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<?php
/**
*
* @package phpBB3
* @copyright (c) 2005 phpBB Group
* @license http://opensource.org/licenses/gpl-license.php GNU Public License
*
*/

/**
* @ignore
*/
if (!defined('IN_PHPBB'))
{
	exit;
}

/**
* A simplified function to deliver avatars
* The argument needs to be checked before calling this function.
*/
function send_avatar_to_browser($file, $browser)
{
	global $config, $phpbb_root_path;

	$prefix = $config['avatar_salt'] . '_';
	$image_dir = $config['avatar_path'];

	// Adjust image_dir path (no trailing slash)
	if (substr($image_dir, -1, 1) == '/' || substr($image_dir, -1, 1) == '\\')
	{
		$image_dir = substr($image_dir, 0, -1) . '/';
	}
	$image_dir = str_replace(array('../', '..\\', './', '.\\'), '', $image_dir);

	if ($image_dir && ($image_dir[0] == '/' || $image_dir[0] == '\\'))
	{
		$image_dir = '';
	}
	$file_path = $phpbb_root_path . $image_dir . '/' . $prefix . $file;

	if ((@file_exists($file_path) && @is_readable($file_path)) && !headers_sent())
	{
		header('Pragma: public');

		$image_data = @getimagesize($file_path);
		header('Content-Type: ' . image_type_to_mime_type($image_data[2]));

		if (strpos(strtolower($browser), 'msie') !== false && strpos(strtolower($browser), 'msie 8.0') === false)
		{
			header('Content-Disposition: attachment; ' . header_filename($file));

			if (strpos(strtolower($browser), 'msie 6.0') !== false)
			{
				header('Expires: -1');
			}
			else
			{
				header('Expires: ' . gmdate('D, d M Y H:i:s \G\M\T', time() + 31536000));
			}
		}
		else
		{
			header('Content-Disposition: inline; ' . header_filename($file));
			header('Expires: ' . gmdate('D, d M Y H:i:s \G\M\T', time() + 31536000));
		}

		$size = @filesize($file_path);
		if ($size)
		{
			header("Content-Length: $size");
		}

		if (@readfile($file_path) == false)
		{
			$fp = @fopen($file_path, 'rb');

			if ($fp !== false)
			{
				while (!feof($fp))
				{
					echo fread($fp, 8192);
				}
				fclose($fp);
			}
		}

		flush();
	}
	else
	{
		header('HTTP/1.0 404 Not Found');
	}
}

/**
* Wraps an url into a simple html page. Used to display attachments in IE.
* this is a workaround for now; might be moved to template system later
* direct any complaints to 1 Microsoft Way, Redmond
*/
function wrap_img_in_html($src, $title)
{
	echo '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-Strict.dtd">';
	echo '<html>';
	echo '<head>';
	echo '<meta http-equiv="content-type" content="text/html; charset=UTF-8" />';
	echo '<title>' . $title . '</title>';
	echo '</head>';
	echo '<body>';
	echo '<div>';
	echo '<img src="' . $src . '" alt="' . $title . '" />';
	echo '</div>';
	echo '</body>';
	echo '</html>';
}

/**
* Send file to browser
*/
function send_file_to_browser($attachment, $upload_dir, $category)
{
	global $user, $db, $config, $phpbb_root_path;

	$filename = $phpbb_root_path . $upload_dir . '/' . $attachment['physical_filename'];

	if (!@file_exists($filename))
	{
		trigger_error($user->lang['ERROR_NO_ATTACHMENT'] . '<br /><br />' . sprintf($user->lang['FILE_NOT_FOUND_404'], $filename));
	}

	// Correct the mime type - we force application/octetstream for all files, except images
	// Please do not change this, it is a security precaution
	if ($category != ATTACHMENT_CATEGORY_IMAGE || strpos($attachment['mimetype'], 'image') !== 0)
	{
		$attachment['mimetype'] = (strpos(strtolower($user->browser), 'msie') !== false || strpos(strtolower($user->browser), 'opera') !== false) ? 'application/octetstream' : 'application/octet-stream';
	}

	if (@ob_get_length())
	{
		@ob_end_clean();
	}

	// Now send the File Contents to the Browser
	$size = @filesize($filename);

