<?php

/**
 * exception for nfs module
 * 
 * @author Joe Gillotti <joe@u13.net> 
 */
class nfs_exception extends Exception {}

/**
 * nfs module
 * 
 * @author Joe Gillotti <joe@u13.net> 
 */
class nfs implements modules {

	private

	/**
	 *  Paths to NFS related files and commands
	 */
	$_paths = array(
		'exports' => '/etc/exports',
		'rmtab' => '/var/lib/nfs/rmtab',
		'etab' => '/var/lib/nfs/etab',
		'exportfs' => '/usr/sbin/exportfs'
	);

	/**
	 * Some checks as we start up
	 * 
	 * @access public
	 */
	public function __construct() {

		// Make sure we're root
		$my_uid = posix_getuid();
		if ($my_uid !== 0) {
			$my_user = posix_getpwuid($my_uid);
			throw new nfs_exception('This must be ran as root; not '.$my_user['name'].' ('.$my_uid.')');
		}
	}
	
	/**
	 * View exported directories in the exports file
	 * 
	 * @access public
	 * @return array the exports
	 */
	public function view_exports() {
		
		// Get contents
		$contents = is_readable($this->_paths['exports']) ? file_get_contents($this->_paths['exports']) : '';

		// Attempt matching for non-commented working exports. Return empty list on failure.
		if (!preg_match_all('/^(?!\#)(\S+)((?:\s+[\w\.\*]+\([a-z,_]+\))+)/m', $contents, $matches, PREG_SET_ORDER)) 
			return array();

		// Store matches prettily here
		$exports = array();

		// Populate it
		for ($i = 0, $num = count($matches); $i < $num; $i++) {

			// Store clients for this export here
			$clients = array();

			// Find them
			if (preg_match_all('/\s+([\w\.\*]+)\(([a-z,_]+)\)/', $matches[$i][2], $c_matches, PREG_SET_ORDER)) 

				for ($c_i = 0, $c_num = count($c_matches); $c_i < $c_num; $c_i++)
					$clients[] = array(
						'host' => $c_matches[$c_i][1],
						'options' => explode(',', $c_matches[$c_i][2])
					);

			
			
			// Append export to our list
			$exports[] = array(
				'directory' => $matches[$i][1],
				'clients' => $clients
			);
		}

		// Give list
		return $exports;
	}

	/**
	 * View remotely mounted exports listed in rmtab
	 * 
	 * @access public
	 * @return array the mounted exports
	 */
	public function view_mounted_exports() {
		
		// Get contents
		$contents = is_readable($this->_paths['rmtab']) ? file_get_contents($this->_paths['rmtab']) : '';

		// Try matching
		if (!preg_match_all('/([\w\.]+):([^:]+)/m', $contents, $matches, PREG_SET_ORDER))
			return array();

		// Keep mounts here
		$mounts = array();

		// Populate it
		for ($i = 0, $num = count($matches); $i < $num; $i++) 
			$mounts[] = array(
				'client' => $matches[$i][1],
				'share' => $matches[$i][2]
			);

		// Give it
		return $mounts;

	}

	public function add_exports($share, $clients) {

		// Store the second part of the exports line here
		$access = '';

		// Populate that with each client and its settings
		for ($i = 0, $num = count($clients); $i < $num; $i++)
			$access .= ' '.$clients[$i]['host'].'('.$clients[$i]['options'].')';

		// Try saving it
		return file_put_contents($this->_paths['exports'], "$share$access", FILE_APPEND);
	}

	/**
	 * Replace specific lines in exports file
	 * 
	 * @param mixed $replacements 
	 * @access public
	 * @return bool
	 */
	public function replace_exports($replacements) {

		// Make sure that's an array
		$replacements = (array) $replacements;

		// Get lines currently in file
		if (!($lines = @file($this->_paths['exports'], FILE_IGNORE_NEW_LINES)))
			return false;
		
		// Go through each line, checking if its one we want to replace
		foreach ($lines as $k => $line) {

			// Potential fixing
			$line = trim($line);

			// Is it in our list of replacements?
			if (array_key_exists(trim($line), $replacements))
				$lines[$k] = $replacements[$line];
		}

		// Try saving it
		return file_put_contents($this->_paths['exports'], implode("\n", $lines));
	}

	/**
	 * Delete specific lines in exports file
	 * 
	 * @param array $kill_lines 
	 * @access public
	 * @return bool 
	 */
	public function delete_exports($kill_lines) {

		// Make sure this is an array so we can kill multiple ones
		$kill_lines = (array) $kill_lines;

		// Get lines currently in file
		if (!($lines = @file($this->_paths['exports'], FILE_IGNORE_NEW_LINES)))
			return false;

		// Go through each line, checking if its one we want to kill
		foreach ($lines as $k => $line) 
			if (in_array(trim($line), $kill_lines))
				unset($lines[$k]); 

		// Try saving it
		return file_put_contents($this->_paths['exports'], implode("\n", $lines));
	}

	/**
	 * Export a directory immediately, but don't save it
	 * 
	 * @param string $client 
	 * @param string $share 
	 * @param string $options 
	 * @access public
	 * @return int
	 */
	public function tmp_export($client, $share, $options) {

		// The return code may not be passed; default to NULL if it isn't
		$code = null;

		// Run the command
		exec("{$this->_paths['exportfs']} -o ".implode(',', $options)." $client:$share", &$out, &$code);

		// If the exit code is zero, it should have succeeded.
		return $code !== null ? $code === 0 : null;
	}

	/**
	 * Reparse the exports file and share appropriately
	 * 
	 * @access public
	 * @return int
	 */
	public function reload() {

		// The return code may not be passed; default to NULL if it isn't
		$code = null;

		// Run the command
		exec("{$this->_paths['exportfs']} -ra", &$out, &$code);

		// If the exit code is zero, it should have succeeded.
		return $code !== null ? $code === 0 : null;
	}

	/**
	 * Show exports that are active and real, by parsing etab
	 * 
	 * @access public
	 * @return void
	 */
	public function view_live_exports() {
		
		// Get exports with this command. Might be really unreliable.
		$contents = is_readable($this->_paths['etab']) ? file_get_contents($this->_paths['etab']) : '';

		// Try matching the exports out of it
		if (preg_match_all('/^(\S+)\s+([\d\.\/\*]+)\(([^\)]+)\)$/m', $contents, $matches, PREG_SET_ORDER) == 0) 
			return array();

		// Store exports here
		$exports = array();

		// Populate it
		for ($i = 0, $num = count($matches); $i < $num; $i++)
			$exports[] = array(
				'share' => $matches[$i][1],
				'host' => $matches[$i][2],
				'options' => explode(',', $matches[$i][3])
			);

		// Give exports list
		return $exports;
	}
}