<?php
/*
 *  Jirafeau, your web file repository
 *  Copyright (C) 2008  Julien "axolotl" BERNARD <axolotl@magieeternelle.org>
 *  Copyright (C) 2015  Jerome Jutteau <j.jutteau@gmail.com>
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as
 *  published by the Free Software Foundation, either version 3 of the
 *  License, or (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/**
 * Transform a string in a path by seperating each letters by a '/'.
  * @return path finishing with a '/'
 */
function
s2p ($s)
{
    $p = '';
    for ($i = 0; $i < strlen ($s); $i++)
        $p .= $s{$i} . '/';
    return $p;
}

/**
 * Convert base 16 to base 64
 * @returns A string based on 64 characters (0-9, a-z, A-Z, "-" and "_")
 */
function
base_16_to_64 ($num)
{
    $m = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ-_';
    $hex2bin = array ('0000', # 0
                      '0001', # 1
                      '0010', # 2
                      '0011', # 3
                      '0100', # 4
                      '0101', # 5
                      '0110', # 6
                      '0111', # 7
                      '1000', # 8
                      '1001', # 9
                      '1010', # a
                      '1011', # b
                      '1100', # c
                      '1101', # d
                      '1110', # e
                      '1111'); # f
    $o = '';    
    $b = '';
    $i = 0;
    # Convert long hex string to bin.
    $size = strlen ($num);
    for ($i = 0; $i < $size; $i++)
        $b .= $hex2bin{hexdec ($num{$i})};
    # Convert long bin to base 64.
    $size *= 4;
    for ($i = $size - 6; $i >= 0; $i -= 6)
        $o = $m{bindec (substr ($b, $i, 6))} . $o;
    # Some few bits remaining ?
    if ($i < 0 && $i > -6)
        $o = $m{bindec (substr ($b, 0, $i + 6))} . $o;
    return $o;
}

/**
  * Generate a random code.
  * @param $l code length
  * @return  random code.
  */
function
jirafeau_gen_random ($l)
{
    if ($l <= 0)
        return 42;

    $code="";
    for ($i = 0; $i < $l; $i++)
        $code .= dechex (rand (0, 15));

    return $code;
}

function is_ssl() {
    if ( isset($_SERVER['HTTPS']) ) {
        if ( 'on' == strtolower($_SERVER['HTTPS']) )
            return true;
        if ( '1' == $_SERVER['HTTPS'] )
            return true;
    } elseif ( isset($_SERVER['SERVER_PORT']) && ( '443' == $_SERVER['SERVER_PORT'] ) ) {
        return true;
    } elseif (isset($_SERVER['HTTP_X_FORWARDED_PROTO'])) {
        if ($_SERVER['HTTP_X_FORWARDED_PROTO'] == 'https')
            return true;
    }
    return false;
}

function
jirafeau_human_size ($octets)
{
    $u = array ('B', 'KB', 'MB', 'GB', 'TB');
    $o = max ($octets, 0);
    $p = min (floor (($o ? log ($o) : 0) / log (1024)), count ($u) - 1);
    $o /= pow (1024, $p);
    return round ($o, 1) . $u[$p];
} 

function
jirafeau_clean_rm_link ($link)
{
    $p = s2p ("$link");
    if (file_exists (VAR_LINKS . $p . $link))
        unlink (VAR_LINKS . $p . $link);
    $parse = VAR_LINKS . $p;
    $scan = array();
    while (file_exists ($parse)
           && ($scan = scandir ($parse))
           && count ($scan) == 2 // '.' and '..' folders => empty.
           && basename ($parse) != basename (VAR_LINKS)) 
    {
        rmdir ($parse);
        $parse = substr ($parse, 0, strlen($parse) - strlen(basename ($parse)) - 1);
    }
}

function
jirafeau_clean_rm_file ($md5)
{
    $p = s2p ("$md5");
    $f = VAR_FILES . $p . $md5;
    if (file_exists ($f) && is_file ($f))
        unlink ($f);
    if (file_exists ($f . '_count') && is_file ($f . '_count'))
        unlink ($f . '_count');
    $parse = VAR_FILES . $p;
    $scan = array();
    while (file_exists ($parse)
           && ($scan = scandir ($parse))
           && count ($scan) == 2 // '.' and '..' folders => empty.
           && basename ($parse) != basename (VAR_FILES)) 
    {
        rmdir ($parse);
        $parse = substr ($parse, 0, strlen($parse) - strlen(basename ($parse)) - 1);
    }
}

