util.random: Use /dev/urandom

1 files changed, 4 insertions, 24 deletions

diff --git a/util/random.lua b/util/random.lua
index 5938a94f..4963e98c 100644
--- 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 {