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#include "VmtHook.h"
VmtHook::VmtHook(void** vmt)
{
this->vmt = vmt;
}
void* VmtHook::Hook(int index, void* hookedFunction)
{
hookedfuncs.insert(std::make_pair(index, vmt[index]));
//make page writeable
DWORD pageProtection;
VirtualProtect(&vmt[index], sizeof(BYTE*), PAGE_EXECUTE_READWRITE, &pageProtection);
//overwrite function pointer in VMT to hook function
vmt[index] = hookedFunction;
//restore page protection
VirtualProtect(&vmt[index], sizeof(BYTE*), pageProtection, &pageProtection);
return hookedfuncs[index];
}
//
//Unhook a single hooked function
bool VmtHook::Unhook(int index)
{
auto entry = hookedfuncs.find(index);
if (entry != hookedfuncs.end())
{
vmt[entry->first] = entry->second;
return true;
}
return false;
}
//
//Unhook the entire Vmt
void VmtHook::Unhook()
{
for (std::pair<int, void*> pair : hookedfuncs)
{
DWORD oldProtection;
VirtualProtect(&vmt[pair.first], sizeof(BYTE*), PAGE_EXECUTE_READWRITE, &oldProtection);
vmt[pair.first] = pair.second;
VirtualProtect(&vmt[pair.first], sizeof(BYTE*), oldProtection, &oldProtection);
}
}
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