/**
 * transforms a php.ini string representing a value in an integer
 * @param $value the value from php.ini
 * @returns an integer for this value
 */
function jirafeau_ini_to_bytes ($value)
{
    $modifier = substr ($value, -1);
    $bytes = substr ($value, 0, -1);
    switch (strtoupper ($modifier))
    {
    case 'P':
        $bytes *= 1024;
    case 'T':
        $bytes *= 1024;
    case 'G':
        $bytes *= 1024;
    case 'M':
        $bytes *= 1024;
    case 'K':
        $bytes *= 1024;
    default:
        break;
    }
    return $bytes;
}

/**
 * gets the maximum upload size according to php.ini
 * @returns the maximum upload size in bytes
 */
function
jirafeau_get_max_upload_size_bytes ()
{
    return min (jirafeau_ini_to_bytes (ini_get ('post_max_size')),
                jirafeau_ini_to_bytes (ini_get ('upload_max_filesize')));
}

/**
 * gets the maximum upload size according to php.ini
 * @returns the maximum upload size string
 */
function
jirafeau_get_max_upload_size ()
{
    return jirafeau_human_size(
            min (jirafeau_ini_to_bytes (ini_get ('post_max_size')),
                 jirafeau_ini_to_bytes (ini_get ('upload_max_filesize'))));
}

/**
 * gets a string explaining the error
 * @param $code the error code
 * @returns a string explaining the error
 */
function
jirafeau_upload_errstr ($code)
{
    switch ($code)
    {
    case UPLOAD_ERR_INI_SIZE:
    case UPLOAD_ERR_FORM_SIZE:
        return t('Your file exceeds the maximum authorized file size. ');
        break;

    case UPLOAD_ERR_PARTIAL:
    case UPLOAD_ERR_NO_FILE:
        return
            t
            ('Your file was not uploaded correctly. You may succeed in retrying. ');
        break;

    case UPLOAD_ERR_NO_TMP_DIR:
    case UPLOAD_ERR_CANT_WRITE:
    case UPLOAD_ERR_EXTENSION:
        return t('Internal error. You may not succeed in retrying. ');
        break;

    default:
        break;
    }
    return t('Unknown error. ');
}

/** Remove link and it's file
 * @param $link the link's name (hash)
 */

function
jirafeau_delete_link ($link)
{
    $l = jirafeau_get_link ($link);
    if (!count ($l))
        return;

    jirafeau_clean_rm_link ($link);

    $md5 = $l['md5'];
    $p = s2p ("$md5");

    $counter = 1;
    if (file_exists (VAR_FILES . $p . $md5. '_count'))
    {
        $content = file (VAR_FILES . $p . $md5. '_count');
        $counter = trim ($content[0]);
    }
    $counter--;

    if ($counter >= 1)
    {
        $handle = fopen (VAR_FILES . $p . $md5. '_count', 'w');
        fwrite ($handle, $counter);
        fclose ($handle);
    }

    if ($counter == 0)
        jirafeau_clean_rm_file ($md5);
}

/**
 * Delete a file and it's links.
 */
function
jirafeau_delete_file ($md5)
{
    $count = 0;
    /* Get all links files. */
    $stack = array (VAR_LINKS);
    while (($d = array_shift ($stack)) && $d != NULL)
    {
        $dir = scandir ($d);

        foreach ($dir as $node)
        {
            if (strcmp ($node, '.') == 0 || strcmp ($node, '..') == 0 ||
                preg_match ('/\.tmp/i', "$node"))
                continue;
            
            if (is_dir ($d . $node))
            {
                /* Push new found directory. */
                $stack[] = $d . $node . '/';
            }
            elseif (is_file ($d . $node))
            {
                /* Read link informations. */
                $l = jirafeau_get_link (basename ($node));
                if (!count ($l))
                    continue;
                if ($l['md5'] == $md5)
                {
                    $count++;
                    jirafeau_delete_link ($node);
                }   
            }
        }
    }
    jirafeau_clean_rm_file ($md5);
    return $count;
}

