[gentoo-commits] repo/gentoo:master commit in: eclass/

[Michał Górny]

commit:     9201c6c58e9a8b9dd184a4d2445b4144cf22df8f
Author:     Michał Górny <mgorny <AT> gentoo <DOT> org>
AuthorDate: Wed Jan 13 14:15:54 2021 +0000
Commit:     Michał Górny <mgorny <AT> gentoo <DOT> org>
CommitDate: Sat Jan 16 09:53:08 2021 +0000
URL:        https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=9201c6c5

dist-kernel-utils.eclass: Support dracut's uefi=yes option

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 <AT> 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 d65dc0924b4..9ab65b097b3 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 uefi=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 [[ ${magic} == MZ ]]; then
+               einfo "Combined UEFI kernel+initramfs executable found"
+               # install the combined executable in place of kernel
+               image=${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