Eric @ EricBess WebHome

<?php
echo "nnn    Dirty paths:n";
$paths[] = 'C://////////Windows//////System';               //  C:/System
$paths[] = 'C:HTMLjavascript..examplescolors.html';    //  C:/HTML/examples/colors.html
$paths[] = '/root/./wwwroot/scripts/../././webpage';        //  /root/wwwroot/webpage
$paths[] = 'wwwroot/webpage/../index.php?querystring';      //  wwwroot/index.php?querystring
$paths[] = 'http://www.php.net/manual/en/../../downloads';  //  http://www.php.net/downloads
$paths[] = 'http://www.php.net/downloads/test/test1/test2//./docs.php';    //  http://www.php.net/docs.php
$paths[] = '../downloads/../docs.php';                      //  ../docs.php
$paths[] = 'localhost//projetos/../_arquivos/../';          //   ""
$paths[] = 'C:/downloads/../../../';                        //  C:/
$paths[] = 'downloads/../../../';                           //  ../../
 
foreach ($paths as $path)
{
    echo "n&quot;" . $path . "&quot;  =  &quot;" . fixpath($path) . "&quot;";
}
?>

<?php
function fixpath($path = "")
{
    // Sanity check
    if ($path == "") {return false;}
 
    // Converts all "" to "/", and erases blank spaces at the beginning and the ending of the string
    $path = trim(preg_replace("/\/", "/", (string)$path));
 
    /*   Breaks the original string in to parts: "root" and "dir".
    *    "root" can be "C:/" (Windows), "/" (Linux) or "http://www.something.com/" (URLs). This will be the start of output string.
    *    "dir" can be "Windows/System", "root/html/examples/", "includes/classes/class.validator.php", etc.
    */
    preg_match_all("/^(/|w:/|(http|ftp)s?://[^/]+/)?(.*)$/i", $path, $matches, PREG_SET_ORDER);
 
    $path_root = $matches[0][1];
    $path_dir  = $matches[0][3];
 
    //  If "dir" part has one or more slashes at the beginning, erases all.
    $path_dir = preg_replace(  array("/^/+/"),  array(""),  $path_dir  );
 
    // Breaks "dir" part on each slash
    $path_parts = explode("/", $path_dir);
 
    // Creates a new array with the right path. Each element is a new dir (or file in the ending, if exists) in sequence.
    for ($i = $j = 0, $real_path_parts = array(); $i < count($path_parts); $i++)
    {
        if ($path_parts[$i] == '.')
        {
            continue;
        }
        else if (($path_parts[$i] == '') && ($i != (count($path_parts) -1)))
        {
        	$real_path_parts = array();
        	$j = 0;
        	continue;
         }
        else if ($path_parts[$i] == '..')
        {
            if (  (isset($real_path_parts[$j-1])  &&  $real_path_parts[$j-1] != '..')  ||  ($path_root != "")  )
            {
                array_pop($real_path_parts);
                $j--;
                continue;
            }
        }
 
        array_push($real_path_parts, $path_parts[$i]);
        $j++;
    }
    return $path_root . implode("/", $real_path_parts);
}
?>