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OpenSSL: Difference between revisions

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* The <tt>threads(3ssl)</tt> man page is pretty good.
* The <tt>threads(3ssl)</tt> man page is pretty good.
* Unless you're using OpenSSL 0.9.9, the <tt>CRYPTO_set_id_callback(3ssl)</tt> is pretty much broken on [[pthreads]] implementations which don't return an integer value from <tt>pthread_self(3)</tt>. This is true for the [[FreeBSD APIs|FreeBSD]] native implementations (the [[LinuxThreads]] emulation package should work, but is broken in other, more grave, ways). On OpenSSL 0.9.9, <tt>CRYPTO_set_idptr_callback(3ssl)</tt> can be used for implementations which return a pointer or an aggregate.
* Unless you're using OpenSSL 0.9.9, the <tt>CRYPTO_set_id_callback(3ssl)</tt> is pretty much broken on [[pthreads]] implementations which don't return an integer value from <tt>pthread_self(3)</tt>. This is true for the [[FreeBSD APIs|FreeBSD]] native implementations (the [[LinuxThreads]] emulation package should work, but is broken in other, more grave, ways). On OpenSSL 0.9.9, <tt>CRYPTO_set_idptr_callback(3ssl)</tt> can be used for implementations which return a pointer or an aggregate.
** [[libdank]]'s OpenSSL layer handles this via a <tt>pthread_once_t</tt> which installs a class of thread-specific data. If the thread executing the callback has a NULL value for <tt>pthread_get_specific()</tt>, a <tt>static</tt> key is incremented and copied into the TSD. The increment, and copy of the result, forms a <tt>static</tt> mutex-protected critical section.


==See also==
==See also==
[http://www.mail-archive.com/openssl-users@openssl.org/msg52117.html "Clarification questions on OpenSSL thread-safe support"], openssl-users mailing list 2008-03-10
*[http://www.mail-archive.com/openssl-users@openssl.org/msg52117.html "Clarification questions on OpenSSL thread-safe support"], openssl-users mailing list 2008-03-10
*[http://www.mail-archive.com/openssl-users@openssl.org/msg46161.html "When to use CRYPTO_set_locking_callback() and CRYPTO_set_id_callback()?"], openssl-users mailing list 2006-08-17

Latest revision as of 03:29, 16 August 2009

Threads

  • The threads(3ssl) man page is pretty good.
  • Unless you're using OpenSSL 0.9.9, the CRYPTO_set_id_callback(3ssl) is pretty much broken on pthreads implementations which don't return an integer value from pthread_self(3). This is true for the FreeBSD native implementations (the LinuxThreads emulation package should work, but is broken in other, more grave, ways). On OpenSSL 0.9.9, CRYPTO_set_idptr_callback(3ssl) can be used for implementations which return a pointer or an aggregate.
    • libdank's OpenSSL layer handles this via a pthread_once_t which installs a class of thread-specific data. If the thread executing the callback has a NULL value for pthread_get_specific(), a static key is incremented and copied into the TSD. The increment, and copy of the result, forms a static mutex-protected critical section.

See also