Move tailLog function into own file

scripts/pi-hole/php/tailLog.php

@@ -0,0 +1,35 @@
+<?php
+/* Pi-hole: A black hole for Internet advertisements
+*  (c) 2017 Pi-hole, LLC (https://pi-hole.net)
+*  Network-wide ad blocking via your own hardware.
+*
+*  This file is copyright under the latest version of the EUPL.
+*  Please see LICENSE file for your rights under this license. */
+
+require "password.php";
+if(!$auth) die("Not authorized");
+
+// Not using SplFileObject here, since direct
+// usage of f-streams will be much faster for
+// files as large as the pihole.log
+$file = fopen("/var/log/pihole.log","r");
+if(isset($_GET["offset"]))
+{
+	$offset = intval($_GET['offset']);
+	if($offset > 0)
+	{
+		// Seeks on the file pointer where we want to continue reading is known
+		fseek($file, $offset);
+		$lines = [];
+		while (!feof($file))
+			array_push($lines,fgets($file));
+		die(json_encode(array("offset" => ftell($file), "lines" => $lines)));
+	}
+}
+
+// Locate the current position of the file read/write pointer
+fseek($file, -1, SEEK_END);
+// Add one to skip the very last "\n" in the log file
+die(json_encode(array("offset" => ftell($file)+1)));
+
+?>