Virtual Offsets (Source Mods)

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Revision as of 04:06, 15 July 2009 by GH0sTy (talk | contribs) (→‎Zombie Panic: Source)
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Calling virtual functions

I got this method from Mani, who I believe got it from Pavol Marko. Thank you!

I hope to expand on an actual explanation when I have the time (and understand it better). Hopefully, someone can expand on this, but for now I'll just post the examples and a list of the CCSPlayer virtual function table offsets.

Offset Lists

Counter-Strike: Source

Day of Defeat: Source

Dystopia

Empires v2.12

Fortress Forever

Half-Life 2: Capture the Flag

Half-Life 2: Deathmatch

Hidden: Source

Insurgency

Left 4 Dead

Obsidian Conflict

Pirates, Vikings, and Knights II

The Ship

SourceForts

Synergy

Synergy SteamWorks (Synergy Orange Box Edition)

Team Fortress 2

Zombie Master

Zombie Panic: Source

GoldenEye: Source

How to use the examples

Basically, this lets you call any virtual function by knowing it's offset. A table is created for each class that lists the address of the function for each virtual function. This method takes advantage of that to call those addresses.

Look at the examples below and edit to match the function you want to call: Use the offset for the function you want to call in this line. (CCSPlayer_offset_list_(SourceMM)) 

void *func = vtable[m_Off_GiveNamedItem];

Change this line to match your return type and parameters: 

union {CBaseEntity *(VfuncEmptyClass::*mfpnew)(const char *, int );

Call the original function with your parameters (change the return type to match the function you're calling): 

return (CBaseEntity *) (reinterpret_cast<VfuncEmptyClass*>(this_ptr)->*u.mfpnew)(ItemName, iSubType);

You'll need to add an empty class for the union. Something like this: 

class VfuncEmptyClass {};

Examples

These examples are for CSS. Mani has created a set of macros to make this easier. If you ask nicely, maybe he'll give them to you or let you post them here. 

datamap_t *VFuncs::GetDataDescMap(CBaseEntity *pThisPtr)
{
	void **this_ptr = *(void ***)&pThisPtr;
	void **vtable = *(void ***)pThisPtr;
	void *func = vtable[m_Off_GetDataDescMap]; 
 
	union {datamap_t *(VfuncEmptyClass::*mfpnew)();
#ifndef __linux__
        void *addr;	} u; 	u.addr = func;
#else /* GCC's member function pointers all contain a this pointer adjustor. You'd probably set it to 0 */
			struct {void *addr; intptr_t adjustor;} s; } u; u.s.addr = func; u.s.adjustor = 0;
#endif
 
	return (datamap_t *) (reinterpret_cast<VfuncEmptyClass*>(this_ptr)->*u.mfpnew)();
 
}
 
void VFuncs::SetModel(CBaseEntity *pThisPtr, const char *ModelName)
{
	void **this_ptr = *(void ***)&pThisPtr;
	void **vtable = *(void ***)pThisPtr;
	void *func = vtable[m_Off_SetModel]; 
 
	union {void (VfuncEmptyClass::*mfpnew)(const char *);
	#ifndef __linux__
			void *addr;	} u; 	u.addr = func;
	#else // GCC's member function pointers all contain a this pointer adjustor. You'd probably set it to 0 
				struct {void *addr; intptr_t adjustor;} s; } u; u.s.addr = func; u.s.adjustor = 0;
	#endif
 
	(void) (reinterpret_cast<VfuncEmptyClass*>(this_ptr)->*u.mfpnew)(ModelName);
 
}
 
void VFuncs::Teleport(CBaseEntity *pThisPtr, const Vector *newPosition, const QAngle *newAngles, const Vector *newVelocity)
{
	void **this_ptr = *(void ***)&pThisPtr;
	void **vtable = *(void ***)pThisPtr;
	void *func = vtable[m_Off_Teleport]; 
 
	union {void (VfuncEmptyClass::*mfpnew)(const Vector *, const QAngle *, const Vector *);
	#ifndef __linux__
			void *addr;	} u; 	u.addr = func;
	#else // GCC's member function pointers all contain a this pointer adjustor. You'd probably set it to 0 
				struct {void *addr; intptr_t adjustor;} s; } u; u.s.addr = func; u.s.adjustor = 0;
	#endif
 
