add compatibility functions to server/ environment

Author: jnorell

server/lib/app.inc.php

@@ -27,6 +27,8 @@
 EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
+require_once 'compatibility.inc.php';
+
 // Set timezone
 if(isset($conf['timezone']) && $conf['timezone'] != '') {	// note: !empty($conf['timezone']) should give the same result and is more idiomatic for current versions of PHP (gwyneth 20220315)
 	date_default_timezone_set($conf['timezone']);

server/lib/compatibility.inc.php

@@ -0,0 +1,80 @@
+<?php
+
+/*
+Copyright (c) 2021, Jesse Norell <jesse@kci.net>
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without modification,
+are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright notice,
+      this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright notice,
+      this list of conditions and the following disclaimer in the documentation
+      and/or other materials provided with the distribution.
+    * Neither the name of ISPConfig nor the names of its contributors
+      may be used to endorse or promote products derived from this software without
+      specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/* random_bytes can be dropped when php 5.6 support is dropped */
+if (! function_exists('random_bytes')) {
+	function random_bytes($length) {
+		return openssl_random_pseudo_bytes($length);
+	}
+}
+
+/* random_int can be dropped when php 5.6 support is dropped */
+if (! function_exists('random_int')) {
+	function random_int($min=null, $max=null) {
+		if (null === $min) {
+			$min = PHP_INT_MIN;
+		}
+
+		if (null === $max) {
+			$min = PHP_INT_MAX;
+		}
+
+		if (!is_int($min) || !is_int($max)) {
+			trigger_error('random_int: $min and $max must be integer values', E_USER_NOTICE);
+			$min = (int)$min;
+			$max = (int)$max;
+		}
+
+		if ($min > $max) {
+			trigger_error('random_int: $max can\'t be lesser than $min', E_USER_WARNING);
+			return null;
+		}
+
+		$range = $counter = $max - $min;
+		$bits = 1;
+
+		while ($counter >>= 1) {
+			++$bits;
+		}
+
+		$bytes = (int)max(ceil($bits/8), 1);
+		$bitmask = pow(2, $bits) - 1;
+
+		if ($bitmask >= PHP_INT_MAX) {
+			$bitmask = PHP_INT_MAX;
+		}
+
+		do {
+			$result = hexdec(bin2hex(random_bytes($bytes))) & $bitmask;
+		} while ($result > $range);
+
+		return $result + $min;
+	}
+}