$st */ $st = fstat($fp); if (($st['mode'] & 0170000) !== 020000) { fclose($fp); $fp = false; } } } if (is_resource($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 { /** @var int $bytes */ $bytes = RandomCompat_intval($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($fp)) line is logic that should only be run once per * page load. */ if (is_resource($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)) { /** * 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 $buf */ $buf .= $read; } while ($remaining > 0); /** * Is our result valid? * @var string|bool $buf */ if (is_string($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' ); } }