havoc-remaster/tools/find_cdpath.py
pyr0ball 27174a1c79 feat: NOCD patch boots Havoc on modern Windows (defeats CD copy protection)
Diagnosed and fixed the crash that killed HAVOC_NOCD.EXE ~1s after launch
(dgVoodoo window appears black, then the process exits). It was not a clean
exit: an ACCESS_VIOLATION (null-pointer read at VA 0x444E6A) during init.

Root cause is a copy-protection check in the WORLDS\ data-file loader
(0x42a480). It opens each file (GRAFIX/LAND/MAP/STUF) from both a local
"WORLDS\<name>" path and a CD-drive path (HAVOC.INI [SETUP] DRIVE=D:\), and
returns a valid stream only when the local open fails and the CD-drive open
succeeds. With files present locally and no D: drive it returned NULL, and the
GRAFIX loader (0x444db0) dereferenced that NULL without checking.

Fix: 14-byte patch at FO 0x29a2b rewrites the return decision to hand back the
successfully-opened local object. The game now boots to the title screen
("HAVOC(tm) by Reality Bytes"), responsive, main loop running.

- docs/PATCHES.md: full patch table (28 patches) + crash write-up
- tools/: RE + patching scripts (r2pipe disasm, minidump parser, ctypes
  debugger, PE/IAT/import analysis)
- run_probe.bat / run_and_log.bat: reliable native launch for repro
- .gitignore: exclude CD images, Ghidra install/project, dgVoodoo, *.ini

Diagnosed via WER minidumps (%LOCALAPPDATA%\CrashDumps) parsed in pure Python
(no cdb/windbg available).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TN4Ytn3gdWRonNmHpisWQv
2026-07-03 09:29:59 -07:00

48 lines
1.7 KiB
Python

import struct, sys, io, r2pipe
sys.stdout = io.TextIOWrapper(sys.stdout.buffer, encoding='utf-8', errors='replace')
data = open('HAVOC_NOCD.EXE','rb').read()
FO2VA = lambda fo: fo + 0x400C00
VA2FO = lambda va: va - 0x400C00
r2 = r2pipe.open("Z:/Development/devl/Havoc/HAVOC_NOCD.EXE",
["-e", "bin.relocs.apply=true"])
# String at FO 0x6B2D4 = VA 0x46BED4: "DRIVE\0\0\0"
# String at FO 0x6B2DC = VA 0x46BEDC: "D:\"
# String at FO 0x6B2E0 = VA 0x46BEE0: "HAVOC"
drive_va = 0x46bed4
havoc_va = 0x46bee0
dcolon_va = 0x46bedc
print("=== Callers that push DRIVE VA 0x46BED4 or D:\\ VA 0x46BEDC ===")
for target in [drive_va, havoc_va, dcolon_va]:
for fo in range(0x400, 0x67000):
if data[fo] == 0x68:
imm = struct.unpack_from('<I', data, fo+1)[0]
if imm == target:
print(" PUSH 0x%08x at FO 0x%05x VA 0x%08x" % (target, fo, FO2VA(fo)))
# Also search for the string "HAVOC" as a MOV target (could be hard-coded path)
print()
# Show the full data block at 0x6B270-0x6B320
print("=== Data at 0x46BE70-0x46BF40 (file list area) ===")
start = VA2FO(0x46be70)
for fo2 in range(start, start + 0xD0, 16):
chunk = data[fo2:fo2+16]
hex_part = ' '.join('%02x' % b for b in chunk)
asc_part = ''.join(chr(b) if 32 <= b < 127 else '.' for b in chunk)
print("VA 0x%08x: %-47s %s" % (FO2VA(fo2), hex_part, asc_part))
print()
# Now find what code READS HAVOC.INI DRIVE key
print("=== Callers of SETUP/DRIVE/D:\\ area ===")
setup_va = None
# Find "SETUP" string
pos = data.find(b'SETUP\x00')
while pos != -1:
print(" 'SETUP' at FO 0x%05x VA 0x%08x" % (pos, FO2VA(pos)))
pos = data.find(b'SETUP\x00', pos+1)
r2.quit()