prosody
ae044691de0f
util/random.lua

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util/random.lua @ 7050:ae044691de0f

util.random: Use /dev/urandom
author Kim Alvefur <zash@zash.se>
date Wed, 06 Jan 2016 03:28:56 +0100
parent 6421:c3011ab945b8
child 7083:ac920b0f9eae
comparison
equal deleted inserted replaced
7049:0eee56075901 7050:ae044691de0f
4 -- 4 --
5 -- This project is MIT/X11 licensed. Please see the 5 -- This project is MIT/X11 licensed. Please see the
6 -- COPYING file in the source package for more information. 6 -- COPYING file in the source package for more information.
7 -- 7 --
8 8
9 local tostring = tostring; 9 local urandom = assert(io.open("/dev/urandom", "r+"));
10 local os_time = os.time;
11 local os_clock = os.clock;
12 local ceil = math.ceil;
13 local H = require "util.hashes".sha512;
14
15 local last_uniq_time = 0;
16 local function uniq_time()
17 local new_uniq_time = os_time();
18 if last_uniq_time >= new_uniq_time then new_uniq_time = last_uniq_time + 1; end
19 last_uniq_time = new_uniq_time;
20 return new_uniq_time;
21 end
22
23 local function new_random(x)
24 return H(x..os_clock()..tostring({}));
25 end
26
27 local buffer = new_random(uniq_time());
28 10
29 local function seed(x) 11 local function seed(x)
30 buffer = new_random(buffer..x); 12 urandom:write(x);
13 urandom:flush();
31 end 14 end
32 15
33 local function bytes(n) 16 local function bytes(n)
34 if #buffer < n+4 then seed(uniq_time()); end 17 return urandom:read(n);
35 local r = buffer:sub(1, n);
36 buffer = buffer:sub(n+1);
37 return r;
38 end 18 end
39 19
40 return { 20 return {
41 seed = seed; 21 seed = seed;
42 bytes = bytes; 22 bytes = bytes;