Increasing Automation in the Backporting of Linux Drivers Using Coccinelle

Abstract

Software is continually evolving, to fix bugs and add new features. Industry users, however, often value stability, and thus may not be able to update their code base to the latest versions. This raises the need to selectively backport new features to older software versions. Traditionally, backporting has been done by cluttering the backported code with preprocessor directives, to replace behaviors that are unsupported in an earlier version by appropriate workarounds. This approach however involves writing a lot of error-prone backporting code, and results in implementations that are hard to read and maintain. We consider this issue in the context of the Linux kernel, for which older versions are in wide use. We present a new backporting strategy that relies on the use of a backporting compatability library and on code that is automatically generated using the program transformation tool Coccinelle. This approach reduces the amount of code that must be manually written, and thus can help the Linux kernel backporting effort scale while maintaining the dependability of the backporting process.

A delta‐oriented approach to support the safe reuse of black‐box code rewriters

“…As stated in the introduction, the Coccinelle tool is used to automatically fix bugs in the C code that implements the Linux kernel, as well as backporting device‐specific drivers . These activities are supported by allowing a software developer to define semantic patches .…”

A Delta-Oriented Approach to Support the Safe Reuse of Black-Box Code Rewriters

“…As stated in the introduction, the Coccinelle tool is used to automatically fix bugs in the C code that implements the Linux kernel, as well as backporting device-specific drivers. 13 These activities are supported by allowing a software developer to define semantic patches. A semantic patch contains (a) the declaration of free variables in a header identified by at symbols (), and (b) the patterns to be matched in the C code coupled to the rewriting rule.…”

Recommending Code Changes for Automatic Backporting of Linux Device Drivers

“…An alternative is provided by the Linux backports project, which provides a compatibility library to 32nd IEEE International Conference on Software Maintenance and Evolution (ICSME), Raleigh, North Carolina, October 2 -10, 2016. hide differences between the current mainline and a host of older versions, and provides patches that allow a set of 800 drivers to target this compatibility library. These patches are either created manually by the backports project maintainers, or are created using manually written rewrite rules, based on the transformation tool Coccinelle [27]. In either case, however, the backports project maintainer has to determine where changes are needed in the code to backport and how to carry out these changes.…”