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| <?php
/**
* Pings a given host and returns a red or green image.
* Green when the host is online, red when offline.
*
* Error: ping: socket: Operation not permitted
* (raw socket required by specified options).
*
* Solution:
* $ chmod +s /path/to/ping
* Alternative:
* $ setcap cap_net_raw+ep /path/to/ping
* Alternative:
* make it passwordless sudo
*
* Keywords: http image ping online check
*
* @author Christian Weiske <weiske@mogic.com>
*/
if (!isset($_GET['host'])) {
sendError('Host missing');
}
$host = $_GET['host'];
if ($host == '') {
sendError('Empty host');
}
if (!isset($_GET['size'])) {
$size = 100;
} else {
$size = intval($_GET['size']);
}
exec('ping -c 1 -w 1 -W 1 ' . escapeshellarg($host) . ' 2>&1', $output, $retval);
if ($retval == 0) {
//all fine
sendSvg($size, 'fill: green');
} else if ($retval == 1) {
//no reply
sendSvg($size, 'fill: red');
} else {
//some other error, e.g. permissions
header('HTTP/1.0 500 Internal server error');
header('Content-type: text/plain');
echo implode("\n", $output) . "\n";
}
function sendSvg($size, $style)
{
$half = intval($size / 2);
header('HTTP/1.0 200 OK');
header('Content-type: image/svg+xml');
echo '<' . '?xml version="1.0"?>' . "\n";
echo <<<XML
<svg xmlns="http://www.w3.org/2000/svg" width="$size" height="$size">
<circle cx="$half" cy="$half" r="$half" style="$style"/>
</svg>
XML;
}
function sendError($msg)
{
header('HTTP/1.0 400 Bad Request');
header('Content-type: text/plain');
echo $msg . "\n";
exit(1);
}
?>
|