/**
 * handles an uploaded file
 * @param $file the file struct given by $_FILE[]
 * @param $one_time_download is the file a one time download ?
 * @param $key if not empty, protect the file with this key
 * @param $time the time of validity of the file
 * @param $ip uploader's ip
 * @param $crypt boolean asking to crypt or not
 * @param $link_name_length size of the link name
 * @returns an array containing some information
 *   'error' => information on possible errors
 *   'link' => the link name of the uploaded file
 *   'delete_link' => the link code to delete file
 */
function
jirafeau_upload ($file, $one_time_download, $key, $time, $ip, $crypt, $link_name_length)
{
    if (empty ($file['tmp_name']) || !is_uploaded_file ($file['tmp_name']))
    {
        return (array(
                 'error' =>
                   array ('has_error' => true,
                          'why' => jirafeau_upload_errstr ($file['error'])),
                 'link' => '',
                 'delete_link' => ''));
    }

    /* array representing no error */
    $noerr = array ('has_error' => false, 'why' => '');

    /* Crypt file if option is enabled. */
    $crypted = false;
    $crypt_key = '';
    if ($crypt == true && !(extension_loaded('mcrypt') == true))
        error_log ("PHP extension mcrypt not loaded, won't encrypt in Jirafeau");
    if ($crypt == true && extension_loaded('mcrypt') == true)
    {
        $crypt_key = jirafeau_encrypt_file ($file['tmp_name'], $file['tmp_name']);
        if (strlen($crypt_key) > 0)
            $crypted = true;
    }

    /* file informations */
    $md5 = md5_file ($file['tmp_name']);
    $name = str_replace (NL, '', trim ($file['name']));
    $mime_type = $file['type'];
    $size = $file['size'];

    /* does file already exist ? */
    $rc = false;
    $p = s2p ("$md5");
    if (file_exists (VAR_FILES . $p .  $md5))
    {
        $rc = unlink ($file['tmp_name']);
    }
    elseif ((file_exists (VAR_FILES . $p) || @mkdir (VAR_FILES . $p, 0755, true))
            && move_uploaded_file ($file['tmp_name'], VAR_FILES . $p . $md5))
    {
        $rc = true;
    }
    if (!$rc)
    {
        return (array(
                 'error' =>
                   array ('has_error' => true,
                          'why' => t('Internal error during file creation.')),
                 'link' =>'',
                 'delete_link' => ''));
    }

    /* Increment or create count file. */
    $counter = 0;
    if (file_exists (VAR_FILES . $p . $md5 . '_count'))
    {
        $content = file (VAR_FILES . $p . $md5. '_count');
        $counter = trim ($content[0]);
    }
    $counter++;
    $handle = fopen (VAR_FILES . $p . $md5. '_count', 'w');
    fwrite ($handle, $counter);
    fclose ($handle);

    /* Create delete code. */
    $delete_link_code = jirafeau_gen_random (5);

    /* md5 password or empty. */
    $password = '';
    if (!empty ($key))
        $password = md5 ($key);

    /* create link file */
    $link_tmp_name =  VAR_LINKS . $md5 . rand (0, 10000) . '.tmp';
    $handle = fopen ($link_tmp_name, 'w');
    fwrite ($handle,
            $name . NL. $mime_type . NL. $size . NL. $password . NL. $time .
            NL . $md5. NL . ($one_time_download ? 'O' : 'R') . NL . date ('U') .
            NL . $ip . NL. $delete_link_code . NL . ($crypted ? 'C' : 'O'));
    fclose ($handle);
    $md5_link = substr(base_16_to_64 (md5_file ($link_tmp_name)), 0, $link_name_length);
    $l = s2p ("$md5_link");
    if (!@mkdir (VAR_LINKS . $l, 0755, true) ||
        !rename ($link_tmp_name,  VAR_LINKS . $l . $md5_link))
    {
        if (file_exists ($link_tmp_name))
            unlink ($link_tmp_name);
        
        $counter--;
        if ($counter >= 1)
        {
            $handle = fopen (VAR_FILES . $p . $md5. '_count', 'w');
            fwrite ($handle, $counter);
            fclose ($handle);
        }
        else
        {
            jirafeau_clean_rm_file ($md5_link);
        }
        return (array(
                 'error' =>
                   array ('has_error' => true,
                          'why' => t('Internal error during file creation. ')),
                 'link' =>'',
                 'delete_link' => ''));
    }
   return (array ('error' => $noerr,
                  'link' => $md5_link,
                  'delete_link' => $delete_link_code,
                  'crypt_key' => $crypt_key));
}

