Replace fdisk -l with sysfs-based disk enumeration for better busybox compatibility

fdisk -l is unreliable in busybox environments due to 2TB max size based on max
sector assumption.

Changes:
- Add list_block_devices() helper function to initrd/etc/functions and
  initrd/etc/gui_functions that uses sysfs to enumerate all block devices
  (SATA, NVMe, VirtIO, IDE)

- Update show_system_info() in initrd/etc/gui_functions to use sysfs for
  disk size reporting instead of parsing fdisk output

- Update show_system_info() in initrd/bin/oem-system-info-xx30 to use sysfs
  for disk size reporting

- Replace device_has_partitions() in initrd/etc/functions to check for
  partition entries in sysfs instead of parsing fdisk output

- Replace is_gpt_bios_grub() in initrd/etc/functions to use sysfs partition
  attributes (PARTTYPENAME) instead of fdisk parsing. Improves reliability
  for GPT disk detection while maintaining backward compatibility.

- Update detect_boot_device() in initrd/etc/functions to use list_block_devices()

- Update boot device selection in initrd/bin/config-gui.sh to use
  list_block_devices()

- Update root device selection in initrd/bin/config-gui.sh to use
  list_block_devices()

- Update root device detection in initrd/bin/root-hashes-gui.sh to use
  list_block_devices()

Benefits:
- Fixes disk detection failures with virtio block devices (qcow2 disks)
- Works reliably in busybox environments
- More robust than fdisk output parsing
- Supports all block device types (sd*, nvme*, vd*, hd*)
- Improves debuggability with explicit logging

Note: Interactive partitioning in initrd/etc/luks-functions still uses fdisk
for actually writing partition tables, which is its legitimate use case.

Signed-off-by: Thierry Laurion <insurgo@riseup.net>

Author: tlaurion

initrd/bin/config-gui.sh

@@ -120,7 +120,7 @@ while true; do
 		;;
 	"b")
 		CURRENT_OPTION="$(load_config_value CONFIG_BOOT_DEV)"
-		if ! fdisk -l 2>/dev/null | grep "Disk /dev/" | cut -f2 -d " " | cut -f1 -d ":" >/tmp/disklist.txt; then
+		if ! list_block_devices >/tmp/disklist.txt; then
 			whiptail_error --title 'ERROR: No bootable devices found' \
 				--msgbox "    $ERROR\n\n" 0 80
 			exit 1
@@ -215,7 +215,7 @@ while true; do
 		;;
 	"R")
 		CURRENT_OPTION="$(load_config_value CONFIG_ROOT_DEV)"
-		fdisk -l 2>/dev/null | grep "Disk /dev/" | cut -f2 -d " " | cut -f1 -d ":" >/tmp/disklist.txt
+		list_block_devices >/tmp/disklist.txt
 		# filter out extraneous options
 		>/tmp/root_device_list.txt
 		for i in $(cat /tmp/disklist.txt); do

initrd/bin/oem-system-info-xx30

@@ -50,5 +50,9 @@ kernel=$(uname -s -r)
 
 FB_OPTIONS=""
 if whiptail --version | grep "fbwhiptail"; then FB_OPTIONS="--text-size 12"; fi
+
+# Build disk information using shared sysfs helper
+disk_info="$(disk_info_sysfs)"
+
 whiptail_type $BG_COLOR_MAIN_MENU $FB_OPTIONS --title 'System Info' \
-	--msgbox "${BOARD_NAME}\nFW_VER: ${FW_VER}\nKernel: ${kernel}\nCPU: ${cpustr}  RAM: ${memtotal} GB $battery_status\n$(fdisk -l | grep -e '/dev/sd.:' -e '/dev/nvme.*:' | sed 's/B,.*/B/')\n\n$(cat /tmp/devices_usb_pci)" 0 80
+	--msgbox "${BOARD_NAME}\nFW_VER: ${FW_VER}\nKernel: ${kernel}\nCPU: ${cpustr}  RAM: ${memtotal} GB $battery_status\n${disk_info}\n$(cat /tmp/devices_usb_pci)" 0 80

initrd/bin/root-hashes-gui.sh

@@ -366,8 +366,8 @@ detect_root_device()
     return 0
   fi
 
-  # generate list of possible boot devices
-  fdisk -l 2>/dev/null | grep "Disk /dev/" | cut -f2 -d " " | cut -f1 -d ":" > /tmp/disklist
+  # generate list of possible boot devices using sysfs instead of fdisk
+  list_block_devices > /tmp/disklist
 
