prosody
f0b2c026e542
util/random.lua

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util/random.lua @ 13552:f0b2c026e542

net.server_epoll: Improve efficiency of sending much buffered data Problem: The string slice operations when a lot of data gets buffered ends up being expensive and memory-consuming. We have util.dbuffer for precisely this kind of thing. I want to keep the behavior of writebuffer being upgraded from nil to a string to full buffer since the last step involves three table allocations, where the previous buffer method only used one. Avoiding those allocations for simple writes like white space keep alive feels like it would keep memory churn down. This work was started in 2020
author Kim Alvefur <zash@zash.se>
date Sat, 09 Nov 2024 00:37:15 +0100
parent 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, "prosody.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";
};