PHP文件上传错误
我用这个代码在WINDOWS上传文件成功，但到LINUX下失败了，请帮我看看什么原因，以下是代码：

————u1.htm————
<form enctype="multipart/form-data" name = "submitform" action="u1.php" method="post">
<input type="hidden" name="max_file_size" value="50000000">
<input type = "hidden" name = "uploadaction" value = "1">
upfile
<input name="userfile" type="file" size="30">

<input name="submit" value="submit" type="submit">
<input name="reset" value="replace" type="reset">
</form>

————u1.php————
<?

$uploadaction=0;
$timelimit=0;
set_time_limit($timelimit);

$uploaddir = '/root/file/';
$uploadfile = $uploaddir.$_FILES['userfile']['name'];
$tmpfile = $_FILES['userfile']['tmp_name'];
$file_size = $_FILES['userfile']['size'];
$errno = $_FILES['userfile']['error'];
echo "The uploadfile is $uploadfile";
echo "The tmpfile is $tmpfile";

  if(!file_exists($uploadfile))
  {
  if(move_uploaded_file($tmpfile,$uploadfile))
  {
  echo "The file $uploadfile($strfilesize)upload successful!";
  }
  else
  {
  echo"The file$uploadfile upload failed(error code:$errno)";
  }


  }


  set_time_limit(30);

?>

运行后错误是：upload failed(error code:0) 


------解决方案--------------------
你的程序没有问题，应当是php.ini配置文件的问题。
------解决方案--------------------
chmod($uploaddir,"777")
文件权限.....
------解决方案--------------------
$errno = $_FILES['userfile']['error'];
其值为 0，没有错误发生，文件上传成功。


你看下move_uploaded_file($tmpfile,$uploadfile)里面的参数路径是否正确，且有读写权限
------解决方案--------------------
/tmp有空间吗？
selinux是否关掉？