qubes-linux-utils/dracut/full-dmroot/qubes_cow_setup.sh
Marek Marczykowski-Górecki 64331d7e09
dracut: add a safety check preventing qubes_cow_setup.sh running in dom0
Theoretically it shouldn't be a problem, because module isn't installed
in initramfs by default (in dom0), but since such error would be fatal
to dom0 (will prevent it from booting), add a safety check for it.

Probably it will be required when (if) we migrate dom0 to Debian
2015-11-11 05:10:59 +01:00

90 lines
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#!/bin/sh
#
# This file should be placed in pre-mount directory in dracut's initramfs, or
# scripts/local-top in case of initramfs-tools
#
# initramfs-tools (Debian) API
PREREQS=""
case "$1" in
prereqs)
# This runs during initramfs creation
echo "$PREREQS"
exit 0
;;
esac
# This runs inside real initramfs
if [ -r /scripts/functions ]; then
# We're running in Debian's initramfs
. /scripts/functions
alias die=panic
alias info=true
alias warn=log_warning_msg
alias log_begin=log_begin_msg
alias log_end=log_end_msg
elif [ -r /lib/dracut-lib.sh ]; then
. /lib/dracut-lib.sh
alias log_begin=info
alias log_end=true
else
die() {
echo "$@"
exit 1
}
alias info=echo
alias warn=echo
alias log_begin=echo
alias log_end=true
fi
info "Qubes initramfs script here:"
if ! grep -q 'root=[^ ]*dmroot' /proc/cmdline; then
warn "dmroot not requested, probably not a Qubes VM"
exit 0
fi
if [ -e /dev/mapper/dmroot ] ; then
die "Qubes: FATAL error: /dev/mapper/dmroot already exists?!"
fi
modprobe xenblk || modprobe xen-blkfront || warn "Qubes: Cannot load Xen Block Frontend..."
log_begin "Waiting for /dev/xvda* devices..."
while ! [ -e /dev/xvda ]; do sleep 0.1; done
log_end
if [ `cat /sys/block/xvda/ro` = 1 ] ; then
log_begin "Qubes: Doing COW setup for AppVM..."
while ! [ -e /dev/xvdc ]; do sleep 0.1; done
VOLATILE_SIZE=$(sfdisk -s /dev/xvdc)
ROOT_SIZE=$(sfdisk -s /dev/xvda) # kbytes
SWAP_SIZE=1024 # kbytes
if [ $VOLATILE_SIZE -lt $(($ROOT_SIZE + $SWAP_SIZE)) ]; then
ROOT_SIZE=$(($VOLATILE_SIZE - $SWAP_SIZE))
fi
sfdisk -q --unit B /dev/xvdc >/dev/null <<EOF
0,$SWAP_SIZE,S
,$ROOT_SIZE,L
EOF
if [ $? -ne 0 ]; then
die "Qubes: failed to setup partitions on volatile device"
fi
while ! [ -e /dev/xvdc1 ]; do sleep 0.1; done
mkswap /dev/xvdc1
while ! [ -e /dev/xvdc2 ]; do sleep 0.1; done
echo "0 `cat /sys/block/xvda/size` snapshot /dev/xvda /dev/xvdc2 N 16" | \
dmsetup --noudevsync create dmroot || die "Qubes: FATAL: cannot create dmroot!"
log_end
else
log_begin "Qubes: Doing R/W setup for TemplateVM..."
echo "0 `cat /sys/block/xvda/size` linear /dev/xvda 0" | \
dmsetup --noudevsync create dmroot || die "Qubes: FATAL: cannot create dmroot!"
log_end
fi
dmsetup mknodes dmroot