small POSIX shell script to safely image drives while filtering out unwanted drives and asking for confirmation

rpi-devicecheck.sh

#!/bin/sh


# libalpine https://github.com/alpinelinux/alpine-conf/blob/master/libalpine.sh.in

PREFIX=@PREFIX@

PROGRAM=$(basename $0)

: ${ROOT:=/}
[ "${ROOT}" = "${ROOT%/}" ] && ROOT="${ROOT}/"
[ "${ROOT}" = "${ROOT#/}" ] && ROOT="${PWD}/${ROOT}"

# echo if in verbose mode
vecho() {
	if [ -n "$VERBOSE" ]; then
		echo "$@"
	fi
}

# echo unless quiet mode
qecho() {
	if [ -z "$QUIET" ]; then
		echo "$@"
	fi
}

# echo to stderr
eecho() {
	echo "$@" >&2
}

# echo to stderr and exit with error
die() {
	eecho "$@"
	exit 1
}

init_tmpdir() {
	local omask="$(umask)"
	local __tmpd="/tmp/$PROGRAM-${$}-$(date +%s)-$RANDOM"
	umask 077 || die "umask"
	mkdir -p "$__tmpd" || exit 1
	trap "rc=\$?; rm -fr \"$__tmpd\"; exit \$rc" 0
	umask $omask
	eval "$1=\"$__tmpd\""
}

default_read() {
	local n
	read n
	[ -z "$n" ] && n="$2"
	eval "$1=\"$n\""
}


cfg_add() {
	$MOCK lbu_add "$@"
}

# return true if given value is Y, y, Yes, yes YES etc
yesno() {
	case $1 in
	[Yy]|[Yy][Ee][Ss]) return 0;;
	esac
	return 1
}

# Detect if we are running Xen
is_xen() {
	test -d /proc/xen
}

# Detect if we are running Xen Dom0
is_xen_dom0() {
	is_xen && \
	grep -q "control_d" /proc/xen/capabilities 2>/dev/null
}

# list of available network interfaces that aren't part of any bridge or bond
available_ifaces() {
	local iflist= ifpath= iface= i=
	if ! [ -d "$ROOT"/sys/class/net ]; then
		ip link | awk -F: '$1 ~ /^[0-9]+$/ {printf "%s",$2}'
		return
	fi
	sorted_ifindexes=$(
		for i in "$ROOT"/sys/class/net/*/ifindex; do
			[ -e "$i" ] || continue
			printf "%s\t%s\n" "$(cat $i)" $i;
		done | sort -n | awk '{print $2}')
	for i in $sorted_ifindexes; do
		ifpath=${i%/*}
		iface=${ifpath##*/}
		# skip interfaces that are part of a bond or bridge
		if [ -d "$ifpath"/master/bonding ] || [ -d "$ifpath"/brport ]; then
			continue
		fi
		iflist="${iflist}${iflist:+ }$iface"
	done
	echo $iflist
}

# from OpenBSD installer

# Ask for a password, saving the input in $resp.
#    Display $1 as the prompt.
#    *Don't* allow the '!' options that ask does.
#    *Don't* echo input.
#    *Don't* interpret "\" as escape character.
askpass() {
	printf %s "$1 "
	set -o noglob
	$MOCK stty -echo
	read -r resp
	$MOCK stty echo
	set +o noglob
	echo
}

# Ask for a password twice, saving the input in $_password
askpassword() {
	local _oifs="$IFS"
	IFS=
	while :; do
		askpass "Password for $1 account? (will not echo)"
		_password=$resp

		askpass "Password for $1 account? (again)"
		# N.B.: Need quotes around $resp and $_password to preserve leading
		#       or trailing spaces.
		[ "$resp" = "$_password" ] && break

		echo "Passwords do not match, try again."
	done
	IFS=$_oifs
}

# test the first argument against the remaining ones, return success on a match
isin() {
	local _a="$1" _b
	shift
	for _b; do
		[ "$_a" = "$_b" ] && return 0
	done
	return 1
}

