respond to Dbghelp.SymGetTypeFromName correctly

nl_luainit.lua

@@ -57,6 +57,7 @@ ffi.cdef[[
   DWORD64 nl_BaseOfDll;
   LONG nl_attach(PVOID *ppPointer, PVOID pDetour);
   LONG nl_detach(PVOID *ppPointer, PVOID pDetour);
+  DWORD tempPrintLastError();
   typedef void CxxClass;
 ]]
 
@@ -399,19 +400,23 @@ end
 
 -- Find a symbol index.
 local function nl_symbol(name)
+  print("calling nl_symbol(\""..name.."\")")
   local si = new("SYMBOL_INFO[1]")
   si[0].SizeOfStruct = sizeof("SYMBOL_INFO")
   si[0].MaxNameLen = 0
-  local ok = Dbghelp.SymFromName(NLAPI.nl_hProcess, name, si)
-  if ok then return si[0] end
+  local ret = Dbghelp.SymFromName(NLAPI.nl_hProcess, name, si)
+  if ret == 1 then return si[0] end
+  NLAPI.tempPrintLastError()
 end
 
 local function nl_type(name)
+  print("calling nl_type(\""..name.."\")")
   local si = new("SYMBOL_INFO[1]")
   si[0].SizeOfStruct = sizeof("SYMBOL_INFO")
   si[0].MaxNameLen = 0
-  local ok = Dbghelp.SymGetTypeFromName(NLAPI.nl_hProcess, NLAPI.nl_BaseOfDll, name, si)
-  if ok then return si[0] end
+  local ret = Dbghelp.SymGetTypeFromName(NLAPI.nl_hProcess, NLAPI.nl_BaseOfDll, name, si)
+  if ret == 1 then return si[0] end
+  NLAPI.tempPrintLastError()
 end
 
 -- Get the value of a symbol.

nl_payload.c

@@ -47,6 +47,32 @@ __declspec(dllexport) LONG nl_detach(PVOID *ppPointer, PVOID pDetour)
 	return ret;
 }
 
+// idk how to thread this through to Lua; this is probably not the best
+// way but it works
+__declspec(dllexport) DWORD tempPrintLastError()
+{
+	// adapted from https://docs.microsoft.com/en-us/windows/win32/debug/retrieving-the-last-error-code
+
+	LPVOID lpMsgBuf;
+	DWORD code = GetLastError();
+
+	FormatMessage(
+			FORMAT_MESSAGE_ALLOCATE_BUFFER |
+			FORMAT_MESSAGE_FROM_SYSTEM |
+			FORMAT_MESSAGE_IGNORE_INSERTS,
+			NULL,
+			code,
+			MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+			(LPTSTR) &lpMsgBuf,
+			0, NULL );
+
+	printf("Error %d: %s", code, (char *)lpMsgBuf);
+
+	LocalFree(lpMsgBuf);
+
+	return 0; // returning b/c declaring the function as VOID instead of DWORD caused mysterious issues
+}
+
 static BOOL nlP_filexists(LPCTSTR szPath)
 {
 	DWORD dwAttrib = GetFileAttributes(szPath);