Security package watcher in PHP

sec-watcher.php

<?php

/**
 * This script checks for security updates in the server and
 * it's expected to be scheduled for a daily run.
 *
 * It will notify the $notify address if one or more security
 * package updates are found.
 */

function exceptionErrorHandler($errNo, $errStr, $errFile, $errLine ) {
    if (error_reporting() == 0) {
        // @ sign temporary disabled error reporting
        return;
    }

    throw new ErrorException($errStr, 0, $errNo, $errFile, $errLine);
} // exceptionErrorHandler

set_error_handler("exceptionErrorHandler");

// Who is sending the notification
$sender = '[email protected]';

// To who the notification will be sent
$notify = '[email protected]';

// Give a name to identify your server. Usually the hostname.
$server = 'domain.tld'; 

// What mounted disk should be checked
$mountedDisk = '/dev/sda'; # '/dev/disk1s1' when macOS;

// What's the maximum usage before sending a notification for disk over usage
$diskUsageBoundary = 80; # %

// #############################################
// ### DON'T CHANGE ANYTHING FROM THIS POINT ###
// ### UNLESS YOU KNOW WHAT YOU'RE DOING     ###
// #############################################

// If this file exist, a reboot is required
$reboot = file_exists('/var/run/reboot-required');

$matches = [];

// Gather info about available updates
// $note    = @file_get_contents('/var/lib/update-notifier/updates-available');
// $note    = preg_replace("/\n/", " ", $note);

try {
    // Gather info about available updates
    $note = file_get_contents('/var/lib/update-notifier/updates-available');
    $note = preg_replace("/\n/", " ", $note);
    
    // Gather info about disk usage
    $res = exec("df -h | grep {$mountedDisk}");
    $res = preg_replace('/\s{2,}/', ' ', $res);

    $intUsedRate = 0;
    $usedRate    = null;

    if (!empty($res) && $res) {
        list($mountPoint, $totalSize, $usedSpace, $freeSpace, $usedRate) = explode(' ', $res);
        $intUsedRate = (int) preg_replace('/[^0-9]/i', '', $usedRate);
    }

    // Clear used rate when not passed the boundary
    if ($diskUsageBoundary > $intUsedRate) {
        $usedRate = null;
    }

    // Set a flag to control whether to send or not send a notification
    $shouldNotify = (bool) (preg_match("/\d+\supdates?/i", $note, $matches) || !empty($usedRate) || $reboot);

    // Notify when needed
    if ($shouldNotify) {
        $headers = "From: {$sender} \n";

        $body = [
            "This is an automated message. \n",
        ];

        $count = (int) preg_replace("/[^0-9]/i", '', $matches[0]);

        if ($count) {
            $body[] = "{$count} pending security updates has been found.";
        }

        if (!empty($usedRate)) {
            $body[] = "{$mountedDisk} is {$usedRate} used. Needs an urgent review.";
            $body[] = "As general it is like: ";

            exec("df -h", $out);
            $body[] = "\t" . implode("\n\t", $out);
        }

        if ($reboot) {
            $body[] = "** A reboot is required. **";
        }

        $body[] = "Please review the '{$server}' server ASAP.";

        // echo implode("\n", $body) . "\n";
        mail($notify, "Server '{$server}' Pending Review", implode("\n", $body) . "\n", $headers, "-f {$sender}");

        // For automated updates, if there're security package updates
        // it can be automatically ran with :
        //    sudo unattended-upgrade -d # verbose or
        //    sudo unattended-upgrade    # quitely
    }
} cacth(Exception $e) {
    $body = "Error Code: {$e->getCode()}\n\nDescription: {$e->getMessage()}\n";
    mail($notify, "Server '{$server}' updates review failed", $body, $headers, "-f {$sender}");
}

echo "Daily updates review complete. \n";

Hey @MESWEB! Thank you for contributing and sharing the link, now I few the comment is way more constructive! ;) I'm updating the Gist with an implementation that doesn't use the @. 🍻 R.