create_disk_image

#!/bin/bash - 
#===============================================================================
#
#          FILE: create_disk_image
# 
#         USAGE: ./create_disk_image [ output_directory [ disk_size [ image_size  ]]] 
# 
#   DESCRIPTION: does the image creation stuff that requires sudo
# 
#===============================================================================

set -o nounset                              # Treat unset variables as an error

for arg in "$@" ; do
    case "$arg" in
        -*) 
            printf 'Usage: %s [ output_directory [ disk_size [ image_size  ]]]\n' "$0"
            printf 'This script also needs root priviledges\n' "$0"
            printf 'required for the mount syscall\n' "$0"
            exit
            ;;
    esac
done

if [ $UID -ne 0 ]; then
    printf 'This script needs root priviledges.\n' >&2
    exit 1
fi

DIR="$( cd "$(dirname "${BASH_SOURCE[0]}")" && pwd )"
output_dir="$DIR/buildroot/output"
br_config_file="$output_dir/.config"
if [ -d "$PWD/output" ];then
    output_dir="$PWD/output"
    br_config_file="$output_dir/.config"
fi
if [ -f "$PWD/.output_dir" ] && [ -d "$(cat "$PWD/.output_dir")" ] ;then
    output_dir="$(cat "$PWD/.output_dir")"
    br_config_file="$output_dir/.config"
fi

disk_size=$(grep BR2_BRBOX_DISKSIZE "$br_config_file" | sed 's;BR2_BRBOX_DISKSIZE="\(.*\)";\1;')
if [ $# -gt 0 ]; then 
    disk_size="$1"
    shift
fi
partition_size=$(grep BR2_BRBOX_PARTITIONSIZE "$br_config_file" | sed 's;BR2_BRBOX_PARTITIONSIZE="\(.*\)";\1;')
if [ $# -gt 0 ]; then 
    partition_size="$1"
    shift
    if [ $# -gt 0 ]; then
        printf 'Too many arguments' >&2
        exit 1
    fi
fi

image_filename="$output_dir/images/bootable-usb-disk.img"

fallocate -l "$disk_size" "$image_filename"
test $? -eq 0 || { printf 'Could not create %s\n' "$image_filename" >&2 ; exit 1; }

BOOTSIZE=1M
STTNGSIZE=16M
ROOT1_LABEL=ROOT1   #linux-1
ROOT2_LABEL=ROOT2   #linux-2
STTNG_LABEL=STTNG   #settings
USRDAT_LABEL=USRDAT #userdata
# IMAGE_VERSION=01.00.12345
GRUB_MENU_ENTRY1='brbox1'
GRUB_MENU_ENTRY2='brbox2'
GRUB2_TIMEOUT=1
ROOTDELAY=5

# Formatting disk
sgdisk -Z "$image_filename" >/dev/null
sgdisk -n 1::+"$BOOTSIZE"   -t 1:ef02 -c 1:boot  "$image_filename" >/dev/null
sgdisk -n 2::+"$partition_size"  -c 2:$ROOT1_LABEL    "$image_filename" >/dev/null
sgdisk -n 3::+"$partition_size"  -c 3:$ROOT2_LABEL    "$image_filename" >/dev/null
sgdisk -n 4::+"$STTNGSIZE"  -c 4:$STTNG_LABEL    "$image_filename" >/dev/null
sgdisk -n 5:: -c 5:$USRDAT_LABEL   "$image_filename" >/dev/null
test $? -eq 0 || { printf 'Could not partition %s\n' "$image_filename" >&2 ; exit 1; }

# needs to write this file to disk, cannot find partitions otherwise
sync

echo "Creating disk image"
loopdevice=$(losetup -f --show "$image_filename")
test $? -eq 0 || { printf 'Could not setup loop device %s\n' "$image_filename" >&2 ; exit 1; }

partx -a "$loopdevice"
test $? -eq 0 || { printf 'Could not find partitions\n' >&2 ; exit 1; }

echo "Formating disk image"
mkfs.ext3 -L $ROOT1_LABEL "${loopdevice}p2" 1>/dev/null 2>/dev/null
test $? -eq 0 || { printf 'Formatting %s failed\n' $ROOT1_LABEL >&2 ; exit 1; }
mkfs.ext3 -L $ROOT2_LABEL "${loopdevice}p3" 1>/dev/null 2>/dev/null
test $? -eq 0 || { printf 'Formatting %s failed\n' $ROOT2_LABEL >&2 ; exit 1; }
mkfs.ext3 -L $STTNG_LABEL "${loopdevice}p4" 1>/dev/null 2>/dev/null
test $? -eq 0 || { printf 'Formatting %s failed\n' $STTNG_LABEL >&2 ; exit 1; }
mkfs.ext3 -L $USRDAT_LABEL "${loopdevice}p4" 1>/dev/null 2>/dev/null
test $? -eq 0 || { printf 'Formatting %s failed\n' $USRDAT_LABEL >&2 ; exit 1; }

