fix: harden mtm-ddwipe confirmation and wipe flow

Add strict shell options, root and block-device validation, and a typed-device confirmation prompt before wiping. Preserve the fallback wipe sequence through secure discard, zero discard, and dd, while tightening error handling and keeping messages concise.

.continue/rules/project.md

@@ -4,25 +4,26 @@ description: mtm-ddwipe project conventions
 
 # Project conventions
 - Use English throughout the project.
-- Keep shell scripts Bash-based when Bash is already used by the project.
+- Keep shell scripts Bash-based.
-- Preserve the current behavior of the main script:
+- Preserve the current behavior of the main script: `mtm-ddwipe` wipes block devices.
-  - `mtm-ddwipe`: wipe devices.
+- Strengthen destructive-action safety checks in `mtm-ddwipe`.
-- Strengthen destructive-action safety checks in `mtm-ddwipe` when making changes.
+- Keep `mtm-ddwipe` interactive by default.
-- Keep `mtm-ddwipe` interactive by default unless a change explicitly adds a safe opt-in flag.
+- Require explicit confirmation before destructive actions.
-- Keep user-facing messages short, clear, and in English.
+- Keep user-facing messages short and clear.
-- Prefer minimal, focused changes that do not alter the intent of the existing scripts, unless the script behavior is intentionally updated.
+- Keep error and help messages short and clear.
-- Maintain `.continue/rules/project.md` whenever project conventions or script behavior change.
+- Prefer minimal, focused changes that preserve intent.
+- Keep `.continue/rules/project.md` aligned with project conventions and concise.
 - `mtm-ddwipe` is a small Bash script with helper functions.
-- Keep the host and line-number removal behavior intact.
+- Keep the host and line-number removal behavior intact for related output processing.
 - `mtm-ddwipe` must print a usage line and support `-h`/`--help`.
 - Validate that wipe targets are real block devices before operating on them.
 - Keep short, explicit confirmation prompts before destructive operations.
-- Keep error and help messages short, clear, and in English.
+- Prefer confirmation prompts that require typing the target device path.
 - Keep help text concise and usage-first.
-- When changing `mtm-ddwipe`, keep destructive safeguards strict and explicit.
+- Keep destructive safeguards strict and explicit.
 - If adding non-interactive support, make it an opt-in safety flag.
 - Keep device identification prompts clear and specific.
-- Preserve the fallback wipe flow unless the change is intentionally about wiping behavior.
+- Preserve the fallback wipe flow: secure discard, zero discard, then zero-fill with `dd`.
 
 # Project identity
 - Main script: `mtm-ddwipe`

mtm-ddwipe

@@ -1,108 +1,154 @@
 #!/bin/bash
+set -euo pipefail
+IFS=$'\n\t'
 
 VERSION="0.0.3"
-STARTDATE=""
+STARTDATE=0
 STARTDATESTRING=""
+DEVICE_PATH=""
 
-show_help() {
+usage() {
-	echo "Usage: mtm-ddwipe DEVICE"
+	cat <<EOF
-	echo "Wipe a block device."
+Usage: mtm-ddwipe-2 DEVICE
-	echo "Version: ${VERSION}"
+Wipe a block device.
+Version: ${VERSION}
+EOF
+}
+
+log() {
+	echo "$*"
+}
+
+die() {
+	echo "Error: $*" >&2
+	exit 1
 }
 
 check_args() {
-	case "${1}" in
+	if [ $# -ne 1 ]; then
+		usage
+		exit 1
+	fi
+
+	case "$1" in
 		-h|--help)
-			show_help
+			usage
 			exit 0
 			;;
-		"")
-			show_help
-			exit 1
-			;;
 		-*)
-			echo "Invalid option."
+			die "Invalid option."
-			show_help
-			exit 1
 			;;
 	esac
 }
 
-check_dev_exist() {
+check_device() {
-	if [ ! -e "${1}" ]; then
+	local dev="$1"
-		echo "Missing device."
-		exit 1
-	fi
-}
 
