Add basic version of creation script

scripts/snap-pac-uki_create.fish

@@ -0,0 +1,41 @@
+#!/bin/fish
+
+# get id and type of last snapshot
+set -l config "root"
+set -l snapshots (snapper -c $config --jsonout ls | jq -c ".$config")
+set -l last (echo $snapshots | jq -c "last")
+set -l id (echo $last | jq ".number")
+set -l type (echo $last | jq ".type")
+
+if not contains $type '"pre"' '"post"'
+    echo "Last snapshot has type \"$type\", therefore no UKI is created."
+    exit
+end
+
+
+# check if UKI already exists
+set -l ukis (ls /boot/EFI/Linux/ | grep "snap-pac-uki-[1-9][0-9]*\.efi" | grep -o '[1-9][0-9]*')
+
+if contains $id $ukis
+    echo "UKI already exists"
+    exit
+end
+
+
+# prepare uki creation
+mkdir -p "/tmp/snap-pac-uki/$id"
+rm -rf "/tmp/snap-pac-uki/$id/*"
+cd "/tmp/snap-pac-uki/$id"
+
+sed "s/BUILD_ID=.*/BUILD_ID=\"Snapshot $id\"/" </usr/lib/os-release >./os-release
+grep options /boot/loader/entries/00-arch.conf | string sub -s 9 | sed ':a;N;$!ba;s/\n/ /g' >./kernel-parameters
+
+
+# create uki
+objcopy \
+    --add-section .osrel="./os-release" --change-section-vma .osrel=0x20000 \
+    --add-section .cmdline="./kernel-parameters" --change-section-vma .cmdline=0x30000 \
+    --add-section .splash="/usr/share/systemd/bootctl/splash-arch.bmp" --change-section-vma .splash=0x40000 \
+    --add-section .linux="/boot/vmlinuz-linux" --change-section-vma .linux=0x2000000 \
+    --add-section .initrd="/boot/initramfs-linux.img" --change-section-vma .initrd=0x3000000 \
+    "/usr/lib/systemd/boot/efi/linuxx64.efi.stub" "/boot/EFI/Linux/snap-pac-uki-$id.efi"