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PID reuse



Hi,

While building and testing courier-40.2 on my OpenBSD-3.2-RELEASE machine,
I ran into a problem.

It's described in detail at http://www.linkdata.se/sourcecode.html

The short version is that some programs (courier among them) depend
on the fact that the same PID must not be generated twice within the space of
a second.

I've looked around for more info about OpenBSD's PID generation behaviour,
but all I found was that it was random, and that random PID's are A Good Thing
securitywise.

But I can't recall seeing this problem in earlier versions of OpenBSD, and checking
the Changelog for OpenBSD 3.1 I found this statement:

"Simplify PID selection algorithm."

Is this an indication that PID selection is broken for some applications 
since 3.1, or is it simply a coincidence?

Given that (many?) programs seem to depend on a certain PID assigment behaviour,
would it be prudent to conform to it, or are there strong and compelling reasons for 
keeping PID generation random?

/Johan

Courier is found at http://www.courier-mta.org/



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