PiShrink/pishrink.sh

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#!/bin/bash
version="v0.1.3"
CURRENT_DIR="$(pwd)"
SCRIPTNAME="${0##*/}"
MYNAME="${SCRIPTNAME%.*}"
LOGFILE="${CURRENT_DIR}/${SCRIPTNAME%.*}.log"
REQUIRED_TOOLS="parted losetup tune2fs md5sum e2fsck resize2fs"
ZIPTOOLS=("gzip xz")
declare -A ZIP_PARALLEL_TOOL=( [gzip]="pigz" [xz]="xz" ) # parallel zip tool to use in parallel mode
declare -A ZIP_PARALLEL_OPTIONS=( [gzip]="-f9" [xz]="-T0" ) # options for zip tools in parallel mode
declare -A ZIPEXTENSIONS=( [gzip]="gz" [xz]="xz" ) # extensions of zipped files
function info() {
echo "$SCRIPTNAME: $1 ..."
}
function error() {
echo -n "$SCRIPTNAME: ERROR occured in line $1: "
shift
echo "$@"
}
function cleanup() {
if losetup "$loopback" &>/dev/null; then
losetup -d "$loopback"
fi
if [ "$debug" = true ]; then
local old_owner=$(stat -c %u:%g "$src")
chown "$old_owner" "$LOGFILE"
fi
}
function logVariables() {
if [ "$debug" = true ]; then
echo "Line $1" >> "$LOGFILE"
shift
local v var
for var in "$@"; do
eval "v=\$$var"
echo "$var: $v" >> "$LOGFILE"
done
fi
}
function checkFilesystem() {
info "Checking filesystem"
e2fsck -pf "$loopback"
(( $? < 4 )) && return
info "Filesystem error detected!"
info "Trying to recover corrupted filesystem"
e2fsck -y "$loopback"
(( $? < 4 )) && return
if [[ $repair == true ]]; then
info "Trying to recover corrupted filesystem - Phase 2"
e2fsck -fy -b 32768 "$loopback"
(( $? < 4 )) && return
fi
error $LINENO "Filesystem recoveries failed. Giving up..."
exit -9
}
help() {
local help
read -r -d '' help << EOM
Usage: $0 [-adhrspvzZ] imagefile.img [newimagefile.img]
-s Don't expand filesystem when image is booted the first time
-v Be verbose
-r Use advanced filesystem repair option if the normal one fails
-z Compress image after shrinking with gzip
-Z Compress image after shrinking with xz
-a Compress image in parallel using multiple cores
-p Remove logs, apt archives, dhcp leases and ssh hostkeys
-d Write debug messages in a debug log file
EOM
echo "$help"
exit -1
}
should_skip_autoexpand=false
debug=false
repair=false
parallel=false
verbose=false
prep=false
ziptool=""
required_tools="$REQUIRED_TOOLS"
while getopts ":adhprsvzZ" opt; do
case "${opt}" in
a) parallel=true;;
d) debug=true;;
h) help;;
p) prep=true;;
r) repair=true;;
s) should_skip_autoexpand=true ;;
v) verbose=true;;
z) ziptool="gzip";;
Z) ziptool="xz";;
*) help;;
esac
done
shift $((OPTIND-1))
if [ "$debug" = true ]; then
info "Creating log file $LOGFILE"
rm "$LOGFILE" &>/dev/null
exec 1> >(stdbuf -i0 -o0 -e0 tee -a "$LOGFILE" >&1)
exec 2> >(stdbuf -i0 -o0 -e0 tee -a "$LOGFILE" >&2)
fi
echo "${0##*/} $version"
#Args
src="$1"
img="$1"
#Usage checks
if [[ -z "$img" ]]; then
help
fi
if [[ ! -f "$img" ]]; then
error $LINENO "$img is not a file..."
exit -2
fi
if (( EUID != 0 )); then
error $LINENO "You need to be running as root."
exit -3
fi
# check selected compression tool is supported and installed
if [[ -n $ziptool ]]; then
if [[ ! " ${ZIPTOOLS[@]} " =~ " $ziptool " ]]; then
error $LINENO "$ziptool is an unsupported ziptool."
exit -17
else
if [[ $parallel == true && ziptool == "gzip" ]]; then
REQUIRED_TOOLS="$REQUIRED_TOOLS pigz"
else
REQUIRED_TOOLS="$REQUIRED_TOOLS $ziptool"
fi
fi
fi
#Check that what we need is installed
for command in $REQUIRED_TOOLS; do
command -v $command >/dev/null 2>&1
if (( $? != 0 )); then
error $LINENO "$command is not installed."
exit -4
fi
done
#Copy to new file if requested
if [ -n "$2" ]; then
info "Copying $1 to $2..."
cp --reflink=auto --sparse=always "$1" "$2"
if (( $? != 0 )); then
error $LINENO "Could not copy file..."
exit -5
fi
old_owner=$(stat -c %u:%g "$1")
chown "$old_owner" "$2"
img="$2"
fi
# cleanup at script exit
trap cleanup ERR EXIT
#Gather info
info "Gathering data"
beforesize="$(ls -lh "$img" | cut -d ' ' -f 5)"
parted_output="$(parted -ms "$img" unit B print)"
rc=$?
