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# This file implements common functions for all boot scripts
# Rerun with sudo if needed
[ $(id -u) = 0 ] || exec sudo $0 $@
export ACTION="$(basename $0)"
# Function to write a message and exit with error code
die() {
echo "$*" >&2
exit 1
}
# Function to setup subhost name and log file
subhost_name() {
CONFIG="$1"
[ -r "$CONFIG" ] || die "Cannot use $CONFIG"
config NAME "$(basename $CONFIG .conf)"
config LOG /tmp/oly-$NAME.log
}
# Function to set up all subhost configuration
subhost_config() {
config BASE
BASE="$(cd $(dirname $CONFIG); realpath $BASE)"
[ -z "$BASE" ] && die "BASE is unset; bogus $CONFIG ?"
[ -d "$BASE" ] || die "$BASE is not a directory; bogus $CONFIG ?"
cd "$BASE" || die "$BASE is inaccessible"
config CABLES ""
config LIVE "$BASE/live"
config UPPER "$BASE/root"
config WORK "$BASE/work"
config LOWER "/"
config START "networking ssh"
config PREMOUNT "$PROGRAMDIR/overlay-premount"
config POSTMOUNT "$PROGRAMDIR/overlay-postmount"
config INIT "$PROGRAMDIR/overlay-init"
config RAM_SIZE 50M
}
# function to reverse the $* words
reverse() {
local OUT=""
for w in $* ; do OUT="$w $OUT" ; done
echo "${OUT% }"
}
# grab and set a configuration variable
# $1 = variable, [ $2 = default .. error otherwise ]
config() {
local V W
read V <<EOF
$(sed "/^$1=.*/{s|^$1=||;s|^\\s*||;s|\\s*\$||;b};d" $CONFIG)
EOF
if [ -z "$V" ] ; then
[ $# -lt 2 ] && die "Missing $1=... in $CONFIG"
V="$2" # use the given default
elif [ -z "${V##!*}" ] ; then
read W <<EOF
$(${V#!})
EOF
[ -z "$W" ] && die "bad $1 config: $V"
V="$W"
fi
eval $1="'$V'"
eval echo "$1=$V" >&2
}
# Install a default $1/etc/network/interfaces on the subhost root $1
setup_networking() {
[ -r $1/etc/network/interfaces ] && return 0
mkdir -p $1/etc/network
cat <<EOF >> $1/etc/network/interfaces
# Generated for $NAME subhost
auto lo
iface lo inet loopback
EOF
for IF in $(ip netns exec $NAME ip link show | grep "^eth") ; do
cat <<EOF >> $1/etc/network/interfaces
auto eth$i
iface eth$i inet manual
EOF
done
}
# Setup the network namespace for the given $CABLES
# $1=netns ( $2="br=mac" .. )
setup_veth_cables() {
local NETNS BR IF MAC C i ADD
NETNS="$1"
shift 1
i=0
for C in "$@" ; do
IF=$NETNS$i
MAC="${C#*=}"
[ -z "$MAC" ] || MAC="address $MAC"
ip link add $IF type veth peer name eth$i $MAC netns $NETNS
ip link set $IF up
BR="${C%=*}"
if [ -z "$BR" ] ; then
ip link set $IF
ifup $IF
else
brctl addif $BR $IF
fi
i=$((i+1))
done
}
# Set up an overlay for $name on $live, with a new tmpfs on its /run,
# and "install" a "reaper" as the upcoming pid 1
setup_overlay() {
local NAME="$1" LIVE="$2" LOWER="$3" UPPER="$4" WORK="$5"
echo setup_overlay "$NAME" "$LIVE" "$LOWER" "$UPPER" "$WORK"
if grep -qE "^[^ ]+ $LIVE " /proc/mounts ; then
die "$LIVE already has a mount"
fi
[ -d "$UPPER" ] || die "UPPER=$UPPER is not a directory"
[ -d "$LOWER" ] || die "LOWER=LOWPER is not a directory"
[ -d "$LIVE" ] || die "LOWER=LOWPER is not a directory"
[ -x "${PREMOUNT%% *}" ] || die "PREMOUNT=${PREMOUNT%% *} not executable"
[ -f "${PREMOUNT%% *}" ] || die "PREMOUNT='$PREMOUNT' is not a command"
[ -x "${POSTMOUNT%% *}" ] || \
die "POSTMOUNT=${POSTMOUNT%% *} not executable"
[ -f "${POSTMOUNT%% *}" ] || \
die "POSTMOUNT='$POSTMOUNT' is not a command"
# UPPER is the same as LOWER then skip the overlay mount
if [ "$UPPER" != "$LOWER" ] ; then
# sanity check
[ -d "$WORK" ] || die "WORK=$WORK is not a directory"
env CONFIG="$CONFIG" $PREMOUNT "$UPPER"
OLY="-olowerdir=$3,upperdir=$UPPER,workdir=$5"
if ! mount -t overlay "$OLY" $1 $2 ; then
umount -R "$UPPER/dev"
umount "$UPPER/run"
die "Cannot set up the overlay mount $2"
fi
elif [ "$LIVE" != "$UPPER" ] ; then
# With UPPER = LOWER we rather make a bind mount to LIVE
env CONFIG="$CONFIG" $PREMOUNT "$UPPER"
mount --bind $UPPER $LOWER
fi
env CONFIG="$CONFIG" $POSTMOUNT "LIVE" "$UPPER"
}
# Find the "unshare" process for $1 and echo the its pid and the pids
# of its child processes.
is_live() {
local NAME=$1
local USPID="$(pgrep -f "unshare.* $NAME ")"
[ -z "$USPID" ] && return 1
echo "$USPID $(ps -hopid --ppid=$USPID)"
}
# Find all overlay-boot processes and list their config files
list_running() {
pgrep -a overlay-boot | awk '{print $4}'
}
# Start cgroup v2 cpuset accounting if enabled.
# Needs manual enabling, with:
# mount -t cgroup2 cgroup2 /sys/fs/cgroup
setup_cgroup2_accounting() {
local NAME="$1" ME="$2"
local ACCDIR="$(awk '$3 == "cgroup2" {print $2; exit}' /proc/mounts)"
[ -z "$ACCDIR" ] && return 0
mkdir -p "$ACCDIR/$NAME"
echo "$ME" > $ACCDIR/$NAME/cgroup.procs
}