prosody
396db0e7084f
util/random.lua

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util/random.lua @ 13136:396db0e7084f

mod_storage_internal: Use a binary search for time based ranges Iterating over an entire archive to find a few items in the far end from where iteration started is expensive, and probably more expensive with the lazy-loading of items added in the previous commit. Since we can now efficiently read items in random order, we can now use a binary search to find a better starting point for iteration.
author Kim Alvefur <zash@zash.se>
date Wed, 12 May 2021 01:32:03 +0200
parent 12975:d10957394a3c
line wrap: on
line source

-- 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";
};