Run PHP command in Centos 7 via shell_exec()

Question

I’m starting in PHP, I want to make a page that triggers some commands on the Linux server. (Ex.: through a button, run a "service dhcpd Restart" or ". /Restart-Tomcat.sh" When I run this application in xampp (Windows), it works well, I open the calculator, notepad and even throw a ping inside a div, as can below.

But when I put there in Linux Centos7 in /var/www/html that field where the ping should appear is empty and no other command is executed.

I already gave the permissions to apache there in the /etc/sudoers.

It will be something specific that needs to change in code to run on Linux?

[HTML] Server Test div { width: 500px; height: 200px; border: Solid black; margin: 100px; }

    img{
        max-width: 500px;
        max-height: 200px;
    }
</style>

<button type="button" id="btn" onclick="geral()">Ping</button>

<div id="campo"></div>



<script>
    function geral() {

var xhttp = new XMLHttpRequest();
var campo = document.getElementById('campo');

xhttp.open("POST", "script.php", false);
xhttp.send();
// console.log(xhttp.responseText);
resposta = xhttp.responseText;

campo.innerHTML = resposta;

} 
</script>

[PHP]

**

header('Content-Type: text/html; charset=utf-8');

$result = shell_exec('ping -C4 www.google.com');

echo '

'.$result.'

';

?>

Answer 1

Sometimes I use shell_exec + php, but more in Debian-derived systems. To work properly, I often need to configure the permissions of the user that php uses, I think it is the www-data user in debian derivatives. Anyway use:

$result = shell_exec('whoami');

So you should find out which user php is using and then just give the necessary permissions, if applicable.