Newbie: How to find all kernel modules that can be loaded?

Newbie: How to find all kernel modules that can be loaded?

[Rodrigo Morales]

As part of my learning journey with Guix, I'm experimenting with kernel
modules. I want to enable and disable and see how they affect my system.
I'm aware that in Guix kernel modules can be enabled and disabled
through kernel-module-loader-service-type.

I want to know all the modules that are available on my system so that I
can add them to kernel-module-loader-service-type. I'm a newbie when it
comes to kernel modules, so I'm not even aware if all of them have a unique
extension. If that's the case, a simple `find /gnu/store -type f -name
'*.<<extension>>' should find them.

I have two questions:

* Are kernel modules defined in unique files? If that's the case, do all of
them have a unique extension?
* Besides using `find` (assuming each kernel module exists in separated
files), do you know another way to find all kernel modules that exist
locally and that could be enabled?

Re: Newbie: How to find all kernel modules that can be loaded?

[Mario Forzanini]

Rodrigo Morales <moralesrodrigo1100@gmail.com> writes:
> I want to know all the modules that are available on my system so that I
> can add them to kernel-module-loader-service-type. I'm a newbie when it
> comes to kernel modules, so I'm not even aware if all of them have a unique
> extension. If that's the case, a simple `find /gnu/store -type f -name
> '*.<<extension>>' should find them.
>
> I have two questions:
>
> * Are kernel modules defined in unique files? If that's the case, do all of
> them have a unique extension?

Yes they should all be object files with extensions '*.ko' or '*.o', and
in more conventional linux systems they are all under /lib/modules. On
Guix I can find them gzipped under
/run/current-system/kernel/lib/modules, so something like this lists a
bunch of modules:

┌(18:56:30) 
└(~) % find /run/current-system/kernel/lib/modules -name '*.ko.gz' -or -name '*.o.gz'

This works on my system but YMMV

> * Besides using `find` (assuming each kernel module exists in separated
> files), do you know another way to find all kernel modules that exist
> locally and that could be enabled?

Well the lsmod(8) man page lists a lot of utilities to gain info about
kernel modules, but they may not work because they look for them in
/lib/modules, e.g.

┌(18:56:44) 
└(~) % depmod -av
depmod: ERROR: could not open directory /lib/modules/6.2.7: No such file or directory
depmod: FATAL: could not search modules: No such file or directory
-- 
Mario

Re: Newbie: How to find all kernel modules that can be loaded?

[Efraim Flashner]

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On Fri, Mar 31, 2023 at 06:58:37PM +0200, Mario Forzanini wrote:
> Rodrigo Morales <moralesrodrigo1100@gmail.com> writes:
> > I want to know all the modules that are available on my system so that I
> > can add them to kernel-module-loader-service-type. I'm a newbie when it
> > comes to kernel modules, so I'm not even aware if all of them have a unique
> > extension. If that's the case, a simple `find /gnu/store -type f -name
> > '*.<<extension>>' should find them.
> >
> > I have two questions:
> >
> > * Are kernel modules defined in unique files? If that's the case, do all of
> > them have a unique extension?
> 
> Yes they should all be object files with extensions '*.ko' or '*.o', and
> in more conventional linux systems they are all under /lib/modules. On
> Guix I can find them gzipped under
> /run/current-system/kernel/lib/modules, so something like this lists a
> bunch of modules:
> 
> ┌(18:56:30) 
> └(~) % find /run/current-system/kernel/lib/modules -name '*.ko.gz' -or -name '*.o.gz'
> 
> This works on my system but YMMV
> 
> > * Besides using `find` (assuming each kernel module exists in separated
> > files), do you know another way to find all kernel modules that exist
> > locally and that could be enabled?
> 
> Well the lsmod(8) man page lists a lot of utilities to gain info about
> kernel modules, but they may not work because they look for them in
> /lib/modules, e.g.
> 
> ┌(18:56:44) 
> └(~) % depmod -av
> depmod: ERROR: could not open directory /lib/modules/6.2.7: No such file or directory
> depmod: FATAL: could not search modules: No such file or directory

A little late on the reply, but you can work around this with the
-b/--basedir flag

depmod -av -b /run/current-system/kernel

-- 
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