possible bug in Apache2::XSLoader and APR::XSLoader

[Torsten Foertsch <to...@gmx.net>]

Hi,

what is the purpose of Apache2::XSLoader and APR::XSLoader?

Both modules contain a load() function that reads:

sub load {
    return unless BOOTSTRAP;
    XSLoader::load(@_);
}

I believe this is wrong. The XSLoader::load function contains this code:

    my @modparts = split(/::/,$module);
    my $modfname = $modparts[-1];

    my $modpname = join('/',@modparts);
    my $modlibname = (caller())[1];
    my $c = @modparts;
    $modlibname =~ s,[\\/][^\\/]+$,, while $c--;	# Q&D basename
    my $file = "$modlibname/auto/$modpname/$modfname.$dl_dlext";

You see $modlibname is built from the caller's filename. If APR::XSLoader is 
used this caller is /path/to/APR/XSLoader.pm and not as expected by the code 
the filename of the caller of APR::XSLoader::load.

As a result XSLoader tries to load the shared lib from the wrong location.

A simple change makes it work as expected:

    goto &XSLoader::load;

This way instead of pushing a new frame on the call stack the current 
(APR::XSLoader::load) frame is replaced by XSLoader::load. Hence caller() 
sees the original caller.

Torsten

Re: possible bug in Apache2::XSLoader and APR::XSLoader

[Torsten Foertsch <to...@gmx.net>]

On Fri 27 Jun 2008, Philippe M. Chiasson wrote:
> > As a result XSLoader tries to load the shared lib from the wrong
> > location.
> >
> > A simple change makes it work as expected:
> >
> >     goto &XSLoader::load;
> >
> > This way instead of pushing a new frame on the call stack the current
> > (APR::XSLoader::load) frame is replaced by XSLoader::load. Hence caller()
> > sees the original caller.
>
> Sounds like a correct fix to me.

Committed as revision 672484.

Hey, that was my first commit to trunk, :-)

Torsten

--
Need professional mod_perl support?
Just hire me: torsten.foertsch@gmx.net

---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@perl.apache.org
For additional commands, e-mail: dev-help@perl.apache.org

Re: possible bug in Apache2::XSLoader and APR::XSLoader

["Philippe M. Chiasson" <go...@ectoplasm.org>]

Torsten Foertsch wrote:
> Hi,
> 
> what is the purpose of Apache2::XSLoader and APR::XSLoader?
> 
> Both modules contain a load() function that reads:
> 
> sub load {
>     return unless BOOTSTRAP;
>     XSLoader::load(@_);
> }
> 
> I believe this is wrong. The XSLoader::load function contains this code:
> 
>     my @modparts = split(/::/,$module);
>     my $modfname = $modparts[-1];
> 
>     my $modpname = join('/',@modparts);
>     my $modlibname = (caller())[1];
>     my $c = @modparts;
>     $modlibname =~ s,[\\/][^\\/]+$,, while $c--;	# Q&D basename
>     my $file = "$modlibname/auto/$modpname/$modfname.$dl_dlext";
> 
> You see $modlibname is built from the caller's filename. If APR::XSLoader is 
> used this caller is /path/to/APR/XSLoader.pm and not as expected by the code 
> the filename of the caller of APR::XSLoader::load.
> 
> As a result XSLoader tries to load the shared lib from the wrong location.
> 
> A simple change makes it work as expected:
> 
>     goto &XSLoader::load;
> 
> This way instead of pushing a new frame on the call stack the current 
> (APR::XSLoader::load) frame is replaced by XSLoader::load. Hence caller() 
> sees the original caller.

Sounds like a correct fix to me.

-- 
Philippe M. Chiasson     GPG: F9BFE0C2480E7680 1AE53631CB32A107 88C3A5A5
http://gozer.ectoplasm.org/       m/gozer\@(apache|cpan|ectoplasm)\.org/