Inadequate error reporting from nnrpd Perl loader

[Julien ÉLIE]

Hi River,

>>> At no point does it indicate there was any error loading the script, or
>>> what the error might be.
>>
>> Isn't the following line what you were looking for?
>> Feb  3 17:39:00 isis nnrpd[2481]: Perl function authenticate not defined
>
> That doesn't really tell me anything -- I already knew that
> authenticate() wasn't working, because no clients were able to
> authenticate.  But before I found the actual problem I spent about 20
> minutes looking at other things (like syntax errors in the script, nnrpd
> configuration, ...).  For a simple case like 'unable to open file', an
> error saying so would be quite nice.

OK, I understand your point.

The code should take care of it but apparently does not.


nnrpd/perl.c
------------
PERLsetup(NULL, script_path, "authenticate");


lib/perl.c
----------
PERLsetup() calls PERLreadfilter() because the first argument is NULL.
We have:

     /* The Perl expression which will be evaluated. */
     xasprintf(&evalfile, "do '%s'", filterfile);

     PerlSilence();
     perl_eval_pv(evalfile, TRUE);
     PerlUnSilence();

     SPAGAIN;

     free(evalfile);
     evalfile = NULL;

     /* Check $@. */
     if (SvTRUE(ERRSV)) {
         failure = true;
         syslog (L_ERROR,"SERVER perl loading %s failed: %s",
                 filterfile, SvPV(ERRSV, PL_na));
     } else {
         failure = false;
     }


$@ contains nothing whereas it would be expected that it contains an error.
According to the Perl documentation:

"If do can read the file but cannot compile it, it returns undef and 
sets an error message in $@ . If do cannot read the file, it returns 
undef and sets $! to the error. Always check $@ first, as compilation 
could fail in a way that also sets $! ."


% perl -e 'do "/pouet"; print $!;'
Aucun fichier ou répertoire de ce type




** Is there a function that gives the value of $! in Perl C API?  I do 
not see one.

Otherwise, would the right thing to do is to define a variable in the 
perl_eval_pv() call (like "do '%s'; $error = $! if $!;" and then get 
$error with get_sv() and checks that it is not NULL?






Incidentally, I read before PerlSilence():

/*
**  Redirects STDOUT/STDERR briefly (otherwise PERL complains to the net
**  connection for NNRPD and that just won't do) -- dave at jetcafe.org
*/

It may explain a behaviour seen a few weeks ago:  The Doctor's gmon.out 
message and a Perl "bizarre" error message (reported in Debian bugs for 
inn2) that should not be sent via the NNTP connection.
Something is not silence'd somewhere...

-- 
Julien ÉLIE

« – Que lui est-il arrivé ? Un choc moral ?
   – Oui, avec un menhir. » (Astérix)