Re: [PATCH] kernel.bbclass: allow exporting files from kernel recipes to sysroot

[<Mikko.Rapeli@bmw.de>]

On Mon, Sep 24, 2018 at 02:56:49PM +0100, richard.purdie@linuxfoundation.org wrote:
> On Mon, 2018-09-24 at 09:43 -0400, Bruce Ashfield wrote:
> > > On Mon, 2018-09-24 at 13:20 +0000, Mikko.Rapeli@bmw.de wrote:
> > > > On Mon, Sep 24, 2018 at 02:11:13PM +0100, Richard Purdie wrote:
> > > > > On Mon, 2018-09-24 at 12:19 +0000, Mikko.Rapeli@bmw.de wrote:
> > > > > > > That was one old way, but not the only. And not for
> > > > > > > exposing
> > > > > > > non
> > > > > > > uapi
> > > > > > > headers.
> > > > > > 
> > > > > > What other ways exist?
> > > > > > 
> > > > > > I don't care how, but I must export custom kernel specific
> > > > > > headers
> > > > > > and
> > > > > > other files to other recipes in a build in ways which are
> > > > > > compatible
> > > > > > with
> > > > > > yocto upstream.
> > > > > > 
> > > > > > I have not seen any documented ways for this.
> > > > > 
> > > > > It may not be documented, perhaps because its actually very
> > > > > simple.
> > > > > 
> > > > > Any recipe can expose headers into the recipe sysroot, they
> > > > > simply
> > > > > install them where needed in do_install as normal.
> > > > > 
> > > > > So all you need is a recipe which installs the right headers
> > > > > and
> > > > > then
> > > > > you DEPEND on that recipe. Where that recipe gets the headers
> > > > > isn't
> > > > > relevant.
> > > > 
> > > > No, this does not work on sumo. My patch is needed for this to
> > > > work.
> > > > 
> > > > Without my patch, users of kernel.bbclass have zero files in
> > > > tmp/sysroot-components even if they install extra files and extra
> > > > header only binary packages.
> > > > 
> > > > A generated image or SDK will have the files if the binary
> > > > package is
> > > > installed but sysroot not.
> > > 
> > > I was replying from the perspective of how this should work in
> > > general.
> > > I agree that for this to work with a kernel recipe we do need the
> > > change that started this thread and that is probably a reasonable
> > > thing
> > > to do.
> > 
> > We have a Yocto bugzilla that can be closed if you are ok with the
> > approach.
> > 
> > To answer the other question about what I've done (and proposed
> > before) was
> > to maintain the kernel.bbclass protections, all call the staging
> > routines myself.
> > 
> > i.e.
> > 
> > do_install_append() {
> >         make headers_install
> > INSTALL_HDR_PATH=${D}${KERNEL_ALT_HEADER_DIR}
> > 
> >         # remove export artifacts
> >         find ${D}${KERNEL_ALT_HEADER_DIR} -name .install -exec rm {}
> > \;
> >         find ${D}${KERNEL_ALT_HEADER_DIR} -name ..install.cmd -exec
> > rm {} \;
> > }
> > 
> > sysroot_stage_all_append() {
> >     sysroot_stage_dir ${D}${KERNEL_ALT_HEADER_DIR}
> > ${SYSROOT_DESTDIR}${KERNEL_ALT_HEADER_DIR}
> > }
> > 
> > And that works to get things exported.
> 
> I'm fine with this approach, I'm kind of surprised anyone thinks
> otherwise as I've always assumed this was what people were doing!
> 
> I'd propose that:
> 
> a) We document the above approach. I prefer it to Mikko's patch since
> it doesn't mess with the blacklist and installs exactly what the recipe
> wants to install which is how we normally write recipes.
> b) To document it, I suggest a comment/reference in kernel.bbclass and
> we add something somewhere in the manual. Adding Scott Rifenbark to cc
> so he can help us sort this out.
> c) Close out the bug Bruce mentions with this documentation as a
> reference.
> 
> I think this means we probably don't need Mikko's patch and it is
> mainly a documentation issue?

My only complaint is that it's not obvious in a kernel recipe that
more than do_install() is needed to export files to sysroot.
It's easy to miss the sysroot_stage_all_append() step.

Overwriting files from kernel recipe fails when they are used to prepare
sysroots for user recipes, but not when the kernel recipe is build:

ERROR: linux-image-1.0.0-r21 do_prepare_recipe_sysroot: The file /usr/include/scsi/scsi_bsg_fc.h is installed by both linux-libc-headers and linux, aborting
ERROR: linux-image-1.0.0-r21 do_prepare_recipe_sysroot: Function failed: extend_recipe_sysroot

In this case linux recipe added kernel specific headers to /usr/include
which conflict with linux-libc-headers and this was only cought when building
the kernel image.

-Mikko