remap.py

#!/usr/bin/env python3

import sys, os
from io import BytesIO
from argparse import ArgumentParser

# pip3 install k2l
import ktool
from kmacho import CPUSubTypeARM64

slices = []

def handle_file(fp) -> BytesIO:
    macho_file = ktool.load_macho_file(fp)
    new_slice_fp = BytesIO()

    for macho_slice in macho_file.slices:
        if macho_slice.subtype == CPUSubTypeARM64.ARM64E2:
            new_slice_fp.write(macho_slice.full_bytes_for_slice())
            new_slice_fp.seek(0)
        
        slices.append(macho_slice)
    
    img = ktool.load_image(new_slice_fp, use_mmaped_io=False)
    img.macho_header.dyld_header.cpu_subtype = CPUSubTypeARM64.ARM64E.value

    # isn't really designed to operate perfectly on non-existient files,
    # but we can make it work
    img.slice.patch(0, img.macho_header.dyld_header.raw)
    new_image_fp = BytesIO()
    new_image_fp.write(img.slice.full_bytes_for_slice())
    new_image_fp.seek(0)
    img = ktool.load_image(new_image_fp, use_mmaped_io=False)

    slices.append(img.slice)
    
    fat_out = ktool.macho_combine(slices)
    fat_out.seek(0)  # ktool should be doing this, but just to be safe.
    return fat_out

if __name__ == "__main__":
    
    parser = ArgumentParser(description="remap")
    
    parser.add_argument('--out', dest='out', default=None)
    parser.add_argument('filename', nargs='?', default='')
    
    args = parser.parse_args()
    
    if args.filename == '':
        parser.print_help()
        exit(1)

    try:
        with open(args.filename, 'rb') as fp:
            out = handle_file(fp)
        with open(args.out if args.out else args.filename, 'wb') as fp:
            fp.write(out.read())
    except FileNotFoundError:
        print('File does not exist')
        exit(2)