# remove all occurrences of first argument from list formed by
# the remaining arguments
rmel() {
	local _a="$1" _b

	shift
	for _b; do
		[ "$_a" != "$_b" ] && printf %s "$_b "
	done
}

# Issue a read into the global variable $resp.
_ask() {
	local _redo=0

	read resp
	case "$resp" in
	!)	echo "Type 'exit' to return to setup."
		sh
		_redo=1
		;;
	!*)	eval "${resp#?}"
		_redo=1
		;;
	esac
	return $_redo
}

# Ask for user input.
#
#    $1    = the question to ask the user
#    $2    = the default answer
#
# Save the user input (or the default) in $resp.
#
# Allow the user to escape to shells ('!') or execute commands
# ('!foo') before entering the input.
ask() {
	local _question="$1" _default="$2"

	while :; do
		printf %s "$_question "
		[ -z "$_default" ] || printf "[%s] " "$_default"
		_ask && : ${resp:=$_default} && break
	done
}

# Ask for user input until a non-empty reply is entered.
#
#    $1    = the question to ask the user
#    $2    = the default answer
#
# Save the user input (or the default) in $resp.
ask_until() {
	resp=
	while [ -z "$resp" ] ; do
		ask "$1" "$2"
	done
}

# Ask for user for y/n until y, yes, n or no is responded
#
#    $1    = the question to ask the user
#    $2    = the default answer
#
#  Returns true/sucess if y/yes was responded. false othewise
ask_yesno() {
	while true; do
		ask "$1" "$2"
		case "$resp" in
			y|yes|n|no) break;;
		esac
	done
	yesno "$resp"
}

# Ask for the user to select one value from a list, or 'done'.
#
# $1 = name of the list items (disk, cd, etc.)
# $2 = question to ask
# $3 = list of valid choices
# $4 = default choice, if it is not specified use the first item in $3
#
# N.B.! $3 and $4 will be "expanded" using eval, so be sure to escape them
#       if they contain spooky stuff
#
# At exit $resp holds selected item, or 'done'
ask_which() {
	local _name="$1" _query="$2" _list="$3" _def="$4" _dynlist _dyndef

	while :; do
		# Put both lines in ask prompt, rather than use a
		# separate 'echo' to ensure the entire question is
		# re-ask'ed after a '!' or '!foo' shell escape.
		eval "_dynlist=\"$_list\""
		eval "_dyndef=\"$_def\""

		# Clean away whitespace and determine the default
		set -o noglob
		set -- $_dyndef; _dyndef="$1"
		set -- $_dynlist; _dynlist="$*"
		set +o noglob
		[ $# -lt 1 ] && resp=done && return

		: ${_dyndef:=$1}
		echo "Available ${_name}s are: $_dynlist."
		printf "Which one %s? (or 'done') " "$_query"
		[ -n "$_dyndef" ] && printf "[%s] " "$_dyndef"
		_ask || continue
		[ -z "$resp" ] && resp="$_dyndef"

		# Quote $resp to prevent user from confusing isin() by
		# entering something like 'a a'.
		isin "$resp" $_dynlist done && break
		echo "'$resp' is not a valid choice."
	done
}

find_modloop_media() {
	devnum=$(mountpoint -d /.modloop) || return
	test -n "$devnum" || return
	modloop_file=$(cat /sys/dev/block/$devnum/loop/backing_file) || return
	test -n "$modloop_file" || return
	# assume that device name and mount point don't contain spaces
	modloop_media=$(df "$modloop_file" | awk 'NR==2{print $6}') || return
	test -n "$modloop_media" || return
	echo "$modloop_media"
}

# Extract fully qualified domain name from current hostname. If none is
# currently set, use the provided fallback.
get_fqdn() {
	local _dn
	_dn=$(hostname -f 2>/dev/null)
	_dn=${_dn#$(hostname -s 2>/dev/null)}
	_dn=${_dn#.}
	echo "${_dn:=$1}"
}

