On 21-01-13 15:35:15, Michał Górny wrote:
> Support dracut's uefi=yes configuration option that creates a combined
> UEFI stub, kernel and initramfs in a single UEFI executable.  If such
> an output is detected, install it in place of the actual kernel image
> and stub out the duplicate initrd to save space.
> 
> Signed-off-by: Michał Górny <mgorny@gentoo.org>
> ---
>  eclass/dist-kernel-utils.eclass | 31 ++++++++++++++++++++++++++++++-
>  1 file changed, 30 insertions(+), 1 deletion(-)
> 
> diff --git a/eclass/dist-kernel-utils.eclass b/eclass/dist-kernel-utils.eclass
> index d65dc0924b40..50ad15f8b1fd 100644
> --- a/eclass/dist-kernel-utils.eclass
> +++ b/eclass/dist-kernel-utils.eclass
> @@ -41,8 +41,20 @@ dist-kernel_build_initramfs() {
>  	local output=${1}
>  	local version=${2}
>  
> +	local rel_image_path=$(dist-kernel_get_image_path)
> +	local image=${output%/*}/${rel_image_path##*/}
> +
> +	local args=(
> +		--force
> +		# if uefi=yes is used, dracut needs to locate the kernel image
> +		--kernel-image "${image}"
> +
> +		# positional arguments
> +		"${output}" "${version}"
> +	)
> +
>  	ebegin "Building initramfs via dracut"
> -	dracut --force "${output}" "${version}"
> +	dracut "${args[@]}"
>  	eend ${?} || die -n "Building initramfs failed"
>  }
>  
> @@ -85,6 +97,23 @@ dist-kernel_install_kernel() {
>  	local image=${2}
>  	local map=${3}
>  
> +	# if dracut is used in eufi=yes mode, initrd will actually
> +	# be a combined kernel+initramfs UEFI executable.  we can easily
> +	# recognize it by PE magic (vs cpio for a regular initramfs)
> +	local initrd=${image%/*}/initrd
> +	local magic
> +	[[ -s ${initrd} ]] && read -n 2 magic < "${initrd}"
> +	if [[ ${magic} == MZ ]]; then

This magic header is matched by both the kernel and the new uefi
executible.  I think a better check would be...

if file "${image_path}" | grep -q 'EFI application'; then

> +		einfo "Combined UEFI kernel+initramfs executable found"
> +		# install the combined executable in place of kernel
> +		image=${initrd}.uefi
> +		mv "${initrd}" "${image}" || die
> +		# put an empty file in place of initrd.  installing a duplicate
> +		# file would waste disk space, and removing it entirely provokes
> +		# kernel-install to regenerate it via dracut.
> +		> "${initrd}"
> +	fi
> +
>  	ebegin "Installing the kernel via installkernel"
>  	# note: .config is taken relatively to System.map;
>  	# initrd relatively to bzImage
> -- 
> 2.30.0

I want to make sure you are not overwriting the original kernel image,
if you do then subsiquent --config runs will include the kernel image,
making the final image grow.

In order to avoid that I did some file juggling, but it looks like it's
cleaner here.

https://gist.github.com/prometheanfire/aeffa1c3f92d3d2af312b3b6915051fb
'worked' but was kinda unclean.


-- 
Matthew Thode (prometheanfire)