Feeds

Binary interfaces in component development

A template class with static data - how can that possibly go wrong?

Intelligent flash storage arrays

Part 2 In the first part of this series we looked at how problems emerge when we make the transformation from source code to binary code, and we saw that even when the code is correct errors can be introduced by using dynamic libraries instead of a monolithic binary.

With some simple examples, we’re starting to see problems, using a logically correct C++ program for which we cannot construct a physical representation using dynamic libraries because of platform constraints.

In software security, the industry experts speak of security exposures that occur in the interactions between systems. I think we’re now seeing a similar issue with the interaction of the abstract C++ system and the physical portable executable format system; but instead of a security problem, we get bugs.

Our example comes from real life code, and a large development team that has lived with consequent problems in its Windows environment for a long time, which have cost a lot of money. The issue comes from the interaction of two C++ language features that behave unexpectedly when combined with dynamic linking. We’ll see how on Windows that code packaged in dynamic libraries doesn’t behave in accordance with the C++ language, and we’ll see how to use tools to investigate and resolve the problem. The code we’ll use to expose this insidious problem is shown in the following generic implementation of the Singleton pattern. As we’ll see, this code works fine provided it is not used with dynamic libraries:

// GenericSingleton.hpp
template <typename T>
class GenericSingleton
{
public:
   T &getInstance();

private:
   static T m_instance;
};

template <typename T>
T & GenericSingleton<T>::getInstance()
{
    return m_instance;
}

template <typename T>
T GenericSingleton<T>::m_instance; 

There’s a template class with all of its definitions in the header file. This organisation of a class template is common, perhaps because placing the template definitions in the header file avoids lots of annoying linker warnings. However, as we’ll see, this practice leads to problems once the transition is made from a small monolithic binary program to a modular software system composed of interacting dynamic libraries.

Firstly, why is this code problematic in conjunction with dynamic libraries? There are issues here on Windows and on Linux, but the manifestations of the problems are different.

Secure remote control for conventional and virtual desktops

More from The Register

next story
Nexus 7 fandroids tell of salty taste after sucking on Google's Lollipop
Web giant looking into why version 5.0 of Android is crippling older slabs
Be real, Apple: In-app goodie grab games AREN'T FREE – EU
Cupertino stands down after Euro legal threats
Download alert: Nearly ALL top 100 Android, iOS paid apps hacked
Attack of the Clones? Yeah, but much, much scarier – report
Microsoft: Your Linux Docker containers are now OURS to command
New tool lets admins wrangle Linux apps from Windows
Bada-Bing! Mozilla flips Firefox to YAHOO! for search
Microsoft system will be the default for browser in US until 2020
prev story

Whitepapers

Why and how to choose the right cloud vendor
The benefits of cloud-based storage in your processes. Eliminate onsite, disk-based backup and archiving in favor of cloud-based data protection.
Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
The hidden costs of self-signed SSL certificates
Exploring the true TCO for self-signed SSL certificates, including a side-by-side comparison of a self-signed architecture versus working with a third-party SSL vendor.
Storage capacity and performance optimization at Mizuno USA
Mizuno USA turn to Tegile storage technology to solve both their SAN and backup issues.