Permission denied warning on unlink - php

Question

I am trying to a delete file selected using a dropdown. I am getting an error 'undefined index "file"' and permission denied warning on unlink.
<?php
$dirname = $_SERVER['DOCUMENT_ROOT']."myphp/project/userdir/neeraj/";
$dir = opendir($dirname);
echo '<form action="delete.php" method="get">';
echo '<select name="file2">';
while(false != ($file = readdir($dir)))
{
if(($file != ".") and ($file != ".."))
{
echo "<option value=".$file.">$file</option>";
}
}
echo '</select>';
echo '<input type="submit" value="Delete" class="submit" />';
echo '</form>';?>
<?php
$dirpath = $_SERVER['DOCUMENT_ROOT']."myphp/project/userdir/neeraj/";
$file_to_delete = $_GET['file2'];
if ( unlink ($dirpath.'/'.$file_to_delete) ) {
echo $file_to_delete . " deleted.";
} else {
echo "Error.";
}
?>

Answer 1

Note that your $dirpath ends with / and later you are trying to unlink:
unlink ($dirpath.'/'.$file_to_delete)
so it actualy gets something like this (note double slash):
[...] myphp/project/userdir/neeraj//$file_to_delete [...]
You should check file permissions to be sure that script has a right to unlink your files:
https://en.wikipedia.org/wiki/File_system_permissions

Answer 2

I guess you get the first error because you do not wrap your code to be executed only on form submit. Change the second section of your code to this:
<?php
if(isset($_GET['file2'])){ //i have posted my form
$dirpath = $_SERVER['DOCUMENT_ROOT']."myphp/project/userdir/neeraj/";
$file_to_delete = $_GET['file2'];
if ( unlink ($dirpath.'/'.$file_to_delete) ) {
echo $file_to_delete . " deleted.";
} else {
echo "Error.";
}
}
?>
The other error is related to the apache user to be able or not to access and delete in the directory where you store the files.