use strict;
our $VERSION = '0.02020505';
# ABSTRACT: An C<objdump> based section scanner.
# $Id:$
class ELF::Extract::Sections::Scanner::Objdump
with ELF::Extract::Sections::Meta::Scanner {
use MooseX::Has::Sugar 0.0300;
use MooseX::Types::Moose (qw( Bool HashRef RegexpRef FileHandle Undef Str Int));
method open_file ( File :$file! ) returns (Bool) {
$self->log->debug("Opening $file");
$self->_file($file);
$self->_filehandle( $self->_objdump );
return 1;
};
method next_section returns (Bool) {
my $re = $self->_section_header_identifier;
my $fh = $self->_filehandle;
while ( my $line = <$fh> ) {
next if $line !~ $re;
my ( $header, $offset ) = ( $+{header}, $+{offset} );
$self->_state( { header => $header, offset => $offset } );
$self->log->info("objdump -D -F : Section $header at $offset");
return 1;
}
$self->_clear_file;
$self->_clear_filehandle;
$self->_clear_state;
return 0;
};
method section_offset returns (Int|Undef) {
if ( not $self->_has_state ) {
$self->log->logcroak('Invalid call to section_offset outside of file scan');
return;
}
return hex( $self->_state->{offset} );
};
method section_size returns (Undef) {
$self->log->logcroak('Can\'t perform section_size on this type of object.');
return;
};
method section_name returns (Str|Undef) {
if ( not $self->_has_state ) {
$self->log->logcroak('Invalid call to section_name outside of file scan');
return;
}
return $self->_state->{header};
};
method can_compute_size returns (Bool){
return 0;
};
has _header_regex => ( isa => RegexpRef, ro, default => sub {
return qr/<(?<header>[^>]+)>/;
}, );
has _offset_regex => ( isa => RegexpRef, ro, default => sub {
return qr/\(File Offset:\s*(?<offset>0x[0-9a-f]+)\)/;
}, );
has _section_header_identifier => ( isa => RegexpRef, ro, lazy_build, );
has _file => ( isa => File, rw, clearer => '_clear_file', );
has _filehandle => ( isa => FileHandle, rw, clearer => '_clear_filehandle', );
has _state => ( isa => HashRef, rw,
predicate => '_has_state', clearer => '_clear_state',
);
method _build__section_header_identifier returns (RegexpRef) {
my $header = $self->_header_regex;
my $offset = $self->_offset_regex;
return qr/${header}\s*${offset}:/;
};
method _objdump returns (FileHandle|Undef){
if ( open my $fh, q{-|}, q{objdump}, qw( -D -F ), $self->_file->cleanup->absolute ) {
return $fh;
}
$self->log->logconfess(qq{An error occured requesting section data from objdump $^ $@ });
return;
};
};
1;
=pod
=head1 NAME
ELF::Extract::Sections::Scanner::Objdump - An C<objdump> based section scanner.
=head1 VERSION
version 0.02020505
=head1 SYNOPSIS
This module is a model implementation of a Naive and system reliant ELF Section detector.
Its currently highly inefficient due to having to run the entire ELF through a disassembly
process to determine the section positions and only I<guesses> at section lengths by
advertising that it can't compute sizes.
TO use this module, simply initialise L<ELF::Extract::Sections> as so
my $extractor = ELF::Extract::Sections->new(
file => "/path/to/file.so" ,
scanner => "Objdump",
);
=head1 IMPLEMENTS ROLES
=head2 ELF::Extract::Sections::Meta::Scanner
L<ELF::Extract::Sections::Meta::Scanner>
=head1 DEPENDS
=head2 MooseX::Has::Sugar
Lots of keywords.
L<MooseX::Has::Sugar>
=head2 MooseX::Types::Moose
Type Constraining Keywords.
L<MooseX::Types::Moose>
=head2 MooseX::Types::Path::Class
File Type Constraints w/ Path::Class
L<MooseX::Types::Path::Class>
=head1 PUBLIC METHODS
=head2 -> open_file ( file => File ) : Bool I< ::Scanner >
Opens the file and assigns our state to that file.
L<ELF::Extract::Sections::Meta::Scanner/open_file>
=head2 -> next_section () : Bool I< ::Scanner >
Advances our state to the next section.
L<ELF::Extract::Sections::Meta::Scanner/next_section>
=head2 -> section_offset () : Int | Undef I< ::Scanner >
Reports the offset of the currently open section
L<ELF::Extract::Sections::Meta::Scanner/section_offset>
=head2 -> section_size () : Undef I< ::Scanner >
Dies, because this module can't compute section sizes.
L<ELF::Extract::Sections::Meta::Scanner/section_size>
=head2 -> section_name () : Str | Undef I< ::Scanner >
Returns the name of the current section
L<ELF::Extract::Sections::Meta::Scanner/section_name>
=head2 -> can_compute_size () : Bool I< ::Scanner >
Returns false
L<ELF::Extract::Sections::Meta::Scanner/can_compute_size>
=head1 PRIVATE ATTRIBUTES
=head2 -> _header_regex : RegexpRef
A regular expression for identifying the
<asdasdead>
Style tokens that denote objdump header names.
Note: This is not XML.
=head2 -> _offset_regex : RegexpRef
A regular expression for identifying offset blocks in objdump's output.
They look like this:
File Offset: 0xdeadbeef
=head2 -> _section_header_identifier : RegexpRef
A regular expression for extracting Headers and Offsets together
<headername> File Offset: 0xdeadbeef
=head2 -> _file : File
A L<Path::Class::File> reference to a file somewhere on a system
=head3 clearer -> _clear_file
=head2 -> _filehandle : FileHandle
A perl FileHandle that points to the output of objdump for L</_file>
=head3 clearer -> _clear_file_handle
=head2 -> _state : HashRef
Keeps track of what we're doing, and what the next header is to return.
=head3 predicate -> _has_state
=head3 clearer -> _clear_state
=head1 PRIVATE ATTRIBUTE BUILDERS
=head2 -> _build__section_header_identifier : RegexpRef
Assembles L</_header_regex> and L</_offset_regex>
L</_section_header_identifier>
=head1 PRIVATE METHODS
=head2 -> _objdump : FileHandle | Undef
Calls the system C<objdump> instance for the currently processing file.
=head1 AUTHOR
Kent Fredric <kentnl@cpan.org>
=head1 COPYRIGHT AND LICENSE
This software is copyright (c) 2009 by Kent Fredric.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
=cut
__END__