[imapfilter-devel] Interactive features bug

[Julian Tibble]

Hi all,

A popular way to run imapfilter is from cron. However, the interactive
features of imapfilter are not disabled when run in this mode, which
can rapidly lead to a machine full of hung imapfilter instances. For
example, this happens if the certificate for a mail server changes. A
quick google suggests that this is a very common problem.

Suggested fix:
Use the posix-function isatty() to disable all interactive features
when stdin is not a tty, exiting with an error message instead.

Regards,
Julian