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Re: thread safe use of openssl

From: Daniel Stenberg <>
Date: Tue, 16 Dec 2003 11:24:14 +0100 (CET)

On Tue, 16 Dec 2003, jose chung wrote:

> Based on my perusal of the CURL code, it doesn't seem like it uses OpenSSL
> in a thread safe manner as it does not implement either the static locking
> or dynamic locking callbacks.

I've been under the impression that our use of OpenSSL does not warrant those
locking methods. I take your mail here as a saying that we do.

I find that odd, since I believe we have lots of users who have used libcurl
multi-threaded for HTTPS transfers...

> Since I couldn't find it, and since I had problems using HTTPS in CURL with
> multithreaded apps, I've implemented static and dynamic locking for VMS,
> AIX, and Win32 into CURL.

I don't want locking methods inside libcurl, since locking is a multi-platform
nightmare. The share interface was added for sharing data between multiple
threads, and I figure we could indeed use that interface for locking/share SSL
resources as well should this be determined to be necessary.

> I'm not certain if CURL has intentionally left this as an exercise for the
> user, but if it hasn't, I'd be happy to contribute what I have.

I would inded be interested, but we should perhaps first clear out what the
problems you've been experiencing resulted in and that this locking is really

    Daniel Stenberg -- --
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Received on 2003-12-16