Author: Peter D. Gray Date: To: exim-users Subject: [Exim] race condition, locking, crash
It occurs to me that there may be a race condition
when updating DB style maps which could cause
exim to crash. If you are using any style of
DB database which uses both a .pag and a .dir file
then the exim_dbmbuild will rename one of the
files, then the other. If exim is
accessing the database between the move of the
.pag file and the .dir file then I believe there
is a good chance of a crash. At best, the result of
any lookups would be undefined.
Am I right in this?
If so, the fix would seem to be some form of locking
on the DB files so exim would pause while exim-dbmbuild
tampered with the files.
I have had this trouble before (not with exim). That is
why I am worried about it.