# alpine setup-disk https://github.com/alpinelinux/alpine-conf/blob/master/setup-disk.in

in_list() {
	local i="$1"
	shift
	while [ $# -gt 0 ]; do
		[ "$i" = "$1" ] && return 0
		shift
	done
	return 1
}

all_in_list() {
	local needle="$1"
	local i
	[ -z "$needle" ] && return 1
	shift
	for i in $needle; do
		in_list "$i" $@ || return 1
	done
	return 0
}

# wrapper to only show given device
_blkid() {
	blkid | grep "^$1:"
}

is_nvme_dev() {
	local i
	for i; do
		case ${i##*/} in
			nvme*) return 0;;
		esac
	done
	return 1
}

has_mounted_part() {
	local p
	local sysfsdev="$(echo ${1#/dev/} | sed 's:/:!:g')"
	# parse /proc/mounts for mounted devices
	for p in $(awk '$1 ~ /^\/dev\// {gsub("/dev/", "", $1); gsub("/", "!", $1); print $1}' \
			"$ROOT"/proc/mounts 2>/dev/null); do
		[ "$p" = "$sysfsdev" ] && return 0
		[ -e "$ROOT"/sys/block/$sysfsdev/$p ] && return 0
	done
	return 1
}

has_holders() {
	local i
	# check if device is used by any md devices
	for i in $1/holders/* $1/*/holders/*; do
		[ -e "$i" ] && return 0
	done
	return 1
}

is_available_disk() {
	local dev="$1"

	# check so it does not have mounted partitions
	has_mounted_part $dev && return 1

	# check so its not part of an md setup
	if has_holders "$ROOT"/sys/block/$dev; then
		[ -n "$USE_RAID" ] && echo "Warning: $dev is part of a running raid" >&2
		return 1
	fi

	return 0
}

find_disks() {
	local p=
	for p in "$ROOT"/sys/block/*/device; do
		local dev="${p%/device}"
		dev=${dev#*/sys/block/}
		if is_available_disk "$dev"; then
			printf %s " $dev"
		fi
	done
}

all_in_list() {
	local needle="$1"
	local i
	[ -z "$needle" ] && return 1
	shift
	for i in $needle; do
		in_list "$i" $@ || return 1
	done
	return 0
}

# ask for a root or data disk
# returns response in global variable $resp
ask_disk() {
	local prompt="$1"
	local help_func="$2"
	local i=
	shift 2
	local default_disk="${DEFAULT_DISK:-$1}"

	resp=
	while ! all_in_list "$resp" $@ "none" "abort"; do
		echo "Available disks are:"
		show_disk_info "$@"
		ask "$prompt"  "$default_disk"
		case "$resp" in
			'abort') exit 0;;
			'none') return 0;;
			'?') $help_func;;
			*) for i in $resp; do
				if ! [ -b "/dev/$i" ]; then
					echo "/dev/$i is not a block device" >&2
					resp=
				fi
			done;;
		esac
	done
}


confirm_erase() {
	local erasedisks="$@"
	if [ "$ERASE_DISKS" = "$erasedisks" ]; then
		return 0
	fi
	echo "WARNING: The following disk(s) will be erased:"
	show_disk_info $@
	ask_yesno "WARNING: Erase the above disk(s) and continue? (y/n)" n
}

show_disk_info() {
	local disk= vendor= model= d= size= busid=
	for disk in $@; do
		local dev="${disk#/dev/}"
		d=$(echo $dev | sed 's:/:!:g')
		vendor=$(cat "$ROOT"/sys/block/$d/device/vendor 2>/dev/null)
		model=$(cat "$ROOT"/sys/block/$d/device/model 2>/dev/null)
		busid=$(readlink -f "$ROOT"/sys/block/$d/device 2>/dev/null)
		size=$(awk '{gb = ($1 * 512)/1000000000; printf "%.1f GB\n", gb}' "$ROOT"/sys/block/$d/size 2>/dev/null)
		if is_dasd $dev eckd; then
			echo "  $dev	($size $vendor ${busid##*/})"
		else
			echo "  $dev	($size $vendor $model)"
		fi
	done
}

diskselect_help() {
	cat <<-__EOF__
		The disk will be erased.
	__EOF__
}

get_bootopt() {
	local opt="$1"
	set -- $(cat /proc/cmdline)
	for i; do
		case "$i" in
			"$opt"|"$opt"=*) echo "${i#*=}"; break;;
		esac
	done
}

