I am running stunnel on a minimal system which has limited flash size, so using extra binary is expensive for me.

I know those mechanisms there are on linux. But I am asking something like this within stunnel codes :

While stunnel running it will check also log size, then when stunnel realized the log size limit (which is defined in conf file for example) reached it will re-open the log file in write mode (by the way old info will be deleted).

Regards

Mehmet