<?php
$user = "daemon";
$script_name = "uid"; //numele scriptului

/////////////////////////////////////////////
//incercam sa creiem un socket daca nu ee root
echo "\n__________________________________________\n";
echo "Trying to start a socket as user $user\n";
$uid_name = posix_getpwnam($user);
$uid_name = $uid_name['uid'];

if(posix_seteuid($uid_name))
{
echo "SUCCESS: You are now $user!\n";
if($socket = @socket_create(AF_INET, SOCK_RAW, 1))
{
echo "SUCCESS: You are NOT root and created a socket! This should not happen!\n";
} else {
echo "ERROR: socket_create() failed because you're not root!\n";
}
$show_process = shell_exec("ps aux | grep -v grep | grep $script_name");
echo "Current process stats::-->\t $show_process";
} else {
exit("ERROR: seteuid($uid_name) failed!\n");
}

/////////////////////////////////////////////
//acuma incercam sa creiem un socket ca root
echo "\n__________________________________________\n";
echo "Trying to start a socket as user 'root'\n";
if(posix_seteuid(0)) // 0 inseamna sa fii root  //
{
echo "SUCCESS: You are now root!\n";
$show_process = shell_exec("ps aux | grep -v grep | grep $script_name");
echo "Current process stats::-->\t $show_process";
if($socket = @socket_create(AF_INET, SOCK_RAW, 1))
{
echo "SUCCESS: You created a socket as root and now should seteuid() to another user\n";
/////////////////////////////////////////
//acuma modificam socketu pt alt user
echo "\n__________________________________________\n";
echo "Switching to user $user\n";
if(posix_seteuid($uid_name))
{
echo "SUCCESS: You are now $user!\n";
if(socket_bind($socket, 0, 7410))
{
echo "SUCCESS: socket_bind() worked as $user!\n";
} else {
echo "ERROR: Must be root to user socket_bind()\n";
}
$show_process = shell_exec("ps aux | grep -v grep | grep $script_name");
echo "Current process stats::-->\t $show_process";
socket_close($socket); //hard to error check but it does close as this user
echo "SUCCESS: You closed the socket as user $user!\n";
} else {
echo "ERROR: seteuid($uid_name) failed while socket was open!\n";
}

} else {
echo "ERROR: Socket failed for some reason!\n";
}
} else {
exit("ERROR: Changing to root failed!\n");
}
?>