elf2bin.py

#!/usr/bin/env python3
from elftools.elf.elffile import ELFFile
import sys, itertools
from collections import namedtuple

MEM_SIZE_IN_BYTES = 0x20000	# 128 KB

in_file = sys.argv[1]
out_file = sys.argv[2]

Section = namedtuple("Section", ["header", "data"])

class AddressSpace:
	def __init__(self, left, right):
		self.left = left
		self.right = right
		assert right > left
		diff = right - left
		assert diff % 4 == 0
		self.data = diff*[0]
		
	def load(self, sec):
		dst = sec.header.p_paddr - self.left
		assert dst >= 0
		
		for i,x in enumerate(sec.data):
			self.data[dst+i] = x


with open(in_file, 'rb') as f:
	##print("> process: {}".format(in_file))
	ef = ELFFile(f)
	
	load = []
	null = []
	for x in ef.iter_segments():
		h = x.header
		if h.p_type == "PT_LOAD":
			load.append(Section(h, x.data()))
		if h.p_type == "PT_NULL":
			null.append(Section(h, x.data()))
			
	if len(load) == 0:
		raise RuntimeError("no load section")
			
	left = None
	right = None
	for x,d in itertools.chain(load, null):
		if left is None:
			left = x.p_paddr
		else:
			left = min(left, x.p_paddr)
			
		if right is None:
			right = x.p_paddr + x.p_memsz
		else:
			right = max(right, x.p_paddr + x.p_memsz)

	mem = AddressSpace(left, right)
	for x in itertools.chain(load, null):
		mem.load(x)
	
	with open(out_file, "w") as of:
		bytes = list(mem.data)
		bytes.extend((MEM_SIZE_IN_BYTES - len(bytes))*[0])
		if len(bytes) > MEM_SIZE_IN_BYTES:
			raise RuntimeError("executable does not fit into memory -- len:" + str(len(bytes)))
		s = ' '.join(["{:02X}".format(e) for e in bytes]) + "\n"
		of.write(s)