util.random: Use /dev/urandom

diff --git a/util/random.lua b/util/random.lua
index 5938a94f820ac4e3379c1f56594d3abe07810a15..4963e98c5645268f196c3d98858e1ccc5a7cc8bd 100644 (file)
--- a/util/random.lua
+++ b/util/random.lua
@@ -6,35 +6,15 @@
 -- COPYING file in the source package for more information.
 --
 
-local tostring = tostring;
-local os_time = os.time;
-local os_clock = os.clock;
-local ceil = math.ceil;
-local H = require "util.hashes".sha512;
-
-local last_uniq_time = 0;
-local function uniq_time()
-       local new_uniq_time = os_time();
-       if last_uniq_time >= new_uniq_time then new_uniq_time = last_uniq_time + 1; end
-       last_uniq_time = new_uniq_time;
-       return new_uniq_time;
-end
-
-local function new_random(x)
-       return H(x..os_clock()..tostring({}));
-end
-
-local buffer = new_random(uniq_time());
+local urandom = assert(io.open("/dev/urandom", "r+"));
 
 local function seed(x)
-       buffer = new_random(buffer..x);
+       urandom:write(x);
+       urandom:flush();
 end
 
 local function bytes(n)
-       if #buffer < n+4 then seed(uniq_time()); end
-       local r = buffer:sub(1, n);
-       buffer = buffer:sub(n+1);
-       return r;
+       return urandom:read(n);
 end
 
 return {