Foro de elhacker.net

<?php
session_start();
$password['prueba']="c893bad68927b457dbed39460e6afd62";
if(isset($_GET['u'])){
   if($password[$_GET['u']]==md5($_GET['p'])){
      $_SESSION['login']=$_GET['u'];
      header("location: main.php");
   }
}
?>
Error

<form action="login.php">
Usuario:<input type=text name=u>
Pass:<input type=password name=p>
<input type=submit>
</form>

<?php
session_start();
if(isset($_SESSION['login'])){
echo "tu eres {$_SESSION['login']}.";
exit;
}
?>
Error

arning: session_start() [function.session-start]: Cannot send session cookie - headers already sent by (output started at /usr/local/apache2/htdocs/sistema/index.php:16) in /usr/local/apache2/htdocs/sistema/index.php on line 28

Warning: Cannot modify header information - headers already sent by (output started at /usr/local/apache2/htdocs/sistema/index.php:16) in /usr/local/apache2/htdocs/sistema/logIn.php on line 27
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