/**
 * Tells if a mime-type is viewable in a browser
 * @param $mime the mime type
 * @returns a boolean telling if a mime type is viewable
 */
function
jirafeau_is_viewable ($mime)
{
    if (!empty ($mime))
    {
        /* Actually, verify if mime-type is an image or a text. */
        $viewable = array ('image', 'text', 'video', 'audio');
        $decomposed = explode ('/', $mime);
        return in_array ($decomposed[0], $viewable);
    }
    return false;
}

// Error handling functions.
//! Global array that contains all registered errors.
$error_list = array ();

/**
 * Adds an error to the list of errors.
 * @param $title the error's title
 * @param $description is a human-friendly description of the problem.
 */
function
add_error ($title, $description)
{
    global $error_list;
    $error_list[] = '<p>' . $title. '<br />' . $description. '</p>';
}

/**
 * Informs whether any error has been registered yet.
 * @return true if there are errors.
 */
function
has_error ()
{
    global $error_list;
    return !empty ($error_list);
}

/**
 * Displays all the errors.
 */
function
show_errors ()
{
    if (has_error ())
    {
        global $error_list;
        echo '<div class="error">';
        foreach ($error_list as $error)
        {
            echo $error;
        }
        echo '</div>';
    }
}

function check_errors ($cfg)
{
    if (file_exists (JIRAFEAU_ROOT . 'install.php')
        && !($cfg['installation_done'] === true))
    {
        header('Location: install.php'); 
        exit;
    }

    /* check if the destination dirs are writable */
    $writable = is_writable (VAR_FILES) && is_writable (VAR_LINKS);

    /* Checking for errors. */
    if (!is_writable (VAR_FILES))
        add_error (t('The file directory is not writable!'), VAR_FILES);

    if (!is_writable (VAR_LINKS))
        add_error (t('The link directory is not writable!'), VAR_LINKS);
    
    if (!is_writable (VAR_ASYNC))
        add_error (t('The async directory is not writable!'), VAR_ASYNC);
}

/**
 * Read link informations
 * @return array containing informations.
 */
function
jirafeau_get_link ($hash)
{
    $out = array ();
    $link = VAR_LINKS . s2p ("$hash") . $hash;

    if (!file_exists ($link))
        return $out;
    
    $c = file ($link);
    $out['file_name'] = trim ($c[0]);
    $out['mime_type'] = trim ($c[1]);
    $out['file_size'] = trim ($c[2]);
    $out['key'] = trim ($c[3], NL);
    $out['time'] = trim ($c[4]);
    $out['md5'] = trim ($c[5]);
    $out['onetime'] = trim ($c[6]);
    $out['upload_date'] = trim ($c[7]);
    $out['ip'] = trim ($c[8]);
    $out['link_code'] = trim ($c[9]);
    if (trim ($c[10]) == 'C')
	    $out['crypted'] = true;
    else
	    $out['crypted'] = false;
    
    return $out;
}

/**
 * List files in admin interface.
 */
function
jirafeau_admin_list ($name, $file_hash, $link_hash)
{
    echo '<fieldset><legend>';
    if (!empty ($name))
        echo t('Filename') . ": $name ";
    if (!empty ($file_hash))
        echo t('file') . ": $file_hash ";
    if (!empty ($link_hash))
        echo t('link') . ": $link_hash ";
    if (empty ($name) && empty ($file_hash) && empty ($link_hash))
        echo t('List all files');
    echo '</legend>';
    echo '<table>';
    echo '<tr>';
    echo '<td>' . t('Filename') . '</td>';
    echo '<td>' . t('Type') . '</td>';
    echo '<td>' . t('Size') . '</td>';
    echo '<td>' . t('Expire') . '</td>';
    echo '<td>' . t('Onetime') . '</td>';
    echo '<td>' . t('Upload date') . '</td>';
    echo '<td>' . t('Origin') . '</td>';
    echo '<td>' . t('Action') . '</td>';
    echo '</tr>';

    /* Get all links files. */
    $stack = array (VAR_LINKS);
    while (($d = array_shift ($stack)) && $d != NULL)
    {
        $dir = scandir ($d);
        foreach ($dir as $node)
        {
            if (strcmp ($node, '.') == 0 || strcmp ($node, '..') == 0 ||
                preg_match ('/\.tmp/i', "$node"))
                continue;
            if (is_dir ($d . $node))
            {
                /* Push new found directory. */
                $stack[] = $d . $node . '/';
            }
            elseif (is_file ($d . $node))
            {
                /* Read link informations. */
                $l = jirafeau_get_link ($node);
                if (!count ($l))
                    continue;

