[Dhooks] Add the ability to work with the this parameter, which is an object #2219

A1mDev · 2024-11-11T06:19:26Z

Sometimes we have to work with this parameter which is a class but dhooks doesn't have this feature, this PR solves this problem. This code has been tested on both post and pre hooks. Below is an example code for working with the new functionality.

/*class CBaseEntity : public IServerEntity
{
	...
protected:
	EHANDLE m_pParent;  // for movement hierarchy	
	...
};*/

MRESReturn Handler_CBaseEntity__OnTakeDamage(Address pThis, Handle hReturn, Handle hParams)
{
	// If EHANDLE type or entity returns entity index.
	// Index num 0, for working with this parameter

	int iParent = DHookGetParamObjectPtrVar(hParams, 0, 384, ObjectValueType_Ehandle);
	if (iParent < 1 || !IsValidEntity(iParent)) {
		return MRES_Ignored;
	}

	char sEntityName[64];
	GetEntityClassname(iParent, sEntityName, sizeof(sEntityName));
	
	PrintToChatAll("[Handler_CBaseEntity__OnTakeDamage] iParent: %s (%d)", sEntityName, iParent);
	
	return MRES_Ignored;
}

Kenzzer

Excellent work, especially given the situation that surround Address. The less we mess with memory directly in plugin, the better !
I just have a few request changes, but otherwise I think this is a good addition to dhooks.

Kenzzer · 2024-11-18T13:13:26Z

extensions/dhooks/natives.cpp

+		/*HookSetup* setup;
+		if(!GetHandleIfValidOrError(g_HookSetupHandle, (void **)&setup, pContext, params[1]))
+		{
+			return pContext->ThrowNativeError("Cannot determine calling convention type, parameter 'this' is only available in member functions");
+		}

-	size_t offset = GetParamOffset(paramStruct, index);
-	void *addr = GetObjectAddr(paramStruct->dg->params.at(index).type, paramStruct->dg->params.at(index).flags, paramStruct->orgParams, offset);
+		if(setup->callConv != CallConv_THISCALL)
+		{
+			return pContext->ThrowNativeError("Parameter 'this' is only available in member functions, specify the calling convention type 'thiscall'");
+		}*/


That check is fine, you should enable it!

This code doesn't work for some reason

Oh yeah we need to pass Handle as the first parameter but we don't so this code doesn't work

I don't know how to get handle in existing code, I'll have to save it somewhere, or use such code to work with the "this" parameter:
int iParent = DHookGetParamObjectPtrVar(hParams, 0, 384, ObjectValueType_Ehandle, g_hDetour);

Kenzzer · 2024-11-18T13:15:28Z

extensions/dhooks/natives.cpp

+		if(paramStruct->dg->thisType != ThisPointer_Address)
+		{
+			return pContext->ThrowNativeError("Parameter 'this' is not specified as an address, it is not available");
+		}


That check should be removed, thispointer type is only relevant for the dhooks callbacks. Plus it would be nice being able to manipulate directly CBaseEntity or CGamerRules, which uses thispointer_cbaseentity and thispointer_ignore respectively.

Kenzzer · 2024-11-18T13:15:57Z

extensions/dhooks/natives.cpp

+		/*HookSetup* setup;
+		if(!GetHandleIfValidOrError(g_HookSetupHandle, (void **)&setup, pContext, params[1]))
+		{
+			return pContext->ThrowNativeError("Cannot determine calling convention type, parameter 'this' is only available in member functions");
+		}
+
+		if(setup->callConv != CallConv_THISCALL)
+		{
+			return pContext->ThrowNativeError("Parameter 'this' is only available in member functions, specify the calling convention type 'thiscall'");
+		}*/
+
+		if(paramStruct->dg->thisType != ThisPointer_Address)
+		{
+			return pContext->ThrowNativeError("Parameter 'this' is not specified as an address, it is not available");
+		}


Kenzzer · 2024-11-18T13:16:09Z

extensions/dhooks/natives.cpp

+		/*HookSetup* setup;
+		if(!GetHandleIfValidOrError(g_HookSetupHandle, (void **)&setup, pContext, params[1]))
+		{
+			return pContext->ThrowNativeError("Cannot determine calling convention type, parameter 'this' is only available in member functions");
+		}

-	size_t offset = GetParamOffset(paramStruct, index);
-	void *addr = GetObjectAddr(paramStruct->dg->params.at(index).type, paramStruct->dg->params.at(index).flags, paramStruct->orgParams, offset);
+		if(setup->callConv != CallConv_THISCALL)
+		{
+			return pContext->ThrowNativeError("Parameter 'this' is only available in member functions, specify the calling convention type 'thiscall'");
+		}*/
+
+		if(paramStruct->dg->thisType != ThisPointer_Address)
+		{
+			return pContext->ThrowNativeError("Parameter 'this' is not specified as an address, it is not available");
+		}
+
+		addr = g_SHPtr->GetIfacePtr();