# dasd-functions https://github.com/alpinelinux/alpine-conf/blob/master/dasd-functions.sh.in

eckd_dasd=
fba_dasd=

_dasdfmt() {
	local block="$(ls /sys/bus/ccw/devices/"$1"/block 2>/dev/null)"
	if ! [ -b "/dev/$block" ]; then
		echo "/dev/$block is not a block device" >&2
	else
		if ask_yesno "WARNING: Erase ECKD DASD $1? (y/n)" "n"; then
			dasdfmt -b 4096 -d cdl -yp "/dev/$block"
		fi
	fi
}

eckdselect_help() {
	cat <<-__EOF__

		Enter each available DASD's address (e.g. 0.0.02d0) to format that DASD.
		Enter multiple addresses separated by a space to format multiple DASDs.
		Enter 'all' to format all available DASDs.

		WARNING: Data will be lost after formatted!

		Enter 'done' or 'none' to finish formatting.
		Enter 'abort' to quit the installer.

	__EOF__
}

show_dasd_info() {
	local busid= vendor= block= devtype= cutype=
	for busid in $@; do
		vendor=$(cat /sys/bus/ccw/devices/$busid/vendor 2>/dev/null)
		devtype=$(cat /sys/bus/ccw/devices/$busid/devtype 2>/dev/null)
		cutype=$(cat /sys/bus/ccw/devices/$busid/cutype 2>/dev/null)
		block="$(ls /sys/bus/ccw/devices/$busid/block 2>/dev/null)"
		echo "  $busid	($devtype $cutype $vendor)"
	done
}

ask_eckd(){
	local prompt="$1"
	local help_func="$2"
	shift 2
	local default_dasd="all"
	apk add --quiet s390-tools

	resp=
	while ! all_in_list "$resp" $@ "$default_dasd" "abort" "done" "none"; do
		echo "Available ECKD DASD(s) are:"
		show_dasd_info "$@"
		ask "$prompt" "$default_dasd"
		case "$resp" in
			'abort') exit 0;;
			'done'|'none') return 0;;
			'?') $help_func;;
			'all') for busid in $@; do _dasdfmt $busid; done;;
			*) for busid in $resp; do _dasdfmt $busid; done;;
		esac
	done
}

check_dasd() {
	eckd_dasd= fba_dasd=
	local dasd="$(get_bootopt dasd)"
	for _dasd in $( echo $dasd | tr ',' ' '); do
		[ -e /sys/bus/ccw/drivers/dasd-eckd/$_dasd ] && eckd_dasd="$eckd_dasd $_dasd"
		[ -e /sys/bus/ccw/drivers/dasd-fba/$_dasd ] && fba_dasd="$fba_dasd $_dasd"
	done
	if [ -n "$eckd_dasd" ]; then
		ask_eckd \
			"Which ECKD DASD(s) would you like to be formatted using dasdfmt? (enter '?' for help)" \
			eckdselect_help "$eckd_dasd"
	fi
}

is_dasd() {
	local disk="${1#*\/dev\/}" dasd_type="$2"
	for _dasd in $(eval "echo \$${dasd_type}_dasd"); do
		[ -e /sys/bus/ccw/drivers/dasd-$dasd_type/$_dasd/block/$disk ] && return 0
	done
	return 1
}

setup_zipl() {
	local mnt="$1" root="$2" modules="$3" kernel_opts="$4"
	local parameters="root=$root modules=$modules $kernel_opts"
	local dasd="$(echo $eckd_dasd $fba_dasd | tr ' ' ',')"
	local s390x_net="$(get_bootopt s390x_net)"
	[ -n "$dasd" ] && parameters="$parameters dasd=$dasd"
	[ -n "$s390x_net" ] && parameters="$parameters s390x_net=$s390x_net"

	cat > "$mnt"/etc/zipl.conf <<- EOF
	[defaultboot]
	defaultauto
	prompt=1
	timeout=5
	default=linux
	target=/boot
	[linux]
	image=/boot/vmlinuz-$KERNEL_FLAVOR
	ramdisk=/boot/initramfs-$KERNEL_FLAVOR
	parameters="$parameters"
	EOF
}