                /* Filter. */
                if (!empty ($name) && !preg_match ("/$name/i", $l['file_name']))
                    continue;
                if (!empty ($file_hash) && $file_hash != $l['md5'])
                    continue;
                if (!empty ($link_hash) && $link_hash != $node)
                    continue;
                /* Print link informations. */
                echo '<tr>';
                echo '<td>' .
                '<form action = "admin.php" method = "post">' .
                '<input type = "hidden" name = "action" value = "download"/>' .
                '<input type = "hidden" name = "link" value = "' . $node . '"/>' .
                '<input type = "submit" value = "' . $l['file_name'] . '" />' .
                '</form>';
                echo '</td>';
                echo '<td>' . $l['mime_type'] . '</td>';
                echo '<td>' . jirafeau_human_size ($l['file_size']) . '</td>';
                echo '<td>' . ($l['time'] == -1 ? '' : strftime ('%c', $l['time'])) .
                     '</td>';
                echo '<td>' . $l['onetime'] . '</td>';
                echo '<td>' . strftime ('%c', $l['upload_date']) . '</td>';
                echo '<td>' . $l['ip'] . '</td>';
                echo '<td>' .
                '<form action = "admin.php" method = "post">' .
                '<input type = "hidden" name = "action" value = "delete_link"/>' .
                '<input type = "hidden" name = "link" value = "' . $node . '"/>' .
                '<input type = "submit" value = "' . t('Del link') . '" />' .
                '</form>' .
                '<form action = "admin.php" method = "post">' .
                '<input type = "hidden" name = "action" value = "delete_file"/>' .
                '<input type = "hidden" name = "md5" value = "' . $l['md5'] . '"/>' .
                '<input type = "submit" value = "' . t('Del file and links') . '" />' .
                '</form>' .
                '</td>';
                echo '</tr>';
            }
        }
    }
    echo '</table></fieldset>';
}

/**
 * Clean expired files.
 * @return number of cleaned files.
 */
function
jirafeau_admin_clean ()
{
    $count = 0;
    /* Get all links files. */
    $stack = array (VAR_LINKS);
    while (($d = array_shift ($stack)) && $d != NULL)
    {
        $dir = scandir ($d);

        foreach ($dir as $node)
        {
            if (strcmp ($node, '.') == 0 || strcmp ($node, '..') == 0 ||
                preg_match ('/\.tmp/i', "$node"))
                continue;
            
            if (is_dir ($d . $node))
            {
                /* Push new found directory. */
                $stack[] = $d . $node . '/';
            }
            elseif (is_file ($d . $node))
            {
                /* Read link informations. */
                $l = jirafeau_get_link (basename ($node));
                if (!count ($l))
                    continue;
                $p = s2p ($l['md5']);
                if ($l['time'] > 0 && $l['time'] < time () || // expired
                    !file_exists (VAR_FILES . $p . $l['md5']) || // invalid
                    !file_exists (VAR_FILES . $p . $l['md5'] . '_count')) // invalid
                {
                    jirafeau_delete_link ($node);
                    $count++;
                }
            }
        }
    }
    return $count;
}


/**
 * Clean old async transferts.
 * @return number of cleaned files.
 */
function
jirafeau_admin_clean_async ()
{
    $count = 0;
    /* Get all links files. */
    $stack = array (VAR_ASYNC);
    while (($d = array_shift ($stack)) && $d != NULL)
    {
        $dir = scandir ($d);

        foreach ($dir as $node)
        {
            if (strcmp ($node, '.') == 0 || strcmp ($node, '..') == 0 ||
                preg_match ('/\.tmp/i', "$node"))
                continue;
            
            if (is_dir ($d . $node))
            {
                /* Push new found directory. */
                $stack[] = $d . $node . '/';
            }
            elseif (is_file ($d . $node))
            {
                /* Read async informations. */
                $a = jirafeau_get_async_ref (basename ($node));
                if (!count ($a))
                    continue;
                /* Delete transferts older than 1 hour. */
                if (date ('U') - $a['last_edited'] > 3600)
                {
                    jirafeau_async_delete (basename ($node));
                    $count++;
                }
            }
        }
    }
    return $count;
}
/**
 * Read async transfert informations
 * @return array containing informations.
 */
function
jirafeau_get_async_ref ($ref)
{
    $out = array ();
    $refinfos = VAR_ASYNC . s2p ("$ref") . "$ref";

    if (!file_exists ($refinfos))
        return $out;
    
