[PATCH 08/12] include: add elf.h support

[Daniel Gomez]

On Mon, Sep 02, 2024 at 01:15:01AM +0900, Masahiro Yamada wrote:
> On Sat, Aug 31, 2024 at 4:54 AM Nicolas Schier <nicolas at fjasle.eu> wrote:
> >
> > On Sat, Aug 24, 2024 at 12:54:50AM +0200 Daniel Gomez wrote:
> > > On Wed, Aug 07, 2024 at 05:46:03PM +0200, Nicolas Schier wrote:
> > > > On Wed, Aug 07, 2024 at 04:18:54PM +0200, Greg Kroah-Hartman wrote:
> > > > > On Wed, Aug 07, 2024 at 02:13:57PM +0000, Daniel Gomez wrote:
> > > > > > > Also, as this is not internal for the kernel, but rather for userspace
> > > > > > > builds, shouldn't the include/ path be different?
> > > > > >
> > > > > > Can you suggest an alternative path or provide documentation that could help
> > > > > > identify the correct location? Perhaps usr/include?
> > > > >
> > > > > That is better than the generic include path as you are attempting to
> > > > > mix userspace and kernel headers in the same directory :(
> > > >
> > > > Please keep in mind, that usr/include/ currently does not hold a single
> > > > header file but is used for dynamically composing the UAPI header tree.
> > > >
> > > > In general, I do not like the idea of keeping a elf.h file here that
> > > > possibly is out-of-sync with the actual system's version (even though
> > > > elf.h should not see that much changes).  Might it be more helpful to
> > > > provide a "development kit" for Linux devs that need to build on MacOS
> > > > that provides necessary missing system header files, instead of merging
> > > > those into upstream?
> > >
> > > I took this suggestion and tried pushing a Homebrew formula/package here [1].
> > > I think I chose a wrong name and maybe something like "development kit" would
> > > have been better. However, would it be possible instead to include the *.rb file
> > > in the scripts/ directory? So users of this can generate the development kit in
> > > their environments. I would maintain the script to keep it in sync with the
> > > required glibc version for the latest kernel version.
> > >
> > > [1] https://protect2.fireeye.com/v1/url?k=96027706-f7896236-9603fc49-000babffaa23-452f645d7a72e234&q=1&e=343dd31c-5e5b-4b09-8ee5-6c59a1ff826e&u=https%3A%2F%2Fgithub.com%2FHomebrew%2Fhomebrew-core%2Fpull%2F181885
> >
> > I think it sounds sensible to hold that formula file in the upstream tree.  But
> > I am not sure if scripts/ is the best location.
> >
> > Masahiro, what do you think?
> 
> 
> I do not know much about the homebrew, but why does the upstream
> kernel need to merge such masOS stuff?

The missing headers (in macOS) need to be provided somehow. One way can be
having the formula (*.rb file) in-tree, so users of this can install them in
their systems. This would also require to have a tarball with the missing
headers either in-tree or somewhere accessible so it can be fetched.

To avoid having the formula and a tarball in-tree, I've created a Homebrew Tap
(3rd-Party Repository) called 'Bee Headers Project' [1][2][3] that can provision
the missing headers. The project provides a bee-headers package and formula
that will install byteswap.h, elf.h and endian.h in the user's system Hombrew
directory. It also provides a *.pc file so pkg-config can be used to find the
location of these headers. I have a v2 with this solution ready, perhaps is
easier to discuss this with the code.

I think we can extend the same package and include extra headers if we need
more in the future. I see for x86_64 asm/types.h and others might be required.
The bee-headers package can then be the repository to place and distribute them.

Please, let me know if you think of an alternative solution, I can give a try
and explore.

[1] Project:
https://github.com/bee-headers
[2] Headers repository:
https://github.com/bee-headers/headers.git
[3] Homebrew Tap formula:
https://github.com/bee-headers/homebrew-bee-headers.git


> 
> 
> 
> >
> > Kind regards,
> > Nicolas
> 
> 
> 
> -- 
> Best Regards
> Masahiro Yamada