Xen static analysis¶
The Xen codebase integrates some scripts and tools that helps the developer to perform static analysis of the code, currently Xen supports three analysis tool that are eclair, coverity and cppcheck. The Xen tree has a script (xen-analysis.py) available to ease the analysis process and it integrates a way to suppress findings on these tools, please check the documenting-violation.rst document to know more about it.
Analyse Xen with Coverity or Eclair¶
The xen-analysis.py script has two arguments to select which tool is used for the analysis:
xen-analysis.py –run-coverity – [optional make arguments]
xen-analysis.py –run-eclair – [optional make arguments]
For example when using Coverity to analyse a Xen build obtained by passing these arguments to the make system: XEN_TARGET_ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu-, the optional make arguments passed to xen-analysis.py must be the same and the command below should be passed to Coverity in its build phase:
xen-analysis.py –run-coverity – XEN_TARGET_ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu-
Which tells to the script to prepare the codebase for an analysis by Coverity and forwards the make arguments to the make build invocation.
When invoking the script, the procedure below will be followed:
Find which files among *.c and *.h has any in-code comment as /* SAF-X-[…] */, the meaning of these comments is explained in documenting-violation.rst. Save the files obtained as <file>.safparse and generate <file> files where the special in-code comments above are substituted with the proprietary in-code comment used by the selected analysis tool. The safe.json and false-positive-<tool>.json text file database are used to link each Xen tag to the right proprietary in-code comment.
Now Xen compilation starts using every <additional make parameters> supplied at the script invocation. Coverity and Eclair are capable of intercepting the compiler running from make to perform their analysis without instrumenting the makefile.
As final step every <file>.safparse file are reverted back as <file> and every artifact related to the analysis will be cleaned. This step is performed even in case any of the previous step fail, to skip this step, call the script adding the –no-clean argument, but before running again the script, call it with the –clean-only argument, that will execute only this cleaning step.
Analyse Xen with Cppcheck¶
Cppcheck tool is integrated in xen-analysis.py script, when using the script, the tool will be called on every source file compiled by the make build system. Here how to start the analysis with Cppcheck:
xen-analysis.py –run-cppcheck [–cppcheck-misra] [–cppcheck-html] – [optional make arguments]
The command above tells the script to prepare the codebase and use Cppcheck tool for the analysis. The optional argument –cppcheck-misra activates the analysis also for MISRA compliance. The optional argument –cppcheck-html instruct cppcheck to produce an additional HTML report.
When invoking the script for Cppcheck analysis, the followed procedure is similar to the one above for Coverity or Eclair, but it has some additional steps:
This step is the same as step 1 for Coverity/Eclair.
The cppcheck dependency are created, build directory for cppcheck analysis and an header file containing internal compiler macro (include/generated/compiler-def.h) are generated
Xen compilation starts using every <additional make parameters> supplied at the script invocation, but because cppcheck is not able to intercept the compiled files and flags on compiler invocation, a script (cppcheck-cc.sh) is passed as CC to the make system, it is a wrapper for the compiler that will also execute cppcheck on every compiled file.
After the compilation and analysis, the cppcheck report will be created putting together all the cppcheck report fragments for every analysed file. Cppcheck will produce a text fragment and an additional XML report fragment if the script is configured to produce the HTML output.
This step is the same as step 3 for Coverity/Eclair.