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File: vendor/paragonie/random_compat/lib/random_bytes_dev_urandom.php

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File: vendor/paragonie/random_compat/lib/random_bytes_dev_urandom.php
Role: Example script
Content type: text/plain
Description: Example script
Class: PHP Pokemon Script
Provides an API to manage a database of Pokemons
Author: By
Last change:
Date: 1 year ago
Size: 5,440 bytes
 

 

Contents

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<?php
/**
 * Random_* Compatibility Library
 * for using the new PHP 7 random_* API in PHP 5 projects
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2015 - 2017 Paragon Initiative Enterprises
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

if (!defined('RANDOM_COMPAT_READ_BUFFER')) {
   
define('RANDOM_COMPAT_READ_BUFFER', 8);
}

if (!
is_callable('random_bytes')) {
   
/**
     * Unless open_basedir is enabled, use /dev/urandom for
     * random numbers in accordance with best practices
     *
     * Why we use /dev/urandom and not /dev/random
     * @ref http://sockpuppet.org/blog/2014/02/25/safely-generate-random-numbers
     *
     * @param int $bytes
     *
     * @throws Exception
     *
     * @return string
     */
   
function random_bytes($bytes)
    {
        static
$fp = null;
       
/**
         * This block should only be run once
         */
       
if (empty($fp)) {
           
/**
             * We use /dev/urandom if it is a char device.
             * We never fall back to /dev/random
             */
           
$fp = fopen('/dev/urandom', 'rb');
            if (!empty(
$fp)) {
               
$st = fstat($fp);
                if ((
$st['mode'] & 0170000) !== 020000) {
                   
fclose($fp);
                   
$fp = false;
                }
            }

            if (!empty(
$fp)) {
               
/**
                 * stream_set_read_buffer() does not exist in HHVM
                 *
                 * If we don't set the stream's read buffer to 0, PHP will
                 * internally buffer 8192 bytes, which can waste entropy
                 *
                 * stream_set_read_buffer returns 0 on success
                 */
               
if (is_callable('stream_set_read_buffer')) {
                   
stream_set_read_buffer($fp, RANDOM_COMPAT_READ_BUFFER);
                }
                if (
is_callable('stream_set_chunk_size')) {
                   
stream_set_chunk_size($fp, RANDOM_COMPAT_READ_BUFFER);
                }
            }
        }

        try {
           
$bytes = RandomCompat_intval($bytes);
        } catch (
TypeError $ex) {
            throw new
TypeError(
               
'random_bytes(): $bytes must be an integer'
           
);
        }

        if (
$bytes < 1) {
            throw new
Error(
               
'Length must be greater than 0'
           
);
        }

       
/**
         * This if() block only runs if we managed to open a file handle
         *
         * It does not belong in an else {} block, because the above
         * if (empty($fp)) line is logic that should only be run once per
         * page load.
         */
       
if (!empty($fp)) {
           
/**
             * @var int
             */
           
$remaining = $bytes;

           
/**
             * @var string|bool
             */
           
$buf = '';

           
/**
             * We use fread() in a loop to protect against partial reads
             */
           
do {
               
/**
                 * @var string|bool
                 */
               
$read = fread($fp, $remaining);
                if (!
is_string($read)) {
                    if (
$read === false) {
                       
/**
                         * We cannot safely read from the file. Exit the
                         * do-while loop and trigger the exception condition
                         *
                         * @var string|bool
                         */
                       
$buf = false;
                        break;
                    }
                }
               
/**
                 * Decrease the number of bytes returned from remaining
                 */
               
$remaining -= RandomCompat_strlen($read);
               
/**
                 * @var string|bool
                 */
               
$buf = $buf . $read;
            } while (
$remaining > 0);

           
/**
             * Is our result valid?
             */
           
if (is_string($buf)) {
                if (
RandomCompat_strlen($buf) === $bytes) {
                   
/**
                     * Return our random entropy buffer here:
                     */
                   
return $buf;
                }
            }
        }

       
/**
         * If we reach here, PHP has failed us.
         */
       
throw new Exception(
           
'Error reading from source device'
       
);
    }
}