[libcxx-commits] [PATCH] D94571: [libcxx] random_device, for OpenBSD specify optimal entropy properties

[Brad Smith via Phabricator via libcxx-commits]

brad created this revision.
brad added reviewers: ldionne, libc++.
brad added a project: libc++.
Herald added a subscriber: krytarowski.
brad requested review of this revision.
Herald added 1 blocking reviewer(s): libc++.

Submitting upstream from OpenBSD tree:

The random_device is an abstraction to the underlying OS PRNG. In OpenBSD's case, we know it has optimal entropy properties so specify what that is.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D94571

Files:
  libcxx/src/random.cpp


Index: libcxx/src/random.cpp
===================================================================
--- libcxx/src/random.cpp
+++ libcxx/src/random.cpp
@@ -33,6 +33,9 @@
 #include <nacl/nacl_random.h>
 #endif
 
+#ifdef __OpenBSD__
+#include <limits>
+#endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
@@ -172,7 +175,11 @@
 double
 random_device::entropy() const _NOEXCEPT
 {
+#ifdef __OpenBSD__
+    return std::numeric_limits<unsigned int>::digits;
+#else
     return 0;
+#endif
 }
 
 _LIBCPP_END_NAMESPACE_STD


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