    $c = file ($refinfos);
    $out['file_name'] = trim ($c[0]);
    $out['mime_type'] = trim ($c[1]);
    $out['key'] = trim ($c[2], NL);
    $out['time'] = trim ($c[3]);
    $out['onetime'] = trim ($c[4]);
    $out['ip'] = trim ($c[5]);
    $out['last_edited'] = trim ($c[6]);
    $out['next_code'] = trim ($c[7]);
    return $out;
}

/**
 * Delete async transfert informations
  */
function
jirafeau_async_delete ($ref)
{
    $p = s2p ("$ref");
    if (file_exists (VAR_ASYNC . $p . $ref))
        unlink (VAR_ASYNC . $p . $ref);
    if (file_exists (VAR_ASYNC . $p . $ref . '_data'))
        unlink (VAR_ASYNC . $p . $ref . '_data');
    $parse = VAR_ASYNC . $p;
    $scan = array();
    while (file_exists ($parse)
           && ($scan = scandir ($parse))
           && count ($scan) == 2 // '.' and '..' folders => empty.
           && basename ($parse) != basename (VAR_ASYNC)) 
    {
        rmdir ($parse);
        $parse = substr ($parse, 0, strlen($parse) - strlen(basename ($parse)) - 1);
    }
}

/**
  * Init a new asynchronous upload.
  * @param $finename Name of the file to send
  * @param $one_time One time upload parameter
  * @param $key eventual password (or blank)
  * @param $time time limit
  * @param $ip ip address of the client
  * @return  a string containing a temporary reference followed by a code or the string "Error"
  */
function
jirafeau_async_init ($filename, $type, $one_time, $key, $time, $ip)
{
    $res = 'Error';

    /* Create temporary folder. */
    $ref;
    $p;
    $code = jirafeau_gen_random (4);
    do
    {
        $ref = jirafeau_gen_random (32);
        $p = VAR_ASYNC . s2p ($ref);
    } while (file_exists ($p));
    @mkdir ($p, 0755, true);
    if (!file_exists ($p))
    {
        echo "Error";
        return;
    }
    
    /* md5 password or empty */
    $password = '';
    if (!empty ($key))
        $password = md5 ($key);

    /* Store informations. */
    $p .= $ref;
    $handle = fopen ($p, 'w');
    fwrite ($handle,
            str_replace (NL, '', trim ($filename)) . NL .
            str_replace (NL, '', trim ($type)) . NL . $password . NL .
            $time . NL . ($one_time ? 'O' : 'R') . NL . $ip . NL .
            date ('U') . NL . $code . NL);
    fclose ($handle);

    return $ref . NL . $code ;
}

/**
  * Append a piece of file on the asynchronous upload.
  * @param $ref asynchronous upload reference
  * @param $file piece of data
  * @param $code client code for this operation
  * @param $max_file_size maximum allowed file size
  * @return  a string containing a next code to use or the string "Error"
  */
function
jirafeau_async_push ($ref, $data, $code, $max_file_size)
{
    /* Get async infos. */
    $a = jirafeau_get_async_ref ($ref);
    
    /* Check some errors. */
    if (count ($a) == 0
        || $a['next_code'] != "$code"
        || empty ($data['tmp_name'])
        || !is_uploaded_file ($data['tmp_name']))
        return "Error";
    
    $p = s2p ($ref);

    /* File path. */
    $r_path = $data['tmp_name'];
    $w_path = VAR_ASYNC . $p . $ref . '_data';

    /* Check that file size is not above upload limit. */
    if ($max_file_size > 0 &&
        filesize ($r_path) + filesize ($w_path) > $max_file_size * 1024 * 1024)
    {
        jirafeau_async_delete ($ref);
        return "Error";
    }

    /* Concatenate data. */
    $r = fopen ($r_path, 'r');
    $w = fopen ($w_path, 'a');
    while (!feof ($r))
    {
        if (fwrite ($w, fread ($r, 1024)) === false)
        {
            fclose ($r);
            fclose ($w);
            jirafeau_async_delete ($ref);
            return "Error";
        }
    }
    fclose ($r);
    fclose ($w);
    unlink ($r_path);
    
