esp_bin2elf.py

# esp-bin2elf written by Joel Sandin <jsandin@gmail.com>
#
# MIT licence
#
# based on the excellent reversing / writeup from Richard Burton:
# http://richard.burtons.org/2015/05/17/esp8266-boot-process/

from esp_rom import EspRom
from esp_elf import XtensaElf, ElfSection, default_section_settings
from esp_bootrom import get_bootrom_contents, symbols


def parse_rom(rom_name, rom_filename, flash_layout, offset=0):
    with open(rom_filename, 'rb') as f:
        rom = EspRom(rom_name, f, flash_layout, offset=offset)

    return rom


def name_sections(rom):
    addr_to_section_name_mapping = {}

    print("Select a unique name for each section in the rom.")
    print("Sensible defaults are available for the following common names:")
    print(" ".join(list(default_section_settings.keys())))
    print("If defaults are unavailable for a name, generic values will be used.")

    for section in rom.sections:
        name = input("Enter a name for 0x%04x> " % section.address)
        addr_to_section_name_mapping[section.address] = name

    return addr_to_section_name_mapping


def convert_rom_to_elf(esp_rom, addr_to_section_name_mapping, filename_to_write=None):
    elf = XtensaElf(esp_rom.name + '.elf', esp_rom.header.entry_addr)

    bootrom_bytes = get_bootrom_contents()
    bootrom_section = ElfSection('.bootrom.text', 0x40000000, bootrom_bytes)
    elf.add_section(bootrom_section, True)

    for section in esp_rom.sections:
        if section.address not in addr_to_section_name_mapping:
            print("Generation failed: no name for 0x%04x." % section.address)
            return None

        name = addr_to_section_name_mapping[section.address]
        elf_section = ElfSection(name, section.address, section.contents)
        elf.add_section(elf_section, True)

    for name, addr in symbols.items():
        elf.add_symbol(name, addr, '.bootrom.text')

    elf.generate_elf()

    if filename_to_write:
        elf.write_to_file(filename_to_write)

    return elf