libmilter: howto cleanup on thread termination

[Ralf Soergel]

Hi there,
in a milter I have to cleanup some things if and only if a thread
terminates.

Milter doc: "N connections mapped onto M threads, M <= N".
Because of this IMO the xxfi_close() callback is not mandatory the
end
of life of a thread.

Is there a callback on thread termination?

Thanks in advance for a hint.

Kind regards
Ralf


--
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[Claus Aßmann]

Ralf Soergel wrote:

> in a milter I have to cleanup some things if and only if a thread
> terminates.

Can you be more specific?
What did you allocate and where?
What do you need to "clean up"?

> Is there a callback on thread termination?

AFAICT the docs don't list one.

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[Ralf Soergel]

Claus Aßmann
<ca+sendmail(-no-copies-please)@mine.informatik.uni-kiel.de> at
Sun,

11 Jun 2017 13:14:05 +0000 (UTC) writes:

>> in a milter I have to cleanup some things if and only if a

>> thread terminates. > > What did you allocate and where?

I use libcrypto API of the openssl package in a milter, handling
S/MIME messages. These libcrypto functions malloc() data per
thread,
e. g. the error message queue of a thread if the first error in
thread
is recorded.

Threads will started by libmilter. After they died, this data
remains
as memory leak. But I will free() the data.

I think, I've now found a solution, using thread specific data.
In pthread_key_create() can set up a destructor function.
This destructor is calling on thread exit. See

https://linux.die.net/man/3/pthread_key_create
and
https://linux.die.net/man/3/pthread_setspecific