    /* Update async file. */
    $code = jirafeau_gen_random (4);
    $handle = fopen (VAR_ASYNC . $p . $ref, 'w');
    fwrite ($handle,
            $a['file_name'] . NL. $a['mime_type'] . NL. $a['key'] . NL .
            $a['time'] . NL . $a['onetime'] . NL . $a['ip'] . NL .
            date ('U') . NL . $code . NL);
    fclose ($handle);
    return $code;
}

/**
  * Finalyze an asynchronous upload.
  * @param $ref asynchronous upload reference
  * @param $code client code for this operation
  * @param $crypt boolean asking to crypt or not
  * @param $link_name_length link name length
  * @return  a string containing the download reference followed by a delete code or the string "Error"
  */
function
jirafeau_async_end ($ref, $code, $crypt, $link_name_length)
{
    /* Get async infos. */
    $a = jirafeau_get_async_ref ($ref);
    if (count ($a) == 0
        || $a['next_code'] != "$code")
        return "Error";
    
    /* Generate link infos. */
    $p = VAR_ASYNC . s2p ($ref) . $ref . "_data";
    if (!file_exists($p))
        return "Error";

    $crypted = false;
    $crypt_key = '';
    if ($crypt == true && extension_loaded('mcrypt') == true)
    {
        $crypt_key = jirafeau_encrypt_file ($p, $p);
        if (strlen($crypt_key) > 0)
            $crypted = true;
    }

    $md5 = md5_file ($p);
    $size = filesize($p);
    $np = s2p ($md5);
    $delete_link_code = jirafeau_gen_random (5);
    
    /* File already exist ? */ 
    if (!file_exists (VAR_FILES . $np))
        @mkdir (VAR_FILES . $np, 0755, true);
    if (!file_exists (VAR_FILES . $np . $md5))
        rename ($p, VAR_FILES . $np . $md5);
    
    /* Increment or create count file. */
    $counter = 0;
    if (file_exists (VAR_FILES . $np . $md5 . '_count'))
    {
        $content = file (VAR_FILES . $np . $md5. '_count');
        $counter = trim ($content[0]);
    }
    $counter++;
    $handle = fopen (VAR_FILES . $np . $md5. '_count', 'w');
    fwrite ($handle, $counter);
    fclose ($handle);
    
    /* Create link. */
    $link_tmp_name =  VAR_LINKS . $md5 . rand (0, 10000) . '.tmp';
    $handle = fopen ($link_tmp_name, 'w');
    fwrite ($handle,
            $a['file_name'] . NL . $a['mime_type'] . NL . $size . NL .
            $a['key'] . NL . $a['time'] . NL . $md5 . NL . $a['onetime'] . NL .
            date ('U') . NL . $a['ip'] . NL . $delete_link_code . NL . ($crypted ? 'C' : 'O'));
    fclose ($handle);
    $md5_link = substr(base_16_to_64 (md5_file ($link_tmp_name)), 0, $link_name_length);
    $l = s2p ("$md5_link");
    if (!@mkdir (VAR_LINKS . $l, 0755, true) ||
        !rename ($link_tmp_name,  VAR_LINKS . $l . $md5_link))
        echo "Error";
    
    /* Clean async upload. */
    jirafeau_async_delete ($ref);
    return $md5_link . NL . $delete_link_code . NL . urlencode($crypt_key);
}

function
jirafeau_crypt_create_iv($base, $size)
{
    $iv = '';
    while (strlen ($iv) < $size)
        $iv = $iv . $base;
    $iv = substr($iv, 0, $size);
    return $iv;
}

/**
 * Crypt file and returns decrypt key.
 * @param $fp_src file path to the file to crypt.
 * @param $fp_dst file path to the file to write crypted file (could be the same).
 * @return decrypt key composed of the key and the iv separated by a point ('.')
 */
function
jirafeau_encrypt_file ($fp_src, $fp_dst)
{
    $fs = filesize ($fp_src);
    if ($fs === false || $fs == 0 || !(extension_loaded('mcrypt') == true))
        return '';