mountdir=$(mktemp -d)
mkdir "$mountdir/root1" "$mountdir/root2"
mount "${loopdevice}p2" "$mountdir/root1"
test $? -eq 0 || { printf 'Could not mount root1\n' >&2 ; exit 1; }
mount "${loopdevice}p3" "$mountdir/root2"
test $? -eq 0 || { printf 'Could not mount root2\n' >&2 ; exit 1; }

echo "Copying files"
rootfs="$output_dir/images/rootfs.tar.xz"
tar -C "$mountdir/root1" -Jxf "$rootfs"
test $? -eq 0 || { printf 'Could not extract files onto root1\n' >&2; exit 1; }
tar -C "$mountdir/root2" -Jxf "$rootfs"
test $? -eq 0 || { printf 'Could not extract files onto root2\n' >&2; exit 1; }

echo "Generating grub configs"
cat <<ENDOFGRUBCFG >"$output_dir/grub.cfg.in"
insmod part_gpt
insmod part_msdos
insmod ext2
search -l $ROOT1_LABEL -s root
if [ -e /boot/grub/grub.cfg ]; then
	configfile /boot/grub/grub.cfg
else
	search -l $ROOT2_LABEL -s root
	configfile /boot/grub/grub.cfg
fi
ENDOFGRUBCFG
test $? -eq 0 || { printf 'Could not create grub.cfg.in\n' >&2 ; exit 1; }

part1uuid=$(sgdisk -i=2 "$loopdevice" |grep 'Partition unique GUID' |cut -d\  -f4)
part2uuid=$(sgdisk -i=3 "$loopdevice" |grep 'Partition unique GUID' |cut -d\  -f4)

cat <<ENDOFGRUBCFG >"$output_dir/grub.cfg"
set timeout=$GRUB2_TIMEOUT
set default=0
insmod ext2
menuentry $GRUB_MENU_ENTRY1 {
    search -l $ROOT1_LABEL -s root
    linux /boot/bzImage rootdelay=$ROOTDELAY consoleblank=0 ro enable_mtrr_cleanup mtrr_spare_reg_nr=1 brboxsystem=$GRUB_MENU_ENTRY1 net.ifnames=0 root=PARTUUID=$part1uuid
}
menuentry $GRUB_MENU_ENTRY2 {
    search -l $ROOT2_LABEL -s root
    linux /boot/bzImage rootdelay=$ROOTDELAY consoleblank=0 ro enable_mtrr_cleanup mtrr_spare_reg_nr=1 brboxsystem=$GRUB_MENU_ENTRY2 net.ifnames=0 root=PARTUUID=$part2uuid
}
ENDOFGRUBCFG
test $? -eq 0 || { printf 'Could not create grub.cfg\n' >&2 ; exit 1; }

echo "Installing grub"
"$output_dir/host/usr/bin/grub-mkimage" -d "$output_dir/host/usr/lib/grub/i386-pc" \
    -O i386-pc -o "$output_dir/images/grub.img" -c "$output_dir/grub.cfg.in" \
    acpi cat boot linux ext2 fat part_msdos part_gpt normal biosdisk \
    search echo search_fs_uuid normal ls ata configfile halt help \
    hello read png vga lspci echo minicmd vga_text terminal
test $? -eq 0 || { printf 'Could not generate grub.img\n' >&2 ; exit 1; }

"$output_dir/host/usr/sbin/grub-bios-setup" \
    -b "$output_dir/host/usr/lib/grub/i386-pc/boot.img" \
    -c "$output_dir/images/grub.img" -d / "$loopdevice"
test $? -eq 0 || { printf 'Could setup grub\n' >&2 ; exit 1; }

cp "$output_dir/grub.cfg" "$mountdir/root1/boot/grub/grub.cfg"
cp "$output_dir/grub.cfg" "$mountdir/root2/boot/grub/grub.cfg"

printf "Cleaning up\n"
umount "$mountdir/root1"
umount "$mountdir/root2"
partx -d "$loopdevice"
losetup -d "$loopdevice"
rm -rf "$mountdir"
sync

chown "$SUDO_UID:$SUDO_GID" "$image_filename"