Signal handling causes segfault

[zenker]

I just discovered that the OPC-UA adapter crashes when receiving two times a SIGINT signal in series. I did not investigate the reason for the crash. Maybe you could have a look.

[ichrispa]

Hi zenker. The problem might be located in the task manager attempting to re-stop an already stopped thread while "collecting" the OPC UA Server thread during shutdown. We need to include a mutex to prevent multiple stop-operations running on the task manager at the same time.

[mhier]

I am still seeing this issue. I think it is also related to fishy memory management / destructor calls. For instance, the csa_opcua_adapter destructor calls this->adapter->~ua_uaadapter(), which destroys the instance this->adapter without deleting it. This pattern can be found all over the adapter. I do not understand the intentions behind this, but it causes duplicate calls to the destructors, which is illegal by the C++ standard.

My advice would be to change the memory management to use smart pointers rather than plain pointers with new/delete, where necessary. Where possible, pointers should be completely avoided and instead just ordinary object instances should be used. For instance the aforementioned csa_opcua_adapter::adapter pointer points to an object with the same lifetime as the owning csa_opcua_adapter object. In that case just a plain member object without any pointer should be used.