some old kernel "cleanup" scripts of mine, still look useful

[Robert P. J. Day]

  once upon a time, as i was diving into the kernel Kbuild
infrastructure, i wrote a number of scripts that would sanity check
the contents of Kconfig files against source files and Makefiles --
not sure if there's a better way to do that these days, but i posted
some of them here if people want to run any of them against their
favourite kernel subsystem:

http://www.crashcourse.ca/wiki/index.php/Kernel_cleanup_scripts

  by "sanity check", i mean that there are a few basic properties of
the kernel build files that should be true, such as:

1) if a Kconfig file defines a config variable, someone else somewhere
   should be checking it

2) if a source file tests an alleged Kconfig variable, some Kconfig
   file should define it

3) if a Makefile conditionally compiles based on a Kconfig variable,
   some Kconfig file should define it

and so on, and so on -- pretty straightforward stuff. and it was
surprising how many irregularities there were (admittedly many of them
minor and causing no problem).

  for example, my script "find_badref_make_configs.sh" would search
either the entire kernel tree or just the directory given by the
optional argument, and identify all Makefiles that tested for
"CONFIG__*" variables that were nowhere defined in the tree. here's
the output from this morning just checking the drivers/ directory:

http://www.crashcourse.ca/wiki/index.php/Kernel_cleanup_scripts#find_badref_make_configs.sh_.28updated_Sep_17.2C_2014.29

there are two typical causes of such things:

* an incomplete *removal* of some feature, or
* an imcomplete *addition* of some feature

for the "ARCH_HIP04" variable listed there, it didn't take long to
stumble on this web page where someone points out that very thing:

http://www.gossamer-threads.com/lists/linux/kernel/2006426

in short, someone added the source and Makefile for that feature, but
hadn't yet added the Kconfig content -- generally frowned upon.

  doing all this once upon a time had a number of benefits for me:

1) forced me to really understand the Kbuild infrastructure
2) improved my shell programming skills
3) let me get some patches into the kernel
4) occasionally, found an actual bug that deserved fixing, for which
   maintainers were grateful

  i have no idea if there's something better these days to do the same
thing -- is there? otherwise, others are free to play with those
scripts and improve them, i'm sure they're not perfect, they used to
generate quite a number of false positives until i reworked them
slightly.

  thoughts?

rday

-- 

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Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

Twitter:                                       http://twitter.com/rpjday
LinkedIn:                               http://ca.linkedin.com/in/rpjday
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