	// To correctly display further errors we need to make sure we are using the correct headers for both (unsetting content-length may not work)

	// Check if headers already sent or not able to get the file contents.
	if (headers_sent() || !@file_exists($filename) || !@is_readable($filename))
	{
		// PHP track_errors setting On?
		if (!empty($php_errormsg))
		{
			trigger_error($user->lang['UNABLE_TO_DELIVER_FILE'] . '<br />' . sprintf($user->lang['TRACKED_PHP_ERROR'], $php_errormsg));
		}

		trigger_error('UNABLE_TO_DELIVER_FILE');
	}

	// Make sure the database record for the filesize is correct
	if ($size > 0 && $size != $attachment['filesize'])
	{
		// Update database record
		$sql = 'UPDATE ' . ATTACHMENTS_TABLE . '
			SET filesize = ' . (int) $size . '
			WHERE attach_id = ' . (int) $attachment['attach_id'];
		$db->sql_query($sql);
	}

	// Now the tricky part... let's dance
	header('Pragma: public');

	/**
	* Commented out X-Sendfile support. To not expose the physical filename within the header if xsendfile is absent we need to look into methods of checking it's status.
	*
	* Try X-Sendfile since it is much more server friendly - only works if the path is *not* outside of the root path...
	* lighttpd has core support for it. An apache2 module is available at http://celebnamer.celebworld.ws/stuff/mod_xsendfile/
	*
	* Not really ideal, but should work fine...
	* <code>
	*	if (strpos($upload_dir, '/') !== 0 && strpos($upload_dir, '../') === false)
	*	{
	*		header('X-Sendfile: ' . $filename);
	*	}
	* </code>
	*/

	// Send out the Headers. Do not set Content-Disposition to inline please, it is a security measure for users using the Internet Explorer.
	$is_ie8 = (strpos(strtolower($user->browser), 'msie 8.0') !== false);
	header('Content-Type: ' . $attachment['mimetype']);

	if ($is_ie8)
	{
		header('X-Content-Type-Options: nosniff');
	}

	if ($category == ATTACHMENT_CATEGORY_FLASH && request_var('view', 0) === 1)
	{
		// We use content-disposition: inline for flash files and view=1 to let it correctly play with flash player 10 - any other disposition will fail to play inline
		header('Content-Disposition: inline');
	}
	else
	{
		if (empty($user->browser) || (!$is_ie8 && (strpos(strtolower($user->browser), 'msie') !== false)))
		{
			header('Content-Disposition: attachment; ' . header_filename(htmlspecialchars_decode($attachment['real_filename'])));
			if (empty($user->browser) || (strpos(strtolower($user->browser), 'msie 6.0') !== false))
			{
				header('expires: -1');
			}
		}
		else
		{
			header('Content-Disposition: ' . ((strpos($attachment['mimetype'], 'image') === 0) ? 'inline' : 'attachment') . '; ' . header_filename(htmlspecialchars_decode($attachment['real_filename'])));
			if ($is_ie8 && (strpos($attachment['mimetype'], 'image') !== 0))
			{
				header('X-Download-Options: noopen');
			}
		}
	}

	if ($size)
	{
		header("Content-Length: $size");
	}

	// Close the db connection before sending the file
	$db->sql_close();

	if (!set_modified_headers($attachment['filetime'], $user->browser))
	{
		// Try to deliver in chunks
		@set_time_limit(0);

		$fp = @fopen($filename, 'rb');

		if ($fp !== false)
		{
			// Deliver file partially if requested
			if ($range = phpbb_http_byte_range($size))
			{
				fseek($fp, $range['byte_pos_start']);

				send_status_line(206, 'Partial Content');
				header('Content-Range: bytes ' . $range['byte_pos_start'] . '-' . $range['byte_pos_end'] . '/' . $range['bytes_total']);
				header('Content-Length: ' . $range['bytes_requested']);
			}

			while (!feof($fp))
			{
				echo fread($fp, 8192);
			}
			fclose($fp);
		}
		else
		{
			@readfile($filename);
		}

		flush();
	}
	file_gc();
}

/**
* Get a browser friendly UTF-8 encoded filename
*/
function header_filename($file)
{
	$user_agent = (!empty($_SERVER['HTTP_USER_AGENT'])) ? htmlspecialchars((string) $_SERVER['HTTP_USER_AGENT']) : '';

