prosody
d26eefe98d09
util/random.lua

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util/random.lua @ 12763:d26eefe98d09

util.dbuffer: Add efficient shortcuts for discard() in certain cases If the buffer is already empty, nothing to do. If we're throwing away the whole buffer, we can just empty it and avoid read_chunk() (which in turn may collapse()). These shortcuts are much more efficient.
author Matthew Wild <mwild1@gmail.com>
date Tue, 11 Oct 2022 11:37:55 +0100
parent 12446:e54b8a5e35ad
child 12975:d10957394a3c
line wrap: on
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-- Prosody IM
-- Copyright (C) 2008-2014 Matthew Wild
-- Copyright (C) 2008-2014 Waqas Hussain
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--

local ok, crand = pcall(require, "util.crand");
if ok and pcall(crand.bytes, 1) then return crand; end

local urandom, urandom_err = io.open("/dev/urandom", "r");

local function bytes(n)
	local data, err = urandom:read(n);
	if not data then
		if err then
			error("Unable to retrieve data from secure random number generator (/dev/urandom): "..tostring(err));
		else
			error("Secure random number generator (/dev/urandom) returned an end-of-file condition");
		end
	end
	return data;
end

if not urandom then
	function bytes()
		error("Unable to obtain a secure random number generator, please see https://prosody.im/doc/random ("..urandom_err..")");
	end
end

return {
	bytes = bytes;
	_source = "/dev/urandom";
};