PHP script wouldn't work

Question

Basically, I want to run below script locally in order start stop restart and get status of service. And it must show output of each command button. I am using php 5.6 in order to run this code.

Below is the code:

<?php
    // define cmds
    $commands = [
    'stop_apache' => [
        'description' => 'Stop Apache2',
        'cmd' => 'systemctl stop apache2'
    ],
    'restart_apache' => [
        'description' => 'Restart Apache2',
        'cmd' => 'systemctl restart apache2'
    ],
    'start_apache' => [
        'description' => 'Start Apache2',
        'cmd' => 'systemctl start apache2'
    ],
    'status_apache' => [
        'description' => 'Status Apache2',
        'cmd' => 'systemctl status apache2'
    ],
    ];

    // handle post
    if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $error = [];
    $result = '';

    // validate input
    if (empty($_POST['service'])) {
        $error = [
            'service' => 'Service type required!'    
        ];
    } elseif (!array_key_exists($_POST['service'], $commands)) {
        $error = [
            'service' => 'Invalid Service!'    
        ];
    }
    }
    ?>
    <form action="" method="post">
    <?php if (!empty($error)): ?>
    <h3>Error</h3>
    <pre><?= print_r($error, true) ?></pre>
    <?php endif ?>
    <?php foreach ($commands as $key => $command): ?>
    <button type="submit" name="service" value="<?= $key ?>"><?= 
    $command['description'] ?></button>
    <?php endforeach ?>
    </form>
   <?php if (!empty($result)): ?>
   <pre><?= print_r($result, true) ?></pre>
   <?php endif ?>

Answer 1

You are most likely going to encounter permission issues because the web server user www-data, will not have permissions to restart the service.

So unless you allow that, it's not going to work. The previous code which works is because you are logging in over SSH with root user.

Ok so if you did add allow www-data to restart the service, your code would be like the following. By using exec() to execute the cmd.

<?php
// define cmds
$commands = [
    'stop_apache' => [
        'description' => 'Stop Apache2',
        'cmd' => 'systemctl stop apache2'
    ],
    'restart_apache' => [
        'description' => 'Restart Apache2',
        'cmd' => 'systemctl restart apache2'
    ],
    'start_apache' => [
        'description' => 'Start Apache2',
        'cmd' => 'systemctl start apache2'
    ],
    'status_apache' => [
        'description' => 'Status Apache2',
        'cmd' => 'systemctl status apache2'
    ],
];

// handle post
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $error = [];
    $result = '';

    // validate input
    if (empty($_POST['service'])) {
        $error = [
            'service' => 'Service type required!'    
        ];
    } elseif (!array_key_exists($_POST['service'], $commands)) {
        $error = [
            'service' => 'Invalid Service!'    
        ];
    }

    if (empty($error)) {
        exec($commands[$_POST['service']]['cmd'], $output, $status_code);
        if ($status_code === 0) {
            $result = 'Service restarted';
        } else {
            $error = 'Could not restart service! Status code: '.$status_code;
        }
    }
}
?>
<form action="" method="post">
    <?php if (!empty($error)): ?>
    <h3>Error</h3>
    <pre><?= print_r($error, true) ?></pre>
    <?php endif ?>
    <?php foreach ($commands as $key => $command): ?>
    <button type="submit" name="service" value="<?= $key ?>"><?= $command['description'] ?></button>
    <?php endforeach ?>
</form>

<?php if (!empty($result)): ?>
<pre><?= print_r($result, true) ?></pre>
<?php endif ?>
</form>

You will notice it will fail with Could not restart service! Status code: 1 - Because www-data wont have permissions. You should read https://serverfault.com/questions/69847/linux-how-to-give-a-user-permission-to-restart-apache on how to fix that, also be aware it opens up the possibility of bad code constantly restarting apache and DOSing.

Personally, I would not do it directly as you want to do, but instead set up a task which is run by root user, and you place the operations (restart, stop etc) in a queue to run.

Hope that helps.

Answer 2

// handle post
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
$error = [];
$result = '';

// validate input
if (empty($_POST['service'])) {
    $error = [
        'service' => 'Service type required!'    
    ];
} elseif (!array_key_exists($_POST['service'], $commands)) {
    $error = [
        'service' => 'Invalid Service!'    
    ];
}
//you need add this line
else $result = $commands[$_POST['service']];
}