find-CBaseEntity_Precache

CBaseEntity_Precache Function Location Workflow

Overview

This workflow is used to locate the CBaseEntity_Precache function in CS2 server binary files. This function is a virtual function on CBaseEntity responsible for precaching resources. It can be identified by finding a small wrapper function that calls it with the "bloodspray" string argument.

Location Steps

1. Search for Signature String

Use find_regex to search for the bloodspray string:

mcp__ida-pro-mcp__find_regex(pattern="bloodspray")

Expected result: Find string address (e.g., 0x18170ac18 for Windows, varies by version)

2. Find Cross-References

Use xrefs_to to find locations that reference this string:

mcp__ida-pro-mcp__xrefs_to(addrs="<string_addr>")

Expected result: Find multiple functions referencing the string. Look for the smallest function (size ~0x19) — this is the wrapper that calls CBaseEntity_Precache.

3. Decompile the Small Wrapper

Decompile the small wrapper function to identify the CBaseEntity_Precache call:

mcp__ida-pro-mcp__decompile(addr="<small_wrapper_addr>")

Expected pseudocode pattern:

__int64 __fastcall sub_XXXXXXXX(__int64 a1, __int64 *a2)
{
  sub_YYYYYYYY(a1, a2);       // <-- This is CBaseEntity_Precache
  return sub_ZZZZZZZZ("bloodspray");
}

The first call (sub_YYYYYYYY) that takes (a1, a2) as arguments is CBaseEntity_Precache.

4. Rename Function

Use rename to give the function a meaningful name:

mcp__ida-pro-mcp__rename(batch={"func": {"addr": "<CBaseEntity_Precache_addr>", "name": "CBaseEntity_Precache"}})

5. Find VTable and Calculate Offset

ALWAYS Use SKILL /get-vtable-index to get vtable offset and index for the function.

VTable class name: CBaseEntity

6. Generate and Validate Unique Signature

ALWAYS Use SKILL /generate-signature-for-function to generate a robust and unique signature for CBaseEntity_Precache.

7. Write IDA analysis output as YAML beside the binary

ALWAYS Use SKILL /write-vfunc-as-yaml to write the analysis results.

Required parameters:

• func_name: CBaseEntity_Precache
• func_addr: The function address from step 3
• func_sig: The validated signature from step 6

VTable parameters:

• vtable_name: CBaseEntity
• vfunc_offset: The offset from step 5
• vfunc_index: The index from step 5

Function Characteristics

The CBaseEntity_Precache function is identified indirectly through a small wrapper function that:

1. Calls CBaseEntity_Precache(a1, a2) as its first statement
2. Then calls another function with the "bloodspray" string literal

Key identification points:

• bloodspray - The string used in the wrapper to locate CBaseEntity_Precache
• The wrapper function is very small (~0x19 bytes)
• CBaseEntity_Precache itself is a larger function (~0x1B1 bytes on Windows)

VTable Information

• VTable Name: CBaseEntity
• VTable Mangled Name:
  • Windows: ??_7CBaseEntity@@6B@
  • Linux: _ZTV11CBaseEntity
• VTable Offset: 0x30 (may change with game updates)
• VTable Index: 6 (may change with game updates)

Output YAML Format

The output YAML filename depends on the platform:

• server.dll → CBaseEntity_Precache.windows.yaml
• server.so / libserver.so → CBaseEntity_Precache.linux.yaml