Beefy Boxes and Bandwidth Generously Provided by pair Networks
No such thing as a small change
 
PerlMonks  

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
You may also want to try a nice GUI debugger, like DDD which has some nice features for drilling into data structures, etc. Beyond that, it is likely worth the effort to liberally sprinkle the code with print statements. When attempting to learn code like this, I find it useful ( although sometimes painful :) to add lines like this
sub foo { print STDERR "Entering sub foo(@_)\n"; # Do something print STDERR "Exiting sub foo: return value $bar\n"; return $bar; }

Failing all of that, I will offer the following two toys. They are not perfect - they may not catch everything - but they have worked quite well for me.

First Toy

This one is a bit strange. It was originally designed to help me update my POD. It crawls through a bit of source and attempts to extract every time a return is called and the context in which it is called. I have modified it slightly so it would not bother parsing the pod in the second loop and instead print to screen. It is a little raw - I am the only one who uses it and I know how it is to be called :)
#!/usr/bin/perl -w # usage: $0 filename [optional output file] # If the output file is not specified, it will print to STDOUT use strict; my $outp; open FILE, $ARGV[0] or die "A grim and horrible death: $!"; if ( defined( $ARGV[1] ) ) { open OUTP, ">$ARGV[1]" or die "Couldn't write: $!"; $outp = \*OUTP; } else { $outp = \*STDOUT; } my ( %calls, $name, @context ); #--- # First parsing phase is to try to gather all the return codes togethe +r, # keyed by the function name #--- while ( <FILE> ) { next if /^\s*#/; next if /^\s*$/; last if /__END__/; $name = $1 if /^sub (\w+)/; #--- # Push the context and get next line if possible #--- if ( /^\s*return (\$?[\w->:]+) (if .+)[;{]$/ || /^\s*return (\$?[\w->:]+) (unless .+)[;{]$/ ) { my ( $code, $context ) = ( $1, $2 ); chomp $context; $context =~ s/^\s+//; push @{$calls{$name}{$code}}, $context; next; } if ( /(.+){$/ ) { chomp; s/^\s+//; push @context, $_ } pop @context if ( /}$/ ); push(@{$calls{$name}{$1}}, $context[-1]),next if ( /\s*return (\$? +[\w->:{}]+ )/ ); } close FILE; for my $name ( sort keys %calls ) { for my $rc ( sort keys %{$calls{$name}} ) { print $outp "$rc when:\n\t"; local $" = "\n\t"; print $outp "@{$calls{$name}{$rc}}\n"; } }

Second Toy

This next one needs at least two parameters. The first arg is the source file. This file will be searched for all subroutine declarations. It will then search through all the remaining files on the command line, looking for those subroutines. When it finds one, it will print the name of the file, the line number and the call itself. It is heavily oriented towards OO perl and it does require perl 5.5 or better - I am something of a compiled regex junky.
#!/usr/bin/perl -w use strict; die "$0 <source> <target> ..." unless @ARGV > 1; my %keyword = (); my ( $source, @targets ) = @ARGV; my $package = ''; #--- # Try to extract the keywords, precompile the regex and store #--- open SRC, $source or die "Couldn't open $source : $!"; while( <SRC> ) { $package = $1 if ( ! $package && /^package\s+(.+);/ ); next unless ( /^sub\s+(.+){\s*$/ ); my $name; $name = $1; next if ( substr($name,0,1) eq "_" ); $name =~ s/\s+$//; $keyword{$name} = qr/([\w:{}]+)->$name/; } close SRC; for my $file ( @targets ) { my ( $line ); open FILE, $file or die "Couldn't open $file : $!"; LINE: while( $line = <FILE> ) { next LINE if ( $line =~ /^\s*#/ || $line =~ /^\s*$/ ); last LINE if $line =~ /__END__/; for ( keys %keyword ) { my $regex = $keyword{$_}; if ( $line =~ /$regex/ ) { my $starts_at = $.; my $lpack = $1 || ''; next LINE if ( $file eq $source ) && ( $line =~ /^ +sub/ ); next LINE if ( $line =~ /Usage/ ); next LINE if ( $lpack =~ /::/ && $lpack ne $packag +e ); while( $line !~ /;/ && ! eof(FILE) ) { $line .= <FILE>; next LINE if $line =~ /^EOF/m; } $line =~ s/^\s*//; printf "%s (%d) %s", uc $file, $starts_at, $line; next LINE; } } } #LINE close FILE; }
< mikfire

In reply to Re: Reverse Engineering Perl Tool? by mikfire
in thread Reverse Engineering Perl Tool? by Anonymous Monk

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or or How to display code and escape characters are good places to start.
Log In?
Username:
Password:

What's my password?
Create A New User
Domain Nodelet?
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others imbibing at the Monastery: (5)
As of 2022-01-21 18:45 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?
    In 2022, my preferred method to securely store passwords is:












    Results (59 votes). Check out past polls.

    Notices?