From 65c55be6cdde4114938ec4de56d73198a26f642c Mon Sep 17 00:00:00 2001
From: Julien Letessier <julien.letessier@gmail.com>
Date: Thu, 15 Jan 2026 16:27:14 +0100
Subject: [PATCH] Make handler stop flag atomic

---
 src/Handler.cpp              |  4 +--
 src/Handler.h                |  3 ++-
 test/handler_stop_atomic.cpp | 17 ++++++++++++
 test/handler_stop_atomic.py  | 50 ++++++++++++++++++++++++++++++++++++
 test/run.sh                  |  1 +
 5 files changed, 72 insertions(+), 3 deletions(-)
 create mode 100644 test/handler_stop_atomic.cpp
 create mode 100644 test/handler_stop_atomic.py

diff --git a/src/Handler.cpp b/src/Handler.cpp
index 5fa65d4..f12dff4 100644
--- a/src/Handler.cpp
+++ b/src/Handler.cpp
@@ -50,7 +50,7 @@ void Handler::run()
     Response::init();
     auto conf = mProxy->conf();
     refreshServerPool();
-    while (!mStop) {
+    while (!mStop.load()) {
         mEventLoop->wait(100000, this);
         postEvent();
         long timeout = conf->clientTimeout();
@@ -78,7 +78,7 @@ void Handler::run()
 
 void Handler::stop()
 {
-    mStop = true;
+    mStop.store(true);
 }
 
 void Handler::refreshServerPool()
diff --git a/src/Handler.h b/src/Handler.h
index a2fc55f..208d39b 100644
--- a/src/Handler.h
+++ b/src/Handler.h
@@ -12,6 +12,7 @@
 #include "Multiplexor.h"
 #include "Stats.h"
 #include "LatencyMonitor.h"
+#include "Sync.h"
 #include "AcceptConnection.h"
 #include "ConnectConnectionPool.h"
 #include "Proxy.h"
@@ -114,7 +115,7 @@ private:
         mAcceptConns.push_back(c);
     }
 private:
-    bool mStop;
+    Atomic<bool> mStop;
     Proxy* mProxy;
     Multiplexor* mEventLoop;
     std::vector<ConnectConnectionPool*> mConnPool;
diff --git a/test/handler_stop_atomic.cpp b/test/handler_stop_atomic.cpp
new file mode 100644
index 0000000..2a883f7
--- /dev/null
+++ b/test/handler_stop_atomic.cpp
@@ -0,0 +1,17 @@
+/*
+ * Compile-only test to ensure Handler::mStop is atomic.
+ */
+
+#define private public
+#include "../src/Handler.h"
+#undef private
+
+#include <type_traits>
+#include <utility>
+
+int main() {
+    using StopType = decltype(std::declval<Handler>().mStop);
+    static_assert(std::is_same<StopType, Atomic<bool>>::value,
+                  "Handler::mStop should be atomic");
+    return 0;
+}
diff --git a/test/handler_stop_atomic.py b/test/handler_stop_atomic.py
new file mode 100644
index 0000000..aae8028
--- /dev/null
+++ b/test/handler_stop_atomic.py
@@ -0,0 +1,50 @@
+#!/usr/bin/env python3
+#
+# Build and run the Handler::mStop atomic type check.
+#
+
+import os
+import platform
+import subprocess
+import tempfile
+from test_util import parse_args, exit_with_result
+
+
+def run_test(project_root):
+    src = os.path.join(project_root, "test", "handler_stop_atomic.cpp")
+    if not os.path.exists(src):
+        print("FAIL: handler_stop_atomic.cpp not found")
+        return False
+
+    with tempfile.TemporaryDirectory() as tmp:
+        exe = os.path.join(tmp, "handler_stop_atomic")
+    cmd = [
+            "g++",
+            "-std=c++11",
+            src,
+            "-o",
+            exe,
+        ]
+    sysname = platform.system()
+    if sysname == "Darwin":
+        cmd.insert(1, "-D_KQUEUE_")
+    elif sysname == "Linux":
+        cmd.insert(1, "-D_EPOLL_")
+        try:
+            subprocess.check_call(cmd, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+        except Exception as exc:
+            print("FAIL: compile handler_stop_atomic:", exc)
+            return False
+        try:
+            subprocess.check_call([exe], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+        except subprocess.CalledProcessError as exc:
+            print("FAIL: handler_stop_atomic returned", exc.returncode)
+            return False
+    return True
+
+
+if __name__ == "__main__":
+    _ = parse_args("Handler stop atomic test")
+    root = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
+    success = run_test(root)
+    exit_with_result(success, "handler stop atomic", "handler stop atomic")
diff --git a/test/run.sh b/test/run.sh
index 7a34a92..4d3200e 100755
--- a/test/run.sh
+++ b/test/run.sh
@@ -150,6 +150,7 @@ TESTS=(
     "test/logger_thread_init.py"
     "test/logger_unbounded_logunit.py"
     "test/string_to_int.py"
+    "test/handler_stop_atomic.py"
     "test/pubsub_long_name.py"
     "test/pubsub_large_message.py"
     "test/transaction_forbid.py"