Conditional built modules in dkms.conf

[JDarnley]

Similar to #392 I am looking for a conditional listing of files in dkms.conf but in contrast to that (I think) I want it to be based on a kernel config option. In my case I specifically want CONFIG_AUXILIARY_BUS.

I make a package using "dkms mkdeb" so I need it to be checked when apt tries to make dkms install it much later and elsewhere for every kernel that dkms tried to install for.

Is there an approved way to query this at "build" time?

[ian-abbott]

I'm not recommending the following as a recommended solution, but it is what I do in Comedi as a workaround.

The dkms.conf file gets sourced in as Bash source after some sanity checks, so it is possible to put the BUILT_MODULE_NAME[n], BUILT_MODULE_LOCATION[n], and DEST_MODULE_LOCATION[n] entries inside a Bash if/then/fi command. One problem is that the array indices need to be in an increasing sequence without gaps, but one way to do that is to use a local variable to hold the current index, and increment it.

For example:

local nn
nn=0
BUILT_MODULE_NAME[$nn]="foo1"
BUILT_MODULE_LOCATION[$nn]="ziggy/"
DEST_MODULE_LOCATION[$((nn++))]="/kernel/ziggy/"
BUILT_MODULE_NAME[$nn]="foo2"
BUILT_MODULE_LOCATION[$nn]="ziggy/"
DEST_MODULE_LOCATION[$((nn++))]="/kernel/ziggy/"
if grep -q '^CONFIG_AUXILIARY_BUS=[ym]' ${kernel_source_dir}/.config' 2>/dev/null; then
BUILT_MODULE_NAME[$nn]="foo-aux"
BUILT_MODULE_LOCATION[$nn]="ziggy/"
DEST_MODULE_LOCATION[$((nn++))]="/kernel/ziggy/"
fi

[scaronni]

Can you please test this merge request? #533

To test, assuming you have already DKMS installed (via packages or some other meaning):

git clone https://github.com/dell/dkms.git
cd dkms
git checkout per_module_config
make
sudo cp dkms /usr/sbin/dkms

This should enable you to avoid having a `dkms.conf`` file that looks like a script.

[JDarnley]

I should be able to test this in some VMs assuming I can remember how to induce the problem and assuming I can then write the right conf file but it won't be soon.

[scaronni]

@ian-abbott any chance you could test? You just need to convert your if line in a directive with the module name.

Thanks!

[ian-abbott]

@ian-abbott any chance you could test? You just need to convert your if line in a directive with the module name.

Some of the tests I use in https://github.com/Linux-Comedi/comedi/blob/master/dkms.conf.in are not quite so straightforward, such as this one:

# Modules that require set_fs() support in the kernel
# (Try and mimic checks done by configure script.)
if test -d /lib/modules/${kernelver}/source ; then
	src="/lib/modules/${kernelver}/source"
else
	src="${kernel_source_dir}"
fi
if grep -q '^CONFIG_SET_FS=y' ${kernel_src_dir}/.config 2>/dev/null ||
	! test -f ${src}/include/asm-generic/uaccess.h ||
	! test -f ${src}/include/asm-generic/access_ok.h &&
	! grep -q CONFIG_SET_FS ${src}/include/asm-generic/uaccess.h 2>/dev/null
then
BUILT_MODULE_NAME[$nn]="serial2002"
BUILT_MODULE_LOCATION[$nn]="comedi/drivers/"
DEST_MODULE_LOCATION[$((nn++))]="/kernel/comedi/drivers/"
fi

[scaronni]

Yes, that one is not covered, but nothing prevents you to just change some parts of the dkms.conf file. This one is a good candidate to test that MR:

if grep -q '^CONFIG_AUXILIARY_BUS=[ym]' ${kernel_source_dir}/.config' 2>/dev/null; then
BUILT_MODULE_NAME[$nn]="foo-aux"
BUILT_MODULE_LOCATION[$nn]="ziggy/"
DEST_MODULE_LOCATION[$((nn++))]="/kernel/ziggy/"
fi

If that gets merged (need to write the tests), maybe we can also add file checks. The idea in the long run is to avoid having scripts embedded in dkms.conf files.

[scaronni]

#533 implements this (will be in 3.3.0). Please reopen if necessary.