public function Archive_Tar::_readHeader

Parameters

mixed $v_binary_data:

mixed $v_header:

Return value

bool:

File

modules/system/system.tar.inc, line 1728

Class

Archive_Tar

Code

public function _readHeader($v_binary_data, &$v_header) 
 {
  if (strlen($v_binary_data) == 0) {
    $v_header['filename'] = '';
    return true;
  }

  if (strlen($v_binary_data) != 512) {
    $v_header['filename'] = '';
    $this->_error('Invalid block size : ' . strlen($v_binary_data));
    return false;
  }

  if (!is_array($v_header)) {
    $v_header = array();
  }
  // ----- Calculate the checksum
  $v_checksum = 0;
  // ..... First part of the header
  $v_binary_split = str_split($v_binary_data);
  $v_checksum += array_sum(array_map('ord', array_slice($v_binary_split, 0, 148)));
  $v_checksum += array_sum(array_map('ord', array(' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ',)));
  $v_checksum += array_sum(array_map('ord', array_slice($v_binary_split, 156, 512)));

  $v_data = unpack($this->_fmt, $v_binary_data);

  if (strlen($v_data["prefix"]) > 0) {
    $v_data["filename"] = "$v_data[prefix]/$v_data[filename]";
  }

  // ----- Extract the checksum
  $v_data_checksum = trim($v_data['checksum']);
  if (!preg_match('/^[0-7]*$/', $v_data_checksum)) {
    $this->_error(
    'Invalid checksum for file "' . $v_data['filename']
      . '" : ' . $v_data_checksum . ' extracted'
      );
    return false;
  }

  $v_header['checksum'] = OctDec($v_data_checksum);
  if ($v_header['checksum'] != $v_checksum) {
    $v_header['filename'] = '';

    // ----- Look for last block (empty block)
    if (($v_checksum == 256) && ($v_header['checksum'] == 0)) {
      return true;
    }

    $this->_error(
    'Invalid checksum for file "' . $v_data['filename']
      . '" : ' . $v_checksum . ' calculated, '
      . $v_header['checksum'] . ' expected'
      );
    return false;
  }

  // ----- Extract the properties
  $v_header['filename'] = rtrim($v_data['filename'], "\0");
  if ($this->_isMaliciousFilename($v_header['filename'])) {
    $this->_error(
    'Malicious .tar detected, file "' . $v_header['filename'] .
      '" will not install in desired directory tree'
      );
    return false;
  }
  $v_header['mode'] = OctDec(trim($v_data['mode']));
  $v_header['uid'] = OctDec(trim($v_data['uid']));
  $v_header['gid'] = OctDec(trim($v_data['gid']));
  $v_header['size'] = $this->_tarRecToSize($v_data['size']);
  $v_header['mtime'] = OctDec(trim($v_data['mtime']));
  if (($v_header['typeflag'] = $v_data['typeflag']) == "5") {
    $v_header['size'] = 0;
  }
  $v_header['link'] = trim($v_data['link']);
  /* ----- All these fields are removed form the header because
        they do not carry interesting info
        $v_header[magic] = trim($v_data[magic]);
        $v_header[version] = trim($v_data[version]);
        $v_header[uname] = trim($v_data[uname]);
        $v_header[gname] = trim($v_data[gname]);
        $v_header[devmajor] = trim($v_data[devmajor]);
        $v_header[devminor] = trim($v_data[devminor]);
        */

  return true;
}