Fix memory leak in tracetools::get_symbol() (ros2#2104)

Signed-off-by: Christophe Bedard <[email protected]>

Author: christophebedard-apexai

rclcpp/include/rclcpp/any_service_callback.hpp

@@ -191,10 +191,14 @@ class AnyServiceCallback
 #ifndef TRACETOOLS_DISABLED
     std::visit(
       [this](auto && arg) {
-        TRACEPOINT(
-          rclcpp_callback_register,
-          static_cast<const void *>(this),
-          tracetools::get_symbol(arg));
+        if (TRACEPOINT_ENABLED(rclcpp_callback_register)) {
+          char * symbol = tracetools::get_symbol(arg);
+          DO_TRACEPOINT(
+            rclcpp_callback_register,
+            static_cast<const void *>(this),
+            symbol);
+          std::free(symbol);
+        }
       }, callback_);
 #endif  // TRACETOOLS_DISABLED
   }

rclcpp/include/rclcpp/any_subscription_callback.hpp

@@ -959,10 +959,14 @@ class AnySubscriptionCallback
 #ifndef TRACETOOLS_DISABLED
     std::visit(
       [this](auto && callback) {
-        TRACEPOINT(
-          rclcpp_callback_register,
-          static_cast<const void *>(this),
-          tracetools::get_symbol(callback));
+        if (TRACEPOINT_ENABLED(rclcpp_callback_register)) {
+          char * symbol = tracetools::get_symbol(callback);
+          DO_TRACEPOINT(
+            rclcpp_callback_register,
+            static_cast<const void *>(this),
+            symbol);
+          std::free(symbol);
+        }
       }, callback_variant_);
 #endif  // TRACETOOLS_DISABLED
   }

rclcpp/include/rclcpp/timer.hpp

@@ -220,10 +220,16 @@ class GenericTimer : public TimerBase
       rclcpp_timer_callback_added,
       static_cast<const void *>(get_timer_handle().get()),
       reinterpret_cast<const void *>(&callback_));
-    TRACEPOINT(
-      rclcpp_callback_register,
-      reinterpret_cast<const void *>(&callback_),
-      tracetools::get_symbol(callback_));
+#ifndef TRACETOOLS_DISABLED
+    if (TRACEPOINT_ENABLED(rclcpp_callback_register)) {
+      char * symbol = tracetools::get_symbol(callback_);
+      DO_TRACEPOINT(
+        rclcpp_callback_register,
+        reinterpret_cast<const void *>(&callback_),
+        symbol);
+      std::free(symbol);
+    }
+#endif
   }
 
   /// Default destructor.