[stunnel-users] Enhancement request - Increase thread stack size

Geoff Thorpe geoff at geoffthorpe.net
Wed Mar 26 16:08:48 CET 2008

On Wed, 2008-03-26 at 08:12 +0100, MichaƂ Trojnara wrote:
> Mccue, Richard Alan wrote:
> > I load an engine into Stunnel to access the private key. The engine loads
> > without incident, but Stunnel consistently aborts when creating a session
> > with the first peer because the thread stack is too small.
> I'm not sure if it's a good idea to sacrifice stunnel scalability for
> compatibility with this engine.  Thread stack size is one of the main
> limitations for the number of concurrent threads on 32-bit platforms.  IMHO
> it's better to fix the engine code to allocate its buffers on the heap.

Which engine is this, BTW?

FWIW, one possible problem is that engines are usually nothing more than
conversion-glue to a vendor-provided library. So if the stack-abuse is
occurring within the vendor code, you're hosed. In any case, presumably
stack size is something environmental that is (and can be) set outside
the realm of stunnel itself? Or is stunnel doing some kind of direct
hacking for thread-setup? If so, I guess it would make sense for this to
be modifiable at run-time (via environment variable or otherwise).


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