override		Whether to override an existing file or not
+	 *
+	 * @throws \phpbb\filesystem\exception\filesystem_exception When the file cannot be copied
+	 */
+	public function copy($origin_file, $target_file, $override = false);
+
+	/**
+	 * Atomically dumps content into a file.
+	 *
+	 * @param string	$filename	The file to be written to.
+	 * @param string	$content	The data to write into the file.
+	 *
+	 * @throws \phpbb\filesystem\exception\filesystem_exception When the file cannot be written
+	 */
+	public function dump_file($filename, $content);
+
+	/**
+	 * Checks the existence of files or directories.
+	 *
+	 * @param string|array|\Traversable	$files	files/directories to check
+	 *
+	 * @return bool	Returns true if all files/directories exist, false otherwise
+	 */
+	public function exists($files);
+
+	/**
+	 * Checks if a path is absolute or not
+	 *
+	 * @param string	$path	Path to check
+	 *
+	 * @return	bool	true if the path is absolute, false otherwise
+	 */
+	public function is_absolute_path($path);
+
+	/**
+	 * Checks if files/directories are readable
+	 *
+	 * @param string|array|\Traversable	$files		files/directories to check
+	 * @param bool						$recursive	Whether or not directories should be checked recursively
+	 *
+	 * @return bool True when the files/directories are readable, otherwise false.
+	 */
+	public function is_readable($files, $recursive = false);
+
+	/**
+	 * Test if a file/directory is writable
+	 *
+	 * @param string|array|\Traversable	$files		files/directories to perform write test on
+	 * @param bool						$recursive	Whether or not directories should be checked recursively
+	 *
+	 * @return bool True when the files/directories are writable, otherwise false.
+	 */
+	public function is_writable($files, $recursive = false);
+
+	/**
+	 * Given an existing path, convert it to a path relative to a given starting path
+	 *
+	 * @param string $end_path		Absolute path of target
+	 * @param string $start_path	Absolute path where traversal begins
+	 *
+	 * @return string Path of target relative to starting path
+	 */
+	public function make_path_relative($end_path, $start_path);
+
+	/**
+	 * Mirrors a directory to another.
+	 *
+	 * @param string		$origin_dir	The origin directory
+	 * @param string		$target_dir	The target directory
+	 * @param \Traversable	$iterator	A Traversable instance
+	 * @param array			$options	An array of boolean options
+	 *									Valid options are:
+	 *										- $options['override'] Whether to override an existing file on copy or not (see copy())
+	 *										- $options['copy_on_windows'] Whether to copy files instead of links on Windows (see symlink())
+	 *										- $options['delete'] Whether to delete files that are not in the source directory (defaults to false)
+	 *
+	 * @throws \phpbb\filesystem\exception\filesystem_exception When the file cannot be copied.
+	 * 															The filename which triggered the error can be
+	 * 															retrieved by filesystem_exception::get_filename()
+	 */
+	public function mirror($origin_dir, $target_dir, \Traversable $iterator = null, $options = array());
+
+	/**
+	 * Creates a directory recursively.
+	 *
+	 * @param string|array|\Traversable	$dirs	The directory path
+	 * @param int						$mode	The directory mode
+	 *
+	 * @throws \phpbb\filesystem\exception\filesystem_exception On any directory creation failure
+	 * 															The filename which triggered the error can be
+	 * 															retrieved by filesystem_exception::get_filename()
+	 */
+	public function mkdir($dirs, $mode = 0777);
+
+	/**
+	 * Global function for chmodding directories and files for internal use
+	 *
+	 * This function determines owner and group whom the file belongs to and user and group of PHP and then set safest possible file permissions.
+	 * The function determines owner and group from common.php file and sets the same to the provided file.
+	 * The function uses bit fields to build the permissions.
+	 * The function sets the appropiate execute bit on directories.
+	 *
+	 * Supported constants representing bit fields are:
+	 *
+	 * filesystem_interface::CHMOD_ALL - all permissions (7)
+	 * filesystem_interface::CHMOD_READ - read permission (4)
+	 * filesystem_interface::CHMOD_WRITE - write permission (2)
+	 * filesystem_interface::CHMOD_EXECUTE - execute permission (1)
+	 *
+	 * NOTE: The function uses POSIX extension and fileowner()/filegroup() functions. If any of them is disabled, this function tries to build proper permissions, by calling is_readable() and is_writable() functions.
+	 *
+	 * @param string|array|\Traversable	$file				The file/directory to be chmodded
+	 * @param int						$perms				Permissions to set
+	 * @param bool						$recursive			If the permissions should be changed recursively
+	 * @param bool						$force_chmod_link	Try to apply permissions to symlinks as well
+	 *
+	 * @throws \phpbb\filesystem\exception\filesystem_exception	the filename which triggered the error can be
+	 * 															retrieved by filesystem_exception::get_filename()
+	 */
+	public function phpbb_chmod($file, $perms = null, $recursive = false, $force_chmod_link = false);
+
+	/**
+	 * A wrapper for PHP's realpath
+	 *
+	 * Try to resolve realpath when PHP's realpath is not available, or
+	 * known to be buggy.
+	 *
+	 * @param string	$path	Path to resolve
+	 *
+	 * @return string	Resolved path
+	 */
+	public function realpath($path);
+
+	/**
+	 * Removes files or directories.
+	 *
+	 * @param string|array|\Traversable	$files	A filename, an array of files, or a \Traversable instance to remove
+	 *
+	 * @throws \phpbb\filesystem\exception\filesystem_exception When removal fails.
+	 * 															The filename which triggered the error can be
+	 * 															retrieved by filesystem_exception::get_filename()
+	 */
+	public function remove($files);
+
+	/**
+	 * Renames a file or a directory.
+	 *
+	 * @param string	$origin		The origin filename or directory
+	 * @param string	$target		The new filename or directory
+	 * @param bool		$overwrite	Whether to overwrite the target if it already exists
+	 *
+	 * @throws \phpbb\filesystem\exception\filesystem_exception	When target file or directory already exists,
+	 * 															or origin cannot be renamed.
+	 */
+	public function rename($origin, $target, $overwrite = false);
+
+	/**
+	 * Creates a symbolic link or copy a directory.
+	 *
+	 * @param string	$origin_dir			The origin directory path
+	 * @param string	$target_dir			The symbolic link name
+	 * @param bool		$copy_on_windows	Whether to copy files if on Windows
+	 *
+	 * @throws \phpbb\filesystem\exception\filesystem_exception When symlink fails
+	 */
+	public function symlink($origin_dir, $target_dir, $copy_on_windows = false);
+
+	/**
+	 * Sets access and modification time of file.
+	 *
+	 * @param string|array|\Traversable	$files			A filename, an array of files, or a \Traversable instance to create
+	 * @param int						$time			The touch time as a Unix timestamp
+	 * @param int						$access_time	The access time as a Unix timestamp
+	 *
+	 * @throws \phpbb\filesystem\exception\filesystem_exception	When touch fails
+	 */
+	public function touch($files, $time = null, $access_time = null);
+}