Source.c:
UNREFERENCED_PARAMETER(RegistryPath);
INT err = KLoggerInit(RegistryPath);

Klogger.h/KLogger.c:
INT KLoggerInit(PUNICODE_STRING RegistryPath)


KLogger.c:
size_t ring_buf_size = get_ring_buf_size(RegistryPath);

size_t get_ring_buf_size(PUNICODE_STRING RegistryPath)
{
    HANDLE reg_key_handle;
    NTSTATUS status;
    OBJECT_ATTRIBUTES obj_attr;
    UNICODE_STRING reg_key_path;
    ULONG key_value = DEFAULT_RING_BUF_SIZE;

    PKEY_VALUE_PARTIAL_INFORMATION part_info;
    ULONG part_info_size;

    InitializeObjectAttributes(&obj_attr, RegistryPath, 0, NULL, NULL);

    // status = ZwOpenKey(&reg_key_handle, KEY_QUERY_VALUE, &obj_attr);
    status = ZwCreateKey(&reg_key_handle, KEY_QUERY_VALUE | KEY_SET_VALUE, &obj_attr, 0,  NULL, REG_OPTION_NON_VOLATILE, NULL);
    if (!NT_SUCCESS(status))
    {
        DbgPrint("[library_driver]: 'ZwCreateKey()' failed");
        return DEFAULT_RING_BUF_SIZE;
    }

    RtlInitUnicodeString(&reg_key_path, REGISTRY_BUF_SIZE_KEY);

    part_info_size = sizeof(KEY_VALUE_PARTIAL_INFORMATION) + sizeof(part_info_size);
    part_info = ExAllocatePool(PagedPool, part_info_size);
    if (part_info == NULL)
    {
        DbgPrint("[library_driver]: 'ExAllocatePool()' failed");
        ZwClose(reg_key_handle);
        return DEFAULT_RING_BUF_SIZE;
    }

    status = ZwQueryValueKey(reg_key_handle, &reg_key_path, KeyValuePartialInformation,
        part_info, part_info_size, &part_info_size);

    switch (status) {
        case STATUS_SUCCESS:
            DbgPrint("[library_driver]: switch: STATUS_SUCCESS");
            if (part_info->Type == REG_DWORD && part_info->DataLength == sizeof(ULONG))
            {
                RtlCopyMemory(&key_value, part_info->Data, sizeof(key_value));
                ZwClose(reg_key_handle);
                ExFreePool(part_info);
                return key_value;
            }
            // break; - not break

        case STATUS_OBJECT_NAME_NOT_FOUND:
            DbgPrint("[library_driver]: switch: STATUS_OBJECT_NAME_NOT_FOUND");
            status = ZwSetValueKey(reg_key_handle, &reg_key_path, 0, REG_DWORD, &key_value, sizeof(key_value));
            if (!NT_SUCCESS(status))
            {
                ZwClose(reg_key_handle);
                ExFreePool(part_info);
                return DEFAULT_RING_BUF_SIZE;
            }

            break;

        default:
            DbgPrint("[library_driver]: switch: default");
            ZwClose(reg_key_handle);
            ExFreePool(part_info);
            return DEFAULT_RING_BUF_SIZE;

            break;

    }

    ZwClose(reg_key_handle);
    ExFreePool(part_info);

    return DEFAULT_RING_BUF_SIZE;
}