    /* Prepare module. */
    $m = mcrypt_module_open('rijndael-256', '', 'ofb', '');
    /* Generate key. */
    $crypt_key = jirafeau_gen_random (10);
    $md5_key = md5($crypt_key);
    $iv = jirafeau_crypt_create_iv ($md5_key, mcrypt_enc_get_iv_size($m));
    /* Init module. */
    mcrypt_generic_init($m, $md5_key, $iv);
    /* Crypt file. */
    $r = fopen ($fp_src, 'r');
    $w = fopen ($fp_dst, 'c');
    while (!feof ($r))
    {
        $enc = mcrypt_generic($m, fread ($r, 1024));
        if (fwrite ($w, $enc) === false)
            return '';
    }
    fclose ($r);
    fclose ($w);
    /* Cleanup. */
    mcrypt_generic_deinit($m);
    mcrypt_module_close($m);
    return $crypt_key;
}

/**
 * Decrypt file.
 * @param $fp_src file path to the file to decrypt.
 * @param $fp_dst file path to the file to write decrypted file (could be the same).
 * @param $k string composed of the key and the iv separated by a point ('.')
 * @return key used to decrypt. a string of length 0 is returned if failed.
 */
function
jirafeau_decrypt_file ($fp_src, $fp_dst, $k)
{
    $fs = filesize ($fp_src);
    if ($fs === false || $fs == 0 || !(extension_loaded('mcrypt') == true))
        return false;

    /* Init module */
    $m = mcrypt_module_open('rijndael-256', '', 'ofb', '');
    /* Extract key and iv. */
    $crypt_key = $k;
    $md5_key = md5($crypt_key);
    $iv = jirafeau_crypt_create_iv ($md5_key, mcrypt_enc_get_iv_size($m));
    /* Decrypt file. */
    $r = fopen ($fp_src, 'r');
    $w = fopen ($fp_dst, 'c');
    while (!feof ($r))
    {
        $dec = mdecrypt_generic($m, fread ($r, 1024));
        if (fwrite ($w, $dec) === false)
            return false;
    }
    fclose ($r);
    fclose ($w);
    /* Cleanup. */
    mcrypt_generic_deinit($m);
    mcrypt_module_close($m);
    return true;
}

/**
 * Check if Jirafeau is password protected for visitors.
 * @return true if Jirafeau is password protected, false otherwise.
 */
function jirafeau_has_upload_password ($cfg)
{
    return count ($cfg['upload_password']) > 0;
}

/**
 * Challenge password for a visitor.
 * @param $password password to be challenged
 * @return true if password is valid, false otherwise.
 */
function jirafeau_challenge_upload_password ($cfg, $password)
{
    if (!jirafeau_has_upload_password($cfg))
        return false;
    forEach ($cfg['upload_password'] as $p)
        if ($password == $p)
            return true;
    return false;
}

/**
 * Test if visitor's IP is authorized to upload.
 * @param $ip IP to be challenged
 * @return true if IP is authorized, false otherwise.
 */
function jirafeau_challenge_upload_ip ($cfg, $ip)
{
    if (count ($cfg['upload_ip']) == 0)
        return true;
    forEach ($cfg['upload_ip'] as $i)
    {
        if ($i == $ip)
            return true;
        // CIDR test for IPv4 only.
        if (strpos ($i, '/') !== false)
        {
            list ($subnet, $mask) = explode('/', $i);
            if ((ip2long ($ip) & ~((1 << (32 - $mask)) - 1) ) == ip2long ($subnet))
                return true;
        }
    }
    return false;
}

/**
 * Get the ip address of the client from REMOTE_ADDR
 * or from HTTP_X_FORWARDED_FOR if behind a proxy
 * @returns an the client ip address
 */
function get_ip_address($cfg) {
    if (count ($cfg['proxy_ip']) == 0 ||
        empty ($_SERVER['HTTP_X_FORWARDED_FOR']))
        return $_SERVER['REMOTE_ADDR'];

    $iplist = explode (',', $_SERVER['HTTP_X_FORWARDED_FOR']);
    if (count ($iplist) == 0)
        return $_SERVER['REMOTE_ADDR'];

    foreach ($cfg['proxy_ip'] as $proxy_ip)
    {
        if ($_SERVER['REMOTE_ADDR'] != $proxy_ip)
            continue;

        // Take the last IP (the one which has been set by our proxy).
        $ip = end($iplist);
        $ip = preg_replace ('/\s+/', '', $ip);
        return $ip;
    }
    return $_SERVER['REMOTE_ADDR'];
}