Re: About |exec /path/to/program in MTAs.
>
> Some smartlist user has had problems with the "exec" in /etc/aliases.
> For example, like this: announce: "|exec /var/list/.bin/flist announce"
> I assume this is for some kind of backward compatibility, but sendmail
> seems to work without the "exec". Does this apply to every MTA in Debian?
>
It is not for backward compatibility, only for reducing the resource usage.
Since MTAs traditionally invoke /bin/sh passing it the text following `|' as
the command (after -c), this exec merely works as the instruction for shell
to execute the rest of the command in place of itself rather than to fork and
wait.
Problems with exec may arise if the MTA is configured to call something other
than /bin/sh (e.g., smrsh - sendmail restricted shell). As far as I know,
Debian's smail calls sh. Sendmail is usually configured to call sh as well;
however, I am not sure about the Debian's one.
> [ If so, I'll remove this "exec"s from the smartlist package. ]
Well, execs are good, they help to keep load lower. I think it's better to
check somehow (e.g., by asking sendmail's maintainer) if Debian sendmail
uses /bin/sh or not. If it does, just keep all execs in place. If it
doesn't... well, the simplest solution would be to get rid of execs, although
users would still need to convince their shell replacements not to complain
about the program that goes after the `|'.
Anyway, if you _want_ to remove execs, do it. It's safe. At the price of
unnecessarily increased system load.
Kit.
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