add example (but useful) dhcp initrd

build-dhcp-initrd

@@ -0,0 +1,62 @@
+#! /bin/bash
+
+base_initrd=dist/initrd
+flavor=dhcp
+dir=tmp/$flavor-initrd
+
+dist=dist/$flavor
+uki=$dist/bootx64.efi
+
+linux_v=6.18.34
+
+set -ex
+
+mkdir -p tmp/dl $dist
+
+linux=tmp/dl/linux-$linux_v
+modules=tmp/dl/modules-$linux_v
+
+[ -e $linux ]   || curl -o $linux   https://dkl.novit.io/dist/kernels/6.18.34
+[ -e $modules ] || curl -o $modules https://dkl.novit.io/dist/layers/modules/6.18.34 # TODO .erofs
+
+rm -fr $dir
+mkdir $dir
+
+cpio --quiet --extract --file $base_initrd --directory $dir
+
+cp -rv $flavor/. $dir
+cp $modules $dir/modules.fs
+
+(cd $dir && find * |cpio --create -H newc -R 0:0) >$dir.cpio
+
+if cpio -tF $dir.cpio 2>&1 |grep bytes.of.junk; then echo "bad cpio archive"; exit 1; fi
+
+zstd -12 -T0 -vf $dir.cpio &&
+mv $dir.cpio.zst $dist/initrd
+cp $linux $dist/vmlinuz
+
+ukify build --output $uki --os-release "Direktil DHCP" \
+    --linux $linux --initrd $dist/initrd --cmdline "console=tty0 console=ttyS0,115200"
+
+MB=$(( 2**20 ))
+sz=$(( ( $(stat -c %s $uki) + MB ) / MB + 2 ))
+
+efi=$dist/efi.img
+
+if [ -e $efi ]; then rm $efi; fi
+
+truncate -s ${sz}M $efi
+sgdisk -n 1:2048:0 -t 1:ef00 -c 1:"EFI System" $efi
+
+offset=$(( 2048 * 512 ))
+
+export MTOOLSRC=$(mktemp)
+trap "rm -f $MTOOLSRC" exit
+echo "drive e: file=\"$efi\" offset=$offset" >$MTOOLSRC
+
+args="-i $efi@@$offset"
+
+mformat -F e:
+mmd e:EFI e:EFI/BOOT
+mcopy $uki e:EFI/BOOT/BOOTX64.EFI
+