find-centitysystem-addentityioevent

name	find-CEntitySystem_AddEntityIOEvent
description	Find and identify the CEntitySystem_AddEntityIOEvent function in CS2 binary using IDA Pro MCP. Use this skill when reverse engineering CS2 server.dll or server.so to locate the AddEntityIOEvent function by searching for the "_DisableUpdateTarget" string reference and analyzing cross-references to find the function called with "SetPosition" parameter.

Find CEntitySystem_AddEntityIOEvent

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

Method

1. Search for the input event string:

   mcp__ida-pro-mcp__find_regex pattern="_DisableUpdateTarget"
   

2. Get cross-references to the string:

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

3. Decompile the referencing functions to find the pattern:

   mcp__ida-pro-mcp__decompile addr="<function_addr>"
   

4. Identify the CEntitySystem_AddEntityIOEvent function:

   • Look for a function that contains calls to a function with "SetPosition" as a parameter
   • The pattern looks like:

     sub_XXXXXX(qword_XXXXXX, a1, "_DisableUpdateTarget", a1, a1, 0, 0, 0LL, 0LL);
     // ... setup code ...
     sub_YYYYYYYY(qword_XXXXXX, a1, "SetPosition", a1, a1, &v27, v16, v20, 0LL, 0LL);
     

   • The function sub_YYYYYYYY called with "SetPosition" parameter is CEntitySystem_AddEntityIOEvent

5. Rename the function:

   mcp__ida-pro-mcp__rename batch={"func": [{"addr": "<function_addr>", "name": "CEntitySystem_AddEntityIOEvent"}]}
   

6. Generate and validate unique signature:

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

7. Write IDA analysis output as YAML beside the binary:

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

   Required parameters:

   • func_name: CEntitySystem_AddEntityIOEvent
   • func_addr: The function address from step 4
   • func_sig: The validated signature from step 6

String References

The function is identified by finding code that:

• Calls CEntitySystem_FireEntityIOEvent (or similar) with "_DisableUpdateTarget"
• Then calls CEntitySystem_AddEntityIOEvent multiple times with "SetPosition"
• Finally calls with "_EnableUpdateTarget"

Function Characteristics

• Parameters:

  • arg0: Entity system pointer (global)
  • arg1: Target entity pointer
  • arg2: Input name (const char*, e.g., "SetPosition")
  • arg3: Activator entity
  • arg4: Caller entity
  • arg5: Value pointer
  • arg6: Delay (float as int)
  • arg7: Output ID
  • arg8: Reserved (0)
  • arg9: Reserved (0)

• Purpose: Adds an entity I/O event to be fired after a specified delay

Related Functions

• CEntitySystem_FireEntityIOEvent - Fires entity I/O events immediately (called with "_DisableUpdateTarget", "_EnableUpdateTarget")
• CEntitySystem_AddEntityIOEvent - Queues entity I/O events with delay (called with "SetPosition")

Output YAML Format

The output YAML filename depends on the platform:

• server.dll → CEntitySystem_AddEntityIOEvent.windows.yaml
• server.so → CEntitySystem_AddEntityIOEvent.linux.yaml

func_va: 0x181170ed0   # Virtual address of the function - This can change when game updates.
func_rva: 0x1170ed0    # Relative virtual address (VA - image base) - This can change when game updates.
func_size: 0x1e3       # Function size in bytes - This can change when game updates.
func_sig: XX XX XX XX XX  # Unique byte signature for pattern scanning - This can change when game updates.