How much overhead do you think executing a shell script and an internal call to test implements? How often do you think IMAP connections are made? Think of all the calls that already wrap around shells. Think of how many exec calls (or their variiants in this case) are made to run tcpserver, authentication programs, bincimap-up, and bincimapd? Why not modify bincimap or bincimap-up to do the same thing on invocation and provide the patch to the bincimap folks instead- a likely better way to do things.It is indeed possible to use wrappers as you do, but this adds overhead
to every invocation of [insert progran here] which I'd rather avoid.
Just don't get caught up in the hype as to how much faster c programs are- when the shell is probably kept in memory, and the stat calls used by test are cached, this isn't a huge performance hit- especially for a connection like imap that is more persistant.
I run about 10K+ users on bincimap through this linkwrapper and generally see almost no load... I know that's vague, but I've never benchmarked the use with or without a simple shell script.
I'd suggest that:It's incredibly easy to add or modify functionality to qpsmtpd
because of the plugin hooks that are built-in.
1. qpsmtpd lacks many plugins and doesn't seem to have a lot of support in the community, along with the various plugin methods to qmail-smtpd. I'm sure there's a good chunk of overhead in there as well, not to mention difficulties like plugin ordering, etc.
2. vpopmail manages qmail users and delivers mail. I'm weary of making it even more of a kitchen sink to start adding plugins and management functions that would likely be used by a small number. It's still changing considerably between major releases.
Saw it- thumbs up. Glad you solved your issue.
Anyway, I've solved the IMAPdir issue a different way (see separate post).
-M
