LibObjectFile is a .NET library to read, manipulate and write linker and executable object files (e.g ELF, ar, DWARF, COFF...)

NOTE: Currently LibObjectFile supports only the following file format:

• ELF object-file format
• DWARF debugging format (version 4)
• Archive ar file format (Common, GNU and BSD variants)

There is a longer term plan to support other file formats (e.g COFF, MACH-O, .lib) but as I don't have a need for them right now, it is left as an exercise for PR contributors! ;)

// Reads an ELF file
using var inStream = File.OpenRead("helloworld");
var elf = ElfObjectFile.Read(inStream);
foreach(var section in elf.Sections)
{
    Console.WriteLine(section.Name);
}
// Print the content of the ELF as readelf output
elf.Print(Console.Out);
// Write the ElfObjectFile to another file on the disk
using var outStream = File.OpenWrite("helloworld2");
elf.Write(outStream);

• Full support of Archive ar file format including Common, GNU and BSD variants.
• Good support for the ELF file format:
  • Read and write from/to a System.IO.Stream
  • Handling of LSB/MSB
  • Support the following sections:
    • String Table
    • Symbol Table
    • Relocation Table: supported I386, X86_64, ARM and AARCH64 relocations (others can be exposed by adding some mappings)
    • Note Table
    • Other sections fallback to ElfCustomSection
  • Program headers with or without sections
  • Print with readelf similar output
• Support for DWARF debugging format:
  • Partial support of Version 4 (currently still the default for GCC)
  • Support for the sections: .debug_info, .debug_line, .debug_aranges, .debug_abbrev and .debug_str
  • Support for Dwarf expressions
  • High level interface, automatic layout/offsets between sections.
  • Integration with ELF to support easy reading/writing back
  • Support for relocatable sections
• Use of a Diagnostics API to validate file format (on read/before write)
• Library requiring net8.0
  • If you are looking for netstandard2.1 support you will need to use 0.4.0 version

The doc/readme.md explains how the library is designed and can be used.

PR Welcome if you are willing to contribute to one of these issues:

• Add more unit tests

There are still a few missing implementation of ElfSection for completeness:

• Dynamic Linking Table (SHT_DYNAMIC)
• Version Symbol Table (SHT_VERSYM)
• Version Needs Table (SHT_VERNEED)

These sections are currently loaded as ElfCustomSection but should have their own ElfXXXTable (e.g ElfDynamicLinkingTable, ElfVersionSymbolTable...)

• Version 4: support for .debug_types, .debug_frame, .debug_loc, .debug_ranges, .debug_pubnames, .debug_pubtypes, .debug_macinfo section
• Version 5

In a future version I would like to implement the following file format:

• COFF
• Mach-O
• Portable in Memory file format to easily convert between ELF/COFF/Mach-O file formats.

LibObjectFile is available as a NuGet package:

In order to build LibObjectFile, you need to have installed the .NET 8 SDK.

Running the tests require Ubuntu 22.04. dotnet test will work on Windows (via WSL) and on that version of Ubuntu. If you're using macOS or another Linux, there's a Dockerfile and a helper script under src to run tests in the right OS version.

This software is released under the BSD-Clause 2 license.

Alexandre MUTEL aka xoofx

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