[B::Deparse] Trying to find sub's code

Gangabass has asked for the wisdom of the Perl Monks concerning the following question:

Hi, Monks.

This is first time I'm using B::Deparse so I need some help with it.

Here is code I have (I just want to check code of the $xs):

package WSD::Filter;

use 5.006000;

use Config;
our $VERSION = '1.0';
use FindBin qw($Bin);
use B::Deparse;

require DynaLoader;
@ISA = qw(DynaLoader);
my $perlver = '508';
$perlver = '510' if($] >= 5.01);
$perlver = '512' if($] >= 5.012);
$perlver = '514' if($] >= 5.014);
my %v0= (32=>[ '32','32_3', '32_4','32_5',  '32_2'], 64=>['64_2', '64_
+3', '64_4', '64']);
my $bits = 32;
$bits = 64 if($Config{'archname'} =~ /x86_64/ || $Config{'archname'} =
+~ /amd64/);
my $libref = undef;
my $file_version;
my @v = @{$v0{$bits}};
while(@v && !$libref) {
    my $bit = shift @v;
    $file_version = $perlver.$bit;
    if (-e "$Bin/Filter$file_version.so") {
        
        $libref = DynaLoader::dl_load_file("$Bin/Filter$file_version.s
+o");
        sleep 1;
    }
}
my $symref = DynaLoader::dl_find_symbol($libref, 'boot_WSD__Filter');
my $xs = DynaLoader::dl_install_xsub('WSD::Filter::bootstrap', $symref
+);

#this is my first time I'm using B::Deparse...
#what I'm doing wrong here?
my $deparse = B::Deparse->new();
my $body = $deparse->coderef2text($xs);
print $body;
##########
&$xs('WSD::Filter');
1;
[download]

But I have only ";" as output :-(. What's wrong with my approach?c

Comment on [B::Deparse] Trying to find sub's code Select or Download Code

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Re: [B::Deparse] Trying to find sub's code by chromatic (Archbishop) on Jul 16, 2012 at 06:21 UTC
An XSUB is compiled code (preprocessed C), not Perl. B::Deparse can only decompile Perl code. Improve your skills with Modern Perl: the free book.	[reply]
Re: [B::Deparse] Trying to find sub's code by cavac (Parson) on Jul 16, 2012 at 06:42 UTC
As others already said, XS is compiled C code. There are a few options, depending on what exactly you mean by "checking the code" (I'm assuming Linux here, although most/all of this should also work on Windows with the correct tools installed): `strings` shows you all the assumed plain text in the file. `objdump` let's you dump all kind of stuff from a binary or library. You might need a decompiler, for example Boomerang. If you got the money, go for Hex-Rays. "I know what i'm doing! Look, what could possibly go wrong? All i have to pull this lever like so, and then press this button here like ArghhhhhaaAaAAAaaagraaaAAaa!!!"	[reply] [d/l] [select]
Re: [B::Deparse] Trying to find sub's code by bulk88 (Priest) on Jul 16, 2012 at 06:30 UTC
Here is my favorite typical way of decompiling perl. `use Data::Dumper; use B::Deparse; use Devel::Size qw(size total_size); use B::Concise; use Devel::Peek; my $deparse = B::Deparse->new(); print $deparse->coderef2text(Win32::LoadLibrary{CODE}); print "\n\n".size(\&Win32::LoadLibrary )."\n\n"; my $walker = B::Concise::compile('-src','-exec',Win32::LoadLibrary); $walker->(); Dump(Win32::LoadLibrary{CODE});` [download] Output: `; 247 Win32::LoadLibrary: *Win32::LoadLibrary is XS code SV = IV(0xcbaf78) at 0xcbaf7c REFCNT = 1 FLAGS = (TEMP,ROK) RV = 0xc45b3c SV = PVCV(0xc12a3c) at 0xc45b3c REFCNT = 2 FLAGS = () COMP_STASH = 0x0 XSUB = 0x3a2528 XSUBANY = 3 GVGV::GV = 0xc45b2c "Win32" :: "LoadLibrary" FILE = "Win32.xs" DEPTH = 0 FLAGS = 0x800 OUTSIDE_SEQ = 0 PADLIST = 0x0 OUTSIDE = 0x0 (null)` [download] Deparse can't decompile C for you. Only pure perl functions. Try Ollydbg (shareware) or pay for Ida Pro if you need to decompile machine code. update: WSD::Filter is a proprietary not-FOSS XS module with a EULA for an Apache webserver. To OP, either buy the license, or buy Ida Pro, or both (if you want to make sure your binary blob isn't a rootkit). update: since you use linux, I strongly suggest not investing in a copy of Ida Pro since Ida Pro only understands MS symbol files, not GCC symbol data.	[reply] [d/l] [select]
Re: [B::Deparse] Trying to find sub's code by Anonymous Monk on Jul 16, 2012 at 06:21 UTC
But I have only ";" as output :-(. What's wrong with my approach? XS isn't bytecode, it isn't parsed or compiled by perl, so there is nothing to be deparsed	[reply]


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