Objective-C¶

This module allows to inspect Objective-C metadata from a Mach-O binary.

If a Mach-O binary embeds Objective-C metadata, they can be accessed through lief.MachO.Binary.objc_metadata / LIEF::MachO::Binary::objc_metadata():

macho: lief.MachO.Binary = ...
metadata: lief.objc.Metadata = macho.objc_metadata
if metadata is not None:
    print("Objective-C metadata found")

std::unique_ptr<LIEF::MachO::Binary> macho;
std::unique_ptr<LIEF::objc::Metadata> metadata = macho->objc_metadata();

if (metadata != nullptr) {
  std::cout << "Objective metadata found\n";
}

let macho: lief::macho::Binary;

if let Some(metadata) = macho.objc_metadata() {
    println!("Objective-C metadata found");
}

Then at this point, one can use the API exposed by the class lief.objc.Metadata / LIEF::objc::Metadata to inspect the Objective-C Metadata.

In particular, the function: lief.objc.Metadata.to_decl()/ LIEF::objc::Metadata::to_decl() can be used to generate a header-like output of all the Objective-C metadata found in the binary.

macho: lief.MachO.Binary = lief.parse("some_macho")
metadata: lief.objc.Metadata = macho.objc_metadata
for clazz in metadata.classes:
    print(f"name={clazz.name}")
    for meth in clazz.methods:
        print(f"  method.name={meth.name}")
print(metadata.to_decl())

std::unique_ptr<LIEF::MachO::FatBinary> fat = LIEF::MachO::Parser::parse(argv[1]);
LIEF::MachO::Binary* bin = fat->at(0);

std::unique_ptr<LIEF::objc::Metadata> metadata = bin->objc_metadata();

for (const std::unique_ptr<LIEF::objc::Class>& clazz : metadata->classes()) {
  log(LOG_LVL, "name={}", clazz->name());
  for (const std::unique_ptr<LIEF::objc::Method>& meth : clazz->methods()) {
    log(LOG_LVL, "  method.name={}", meth->name());
  }
}

log(LOG_LVL, metadata->to_decl());

let Some(lief::Binary::MachO(fat)) = lief::Binary::parse(&path) else { process::exit(1); };
let Some(bin) = fat.iter().next() else { process::exit(1); };
let Some(metadata) = bin.objc_metadata() else { process::exit(1); };

for class in metadata.classes() {
    println!("name={}", class.name());
    for method in class.methods() {
        println!("  method.name={}", method.name());
    }
}
println!("{}", metadata.to_decl());

This Objective-C support is based on iCDump which is detailed here:

You can find the documentation of the API for the different languages here:

Python API

C++ API

Rust API: https://lief-rs.s3.fr-par.scw.cloud/doc/latest/lief/index.html