Prevent accessing of global c++ objects once they are deleted

[Emantor]

Fixes (Maybe) #729.
Reset objects_deleted after reset is called.

[kraj]

hmm reading through #729 it seems to be a fix for openSSL's behavior where its using atexit, I wonder if openSSL exit sequence should not call atexit and let the system cleanup happen via system runtime. atexit seems to be tied to implementation and for c++ it may run concurrently alongside destructors [1], in C it maybe called concurrently with other functions too.

[1] https://en.cppreference.com/w/cpp/utility/program/atexit

[jschlyter]

Please rebase on develop and mark as ready when ready.

[MorningLightMountain713]

I look forward to this getting merged. Here is a before and after of this patch applied:

[bjosv]

Not sure if there is a better way but I guess this work unless we look into some refactoring.
Maybe add a comment with the reason for using a objects_deleted.

[petrovr]

One flag isInitialised, another flags objects_deleted , tomorrow yet another flag... :( .
And all those changes because third party software "cache sessions".

[petrovr]

Almost all issues shows call-stack that starts "at exit", call softhsm ...CloseSession... and then crash i.e., bus error, or segmentation fault, or core dump.

More or less this is expected when a project uses unreliable and non-portable functionality like at-exit. In addition refuses to proposes portable solution. For instance cygwin hang is because of "at exit" functionality.

With similar defects third parties try to force project to fix external issues.

May be just to stop processing when is detected "lazy" clean-up request. I mean to check for null pointers in close session.

---

Off topic: Long time ago in pkix-ssh implementation allows use of identity (keys) from engine. This is an openssl loadable module and one thing is clear indirectly - in general module cannot be considered as stateless. It may open database and so close of database should be triggered as well. It may use network connections, devices , and etc.. Clean shutdown of used resources is preferred.
In consequence pkix-ssh explicitly clean(free) all used keys and unload modules in main function. Additionally, is performed clean-up of openssl.
With such model "crash" is gone.