Initial commit

main.c

@@ -0,0 +1,83 @@
+#include <windows.h>
+#include <stdio.h>
+
+typedef BOOL (WINAPI *GETVERSIONEXA)(LPOSVERSIONINFOA);
+
+BOOL WINAPI FakeGetVersionExA(LPOSVERSIONINFOA lpVersionInformation)
+{
+    if (!lpVersionInformation) return FALSE;
+
+    lpVersionInformation->dwMajorVersion = 5;
+    lpVersionInformation->dwMinorVersion = 1;
+    lpVersionInformation->dwBuildNumber  = 2600;
+    lpVersionInformation->dwPlatformId   = VER_PLATFORM_WIN32_NT;
+
+    if (lpVersionInformation->dwOSVersionInfoSize == sizeof(OSVERSIONINFOA))
+        lstrcpyA(lpVersionInformation->szCSDVersion, "Service Pack 3");
+
+    return TRUE;
+}
+
+void PatchGetVersionEx()
+{
+    HMODULE hKernel;
+    FARPROC real;
+    DWORD oldProtect;
+    BYTE *p;
+    DWORD rel;
+
+    hKernel = GetModuleHandleA("kernel32.dll");
+    if (!hKernel)
+        return;
+
+    real = GetProcAddress(hKernel, "GetVersionExA");
+    if (!real)
+        return;
+
+    // Allow writing to the first 5 bytes
+    if (!VirtualProtect((LPVOID)real, 5, PAGE_EXECUTE_READWRITE, &oldProtect))
+        return;
+
+    p = (BYTE*)real;
+    rel = (DWORD)FakeGetVersionExA - ((DWORD)real + 5);
+
+    p[0] = 0xE9;               // JMP rel32
+    *(DWORD*)(p + 1) = rel;    // Write relative offset
+
+    // Restore protection
+    VirtualProtect((LPVOID)real, 5, oldProtect, &oldProtect);
+}
+
+int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrev, LPSTR lpCmd, int nShow)
+{
+    const char targetExe[] = "dactyloidae.exe";
+    char exePath[MAX_PATH];
+    char *p;
+    STARTUPINFOA si;
+    PROCESS_INFORMATION pi;
+
+    PatchGetVersionEx();
+
+    GetModuleFileNameA(NULL, exePath, MAX_PATH);
+
+    p = strrchr(exePath, '\\');
+    if (!p)
+        return 0;
+
+    lstrcpyA(p + 1, targetExe);
+
+    ZeroMemory(&si, sizeof(si));
+    ZeroMemory(&pi, sizeof(pi));
+    si.cb = sizeof(si);
+
+    if (!CreateProcessA(exePath, NULL, NULL, NULL, FALSE, 0, NULL, NULL, &si, &pi))
+    {
+        MessageBoxA(NULL, "Failed to launch Dactyloidae.", "Error", MB_ICONERROR);
+        return 0;
+    }
+
+    CloseHandle(pi.hThread);
+    CloseHandle(pi.hProcess);
+
+    return 0;
+}