From 0377fd88d420e03197e5428a2b4e283682c18cd1 Mon Sep 17 00:00:00 2001
From: Matthew Parkinson <mattpark@microsoft.com>
Date: Sun, 28 Mar 2021 20:31:49 +0100
Subject: [PATCH] Improve BSDs support.

---
 src/mem/entropy.h       |  1 +
 src/pal/pal_dragonfly.h | 13 +++++++++++++
 src/pal/pal_netbsd.h    |  7 ++++++-
 3 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/src/mem/entropy.h b/src/mem/entropy.h
index 359e185..17b69a2 100644
--- a/src/mem/entropy.h
+++ b/src/mem/entropy.h
@@ -1,4 +1,5 @@
 #include "../ds/address.h"
+#include "../pal/pal.h"
 
 #include <cstdint>
 #include <random>
diff --git a/src/pal/pal_dragonfly.h b/src/pal/pal_dragonfly.h
index f0c3daf..5b572d9 100644
--- a/src/pal/pal_dragonfly.h
+++ b/src/pal/pal_dragonfly.h
@@ -25,6 +25,19 @@ namespace snmalloc
      * to add new features that they should add any required feature flags.
      */
     static constexpr uint64_t pal_features = PALPOSIX::pal_features;
+
+    /**
+     * Source of Entropy
+     *
+     * DragonflyBSD does not have getentropy, so use getrandom instead.
+     */
+    static uint64_t get_entropy64()
+    {
+      uint64_t result;
+      if (getrandom(&result, sizeof(result), 0) != sizeof(result))
+        error("Failed to get system randomness");
+      return result;
+    }
   };
 } // namespace snmalloc
 #endif
diff --git a/src/pal/pal_netbsd.h b/src/pal/pal_netbsd.h
index d6ebf71..ee1d566 100644
--- a/src/pal/pal_netbsd.h
+++ b/src/pal/pal_netbsd.h
@@ -22,8 +22,13 @@ namespace snmalloc
      * generic BSD with support for arbitrary alignment from `mmap`.  This
      * field is declared explicitly to remind anyone modifying this class to
      * add new features that they should add any required feature flags.
+     *
+     * We disable the default implementation of randomness on NetBSD as it
+     * does not have the getentropy call. This will currently fallback to
+     * C++ libraries std::random_device.
      */
-    static constexpr uint64_t pal_features = PALBSD_Aligned::pal_features;
+    static constexpr uint64_t pal_features =
+      PALBSD_Aligned::pal_features & ~Entropy;
   };
 } // namespace snmalloc
 #endif