Parse __TEXT __text segment for Mach-O binary in python

parse_text_segment.py

#!/usr/bin/env python3

from macholib.MachO import MachO
import os
import hashlib

# Taken and a bit modified from https://www.programcreek.com/python/example/111986/macholib.MachO.MachO
def extract_shellcode(filename):
    macho_filename = filename
    fileoffset = 0
    shellcodesize = 0
    m = MachO(macho_filename)
    for (load_cmd, cmd, data) in m.headers[0].commands:
        if data:
            if hasattr(data[0], "sectname"):
                sectionName = str(getattr(data[0], 'sectname', ''))
                if "text" in sectionName:
                    fileoffset=data[0].offset
                    shellcodesize+=data[0].size
                    break
    with open(macho_filename, 'rb') as f:
        f.seek(fileoffset, 1)
        print("read __text section from {} with length {}".format(fileoffset, shellcodesize))
        shellcode_bytes = f.read(shellcodesize)

        h = hashlib.sha256()
        h.update(shellcode_bytes)
        print(h.hexdigest())

        f.close()

    
path = '../MyApp.app/MyApp'
extract_shellcode(path)