#!/usr/bin/env python3
"""Dump a CardsDLL vtable as image VAs, and find sibling vtables that hold a
different function in the same slot (a type/mode dispatch).

    vtab.py <slot_image_va_hex> [before] [after]
"""
import glob
import os
import re
import struct
import sys

CARDS_IMG = 0x180000000


def pid():
    for d in glob.glob("/proc/[0-9]*"):
        try:
            if open(os.path.join(d, "comm")).read().strip() == "FIFA17.exe":
                return int(os.path.basename(d))
        except OSError:
            pass
    raise SystemExit("no FIFA17.exe")


P = pid()
BASE = [int(l.split("-")[0], 16) for l in open(f"/proc/{P}/maps") if "CardsDLL" in l][0]


def img2live(va):
    return BASE + (va - CARDS_IMG)


def live2img(la):
    return CARDS_IMG + (la - BASE)


slot = int(sys.argv[1], 16)
before = int(sys.argv[2]) if len(sys.argv) > 2 else 10
after = int(sys.argv[3]) if len(sys.argv) > 3 else 10

mem = open(f"/proc/{P}/mem", "rb", 0)
start = slot - before * 8
mem.seek(img2live(start))
buf = mem.read((before + after) * 8)
print(f"  vtable neighbourhood of image 0x{slot:x}")
target = None
for k in range(0, len(buf) - 7, 8):
    a = start + k
    p = struct.unpack_from("<Q", buf, k)[0]
    ivа = live2img(p) if BASE <= p < BASE + 0x400000 else None
    mark = " <== the team-pair assigner" if a == slot else ""
    if a == slot:
        target = ivа
    print(f"    0x{a:x} [{a-slot:+#5x}] -> "
          + (f"image 0x{ivа:x}" if ivа else f"raw 0x{p:x}") + mark)

# Find every other .rdata slot pointing at a DIFFERENT function but whose
# neighbours overlap this vtable -> sibling implementations of the same slot.
print("\n  === sibling vtables: same neighbour, different slot function ===")
mem.seek(img2live(0x1801e5000))
rdata = mem.read(0x28a000 - 0x1e5000)
# take the two neighbours around the slot as a signature
sig_prev = struct.unpack_from("<Q", buf, (before - 1) * 8)[0]
sig_next = struct.unpack_from("<Q", buf, (before + 1) * 8)[0]
found = 0
for name, sig in (("preceding", sig_prev), ("following", sig_next)):
    pat = struct.pack("<Q", sig)
    i = rdata.find(pat)
    while i >= 0:
        if i % 8 == 0:
            here = 0x1801e5000 + i
            # the slot in THIS vtable at the same relative position
            off = i + (8 if name == "preceding" else -8)
            if 0 <= off <= len(rdata) - 8:
                fn = struct.unpack_from("<Q", rdata, off)[0]
                if BASE <= fn < BASE + 0x400000:
                    fimg = live2img(fn)
                    if fimg != target:
                        print(f"    vtable @image 0x{here:x} ({name} matches) "
                              f"slot -> image 0x{fimg:x}  DIFFERENT")
                        found += 1
        i = rdata.find(pat, i + 1)
print(f"    {found} sibling implementation(s)")