update ceph source to reef 18.1.2

[ceph.git] / ceph / src / jaegertracing / opentelemetry-cpp / sdk / src / common / random.cc

diff --git a/ceph/src/jaegertracing/opentelemetry-cpp/sdk/src/common/random.cc b/ceph/src/jaegertracing/opentelemetry-cpp/sdk/src/common/random.cc
new file mode 100644 (file)
index 0000000..77b88cf
--- /dev/null
+++ b/ceph/src/jaegertracing/opentelemetry-cpp/sdk/src/common/random.cc
@@ -0,0 +1,80 @@
+
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#include "src/common/random.h"
+#include "src/common/platform/fork.h"
+
+#include <cstring>
+#include <random>
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace sdk
+{
+namespace common
+{
+// Wraps a thread_local random number generator, but adds a fork handler so that
+// the generator will be correctly seeded after forking.
+//
+// See https://stackoverflow.com/q/51882689/4447365 and
+//     https://github.com/opentracing-contrib/nginx-opentracing/issues/52
+namespace
+{
+class TlsRandomNumberGenerator
+{
+public:
+  TlsRandomNumberGenerator() noexcept
+  {
+    Seed();
+    platform::AtFork(nullptr, nullptr, OnFork);
+  }
+
+  static FastRandomNumberGenerator &engine() noexcept { return engine_; }
+
+private:
+  static thread_local FastRandomNumberGenerator engine_;
+
+  static void OnFork() noexcept { Seed(); }
+
+  static void Seed() noexcept
+  {
+    std::random_device random_device;
+    std::seed_seq seed_seq{random_device(), random_device(), random_device(), random_device()};
+    engine_.seed(seed_seq);
+  }
+};
+
+thread_local FastRandomNumberGenerator TlsRandomNumberGenerator::engine_{};
+}  // namespace
+
+FastRandomNumberGenerator &Random::GetRandomNumberGenerator() noexcept
+{
+  static thread_local TlsRandomNumberGenerator random_number_generator{};
+  return TlsRandomNumberGenerator::engine();
+}
+
+uint64_t Random::GenerateRandom64() noexcept
+{
+  return GetRandomNumberGenerator()();
+}
+
+void Random::GenerateRandomBuffer(opentelemetry::nostd::span<uint8_t> buffer) noexcept
+{
+  auto buf_size = buffer.size();
+
+  for (size_t i = 0; i < buf_size; i += sizeof(uint64_t))
+  {
+    uint64_t value = GenerateRandom64();
+    if (i + sizeof(uint64_t) <= buf_size)
+    {
+      memcpy(&buffer[i], &value, sizeof(uint64_t));
+    }
+    else
+    {
+      memcpy(&buffer[i], &value, buf_size - i);
+    }
+  }
+}
+}  // namespace common
+}  // namespace sdk
+OPENTELEMETRY_END_NAMESPACE