OnServerVoiceDataIsPlayingDemoCallee Patch Workflow

Overview

This Windows-only patch finder converts the already-generated IVEngineClient2_IsPlayingDemo.windows.yaml vfunc metadata into OnServerVoiceData_IsPlayingDemo_Callee.windows.yaml.

The target call site is inside C_ServerVoiceHandler::OnServerVoiceData:

mov     rcx, cs:g_pSource2EngineToClient
mov     rax, [rcx]
call    qword ptr [rax+150h]    ; IVEngineClient2::IsPlayingDemo
test    al, al
jz      short loc_...

The patch address is the address of the indirect call instruction itself.

Prerequisite

The following input YAML must already exist in the current client module output directory:

IVEngineClient2_IsPlayingDemo.windows.yaml

Its required fields are:

func_name: IVEngineClient2_IsPlayingDemo
vtable_name: IVEngineClient2
vfunc_offset: '0x150'
vfunc_index: 42
vfunc_sig: FF 90 50 01 00 00 84 C0 74 ?? 83 FD ??

Deterministic Preprocessor

Run through the configured ida_analyze_bin.py pipeline. The corresponding script is:

ida_preprocessor_scripts/find-OnServerVoiceData_IsPlayingDemo_Callee.py

The script performs these checks without LLM invocation:

1. Rejects every platform except Windows.
2. Reads the input vfunc YAML from the current client output directory.
3. Verifies the function name, vtable name, and vfunc_offset / 8 == vfunc_index relationship.
4. Verifies that vfunc_sig starts with the concrete encoding of call qword ptr [rax+vfunc_offset].
5. Calls IDA MCP find_bytes with the full vfunc_sig and requires exactly one match.
6. Writes the match address as patch_va, derives patch_rva from the image base, copies vfunc_sig to patch_sig, and writes patch_sig_disp: 0.

Output

For game version 14173, the expected output is:

patch_name: OnServerVoiceData_IsPlayingDemo_Callee
patch_va: '0x180aec45d'
patch_rva: '0xaec45d'
patch_sig: FF 90 50 01 00 00 84 C0 74 ?? 83 FD ??
patch_sig_disp: 0

No patch_bytes field is generated because this skill identifies the callee call site; the downstream consumer decides how that call instruction is patched.

Failure Conditions

Stop and report failure when any of the following occurs:

• The input YAML is missing or malformed.
• The vfunc offset and index disagree.
• The signature does not begin at the expected indirect call.
• The signature has zero or multiple matches.
• The match address or image base is invalid.