[Python-Dev] Testers wanted: mailbox.py bugfix
A.M. Kuchling
amk at amk.ca
Thu Jan 18 14:07:02 CET 2007
On Wed, Jan 17, 2007 at 03:36:58PM -0600, Charles Cazabon wrote:
> I can't speak for MMDF or Babyl, but it's a well-known requirement that all
> programs on a system must use the same type of locking when mbox files are
> used; the administrator picks his favourite (fcntl, dotlocking, whatever) and
> then has to ensure all mbox-aware programs are compiled to use that locking
> style.
That's not actually the bug, The problem is that code that does:
<open mailbox>
<read mailbox>
... wait around a bit ...
<lock mailbox>
<modify mailbox>
<unlock mailbox>
can corrupt the mailbox if something else comes in and modifies the
mailbox during the "wait around a bit" phase. This happens because an
table of contents is generated when the mailbox is read and then never
updated, missing changes made by other processes after the ToC is
read.
--amk
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