util/random.lua

   1 -- Prosody IM
   2 -- Copyright (C) 2008-2014 Matthew Wild
   3 -- Copyright (C) 2008-2014 Waqas Hussain
   4 --
   5 -- This project is MIT/X11 licensed. Please see the
   6 -- COPYING file in the source package for more information.
   7 --
   8
   9 local ok, crand = pcall(require, "util.crand");
  10 if ok then return crand; end
  11
  12 local urandom, urandom_err = io.open("/dev/urandom", "r");
  13
  14 local function bytes(n)
  15         local data, err = urandom:read(n);
  16         if not data then
  17                 if err then
  18                         error("Unable to retrieve data from secure random number generator (/dev/urandom): "..tostring(err));
  19                 else
  20                         error("Secure random number generator (/dev/urandom) returned an end-of-file condition");
  21                 end
  22         end
  23         return data;
  24 end
  25
  26 if not urandom then
  27         function bytes()
  28                 error("Unable to obtain a secure random number generator, please see https://prosody.im/doc/random ("..urandom_err..")");
  29         end
  30 end
  31
  32 return {
  33         bytes = bytes;
  34         _source = "/dev/urandom";
  35 };