find-CBaseEntity_GetHammerUniqueId

Find CBaseEntity_GetHammerUniqueId

Locate CBaseEntity_GetHammerUniqueId in CS2 server.dll or libserver.so using IDA Pro MCP tools.

Method

1. Search for Reference String

Search for the string "hammerUniqueId":

mcp__ida-pro-mcp__find_regex pattern="hammerUniqueId"

Note the string address.

2. Find Cross-References

Get xrefs to the string address:

mcp__ida-pro-mcp__xrefs_to addrs="<string_address>"

There may be multiple xrefs. The target function is a small function (~0x146 bytes) that matches the code pattern below. Decompile each candidate to find the match.

3. Identify the Target Function

Decompile each candidate and look for this code pattern:

Windows binary:

void __fastcall sub_180XXXXXX(__int64 a1, _QWORD *a2)
{
  //...

  if ( (*(unsigned __int8 (__fastcall **)(__int64))(*(_QWORD *)qword_XXXXXXXXX + 176LL))(qword_XXXXXXXXX)
    || (*(unsigned __int8 (__fastcall **)(__int64))(*(_QWORD *)a1 + <vfunc_offset>LL))(a1) )  // <-- vfunc_offset for CBaseEntity_GetHammerUniqueId
  {
    v7[0] = -1453088712LL;
    v7[1] = "hammerUniqueId";
    v5 = (_QWORD *)sub_XXXXXXXXX(a2, (int *)v7, 0LL);
    if ( v5 && ((*(_BYTE *)v5 >> 2) & 0xF) == 6 )
      v6 = sub_XXXXXXXXX(v5, (__int64)byte_XXXXXXXXX);
    else
      v6 = byte_XXXXXXXXX;
    CUtlString::Set((CUtlString *)(a1 + <member_offset>), v6);
  }
}

Linux binary:

__int64 __fastcall sub_XXXXXX(_BYTE *a1, __int64 a2)
{
  //...

  if ( (*(unsigned __int8 (__fastcall **)(_QWORD *))(*qword_XXXXXXX + 184LL))(qword_XXXXXXX)
    || (result = (*(__int64 (__fastcall **)(_BYTE *))(*(_QWORD *)a1 + <vfunc_offset>LL))(a1), (_BYTE)result) )  // <-- vfunc_offset for CBaseEntity_GetHammerUniqueId
  {
    v8 = -1453088712LL;
    v9 = "hammerUniqueId";
    v6 = (_WORD *)sub_XXXXXXX(a2, &v8, 0LL);
    v7 = &byte_XXXXXXX;
    if ( v6 )
    {
      if ( ((*v6 >> 2) & 0xF) == 6 )
        v7 = (const char *)sub_XXXXXXX(v6, &byte_XXXXXXX);
    }
    return sub_XXXXXXX(a1 + <member_offset>, v7);
  }
  return result;
}

Key identifying traits:

• OR condition: a global vtable call (offset ~176/184) OR a vtable call on a1 at <vfunc_offset>
• Constant -1453088712 (0xA9540B48) used as a hash/key
• String "hammerUniqueId" stored immediately after
• Result written via CUtlString::Set to a member of a1

Extract <vfunc_offset> from the second branch of the OR condition (the call on a1). This is the CBaseEntity_GetHammerUniqueId vtable offset.

Note the instruction address of that vtable call for signature generation.

Calculate:

• VTable Offset: The value from the pattern (e.g., Windows: 888 = 0x378, Linux: 880 = 0x370)
• VTable Index: offset / 8 (e.g., 888 / 8 = 111)

4. Generate vfunc offset signature for CBaseEntity_GetHammerUniqueId

ALWAYS Use SKILL /generate-signature-for-vfuncoffset to generate a robust and unique signature for CBaseEntity_GetHammerUniqueId, with inst_addr and vfunc_offset from step 3.

5. Write Analysis Results as YAML

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

Required parameters:

• func_name: CBaseEntity_GetHammerUniqueId
• vfunc_sig: <vfunc_sig> from step 4

VTable parameters:

• vtable_name: CBaseEntity
• vfunc_index: The vtable index from step 3
• vfunc_offset: The vtable offset from step 3

VTable Information

• VTable Name: CBaseEntity::vftable'`
• VTable Mangled Name (Windows): ??_7CBaseEntity@@6B@
• VTable Mangled Name (Linux): _ZTV11CBaseEntity
• VTable Index: 111 - This can change when game updates.
• VTable Offset: 0x378 (111 * 8 = 888) - This can change when game updates.

• Note that for libserver.so, the first 16 bytes of "vftable" are for RTTI. The real vftable = _ZTV11CBaseEntity + 0x10.

Output YAML Format

The output YAML filename depends on the platform:

• server.dll -> CBaseEntity_GetHammerUniqueId.windows.yaml
• libserver.so -> CBaseEntity_GetHammerUniqueId.linux.yaml

func_name: CBaseEntity_GetHammerUniqueId
vfunc_sig: <vfunc_sig>
vtable_name: CBaseEntity
vfunc_offset: '0x378'
vfunc_index: 111

Notes

• This virtual function returns a boolean indicating whether the entity has a Hammer unique ID.
• The containing function uses the result to conditionally read a "hammerUniqueId" key from KeyValues and store it as a CUtlString member on the entity.
• Windows and Linux have slightly different vfunc offsets due to vtable layout differences (Windows: 888, Linux: 880 in recent builds).