I've written some ATL COM classes using OpenSSL (not a complete COM wrapper for
OpenSSL!) and want to share the following recomendations:
1) Use ATL if possible. MFC COM objects require a lot of tweaking for working
correctly with ASP. If you want to use ATL, choose the Simple Object, not the ASP
Object in the wizard.
2) Memory leaks - please check them carefully (using some tool like NuMega DevPartner
Studio). Some huge memory leaks will be left if your program creates a PKCS#7 object,
for instance, and forgets to destroy it. So design a wrapper that destroy all these
structures automatically if possible. Remember, COM wrappers are for VB/ASP (maybe
Delphi) programmers, and must be easy to use.
3) Please don't forget to call CRYPTO_set_locking_callback
(an example is given in crypto\threads\th-lock.c). It helps to alleviate threading
issues.
4) Put some code in DllMain /DLL_PROCESS_ATTACH, DLL_PROCESS_DETACH, DLL_THREAD_ATTACH
and DLL_THREAD_DETACH that handles the correct initialization/finalization of OpenSSL
for processes and threads. Remove the DisableThreadLibraryCalls that is generated by
the ATL COM Wizard.
5) From the ATL 101 classes: ASP is VBScript/JScript (maybe PerlScript ;-) and ByRef
parameters for your parameters must be Variant. Binary data is better handled as a
Byte Array, not a String (Unicode issues etc.).
----- Original Message -----
From: Colin Chalmers
To: [EMAIL PROTECTED]
Sent: Tuesday, December 19, 2000 4:56 AM
Subject: Re: thread safety
jinwon,
I too was considering making a COM wrapper for openssl but have not got round to
starting it yet (and I believe I'm not the only one).
Would you be willing to share your code when finished or that we perhaps share some
tasks/work to even the load?
/colin chalmers
----- Original Message -----
From: jinwon jang
To: [EMAIL PROTECTED]
Sent: Tuesday, December 19, 2000 1:20 AM
Subject: thread safety
Hello,
I'm planning to use openssl as a library that will be used with other application such
as COM object on windows NT4.0 and windows 2000 platforms. And the COM object is
called from ASP(Active Server Page) pages.
I'd like to confirm whether openssl is thread safe with MS windows NT and windows2000.
Since ASP is multi-threaded environment, it is not good enough to use thread-safe COM
object without thread safety of openssl.
Thanks,
jinwon jang
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