emacs-binary-utils

This repository contains a bunch of Emacs packages for working with binary files:

• binfile.el
• objdump.el
• asm-data.el
• asm-jump.el
• asm2src.el
• compiled-file.el
• compdb.el

binfile.el - Disassemble binary files

An extendable package for examining binary files. It can disassemble many types of ELF files and postprocess the results to be more easily readable (e.g. it can parse relocations reported by objdump and output them intermixed with code).

The main command is binfile-disassemble, which prompts for a function name (by default, the function at point) and, if it can't be guessed, a binary file. The binary file is by default provided by compiled-file.el library.

Using compdb-output-filename as compiled-file-function allows automatically finding binary (.o) files for current buffer from compile_commands.json file.

The other commands are:

• binfile-insert-data

  Insert data (a symbol, a section, or an address range) from a binary file into the current disassembly buffer. It can be used to examine .data, .rodata sections etc.

• binfile-diff

  Display a diff buffer for examining a difference between two disassembled binary files.

• binfile-symbol-info

  Prompt for a symbol and a binary filename, and display information about that symbol.

objdump.el - A library for working with objdump utility

This library provides functions for working with the objdump program. It can read the symbol table, disassemble code, extract contents of sections, mangle/demangle names.

The API functions are:

• objdump-file-dynamic-p

  Check if file is dynamic.

• objdump-read-symtab

  Read the symbol table from a file.

• objdump-mangle, objdump-demangle, objdump-symbol-mangled-p, objdump-symbol-demangled-p

  Mangle and demangle symbols; check if they are mangled.

• objdump-disassemble

  Disassemble a portion of a code section.

• objdump-raw

  Get the raw contents of a section.

asm-data.el - Conversion between data representations in ASM buffers

This package lets you change the way data is represented in ASM buffers. For example, when the buffer contains:

.4byte 1819043176
.byte 111
.byte 0

calling asm-data-convert and selecting the ".asciz" directive changes that to:

.asciz "hello"

This representation can again be changed, e.g. to 2byte (here called with a prefix argument for hexadecimal number representation):

.2byte 0x6568
.2byte 0x6c6c
.2byte 0x006f

It can convert data to .ascii, .asciz, .byte, .2byte, .4byte, .8byte, .octa (16-byte), .single and .zero GAS directives.

Integers can be converted to unsigned/signed decimal/hex/binary representation.

Floating-point directive .single assumes 32-bit floats.

The variable asm-data-endianness controls the type of numbers<->bytes conversion.

asm-jump.el - Buttons for jumps in ASM mode

This package provides the function asm-jump-process-buffer which scans the current buffer for ASM jump statements and makes buttons for them.

The action for buttons created by this function will search the current buffer for the referenced label and move the point there.

Another command, asm-jump-reverse finds the first jump statement to the current label.

asm2src.el - ASM to source file overlays

This package allows you to jump from ASM buffer to a source file and vice versa.

asm2src-process-buffer is the main function which scans the current ASM buffer for file mappings, it must be called once before further usage.

When using binfile and the rest of the packages here, you should add:

(setq objdump-disassembly-extra-args '("-l"))
(add-hook 'binfile-disassembly-hook #'asm2src-process-buffer)

To your init file. The first line makes objdump output source file mappings when dumping disassembly, and the second makes sure we can parse and use that in Emacs.

asm2src-jump allows you to jump to the source buffer from the preprocessed ASM buffer. It sets a transient keymap, asm2src-jump-keymap for the duration of the command: C-c C-c or RET goes to the source file, p goes to the previous mapped location, n goes to the next.

asm2src-jump-to-asm is the inverse, it should be invoked in a source file and will go to the first ASM buffer containing the source line.

asm2src-add-mapping can be used to add a custom ASM<->source directory mapping.

compiled-file.el - Get/set the compiled file for current source file

This helper package defines a variable compiled-file which can be set to the path to the object file for current source file.

It can also automatically find an object file if the variable compiled-file-directory is set to the build directory.

Having the path to a binary file of the current source is used by some other packages to automatically switch from source to disassembly and vice-versa.

compdb.el - Work with compilation databases

This package provides utilities for working with compilation databases.

The main API functions are:

• compdb-path

Locate database for FILENAME by scanning directory tree upwards.

• compdb

Get parsed compilation database for a project. The return value is either nil if the database does not exist, or a hash table.

• compdb-compile

Compile the file the current buffer is visiting.

• compdb-switch

Switch the current compilation database. This works by replacing the current compilation database with a symbolic link to the new database.

License

Copyright (C) 2022-2024 Michał Krzywkowski

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at
your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <https://www.gnu.org/licenses/>.