Avoid blocking more than 100 ms in the random device reader. Scale up

how much we ask for on the basis of how many bits we're counting each
byte as contributing. Change /dev/*random estimate to 7 bits per byte.

Small cleanup in HMAC_RNG.

1 files changed, 2 insertions, 1 deletions

diff --git a/src/rng/hmac_rng/hmac_rng.cpp b/src/rng/hmac_rng/hmac_rng.cpp
index 55503382a..74ba522a4 100644
--- a/src/rng/hmac_rng/hmac_rng.cpp
+++ b/src/rng/hmac_rng/hmac_rng.cpp
@@ -75,7 +75,8 @@ void HMAC_RNG::reseed(size_t poll_bits)
 
       while(!accum.polling_goal_achieved() && poll_attempt < poll_bits)
          {
-         entropy_sources[poll_attempt % entropy_sources.size()]->poll(accum);
+         const size_t src_idx = poll_attempt % entropy_sources.size();
+         entropy_sources[src_idx]->poll(accum);
          ++poll_attempt;
          }
       }