I've just upgraded my (Debian Woody) web-hosting system from Exim 3 to
Exim 4, and been bitten by a problem similar to that described in
http://www.exim.org/mail-archives/exim-users/Week-of-Mon-20020826/msg00168.html
In my case, the router sets user=julian, and then calls a filter which
does some stuff including copying the message to a file which I want
to be owned by julian. Delivery fails with the message,
2006-10-14 08:25:51 unable to set gid=1000 or uid=1000 (euid=104): stevbrad router (recipient is julian@???)
2006-10-14 08:25:51 internal problem in stevbrad router (recipient is
julian@???): failure to transfer data from subprocess: status=0100 readerror='No such file or directory'
2006-10-14 08:25:51 H=nutty.inf.ed.ac.uk [129.215.216.3] F=<jcb@???> temporarily rejected RCPT <julian@???>: internal problem in stevbrad router (recipient is julian@???): failure to transfer data from subprocess: status=0100 readerror='No such file or directory'
(1000 is julian, 104 is Debian-exim).
I presume that this is because in verification (and incidentally I had
to switch on a lot of debugging to see that this error comes from the
verification phase), exim tries to switch to julian before reading the
filter file.
At the moment I've been working round it by making the exim user root,
but from the posting referenced about I see there are other inelegant
but more secure workarounds which should work for me.
What I'm writing to say is: how about mentioning this rather odd
feature in the manual? It's very unintuitive that verification should
fail in this way when delivery without verification would work - and
it worked in exim3 (in my case, anyway), so it's a problem for
upgraders. It has also taken me some time to work out what's going on!
I'm not sure where in the manual would be best, but maybe in a note
attached to the description(s) of the user options.
