linux image tools

howto.sh

2274631  source image-tools
2274661  make-blank-image virtualdisk.img 1000
2274662  make-paritions virtualdisk.img
2274663  format-partitions virtualdisk.img
2274666  install-to-root virtualdisk.img ~/morty/arch/x86_64/boot/bzImage
# the next copies busybox/_install to /tmp/busybox/ and add init.
2274633  build-initramfs ~/busybox ~/morty   # custom-initramfs.cpio.gz
XXXXXXX  install-to-root virtualdisk.img custom-initramfs.cpio.gz

XXXXXXX  cat <<EOF > startup.nsh
XXXXXXX  \EFI\BOOT\BOOTX64.EFI
XXXXXXX  EOF
2274667  setup-grub /boot/bzImage /boot/custom-initramfs.cpio.gz   # creates bootx64.efi
2274669  install-to-boot virtualdisk.img bootx64.efi
2274668  install-to-boot virtualdisk.img startup.nsh

2274674  VBoxManage convertdd virtualdisk.{img,vdi} --format VDI
2274675  VirtualBox

image-tools.sh

#!/usr/bin/env bash

function info() {
	local GREEN="\e[32m"
	echo -e "\e[32m[INFO]\e[0m $*" >&2
}

function err() {
	echo -e "\e[31m[ERROR]\e[0m $*" >&2
}


function make-blank-image() {
	local OUTPUT_FILE="${1}"
	local SIZE="${2}"
	info "making a image file "${OUTPUT_FILE}" of ${SIZE}Mbytes"
	dd if=/dev/zero \
		of="${OUTPUT_FILE}" \
		bs=1M count="${SIZE}"
}


function make-paritions() {
	local INPUT_FILE="${1}"
	local SWAP_SIZE=512
	local GPT_START="0%"
	local GPT_END=257
	local SWAP_START=$((${GPT_END} + 1))
	local SWAP_END=$((${SWAP_START} + ${SWAP_SIZE}))
	local MAIN_START=$((${SWAP_END} + 1))
	local MAIN_END_KBYTES=$(du ${INTPUT_FILE} | awk '{ print $1 }') 
	local MAIN_END=$(bc <<<"${MAIN_END_KBYTES} / 1024")
	info "Making GPT from ${GPT_START} ${GPT_END}"
	parted --script "${INPUT_FILE}" mklabel gpt mkpart p fat32 ${GPT_START} ${GPT_END} set 1 boot on
	info "Making swap from ${SWAP_START} ${SWAP_END}"
	parted --script "${INPUT_FILE}" mkpart p linux-swap ${SWAP_START} ${SWAP_END}
	info "Making main partition from ${MAIN_START} ${MAIN_END}"
	parted --script "${INPUT_FILE}" mkpart p ext4 ${MAIN_START} ${MAIN_END}
}


function format-partitions() {
	local INPUT_FILE="${1}"
	sudo kpartx -av "${INPUT_FILE}"
	sleep 1
	sudo mkfs.vfat /dev/mapper/loop0p1
	sleep 1
	sudo mkfs.ext4 /dev/mapper/loop0p3
	sleep 1
	sudo kpartx -d "${INPUT_FILE}"
}


function install-to-root() {
	local INPUT_FILE="${1}"
	local KERNEL_IMAGE_LOCATION="${2}"
	mkdir -p /tmp/root
	sudo kpartx -av "${INPUT_FILE}"
	sleep 1
	sudo mount /dev/mapper/loop0p3 /tmp/root
	sudo mkdir /tmp/root/boot
	sudo cp ${KERNEL_IMAGE_LOCATION} /tmp/root/boot
	sudo umount /tmp/root
	sudo kpartx -d "${INPUT_FILE}"
}

function install-to-boot() {
	set -x
	local INPUT_FILE="${1}"
	local BOOT_IMAGE_LOCATION="${2}"
	mkdir -p /tmp/boot
	sudo kpartx -av "${INPUT_FILE}"
	sleep 1
	sudo mount /dev/mapper/loop0p1 /tmp/boot
	sudo mkdir -p /tmp/boot/EFI/boot/
	sudo cp ${BOOT_IMAGE_LOCATION} /tmp/boot/EFI/boot/
	sudo umount /tmp/boot
	sudo kpartx -d "${INPUT_FILE}"
	set +x
}


function setup-grub(){
	local KERNEL_PATH="${1}"
	local INITRAMFS_PATH="${2}"
	cat <<- EOF > /tmp/grub.cfg
	insmod part_gpt
	insmod part_msdos
	insmod fat
	insmod efi_gop
	insmod efi_uga
	insmod video_bochs
	insmod video_cirrus

	menuentry "Start The Magic.." {
	  set root=(hd1,gpt3)
	  linux ${KERNEL_PATH} 
	  initrd ${INITRAMFS_PATH}
	}
	EOF
	grub-mkstandalone -d /usr/lib/grub/x86_64-efi \
		-O x86_64-efi \
		--modules="part_gpt part_msdos" \
		--fonts="unicode" \
		-o "./bootx64.efi" "boot/grub/grub.cfg=/tmp/grub.cfg" -v
}


function build-initramfs() {
	local BUSYBOX_DIR=${1}
	cp -ar "${BUSYBOX_DIR}"/_install /tmp/busybox
	cat <<- "EOF" > /tmp/busybox/init
	#!/bin/busybox sh
	echo "Starting kernel $(uname -r)"
	exec /bin/sh
	EOF
	local KERNEL_DIR="${2}"
	(
	cat <<- EOF
	# A simple initramfs
	dir /dev 0755 0 0
	nod /dev/console 0600 0 0 c 5 1
	dir /root 0700 0 0
	dir /sbin 0755 0 0
	dir /bin 0755 0 0
	file /bin/busybox /tmp/busybox/bin/busybox 755 0 0
	EOF

	for i in $(find /tmp/busybox/sbin/ -type l )
	do 
		cur_link="${i##/tmp/busybox/sbin/}"
		echo "slink /sbin/${cur_link} busybox 777 0 0"
	done
	for i in $(find /tmp/busybox/bin/* -type l )
	do
		cur_link="${i##/tmp/busybox/bin/}"
		echo "slink /bin/${cur_link} busybox 777 0 0"
	done
	echo "file /init /tmp/busybox/init 755 0 0"
	) > /tmp/initramfs-list
	${KERNEL_DIR}/usr/gen_init_cpio /tmp/initramfs-list > custom-initramfs.cpio.gz
}