Add open_basedir to lessjs when run with nodejs

fs.js

var fs;
try
{
    fs = require("graceful-fs");
}
catch(e)
{
	fs  = require("fs");
}
/**
 * Edited file  less-node/fs.js
 * Add open_basedir to lessjs, Thanks @gimenete https://gist.github.com/gimenete/9377962
 * To use open_basedir, add variable open_basedir to "enviroment"
 * example: export open_basedir="/test_open_basedir/"; lessc test.less > test.css 
 */
if( typeof(process.env.open_basedir) == "string" && process.env.open_basedir.length ){
	var basedir = process.env.open_basedir;
	var _fs = {
		readFile: fs.readFile,
		stat: fs.stat
	};
	fs.readFile = function(filename) {
		if (filename.indexOf(basedir) !== 0) {
			return arguments[arguments.length-1](new Error('Forbidden'))
		}
		return _fs.readFile.apply(fs, arguments)
	}

	fs.stat = function(filename) {
		if (filename.indexOf(basedir) !== 0) {
			return arguments[arguments.length-1](new Error('Forbidden'))
		}
		return _fs.stat.apply(fs, arguments)
	}
}

//console.log( "/* env:" + JSON.stringify(process.env, null, 2) + " */");
module.exports = fs;