Merge pull request #2900 from DataDog/glopes/abort-on-shutdown

Fix abort() call on appsec helper unload

Author: cataphract

appsec/src/helper/main.cpp

@@ -125,6 +125,8 @@ int appsec_helper_main_impl()
 
         runner->run();
 
+        runner->unregister_for_rc_notifications();
+
         finished.store(true, std::memory_order_release);
     }};
     thread_id = thr.native_handle();

appsec/src/helper/runner.cpp

@@ -123,7 +123,7 @@ void runner::register_for_rc_notifications()
                 std::atomic_load(&RUNNER_FOR_NOTIFICATIONS);
             if (!runner) {
                 // NOLINTNEXTLINE(bugprone-lambda-function-name)
-                SPDLOG_ERROR("No runner to notify of remote config updates");
+                SPDLOG_WARN("No runner to notify of remote config updates");
                 ddog_remote_config_path_free(path);
                 return;
             }
@@ -136,15 +136,19 @@ void runner::register_for_rc_notifications()
         });
 }
 
-runner::~runner() noexcept
+void runner::unregister_for_rc_notifications()
 {
+    SPDLOG_INFO("Unregister runner for RC update callback");
     try {
         std::shared_ptr<runner> expected = shared_from_this();
         std::atomic_compare_exchange_strong(&RUNNER_FOR_NOTIFICATIONS,
             &expected, std::shared_ptr<runner>(nullptr));
     } catch (...) {
-        // can only happened if there is no shared_ptr for the runner
-        // in this case a std::bad_weak_ptr is thrown
+        // can only happen if there is no shared_ptr for the runner
+        // in this case a std::bad_weak_ptr is thrown.
+        // But we only expose runner through a shared pointer, so this would
+        // require extraordinary actions to destroy the shared pointer but not
+        // the object.
         std::abort();
     }
 }

appsec/src/helper/runner.hpp

@@ -26,14 +26,16 @@ class runner : public std::enable_shared_from_this<runner> {
     runner &operator=(const runner &) = delete;
     runner(runner &&) = delete;
     runner &operator=(runner &&) = delete;
-    ~runner() noexcept;
+    ~runner() = default;
 
     static void resolve_symbols();
 
     void run() noexcept(false);
 
     void register_for_rc_notifications();
 
+    void unregister_for_rc_notifications();
+
     [[nodiscard]] bool interrupted() const
     {
         return interrupted_.load(std::memory_order_acquire);