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Windows Hotpatching: A Walkthrough

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As discussed in the last post, Windows 2003 SP1 introduced a technology known as Hotpatching. An integral part of this technology is Hotpatching, which refers to the process of applying an updated on the fly by using runtime code modification techniques. Although Hotpatching has caught a bit of attention, suprisingly little information has been published about its inner workings. As the technology is patented, however, there is quite a bit of information that can be obtained by reading the patent description. Continue »

#ifdef _WIN32

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When writing processor-specific code, the _M_IX86, _M_AMD64 and _M_IA64 can be used for conditional compilation – so far, so good. But sometimes code is not exactly processor-specific but rather specific to the natural machine word length (i.e. 32 bit or 64 bit). Fur such situations, there are defines, too – however there is a little catch: For ancient 16 bit code, there is _WIN16. For 64 bit, the WDK build environment defines _WIN64 by default. Continue »

Windows Hotpatching

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Several years ago, with Windows Server 2003 SP1, Microsoft introduced a technology and infrastructure called Hotpatching. The basic intent of this infrastructure is to provide a means to apply hotfixes on the fly, i.e. without having to reboot the system – even if the hotfix contains changes on critical system components such as the kernel iteself, important drivers, or user mode libraries such as shell32.dll. Trying to applying hotfixes on the fly introduces a variety of problems – the most important being: Continue »