>> This morning my filter program (the exim child process) which uses
>> libspf2 to look up SPF records threw an error. The error is actually
>> generated by libspf2, written to stderr, and appears in the exim main
>> log, e.g.:
>
> As far as I can tell, this must be something that your local_scan function
> is doing, because it isn't something Exim normally does. (The return_fail
> mechanism used for the pipe transport isn't provided to local_scan
> functions.)
That was my thinking too, but the error only occurred when something
wrote to stderr, so I started looking at exim. I've been reading the
code and found this (exim-4.62):
$ nl -ba src/child.c
[snip]
379 (void)close(inpfd[pipe write]);
380 force fd(inpfd[pipe read], 0);
381
382 (void)close(outpfd[pipe read]);
383 force fd(outpfd[pipe write], 1);
384
385 (void)close(2);
386 (void)dup2(1, 2);
stdout and stderr share file descriptor 1. My code is looking for
results on stdout. SPF library output to stderr appears on stdout and
that trips up my stuff.
Jack
