#!/bin/sh

. ../lib/common.sh

cleanup()
{
    umount "${tmpdir}/root" || :
    qemu-nbd -d /dev/nbd0 || :
    rm -rf "$tmpdir"
}

set -ef
trap cleanup EXIT INT

devmgr=${DEVMGR:-proc}
arch=${ARCH:-$(uname -m)}
kernel=${KERNEL:-$(uname -r)}
vmlinuz=${VMLINUZ:-"/boot/vmlinuz-${kernel}"}

mkdir -p "${tmpdir:=${TMPDIR:-/tmp}/${0##*/}.$$}"

root="${tmpdir}/root"
config="${tmpdir}/config"
image="${tmpdir}/root.qcow2"
initrd="${tmpdir}/initramfs-$(uname -r)"

qemu-img create -f qcow2 "$image" 1G
qemu-nbd -c /dev/nbd0 "$image"

# o: Create MBR table.
# n: Add new partition to table.
# p: Primary partition.
# 1: Partition number.
# newline: Use default value for first sector.
# newline: Use default value for last sector.
# w: Write changes and re-read partition table.
fdisk /dev/nbd0 << EOF
o
n
p
1


w
EOF

cat > "$config" << EOF
hooks=$devmgr
root=LABEL=root
EOF

mkdir -p "$root"

mkfs.ext4 -L root /dev/nbd0p1
mount /dev/nbd0p1 "$root"

(
    tmpdir=$root; cd "$tmpdir"

    mkdir -p \
        dev sys tmp run proc \
        root usr/lib usr/bin

    ln -s usr/lib lib
    ln -s usr/bin bin
    ln -s usr/bin sbin
    ln -s bin     usr/sbin

    copy_exec sh
    copy_exec e2label

    cat > sbin/init << EOF
#!/bin/sh
exec e2label /dev/disk/by-label/root success
EOF

    chmod +x sbin/init
)

umount "$root"
qemu-nbd -d /dev/nbd0

(cd .. && ./tinyramfs -lk "$kernel" -c "$config" "$initrd")

set -- \
    -no-reboot \
    -initrd "$initrd" \
    -kernel "$vmlinuz" \
    -device virtio-scsi \
    -drive  file="$image",if=virtio

if [ -c /dev/kvm ]; then
    set -- -enable-kvm -cpu host "$@"
fi

if [ "$DEBUG" ]; then
    set -- -append 'panic=-1 rdpanic debug rddebug console=ttyS0' -nographic "$@"
else
    set -- -append 'panic=-1 rdpanic' -display none "$@"
fi

"qemu-system-${arch}" "$@"

qemu-nbd -c /dev/nbd0 "$image"

# Re-read partition table.
fdisk /dev/nbd0 << EOF
w
EOF

[ "$(e2label /dev/nbd0p1)" = success ]