Some question about Virtual Offset

Dekart · **Author**

I write plugin for Meta Mod:Source for CS:S game. My plugin based on sample_mm plugin from source codes of Meta Mod from this download page http://www.sourcemm.net/downloads.

I want make simple plugin, that able enable flash effect for all players by entering command in the console, for example "flashbang".

I modified "Hook_ClientCommand" function in sample_mm.cpp:

Code:

#if SOURCE_ENGINE >= SE_ORANGEBOX
void SamplePlugin::Hook_ClientCommand(edict_t *pEntity, const CCommand &args)
#else
void SamplePlugin::Hook_ClientCommand(edict_t *pEntity)
#endif
{
#if SOURCE_ENGINE <= SE_DARKMESSIAH
	CCommand args;
#endif

	if (!pEntity || pEntity->IsFree())
	{
		return;
	}

	const char *cmd = args.Arg(0);
	if (strcmp(cmd, "flashbang") == 0)
	{
		int i;
		edict_t *pEnt;
		for (i=1; i<=64; i++)
		{
			pEnt = engine->PEntityOfEntIndex(i);
			if (pEnt && !pEnt->IsFree() && FStrEq(pEnt->GetClassName(), "player"))
			{
				gVFuncs.SomeFunc(pEnt->GetUnknown()->GetBaseEntity());
			}
		}
		
		RETURN_META(MRES_SUPERCEDE);
	}
}

and I make "VFuncs" class as in this example http://wiki.alliedmods.net/Virtual_O..._(Source_Mods)

but my "VFuncs" class have single function, that enable flash effect for certain player entity

Code:

void VFuncs::SomeFunc(CBaseEntity *pThisPtr)
{
	void **this_ptr = *(void ***)&pThisPtr;
	void **vtable = *(void ***)pThisPtr;
	void *func = vtable[348]; 
 
	union {void (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
 
	(void) (reinterpret_cast<VfuncEmptyClass*>(this_ptr)->*u.mfpnew)();
 
}

In this code 348 is offset CCSPlayer::FlashlightTurnOn() function in Virtual Table from Virtual Table Offset List page.

I have successfully compiled plugin, and started server with Metamod plugin and my plugin. But when I enter into client console "flashbang" command nothing happens.

In what may be a problem?

donrevan · *Last edited by donrevan; 03-12-2012 at 16:48.*

Seems like you Mixed Client commands with Server commands. They are Not the same.
I assum(because of the loop thru each Client) you want to create the Server command "flashlight" to enable the flashlight of each Player. Just use the "CON_COMMAND" MACRO to create One.

Code:

CON_COMMAND(flashlight,"Turns on flashlight for each player")
{
//Code here
}

Dekart · *Last edited by Dekart; 03-13-2012 at 00:57.*

I added this code to code of my plugin:

Code:

CON_COMMAND(flashbang, "flashbang") 
{
	int i;
	int j;
	edict_t *pEnt;
	for (i=1; i<=64; i++)
	{
		pEnt = engine->PEntityOfEntIndex(i);
		if (pEnt && !pEnt->IsFree() && FStrEq(pEnt->GetClassName(), "player"))
		{
			gVFuncs.SomeFunc(pEnt->GetUnknown()->GetBaseEntity());
		}
	}
}

This function get control when I write command "flashbang" into server console.
(I checked this with the debugger in Visual Studio)

And then function

Code:

gVFuncs.SomeFunc(pEnt->GetUnknown()->GetBaseEntity());

also get control.

and function

Code:

(void) (reinterpret_cast<VfuncEmptyClass*>(this_ptr)->*u.mfpnew)();

get control too.

But nothing happens again

I think problem into call to virtual function, and I cannot understand why this is so.

Dekart · 03-13-2012 , 03:45 Re: Some question about Virtual Offset

hm... I solved this problem, but i have new question.

How to control player's money or control the player's buying of ammunition (weapons & vests) in CS:S?

