Internal/IdentificationHelper.php
public static function getListeningProcessId($socketAddress)
    {
        if (!self::isLocalAddress($socketAddress)) {
            return;
        }
        $lsofPath = self::findLsof();
        $unix = self::isUnixAddress($socketAddress);
        $lsofArgs = self::buildLsofArgs($socketAddress, $unix);
        exec(escapeshellarg($lsofPath).' '.$lsofArgs.' 2>/dev/null', $output, $exitCode);
        if ($exitCode !== 0 || $output === null) {
            return;
        }
        if ($unix) {
            return self::findProcessIdFromLsofOutput($output);
        } else {
            return self::findListeningProcessIdFromLsofOutput($output);
        }
    }
public static function getListeningProcessId($socketAddress)
    {
        if (!self::isLocalAddress($socketAddress)) {
            return;
        }
        $lsofPath = self::findLsof();
        $unix = self::isUnixAddress($socketAddress);
        $lsofArgs = self::buildLsofArgs($socketAddress, $unix);
        exec(escapeshellarg($lsofPath).' '.$lsofArgs.' 2>/dev/null', $output, $exitCode);
        if ($exitCode !== 0 || $output === null) {
            return;
        }
        if ($unix) {
            return self::findProcessIdFromLsofOutput($output);
        } else {
            return self::findListeningProcessIdFromLsofOutput($output);
        }
    }
@param string $socketAddress

@throws Exception\RuntimeException

@return int|null