Kenzzer · 2024-11-18T19:11:37Z

extensions/dhooks/natives.cpp

-	if(paramStruct->dg->params.at(index).type != HookParamType_ObjectPtr && paramStruct->dg->params.at(index).type != HookParamType_Object)
-	{
-		return pContext->ThrowNativeError("Invalid object value type %i", paramStruct->dg->params.at(index).type);
+		if(paramStruct->dg->params.at(index).type != HookParamType_ObjectPtr && paramStruct->dg->params.at(index).type != HookParamType_Object)
+		{
+			return pContext->ThrowNativeError("Invalid object value type %i", paramStruct->dg->params.at(index).type);
+		}
+
+		size_t offset = GetParamOffset(paramStruct, index);
+		addr = GetObjectAddr(paramStruct->dg->params.at(index).type, paramStruct->dg->params.at(index).flags, paramStruct->orgParams, offset);
 	}
+	else
+	{
+		/*HookSetup* setup;
+		if(!GetHandleIfValidOrError(g_HookSetupHandle, (void **)&setup, pContext, params[1]))
+		{
+			return pContext->ThrowNativeError("Cannot determine calling convention type, parameter 'this' is only available in member functions");
+		}

-	size_t offset = GetParamOffset(paramStruct, index);
-	void *addr = GetObjectAddr(paramStruct->dg->params.at(index).type, paramStruct->dg->params.at(index).flags, paramStruct->orgParams, offset);
+		if(setup->callConv != CallConv_THISCALL)
+		{
+			return pContext->ThrowNativeError("Parameter 'this' is only available in member functions, specify the calling convention type 'thiscall'");
+		}*/
+
+		if(paramStruct->dg->thisType != ThisPointer_Address)
+		{
+			return pContext->ThrowNativeError("Parameter 'this' is not specified as an address, it is not available");
+		}
+
+		addr = g_SHPtr->GetIfacePtr();
+	}


extensions/dhooks/natives.cpp

Kenzzer · 2024-11-18T19:12:22Z

extensions/dhooks/natives.cpp

+	void *addr = NULL;
+
+	if(params[2] != 0)
 	{
-		return pContext->ThrowNativeError("Invalid param number %i max params is %i", params[2], paramStruct->dg->params.size());
-	}
+		if(params[2] <= 0 || params[2] > (int)paramStruct->dg->params.size())
+		{
+			return pContext->ThrowNativeError("Invalid param number %i max params is %i", params[2], paramStruct->dg->params.size());
+		}

-	int index = params[2] - 1;
+		int index = params[2] - 1;

-	if(paramStruct->dg->params.at(index).type != HookParamType_ObjectPtr && paramStruct->dg->params.at(index).type != HookParamType_Object)
-	{
-		return pContext->ThrowNativeError("Invalid object value type %i", paramStruct->dg->params.at(index).type);
+		if(paramStruct->dg->params.at(index).type != HookParamType_ObjectPtr && paramStruct->dg->params.at(index).type != HookParamType_Object)
+		{
+			return pContext->ThrowNativeError("Invalid object value type %i", paramStruct->dg->params.at(index).type);
+		}
+
+		size_t offset = GetParamOffset(paramStruct, index);
+		addr = GetObjectAddr(paramStruct->dg->params.at(index).type, paramStruct->dg->params.at(index).flags, paramStruct->orgParams, offset);
 	}
+	else
+	{
+		/*HookSetup* setup;
+		if(!GetHandleIfValidOrError(g_HookSetupHandle, (void **)&setup, pContext, params[1]))
+		{
+			return pContext->ThrowNativeError("Cannot determine calling convention type, parameter 'this' is only available in member functions");
+		}

-	size_t offset = GetParamOffset(paramStruct, index);
-	void *addr = GetObjectAddr(paramStruct->dg->params.at(index).type, paramStruct->dg->params.at(index).flags, paramStruct->orgParams, offset);
+		if(setup->callConv != CallConv_THISCALL)
+		{
+			return pContext->ThrowNativeError("Parameter 'this' is only available in member functions, specify the calling convention type 'thiscall'");
+		}*/
+
+		if(paramStruct->dg->thisType != ThisPointer_Address)
+		{
+			return pContext->ThrowNativeError("Parameter 'this' is not specified as an address, it is not available");
+		}
+
+		addr = g_SHPtr->GetIfacePtr();
+	}


A1mDev added 4 commits November 11, 2024 11:34

Update natives.cpp

2d008c1

Merge branch 'master' into dhooks-update

a262653

Update dhooks.inc

9c07ebe

Non-working code commented out

358eef1

Kenzzer requested changes Nov 18, 2024

View reviewed changes

A1mDev added 2 commits November 19, 2024 09:34

Update natives.cpp

945499b

Allow working with the parameter "this", which is a class CBaseEntity

88024a7

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

[Dhooks] Add the ability to work with the this parameter, which is an object #2219

[Dhooks] Add the ability to work with the this parameter, which is an object #2219

A1mDev commented Nov 11, 2024 •

edited

Loading

Kenzzer left a comment

Kenzzer Nov 18, 2024

A1mDev Nov 19, 2024

A1mDev Nov 19, 2024

A1mDev Nov 19, 2024

Kenzzer Nov 18, 2024

Kenzzer Nov 18, 2024

Kenzzer Nov 18, 2024

Kenzzer Nov 18, 2024

Kenzzer Nov 18, 2024

[Dhooks] Add the ability to work with the this parameter, which is an object #2219

Are you sure you want to change the base?

[Dhooks] Add the ability to work with the this parameter, which is an object #2219

Conversation

A1mDev commented Nov 11, 2024 • edited Loading

Kenzzer left a comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

A1mDev commented Nov 11, 2024 •

edited

Loading