Opdis

			Opdis

A Ruby C extension (and gem) for the opdis library, available from http://freshmeat.net/projects/opdis .

BUILD

The standard C extension build process is used:

bash# ruby1.9 extconf.rb
bash# make

Note that the Ruby headers must be installed. On Ubuntu, these are in the ruby-dev or ruby1.9-dev package.

The gem is built using the standard gem build command:

bash# gem build Opdis.gemspec

The top-level Makefile supports each of these builds with the commands 'make' and 'make gem'.

bash# make
# builds C extension
bash# make gem
# builds the gem

BINUTILS AND SUPPORTED ARCHITECTURES

The implementation of binutils (and libopcodes) does not provide a way to determine the supported platforms at compile time, unless the config.h file used to build the binutils package is present.

The extconf.rb file has been modified in order to detect the architectures supported by the local copy of binutils, and to allow the user to specify which architectures they want supported.

It does this using the following steps:

1. run objdump -i to get the supported architectures
2. each line that matches one of binutils' known architectures is
       added as a #define to CPPFLAGS
3. if no architectures have been found, or if objdump failed to run,
   default to the i386 architecture.

The binary used in step 1 can be specified by the user via the --with-objdump flag. For example:

bash# cat /tmp/objdump.sh
#/bin/sh
echo 'arm'
echo 'sparc'
echo 'm68k'
bash# ruby1.9 extconf.rb --with-objdump=/tmp/objdump.sh
    checking for init_disassemble_info() in -lopcodes... yes
    Adding architecture 'arm'
    Adding architecture 'sparc'
    Adding architecture 'm68k'
    creating Makefile

This makes it possible to force compilation of support for specific architectures when there is no working objdump present. Note that libopcodes must have been compiled with support for the architectures, or you will get runtime errors.

EXAMPLES

Extended examples are provided in the 'examples' directory. The following code snippets give a brief overview of using the BFD and Opdis extensions together.

require 'BFD' require 'Opdis'

Bfd::Target.new('/tmp/a.out') do |tgt| Opdis::Disassembler.new do |dis| dis.disasm_entry( tgt ) { |insn| puts insn } end end

tgt = Bfd::Target.new('/tmp/a.out') tgt.sections.values.each { |s| puts s.name } } Opdis::Disassembler.new do |dis| dis.disasm_section( tgt.sections['.text.] ) { |i| puts i } end

Opdis::Disassembler.architectures.each { |arch| puts arch }

Opdis::Disassembler.new( arch: 'x86_64_intel' ) do |dis| dis.disassemble( [0x90, 0xCC, 0x90] ) { |insn| puts insn } end

Opdis::Disassembler.new( arch: 'x86_intel' ) do |dis| dis.disassemble( "\x90\xCC\x90" ) { |insn| puts insn } end