	// There be dragons here.
	// Not many follows the RFC...
	if (strpos($user_agent, 'MSIE') !== false || strpos($user_agent, 'Safari') !== false || strpos($user_agent, 'Konqueror') !== false)
	{
		return "filename=" . rawurlencode($file);
	}

	// follow the RFC for extended filename for the rest
	return "filename*=UTF-8''" . rawurlencode($file);
}

/**
* Check if downloading item is allowed
*/
function download_allowed()
{
	global $config, $user, $db;

	if (!$config['secure_downloads'])
	{
		return true;
	}

	$url = (!empty($_SERVER['HTTP_REFERER'])) ? trim($_SERVER['HTTP_REFERER']) : trim(getenv('HTTP_REFERER'));

	if (!$url)
	{
		return ($config['secure_allow_empty_referer']) ? true : false;
	}

	// Split URL into domain and script part
	$url = @parse_url($url);

	if ($url === false)
	{
		return ($config['secure_allow_empty_referer']) ? true : false;
	}

	$hostname = $url['host'];
	unset($url);

	$allowed = ($config['secure_allow_deny']) ? false : true;
	$iplist = array();

	if (($ip_ary = @gethostbynamel($hostname)) !== false)
	{
		foreach ($ip_ary as $ip)
		{
			if ($ip)
			{
				$iplist[] = $ip;
			}
		}
	}

	// Check for own server...
	$server_name = $user->host;

	// Forcing server vars is the only way to specify/override the protocol
	if ($config['force_server_vars'] || !$server_name)
	{
		$server_name = $config['server_name'];
	}

	if (preg_match('#^.*?' . preg_quote($server_name, '#') . '.*?$#i', $hostname))
	{
		$allowed = true;
	}

	// Get IP's and Hostnames
	if (!$allowed)
	{
		$sql = 'SELECT site_ip, site_hostname, ip_exclude
			FROM ' . SITELIST_TABLE;
		$result = $db->sql_query($sql);

		while ($row = $db->sql_fetchrow($result))
		{
			$site_ip = trim($row['site_ip']);
			$site_hostname = trim($row['site_hostname']);

			if ($site_ip)
			{
				foreach ($iplist as $ip)
				{
					if (preg_match('#^' . str_replace('\*', '.*?', preg_quote($site_ip, '#')) . '$#i', $ip))
					{
						if ($row['ip_exclude'])
						{
							$allowed = ($config['secure_allow_deny']) ? false : true;
							break 2;
						}
						else
						{
							$allowed = ($config['secure_allow_deny']) ? true : false;
						}
					}
				}
			}

			if ($site_hostname)
			{
				if (preg_match('#^' . str_replace('\*', '.*?', preg_quote($site_hostname, '#')) . '$#i', $hostname))
				{
					if ($row['ip_exclude'])
					{
						$allowed = ($config['secure_allow_deny']) ? false : true;
						break;
					}
					else
					{
						$allowed = ($config['secure_allow_deny']) ? true : false;
					}
				}
			}
		}
		$db->sql_freeresult($result);
	}

	return $allowed;
}

/**
* Check if the browser has the file already and set the appropriate headers-
* @returns false if a resend is in order.
*/
function set_modified_headers($stamp, $browser)
{
	// let's see if we have to send the file at all
	$last_load 	=  isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) ? strtotime(trim($_SERVER['HTTP_IF_MODIFIED_SINCE'])) : false;
	if ((strpos(strtolower($browser), 'msie 6.0') === false) && (strpos(strtolower($browser), 'msie 8.0') === false))
	{
		if ($last_load !== false && $last_load >= $stamp)
		{
			send_status_line(304, 'Not Modified');
			// seems that we need those too ... browsers
			header('Pragma: public');
			header('Expires: ' . gmdate('D, d M Y H:i:s \G\M\T', time() + 31536000));
			return true;
		}
		else
		{
			header('Last-Modified: ' . gmdate('D, d M Y H:i:s', $stamp) . ' GMT');
		}
	}
	return false;
}

function file_gc()
{
	global $cache, $db;
	if (!empty($cache))
	{
		$cache->unload();
	}
	$db->sql_close();
	exit;
}

