mkimage-profiles/bin/tar2vm
Michael Shigorin 6c9ca9af08 tar2vm: added xfs note
The issue at hand is the ability to accomodate boot sector
payload at the start of the filesystem's underlying block device.

XFS doesn't spare that space.

Thanks vsu@ for the reminder, by the way.
2013-04-19 21:00:29 +04:00

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#!/bin/bash -e
# usage:
# tar2vm chroot.tar image.raw [size_in_bytes]
. shell-error
if [ $# -lt 2 ]; then
fatal "error: tar2vm needs at least two arguments"
fi
# this needs env_keep sudo setup to actually work
if [ -n "$GLOBAL_BUILDDIR" ]; then
WORKDIR="$GLOBAL_BUILDDIR/vmroot"
else
WORKDIR="$(mktemp --tmpdir -d vmroot-XXXXX)"
fi
[ -n "$WORKDIR" ] || fatal "couldn't come up with suitable WORKDIR"
[ -n "$GLOBAL_DEBUG" ] || message "WORKDIR: $WORKDIR"
# a tarball containing chroot with a kernel
TAR="$1"
[ -s "$TAR" ] || fatal "source tarball doesn't really exist"
# a path to the image to be generated
IMG="$2"
[ -d "$(dirname "$IMG")" ] || fatal "target directory doesn't exist"
# image size in bytes (256M is a fallback)
TARSIZE="$(stat -Lc %s "$TAR")"
DEFSIZE="$((2 * $TARSIZE))"
DISKSIZE="${3:-${DEFSIZE:-268435456}}"
# ...and in megabytes
DISKSIZEM="$(($DISKSIZE / 1048576))"
# tested to work: ext[234], jfs
# NB: xfs doesn't have a spare sector for the bootloader
ROOTFSTYPE="${4:-ext4}"
# single root partition hardwired so far,
# add another image for swap if needed
ROOTDEV="/dev/sda1"
# last preparations...
for i in losetup sfdisk parted kpartx mkfs."$ROOTFSTYPE"; do
if ! type -t "$i" >&/dev/null; then
fatal "$i required but not found"
fi
done
LOOPDEV="$(losetup --find)"
ROOTFS="$WORKDIR/chroot"
exit_handler()
{
rc=$?
if [ -n "$ROOTFS" ]; then
umount "$ROOTFS"{/dev,/proc,/sys,}
if [ -n "$LOOPDEV" ]; then
kpartx -d "$LOOPDEV"
losetup --detach "$LOOPDEV"
fi
rm -r -- "$ROOTFS"
rmdir -- "$WORKDIR"
fi
exit $rc
}
trap exit_handler EXIT
# prepare disk image and a filesystem inside it
rm -f -- "$IMG"
dd if=/dev/zero of="$IMG" conv=notrunc \
bs=1 count=1 seek="$(($DISKSIZE - 1))"
losetup "$LOOPDEV" "$IMG"
parted --script "$LOOPDEV" mklabel msdos
parted --script "$LOOPDEV" mkpart primary ext2 1 "$DISKSIZEM"
kpartx -a "$LOOPDEV"
LOOPDEV1="/dev/mapper/$(basename "$LOOPDEV")p1"
mkfs."$ROOTFSTYPE" "$LOOPDEV1"
# mount and populate it
mkdir -pm755 "$ROOTFS"
mount "$LOOPDEV1" "$ROOTFS"
tar -C "$ROOTFS" --numeric-owner -xf "$TAR"
for i in /dev /proc /sys; do mount --bind "$i" "$ROOTFS$i"; done
# NB: different storage modules might be needed for non-kvm
echo "$LOOPDEV1 / $ROOTFSTYPE defaults 1 1" >> "$ROOTFS/etc/fstab"
echo "MODULES_PRELOAD=sd_mod ata_piix $ROOTFSTYPE" >> "$ROOTFS/etc/initrd.mk"
KERNEL="$(readlink $ROOTFS/boot/vmlinuz | sed 's,vmlinuz-,,')"
chroot "$ROOTFS" make-initrd -k "$KERNEL"
sed -i "s,$LOOPDEV1,$ROOTDEV," "$ROOTFS/etc/fstab"
# configure and install bootloader
REGEXP='^Disk .*: ([0-9]+) cylinders, ([0-9]+) heads, ([0-9]+) sectors/track*$'
set -- $(sfdisk -l "$LOOPDEV" | grep -E "$REGEXP" | sed -r "s@$REGEXP@\1 \2 \3@")
LILO_COMMON="lba32
delay=1
vga=0
image=/boot/vmlinuz
initrd=/boot/initrd.img
append=\"root=$ROOTDEV rootdelay=3\"
label=linux"
cat > "$ROOTFS"/etc/lilo-loop.conf << EOF
boot=$LOOPDEV
disk=$LOOPDEV
bios=0x80
cylinders=$1
heads=$2
sectors=$3
partition=$LOOPDEV1
start=63
$LILO_COMMON
EOF
chroot "$ROOTFS" lilo -C /etc/lilo-loop.conf
cat > "$ROOTFS"/etc/lilo.conf << EOF
boot=${ROOTDEV%[0-9]*}
$LILO_COMMON
EOF
if [ -n "$SUDO_USER" ]; then
chown "$SUDO_USER" "$IMG" "$ROOTFS" "$WORKDIR"
fi