	(void) (reinterpret_cast<VfuncEmptyClass*>(this_ptr)->*u.mfpnew)(newPosition, newAngles, newVelocity);
 
}
 
Vector VFuncs::EyePosition( CBaseEntity *pThisPtr )
{
	void **this_ptr = *(void ***)&pThisPtr;
	void **vtable = *(void ***)pThisPtr;
	void *func = vtable[m_Off_EyePosition]; 
 
	union {Vector (VfuncEmptyClass::*mfpnew)( void );
	#ifndef __linux__
			void *addr;	} u; 	u.addr = func;
	#else // GCC's member function pointers all contain a this pointer adjustor. You'd probably set it to 0 
				struct {void *addr; intptr_t adjustor;} s; } u; u.s.addr = func; u.s.adjustor = 0;
	#endif
 
	return (Vector) (reinterpret_cast<VfuncEmptyClass*>(this_ptr)->*u.mfpnew)( );
 
}
 
QAngle &VFuncs::EyeAngles( CBaseEntity *pThisPtr )
{
	void **this_ptr = *(void ***)&pThisPtr;
	void **vtable = *(void ***)pThisPtr;
	void *func = vtable[m_Off_EyeAngles]; 
 
	union {QAngle& (VfuncEmptyClass::*mfpnew)( void );
	#ifndef __linux__
			void *addr;	} u; 	u.addr = func;
	#else // GCC's member function pointers all contain a this pointer adjustor. You'd probably set it to 0 
				struct {void *addr; intptr_t adjustor;} s; } u; u.s.addr = func; u.s.adjustor = 0;
	#endif
 
	return (QAngle&) (reinterpret_cast<VfuncEmptyClass*>(this_ptr)->*u.mfpnew)( );
 
}
 
 
void VFuncs::Ignite(CBaseEntity *pThisPtr, float flFlameLifetime, bool bNPCOnly, float flSize, bool bCalledByLevelDesigner)
{
	void **this_ptr = *(void ***)&pThisPtr;
	void **vtable = *(void ***)pThisPtr;
	void *func = vtable[m_Off_Ignite]; 
 
	union {void (VfuncEmptyClass::*mfpnew)(float , bool , float , bool );
	#ifndef __linux__
			void *addr;	} u; 	u.addr = func;
	#else // GCC's member function pointers all contain a this pointer adjustor. You'd probably set it to 0 
				struct {void *addr; intptr_t adjustor;} s; } u; u.s.addr = func; u.s.adjustor = 0;
	#endif
 
	(void) (reinterpret_cast<VfuncEmptyClass*>(this_ptr)->*u.mfpnew)(flFlameLifetime, bNPCOnly, flSize, bCalledByLevelDesigner);
 
}
 
CBaseEntity *VFuncs::GiveNamedItem(CBaseEntity *pThisPtr, const char *ItemName, int iSubType)
{
	void **this_ptr = *(void ***)&pThisPtr;
	void **vtable = *(void ***)pThisPtr;
	void *func = vtable[m_Off_GiveNamedItem]; 
 
	union {CBaseEntity *(VfuncEmptyClass::*mfpnew)(const char *, int );
	#ifndef __linux__
			void *addr;	} u; 	u.addr = func;
	#else // GCC's member function pointers all contain a this pointer adjustor. You'd probably set it to 0 
				struct {void *addr; intptr_t adjustor;} s; } u; u.s.addr = func; u.s.adjustor = 0;
	#endif
 
	return (CBaseEntity *) (reinterpret_cast<VfuncEmptyClass*>(this_ptr)->*u.mfpnew)(ItemName, iSubType);
}
 
void VFuncs::CommitSuicide(CBaseEntity *pThisPtr)
{
	void **this_ptr = *(void ***)&pThisPtr;
	void **vtable = *(void ***)pThisPtr;
	void *func = vtable[m_Off_CommitSuicide]; 
 
	union {CBaseEntity *(VfuncEmptyClass::*mfpnew)( void );
	#ifndef __linux__
			void *addr;	} u; 	u.addr = func;
	#else // GCC's member function pointers all contain a this pointer adjustor. You'd probably set it to 0 
				struct {void *addr; intptr_t adjustor;} s; } u; u.s.addr = func; u.s.adjustor = 0;
	#endif
 
	(reinterpret_cast<VfuncEmptyClass*>(this_ptr)->*u.mfpnew)();
}
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