change in behaviour

David Lee t.d.lee at
Fri May 9 15:16:39 IST 2008

On Fri, 9 May 2008, Greg Matthews wrote:

> Installing MailScanner at a customer site on RHEL3 I noticed file
> locking problems. It seems the auto-detecting of required lock type
> (dependent on sendmail version) does not work in 4.68.8.
> When I manually set the lock type to flock, the locking problems
> disappeared.
> Waaay back on this list there was much discussion about lock type and
> then Julian made MailScanner autodetect the required locking... am I
> misremembering? Anyway, 4.68.8 defaulted to posix whereas the previous
> version (4.50.15) autodetected correctly and worked with a blank "Lock
> Type ="

My own recollection (itself perhaps faulty) of the possible auto-detect
implies that you might be mis-remembering.

I think there were a couple of spates of discussion about the desirability
of autodetect, but I think the outcome was that there was no simple,
sure-fire reliable way for other software (e.g. the MS perl script) to
achieve, without fault, the auto-detection of locking-type in the host's

So I think the state for the last few years has been:
 o  no auto-detect;
 o  default OK for most modern OSes (modern sendmail) for most occasions
    (but not "all OSes for all sendmail versions for all occasions");
 o  still an element of human-checking recommended.

Presumably Julian would welcome a contributed snippet of perl code that
really could reliably auto-detect all sendmail versions on any OS.

(Happy to be contradicted on this...!)


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