From 93ffedc620e1df2b0007fdd334c1319427502ea1 Mon Sep 17 00:00:00 2001
From: Michael Wallner <mike@php.net>
Date: Fri, 30 Oct 2020 13:37:41 +0100
Subject: [PATCH] thread safe randoms

---
 test/lib/random.cpp | 10 ++++++++++
 test/lib/random.hpp | 17 ++++++++---------
 test/setup.cpp      |  3 +++
 3 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/test/lib/random.cpp b/test/lib/random.cpp
index 6aab8875..1d9a20c9 100644
--- a/test/lib/random.cpp
+++ b/test/lib/random.cpp
@@ -3,6 +3,16 @@
 
 #include <unistd.h> // getpid()
 
+mt19937_64 rnd_eng;
+mutex rnd_mtx;
+
+void random_setup() {
+  using namespace chrono;
+
+  auto time = duration_cast<nanoseconds>(system_clock::now().time_since_epoch());
+  rnd_eng.seed(static_cast<mt19937_64::result_type>(time.count()));
+}
+
 unsigned random_port() {
   do {
     auto port = random_num(5000, 32000);
diff --git a/test/lib/random.hpp b/test/lib/random.hpp
index 723146a9..322de6af 100644
--- a/test/lib/random.hpp
+++ b/test/lib/random.hpp
@@ -22,22 +22,21 @@
 #include <string>
 #include <type_traits>
 #include <utility>
+#include <mutex>
 
 using namespace std;
 
 using kv_pair = pair<string, string>;
 
-template<typename T>
-enable_if_t<is_integral_v<T>, T> random_num(T min, T max) {
-  using namespace chrono;
-  using rnd = mt19937_64;
-  using dst = uniform_int_distribution<uintmax_t>;
+extern mt19937_64 rnd_eng;
+extern mutex rnd_mtx;
 
-  static auto time = duration_cast<nanoseconds>(system_clock::now().time_since_epoch());
-  static auto seed = static_cast<rnd::result_type>(time.count());
-  static auto rgen = rnd{seed};
+void random_setup();
 
-  return dst(min, max)(rgen);
+template<typename T>
+enable_if_t<is_integral_v<T>, T> random_num(T min, T max) {
+  lock_guard m{rnd_mtx};
+  return uniform_int_distribution<T>(min, max)(rnd_eng);
 }
 
 unsigned random_port();
diff --git a/test/setup.cpp b/test/setup.cpp
index 9591a356..a0325af5 100644
--- a/test/setup.cpp
+++ b/test/setup.cpp
@@ -1,5 +1,6 @@
 #include "mem_config.h"
 #include "test/lib/env.hpp"
+#include "test/lib/random.hpp"
 #include <cstdlib>
 #include <cstdio>
 #include <cstring>
@@ -78,6 +79,8 @@ static inline void setup_sasl() {
 #endif
 
 int setup(int &, char ***argv) {
+  random_setup();
+
   setup_signals();
   setup_asan(*argv);
   setup_sasl();
-- 
2.30.2