kallsyms.py

import argparse

from construct import Int16ul, Int64ul

def main(args):
    with open(args.kernel, 'rb') as f:
        data = f.read()

    sym_addrs = data.find(Int64ul.build(0xffffff8008080000) * 2)
    for offset in range(0, len(data), 0x100):
        count = Int64ul.parse(data[offset:offset + 8])
        if count >= 0x1000 and count <= 0x20000:
            if data[offset + 8:offset + 0x100] == b'\x00' * (0x100 - 8):
                sym_names = offset + 0x100
                sym_count = count

    #print("[*] Symbols count = %d" % sym_count)
    #print("[*] Symbols addresses = %#x" % sym_addrs)
    #print("[*] Symbols names = %#x" % sym_names)

    for offset in range(0, len(data), 0x100):
        last = 0
        for token in range(1, 200):
            curr = Int16ul.parse(data[offset + token * 2:offset + (token + 1) * 2])
            if curr > last:
                last = curr
            else:
                break
        else:
            token_index = offset

    token_table = token_index - 1
    while data[token_table:token_table + 1] == b'\x00':
        token_table -= 1
    while data[token_table:token_table + 2] != b'\x00\x00':
        token_table -= 1
    token_table += 2

    #print("[*] Token Table = %#x" % token_table)
    #print("[*] Token Index = %#x" % token_index)

    nametbl = []
    tokentbl = []
    for i in range(256):
        idx = Int16ul.parse(data[token_index + i * 2:token_index + (i + 1) * 2])
        token = b""
        j = 0
        while data[token_table + idx + j:token_table + idx + j + 1] != b'\x00':
            token += data[token_table + idx + j: token_table + idx + j + 1]
            j += 1
        # print("token %d: %s" % (i, token))
        tokentbl.append(token)
    
    for i in range(sym_count):
        nlen = data[sym_names]
        sym_names += 1
        name = b""
        while nlen > 0:
            j = data[sym_names]
            # print("j: %d, token: %s" % (j, tokentbl[j]))
            name += tokentbl[j]
            sym_names += 1
            nlen -= 1
        # print("Name %d: %s" % (i, name))
        nametbl.append(name)

        addr = Int64ul.parse(data[sym_addrs + i * 8:sym_addrs + (i + 1) * 8])
        print("%016x %s %s" % (addr, chr(name[0]), name[1:].decode("utf-8")))

if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('kernel')
    main(parser.parse_args())