Initial public release of rem-essentials

2026-08-11 16:48:50 +02:00
commit d611924a5e
161 changed files with 9792 additions and 0 deletions
@@ -0,0 +1,108 @@
+#pragma once
+
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#include <cassert>
+#include <initializer_list>
+
+void Patch(DWORD vOffset, const LPVOID mem, UINT len);
+
+template <typename Type>
+inline void Patch(DWORD vOffset, Type value)
+{
+    Patch(vOffset, &value, sizeof(Type));
+}
+
+void PatchBytes(DWORD vOffset, std::initializer_list<BYTE> bytes);
+
+void Nop(DWORD vOffset, UINT len);
+
+inline void ReadWriteProtect(DWORD location, DWORD size)
+{
+    DWORD _;
+    VirtualProtect((PVOID) location, size, PAGE_EXECUTE_READWRITE, &_);
+}
+
+template <typename Func>
+Func SetRelPointer(DWORD location, Func hookFunc)
+{
+    // Set and calculate the relative offset for the hook function
+    DWORD& relOriginalLocation = GetValue<DWORD>(location);
+    DWORD originalPointer = location + relOriginalLocation + 4;
+
+    DWORD hookFuncLocation = *((PDWORD) &hookFunc);
+    relOriginalLocation = hookFuncLocation - (location + 4);
+
+    return GetFuncDef<Func>(originalPointer);
+}
+
+template <typename Func>
+void Hook(DWORD location, Func hookFunc, UINT instrLen, bool jmp = false)
+{
+    assert(instrLen >= 5);
+
+    // Set the opcode for the call or jmp instruction
+    Patch<BYTE>(location, jmp ? 0xE9 : 0xE8); // 0xE9 = jmp, 0xE8 = call
+
+    // Set the relative address
+    SetRelPointer(location + 1, hookFunc);
+
+    // Nop out excess bytes
+    if (instrLen > 5)
+        Nop(location + 5, instrLen - 5);
+}
+
+template <typename Func>
+Func Trampoline(DWORD location, Func hookFunc, UINT instrLen)
+{
+    // Allocate memory for gateway function.
+    PBYTE gatewayFunc = (PBYTE) VirtualAlloc(nullptr, instrLen + 5, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);
+
+    // Copy the instruction(s) that will be overwritten by setting the hooks to the gateway code.
+    ReadWriteProtect(location, instrLen);
+    memcpy(gatewayFunc, (PVOID) location, instrLen);
+
+    // Jmp from location to hook function.
+    Hook(location, hookFunc, instrLen, true);
+    // Jmp from gateway to original function.
+    Hook((DWORD) (gatewayFunc + instrLen), GetFuncDef<Func>(location + instrLen), 5, true);
+
+    // Return handle for calling the gateway function which in turn calls the original function.
+    return GetFuncDef<Func>((DWORD) gatewayFunc);
+}
+
+template <typename Func>
+void CleanupTrampoline(Func trampolineFunc)
+{
+    VirtualFree((LPVOID) *((PDWORD) &trampolineFunc), 0, MEM_RELEASE);
+}
+
+template <typename Func>
+Func SetPointer(DWORD location, Func hookFunc)
+{
+    DWORD originalPointer = GetValue<DWORD>(location);
+    *(Func*) location = hookFunc;
+
+    return GetFuncDef<Func>(originalPointer);
+}
+
+template <typename Type>
+inline Type& GetValue(DWORD location)
+{
+    ReadWriteProtect(location, sizeof(Type));
+    return *(Type*) location;
+}
+
+template <class Func>
+inline Func GetFuncDef(DWORD funcAddr)
+{
+    return *(Func*) &funcAddr;
+}
+
+DWORD GetUnloadedModuleHandle(LPCTSTR moduleName);
+
+struct NopStr
+{
+    UINT len;
+    LPCSTR nopSequence;
+};