-check_dev_block() {
+	[ -e "$dev" ] || die "Missing device: $dev"
-	if [ ! -b "${1}" ]; then
+	[ -b "$dev" ] || die "Not a block device: $dev"
-		echo "Not a block device."
-		exit 1
-	fi
 }
 
 confirm_wipe() {
-	lsblk "${1}"
+	local dev="$1"
+	local choice=""
+
+	lsblk "$dev"
 	echo ""
-	read -r -p "Wipe ${1} (y/[n])? " CHOICE
+	read -r -p "Type the device path to confirm wipe: " choice
-	case "${CHOICE}" in
+	[ "$choice" = "$dev" ] || die "Canceled"
-		y|Y)
+	echo ""
-			echo ""
+}
-			;;
+
-		*)
+confirm_root() {
-			echo "Canceled"
+	if [ "${EUID:-$(id -u)}" -ne 0 ]; then
-			exit 1
+		die "This tool must be run as root."
-			;;
+	fi
-	esac
 }
 
 print_time() {
+	local enddate calctime
+
 	echo ""
 	echo "Start date :"
-	echo "${STARTDATESTRING}"
+	echo "$STARTDATESTRING"
 
-	ENDDATE=$(date +%s)
+	enddate=$(date +%s)
 	echo ""
 	echo "End date :"
 	date
 
-	CALCTIME=$((ENDDATE-STARTDATE))
+	calctime=$((enddate - STARTDATE))
 	echo ""
 	echo "Total time :"
-	date -d@${CALCTIME} -u +%H:%M:%S
+	date -d@"${calctime}" -u +%H:%M:%S
+}
+
+wipe_with_blkdiscard_secure() {
+	local dev="$1"
+
+	log "blkdiscard secure"
+	blkdiscard -f -p 500M -s -v "$dev"
+}
+
+wipe_with_blkdiscard_zero() {
+	local dev="$1"
+
+	log "blkdiscard zero"
+	blkdiscard -f -p 500M -z -v "$dev"
+}
+
+wipe_with_dd() {
+	local dev="$1"
+
+	log "dd zero"
+	dd if=/dev/zero of="$dev" bs=1M status=progress conv=fsync
+	log "Wiped with dd, check if full size is written."
+	log "Otherwise use a mechanical destruction of the device."
 }
 
 wipe_dev() {
+	local dev="$1"
+
 	STARTDATE=$(date +%s)
 	STARTDATESTRING="$(date)"
-	echo "Begin wiping device ${1}"
+	DEVICE_PATH="$dev"
+
+	log "Begin wiping device $dev"
 	echo ""
-	echo "Start date :"
+	log "Start date :"
-	echo "${STARTDATESTRING}"
+	log "$STARTDATESTRING"
 	echo ""
-	echo "blkdiscard secure"
+
-	if ! blkdiscard -f -p 500M -s -v "${1}"; then
+	if wipe_with_blkdiscard_secure "$dev"; then
 		echo ""
-		echo "blkdiscard zero"
+		log "Device $dev wiped."
-		if ! blkdiscard -f -p 500M -z -v "${1}"; then
+		return
-			echo ""
-			echo "dd zero"
-			if ! dd if=/dev/zero of="${1}" bs=1M status=progress; then
-				echo "Wiped with dd, check if full size is writed."
-				echo "Otherwise use a mechanical destruction of the device."
-				print_time
-				exit 1
-			fi
-		fi
 	fi
+
 	echo ""
-	echo "Device ${1} wiped."
+	if wipe_with_blkdiscard_zero "$dev"; then
+		echo ""
+		log "Device $dev wiped."
+		return
+	fi
+
+	echo ""
+	if wipe_with_dd "$dev"; then
+		echo ""
+		log "Device $dev wiped."
+		return
+	fi
+
+	die "Wipe failed. The device may not be fully overwritten."
 }
 
-check_args "${1}"
+main() {
-check_dev_exist "${1}"
+	check_args "$@"
-check_dev_block "${1}"
+	confirm_root
-confirm_wipe "${1}"
+	check_device "$1"
-wipe_dev "${1}"
+	confirm_wipe "$1"
-print_time
+	wipe_dev "$1"
+	print_time
+}
+
+main "$@"