Emil · *Last edited by Emil; 03-15-2012 at 15:45.*

you can control the players money thru "CCSPlayer.m_iAccount", and helmet and west thru "CCSPlayer.m_bHasHelmet" and "CCSPlayer.m_ArmorValue"

Code:

void getOffsetInTable(SendTable* table, const std::string& propertyName, int* offset)
{
  int NumProps = table->GetNumProps();
  std::string propName = propertyName.substr(0, propertyName.find_first_of("."));

  for(int i=0; i<NumProps; i++)
  {
    SendProp* prop = table->GetProp(i);
    const char* name = prop->GetName();
    if(FStrEq(prop->GetName(), propName.c_str())){
      *offset = *offset + prop->GetOffset();
      if(prop->GetType() == DPT_DataTable){
        if(propertyName.length() > propName.length() + 1){
          getOffsetInTable(prop->GetDataTable(), propertyName.substr(propName.length() + 1), offset);
        }
      }
      return;
    }
  }
}



int findNetOffset(const std::string& className, const std::string& propertyName)
{
  ServerClass *sc = m_serverdll->GetAllServerClasses();
  while (sc)
  {
    if(FStrEq(sc->GetName(), className.c_str()))
    {
      int offset = 0;
      getOffsetInTable(sc->m_pTable, propertyName, &offset);
      return offset;
    }
    sc = sc->m_pNext;
  }

  return 0;
}



// Set the cash amount of player
void setPlayerCash(edict_t* player, int cash)
{
  m_cashOffset = findNetOffset("CCSPlayer", "m_iAccount");

  if(player && m_cashOffset){
    int* cashPtr = (int*)((unsigned char*)player->GetUnknown()->GetBaseEntity() + m_cashOffset);
    *cashPtr = cash;
  }
}



//Sets wheter or not a player is wearing a helmet
void setPlayerHelmet(edict_t* player, bool hasHelmet)
{
  m_helmetOffset = findNetOffset("CCSPlayer", "m_bHasHelmet");

  if(player && m_helmetOffset){
    bool* helmetPtr = (bool*)((unsigned char*)player->GetUnknown()->GetBaseEntity() + m_helmetOffset);
    *helmetPtr = hasHelmet;
  }
}



//Sets a players armor
void setPlayerArmor(edict_t* player, int armor)
{
  m_armorOffset = findNetOffset("CCSPlayer", "m_ArmorValue");

  if(player && m_armorOffset){
    int* armorPtr = (int*)((unsigned char*)player->GetUnknown()->GetBaseEntity() + m_armorOffset);
    *armorPtr = armor;
  }
}

You can give a player a weapon with CCSPlayer::GiveNamedItem

CSS weapon names are

weapon_ak47
weapon_aug
weapon_awp
weapon_c4
weapon_deagle
weapon_elite
weapon_famas
weapon_fiveseven
weapon_flashbang
weapon_g3sg1
weapon_galil
weapon_glock
weapon_hegrenade
weapon_knife
weapon_m249
weapon_m3
weapon_m4a1
weapon_mac10
weapon_mp5navy
weapon_p228
weapon_p90
weapon_scout
weapon_sg550
weapon_sg552
weapon_smokegrenade
weapon_tmp
weapon_ump45
weapon_usp
weapon_xm1014

Code:

extern CBaseEntity* CCSPlayer_GiveNamedItem(CBasePlayer *pCBE, char const* itemName, int iSubType = 0);

//392	CCSPlayer::GiveNamedItem(char  const*,int)
VFUNC_CALL2(392, CBaseEntity *, CBasePlayer, CCSPlayer_GiveNamedItem, char const*, int);



void giveItem(edict_t* player, const char* name)
{
  if(player){
    CCSPlayer_GiveNamedItem((CBasePlayer *) player->GetUnknown()->GetBaseEntity(), name);
  }
}

asherkin · 03-15-2012 , 17:45 Re: Some question about Virtual Offset

Quote:

Originally Posted by Emil

stuff

You shouldn't be using libstdc++ stuff (STL classes) if you're planing on releasing a Linux version.

Dekart · 03-20-2012 , 00:22 Re: Some question about Virtual Offset

Thank you all for your help.

Dekart · *Last edited by Dekart; 03-21-2012 at 04:12.*

I continue work above my plugin, and now i need change name of player in the game.

I found in wiki function in CCSPlayer class, that can change player name, and i found some information about this function. http://wiki.alliedmods.net/CCSPlayer#ChangeName

Code:

void CCSPlayer::ChangeName(const char* Name)

But i can't found information about how use it.

Could you tell where i can to find an examples the using it?