qubes-linux-utils/dracut/full-dmroot/qubes_cow_setup.sh
Marek Marczykowski-Górecki 5eb526da4b
dracut: fix checking for "Root filesystem" label, improve udev sync
Don't try to dereference "Root filesytem" partlabel symlink, unless it's
really present (not only directory for it).

Also, use udevadm settle for waiting for /dev/xvda, instead of naive
wait sleep loop.
2019-02-06 20:20:08 +01:00

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#!/bin/sh
#
# This file should be placed in pre-trigger 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 "$@"
exit 1
}
alias info=echo
alias warn=echo
alias log_begin=echo
alias log_end=true
fi
info "Qubes initramfs script here:"
if ! grep -q 'root=[^ ]*dmroot' /proc/cmdline; then
warn "dmroot not requested, probably not a Qubes VM"
exit 0
fi
if [ -e /dev/mapper/dmroot ] ; then
die "Qubes: FATAL error: /dev/mapper/dmroot already exists?!"
fi
modprobe xenblk || modprobe xen-blkfront || warn "Qubes: Cannot load Xen Block Frontend..."
log_begin "Waiting for /dev/xvda* devices..."
udevadm settle --exit-if-exists=/dev/xvda
log_end
# prefer partition if exists
if [ -b /dev/xvda1 ]; then
if [ -e "/dev/disk/by-partlabel/Root\\x20filesystem" ]; then
ROOT_DEV=$(basename $(readlink "/dev/disk/by-partlabel/Root\\x20filesystem"))
else
ROOT_DEV=xvda3
fi
else
ROOT_DEV=xvda
fi
SWAP_SIZE=$(( 1024 * 1024 * 2 )) # sectors, 1GB
if [ `cat /sys/class/block/$ROOT_DEV/ro` = 1 ] ; then
log_begin "Qubes: Doing COW setup for AppVM..."
while ! [ -e /dev/xvdc ]; do sleep 0.1; done
VOLATILE_SIZE=$(cat /sys/class/block/xvdc/size) # sectors
ROOT_SIZE=$(cat /sys/class/block/$ROOT_DEV/size) # sectors
if [ $VOLATILE_SIZE -lt $SWAP_SIZE ]; then
die "volatile.img smaller than 1GB, cannot continue"
fi
sfdisk -q --unit S /dev/xvdc >/dev/null <<EOF
1,$SWAP_SIZE,S
,,L
EOF
if [ $? -ne 0 ]; then
die "Qubes: failed to setup partitions on volatile device"
fi
while ! [ -e /dev/xvdc1 ]; do sleep 0.1; done
mkswap /dev/xvdc1
while ! [ -e /dev/xvdc2 ]; do sleep 0.1; done
echo "0 `cat /sys/class/block/$ROOT_DEV/size` snapshot /dev/$ROOT_DEV /dev/xvdc2 N 16" | \
dmsetup --noudevsync create dmroot || die "Qubes: FATAL: cannot create dmroot!"
dmsetup mknodes dmroot
log_end
else
log_begin "Qubes: Doing R/W setup for TemplateVM..."
while ! [ -e /dev/xvdc ]; do sleep 0.1; done
sfdisk -q --unit S /dev/xvdc >/dev/null <<EOF
1,$SWAP_SIZE,S
EOF
if [ $? -ne 0 ]; then
die "Qubes: failed to setup partitions on volatile device"
fi
while ! [ -e /dev/xvdc1 ]; do sleep 0.1; done
mkswap /dev/xvdc1
mkdir -p /etc/udev/rules.d
printf 'KERNEL=="%s", SYMLINK+="mapper/dmroot"\n' "$ROOT_DEV" >> \
/etc/udev/rules.d/99-root.rules
udevadm control -R
udevadm trigger
log_end
fi