if (( $rc )); then
error $LINENO "parted failed with rc $rc"
info "Possibly invalid image. Run 'parted $img unit B print' manually to investigate"
exit -6
fi
partnum="$(echo "$parted_output" | tail -n 1 | cut -d ':' -f 1)"
partstart="$(echo "$parted_output" | tail -n 1 | cut -d ':' -f 2 | tr -d 'B')"
loopback="$(losetup -f --show -o "$partstart" "$img")"
tune2fs_output="$(tune2fs -l "$loopback")"
currentsize="$(echo "$tune2fs_output" | grep '^Block count:' | tr -d ' ' | cut -d ':' -f 2)"
blocksize="$(echo "$tune2fs_output" | grep '^Block size:' | tr -d ' ' | cut -d ':' -f 2)"
logVariables $LINENO beforesize parted_output partnum partstart tune2fs_output currentsize blocksize
#Check if we should make pi expand rootfs on next boot
if [ "$should_skip_autoexpand" = false ]; then
#Make pi expand rootfs on next boot
mountdir=$(mktemp -d)
mount "$loopback" "$mountdir"
#From https://raw.githubusercontent.com/RPi-Distro/pi-gen/master/stage2/01-sys-tweaks/files/resize2fs_once
cat <<\EOF > "$mountdir/etc/init.d/resize2fs_once"
#!/bin/sh
### BEGIN INIT INFO
# Provides: resize2fs_once
# Required-Start:
# Required-Stop:
# Default-Start: 3
# Default-Stop:
# Short-Description: Resize the root filesystem to fill partition
# Description:
### END INIT INFO
. /lib/lsb/init-functions
case "$1" in
start)
log_daemon_msg "Starting resize2fs_once"
ROOT_DEV=$(findmnt / -o source -n) &&
resize2fs $ROOT_DEV &&
update-rc.d resize2fs_once remove &&
rm /etc/init.d/resize2fs_once &&
log_end_msg $?
;;
*)
echo "Usage: $0 start" >&2
exit 3
;;
esac
EOF
chmod +x "$mountdir/etc/init.d/resize2fs_once"
ln -s "$mountdir/etc/init.d/resize2fs_once" "$mountdir/etc/rc3.d/resize2fs_once"
umount "$mountdir"
else
echo "Skipping autoexpanding process..."
fi
if [[ $prep == true ]]; then
info "Syspreping: Removing logs, apt archives, dhcp leases and ssh hostkeys"
mountdir=$(mktemp -d)
mount "$loopback" "$mountdir"
rm -rf "$mountdir/var/cache/apt/archives/*" "$mountdir/var/lib/dhcpcd5/*" "$mountdir/var/log/*" "$mountdir/var/tmp/*" "$mountdir/tmp/*" "$mountdir/etc/ssh/*_host_*"
umount "$mountdir"
fi
#Make sure filesystem is ok
checkFilesystem
if ! minsize=$(resize2fs -P "$loopback"); then
rc=$?
error $LINENO "resize2fs failed with rc $rc"
exit -10
fi
minsize=$(cut -d ':' -f 2 <<< "$minsize" | tr -d ' ')
logVariables $LINENO currentsize minsize
if [[ $currentsize -eq $minsize ]]; then
error $LINENO "Image already shrunk to smallest size"
exit -11
fi
#Add some free space to the end of the filesystem
extra_space=$(($currentsize - $minsize))
logVariables $LINENO extra_space
for space in 5000 1000 100; do
if [[ $extra_space -gt $space ]]; then
minsize=$(($minsize + $space))
break
fi
done
logVariables $LINENO minsize
#Shrink filesystem
info "Shrinking filesystem"
resize2fs -p "$loopback" $minsize
rc=$?
if (( $rc )); then
error $LINENO "resize2fs failed with rc $rc"
mount "$loopback" "$mountdir"
mv "$mountdir/etc/rc.local.bak" "$mountdir/etc/rc.local"
umount "$mountdir"
losetup -d "$loopback"
exit -12
fi
sleep 1
#Shrink partition
partnewsize=$(($minsize * $blocksize))
newpartend=$(($partstart + $partnewsize))
logVariables $LINENO partnewsize newpartend
parted -s -a minimal "$img" rm "$partnum"
rc=$?
if (( $rc )); then
error $LINENO "parted failed with rc $rc"
exit -13
fi
parted -s "$img" unit B mkpart primary "$partstart" "$newpartend"
rc=$?
if (( $rc )); then
error $LINENO "parted failed with rc $rc"
exit -14
fi
#Truncate the file
info "Shrinking image"
endresult=$(parted -ms "$img" unit B print free)
rc=$?
if (( $rc )); then
error $LINENO "parted failed with rc $rc"
exit -15
fi
endresult=$(tail -1 <<< "$endresult" | cut -d ':' -f 2 | tr -d 'B')
logVariables $LINENO endresult
truncate -s "$endresult" "$img"
rc=$?
if (( $rc )); then
error $LINENO "trunate failed with rc $rc"
exit -16
fi
# handle compression
if [[ -n $ziptool ]]; then
options=""
envVarname="${MYNAME^^}_${ziptool^^}" # PISHRINK_GZIP or PISHRINK_XZ environment variables allow to override all options for gzip or xz
[[ $parallel == true ]] && options="${ZIP_PARALLEL_OPTIONS[$ziptool]}"
[[ -v $envVarname ]] && options="${!envVarname}" # if environment variable defined use these options
[[ $verbose == true ]] && options="$options -v" # add verbose flag if requested
if [[ $parallel == true ]]; then
parallel_tool="${ZIP_PARALLEL_TOOL[$ziptool]}"
info "Using $parallel_tool on the shrunk image"
if ! $parallel_tool ${options} "$img"; then
rc=$?
error $LINENO "$parallel_tool failed with rc $rc"
exit -18
fi
else # sequential
info "Using $ziptool on the shrunk image"
if ! $ziptool ${options} $img; then
rc=$?
error $LINENO "$ziptool failed with rc $rc"
exit -19
fi
fi
img=$img.${ZIPEXTENSIONS[$ziptool]}
fi
aftersize=$(ls -lh "$img" | cut -d ' ' -f 5)
logVariables $LINENO aftersize
info "Shrunk $img from $beforesize to $aftersize"