setup_partitions_eckd() {
	local blocks_per_track=12 tracks_per_cylinder=15 boot_track= swap_track=
	local diskdev="$1" boot_size="$2" swap_size="$3" sys_type="$4"
	boot_track=$(($boot_size * 1024 / 4 / blocks_per_track))
	[ "$swap_size" != 0 ] && swap_track=$(($swap_size * 1024 / 4 / blocks_per_track + boot_track + 1))
	local conf="$(mktemp)"

	if [ -n "$swap_track" ]; then
		cat > "$conf" <<- EOF
		[first,$boot_track,native]
		[$((boot_track + 1)),$swap_track,swap]
		[$((swap_track + 1)),last,$sys_type]
		EOF
	else
		cat > "$conf" <<- EOF
		[first,$boot_track,native]
		[$((boot_track + 1)),last,$sys_type]
		EOF
	fi
	fdasd -s -c "$conf" $diskdev
	rm $conf
}

image="$1"

if [[ -z $image ]]; then
	printf '%s\n' "no file provided" >&2
	exit 1
fi
if [ ! -f $image ]; then
	printf '%s\n' "file not found: $image" >&2
	exit 1
fi

# block_devs="$(lsblk --nodeps -brno name,rm,size,vendor,model)"
# block_devs="$(printf '%s' "$block_devs" | tr ' ' "\t")"
#
# OLDIFS=$IFS 
# IFS=$(printf "\n\b")
# for dev in $block_devs; do
# 	name="$(printf '%s' "$dev" | cut -f 1)"
# 	if  [ -f /sys/block/$name/device/power/runtime_active_time ]; then
# 		atime="$(cat /sys/block/$name/device/power/runtime_active_time)"
# 		if [ $(printf '%s' "$dev" | cut -f 2 ) -eq 1 ]; then
# 			if [ $(printf '%s' "$dev" | cut -f 3 ) -ne 0 ]; then
# 				info=$(paste <(printf '%s' "$dev") <(printf "$atime\n\n"))
# 				#removable="$(printf '%s' "$dev$removable")"
# 				#removable="$(printf '%s' "$info$removable")"
# 			fi
# 		fi
# 	fi
# done
#
# removable=$(printf '%s' "$removable" | sed 's/^[ \t]*//;s/[ \t]*$//' | sort -nk 6)
#
# for dev in $removable; do
# 	name=$(printf "$dev" | cut -f 1)
# 	size=$(printf "$dev" | cut -f 3)
# 	model="$(printf "$dev" | cut -f 4,5 | xargs)"
# 	hsize=$(numfmt --to=iec-i --suffix=B $size)
# 	nsize=$(numfmt --grouping $size)
# 	out=$(printf "/dev/$name\t$model\t$hsize\t($nsize bytes)\n$out")
# done
# IFS=$OLDIFS
#
# nlines=$(printf "$out\n" | wc -l)

check_dasd

diskdevs=

# no disks so lets exit quietly.
while [ -z "$disks" ]; do
	disks=$(find_disks)
	[ -n "$disks" ] && break

	# ask to unmount the boot mmc for rpi and similar
	modloop_media=$(find_modloop_media)

	if [ -z "$modloop_media" ] || ! ask_yesno "No disks available. Try boot media $modloop_media? (y/n)" n; then
		[ -z "$QUIET" ] && echo "No disks found." >&2
		exit 0
	fi

	DO_UMOUNT=1 modloop_media=$modloop_media copy-modloop
done

ask_disk "Which disk(s) would you like to use? (or '?' for help or 'none')" diskselect_help $disks

# sel=$(printf "$out" | 
# 	column -ts "$(printf "\t")" | 
# 	fzf --height=$(($nlines+3)) --header="Please select the drive to flash" | 
# 	tr -s ' ' "\t" | 
# 	cut -f 1)

rsync --write-devices -vh --progress $image /dev/$resp
sync
#echo $resp