/**
* HTTP range support (RFC 2616 Section 14.35)
*
* Allows browsers to request partial file content
* in case a download has been interrupted.
*
* @param int $filesize		the size of the file in bytes we are about to deliver
*
* @return mixed		false if the whole file has to be delivered
*					associative array on success
*/
function phpbb_http_byte_range($filesize)
{
	// Only call find_range_request() once.
	static $request_array;

	if (!$filesize)
	{
		return false;
	}

	if (!isset($request_array))
	{
		$request_array = phpbb_find_range_request();
	}
	
	return (empty($request_array)) ? false : phpbb_parse_range_request($request_array, $filesize);
}

/**
* Searches for HTTP range request in super globals.
*
* @return mixed		false if no request found
*					array of strings containing the requested ranges otherwise
*					e.g. array(0 => '0-0', 1 => '123-125')
*/
function phpbb_find_range_request()
{
	$globals = array(
		array('_SERVER',	'HTTP_RANGE'),
		array('_ENV',		'HTTP_RANGE'),
	);

	foreach ($globals as $array)
	{
		$global	= $array[0];
		$key	= $array[1];

		// Make sure range request starts with "bytes="
		if (isset($GLOBALS[$global][$key]) && strpos($GLOBALS[$global][$key], 'bytes=') === 0)
		{
			// Strip leading 'bytes='
			// Multiple ranges can be separated by a comma
			return explode(',', substr($GLOBALS[$global][$key], 6));
		}
	}

	return false;
}

/**
* Analyses a range request array.
*
* A range request can contain multiple ranges,
* we however only handle the first request and
* only support requests from a given byte to the end of the file.
*
* @param array	$request_array	array of strings containing the requested ranges
* @param int	$filesize		the full size of the file in bytes that has been requested
*
* @return mixed		false if the whole file has to be delivered
*					associative array on success
*						byte_pos_start		the first byte position, can be passed to fseek()
*						byte_pos_end		the last byte position
*						bytes_requested		the number of bytes requested
*						bytes_total			the full size of the file
*/
function phpbb_parse_range_request($request_array, $filesize)
{
	// Go through all ranges
	foreach ($request_array as $range_string)
	{
		$range = explode('-', trim($range_string));

		// "-" is invalid, "0-0" however is valid and means the very first byte.
		if (sizeof($range) != 2 || $range[0] === '' && $range[1] === '')
		{
			continue;
		}

		if ($range[0] === '')
		{
			// Return last $range[1] bytes.

			if (!$range[1])
			{
				continue;
			}

			if ($range[1] >= $filesize)
			{
				return false;
			}

			$first_byte_pos	= $filesize - (int) $range[1];
			$last_byte_pos	= $filesize - 1;
		}
		else
		{
			// Return bytes from $range[0] to $range[1]

			$first_byte_pos	= (int) $range[0];
			$last_byte_pos	= (int) $range[1];

			if ($last_byte_pos && $last_byte_pos < $first_byte_pos)
			{
				// The requested range contains 0 bytes.
				continue;
			}

			if ($first_byte_pos >= $filesize)
			{
				// Requested range not satisfiable
				return false;
			}

			// Adjust last-byte-pos if it is absent or greater than the content.
			if ($range[1] === '' || $last_byte_pos >= $filesize)
			{
				$last_byte_pos = $filesize - 1;
			}
		}

		// We currently do not support range requests that end before the end of the file
		if ($last_byte_pos != $filesize - 1)
		{
			continue;
		}

		return array(
			'byte_pos_start'	=> $first_byte_pos,
			'byte_pos_end'		=> $last_byte_pos,
			'bytes_requested'	=> $last_byte_pos - $first_byte_pos + 1,
			'bytes_total'		=> $filesize,
		);
	}
}