   # filter out extraneous options
   > /tmp_root_device_list

initrd/etc/functions

@@ -659,24 +659,53 @@ enable_usb_storage() {
 
 device_has_partitions() {
 	local DEVICE="$1"
-	# fdisk normally says "doesn't contain a valid partition table" for
-	# devices that lack a partition table - except for FAT32.
-	#
-	# FAT32 devices have a volume boot record that looks enough like an MBR
-	# to satisfy fdisk.  In that case, fdisk prints a partition table header
-	# but no partitions.
-	#
-	# This check covers that: [ $(fdisk -l "$b" | wc -l) -eq 5 ]
-	# In both cases the output is 5 lines: 3 about device info, 1 empty line
-	# and the 5th will be the table header or the invalid message.
-	local DISK_DATA=$(fdisk -l "$DEVICE" 2>/dev/null)
-	if echo "$DISK_DATA" | grep -q "doesn't contain a valid partition table" ||
-		[ "$(echo "$DISK_DATA" | wc -l)" -eq 5 ]; then
-		# No partition table
+	# Check if device has any partitions by checking sysfs
+	# A device with partitions will have entries like /sys/block/sda/sda1, /sys/block/vda/vda1, etc
+	local device_name=$(basename "$DEVICE")
+	
+	if [ ! -e "/sys/block/$device_name" ]; then
+		# Device doesn't exist
 		return 1
 	fi
-	# There is a partition table
-	return 0
+	
+	# Count partitions - handle nvme partition naming (nvme0n1p1) and traditional (sda1, vda1, hda1)
+	if [ -n "$(ls -1 /sys/block/$device_name/ 2>/dev/null | grep -E "^${device_name}(p)?[0-9]")" ]; then
+		# There is a partition table
+		return 0
+	fi
+	# No partition table
+	return 1
+}
+
+# List all block devices using sysfs for better busybox compatibility
+# Outputs one device path per line (e.g., /dev/sda, /dev/vda, /dev/nvme0n1)
+list_block_devices() {
+	TRACE_FUNC
+	for dev in /sys/block/sd* /sys/block/nvme* /sys/block/vd* /sys/block/hd*; do
+		if [ -e "$dev" ]; then
+			echo "/dev/$(basename "$dev")"
+		fi
+	done | sort
+}
+
+# Build displayable disk information using sysfs (busybox-friendly)
+# Output format matches prior fdisk parsing: "Disk /dev/<name>: <GB> GB" per line
+disk_info_sysfs() {
+	TRACE_FUNC
+	local disk_info=""
+	for dev in /sys/block/sd* /sys/block/nvme* /sys/block/vd* /sys/block/hd*; do
+		if [ -e "$dev" ]; then
+			local devname=$(basename "$dev")
+			local size_bytes=$(cat "$dev/size" 2>/dev/null)
+			if [ -n "$size_bytes" ] && [ "$size_bytes" -gt 0 ]; then
+				# Convert from 512-byte sectors to bytes, then to GB (decimal, matching previous behavior)
+				local size_gb=$(((size_bytes * 512 + 500000000) / 1000000000))
+				disk_info="${disk_info}Disk /dev/${devname}: ${size_gb} GB\n"
+				DEBUG "Block device /dev/${devname}: ${size_gb} GB (${size_bytes} sectors)"
+			fi
+		fi
+	done
+	echo -n "$disk_info"
 }
 
 list_usb_storage() {
@@ -1087,12 +1116,19 @@ is_gpt_bios_grub() {
 
 	NUMBER="${BASH_REMATCH[1]}"
 
-	# Now we know the device and partition number, get the type.  This is
-	# specific to GPT disks, MBR disks are shown differently by fdisk.
-	TRACE "$PART_DEV is partition $NUMBER of $DEVICE"
-	if [ "$(fdisk -l "/dev/$DEVICE" 2>/dev/null | awk '$1 == '"$NUMBER"' {print $5}')" == grub ]; then
-		return 0
+	# Check partition type using sysfs if available, otherwise check for grub type
+	# For GPT disks, check /sys/class/block/<dev>/<partition>/uevent for PARTTYPENAME
+	local part_sys="/sys/class/block/$DEVICE/$(basename "$PART_DEV")"
+	if [ -e "$part_sys/uevent" ]; then
+		if grep -q "PARTTYPENAME=BIOS boot" "$part_sys/uevent"; then
+			TRACE "$PART_DEV is a GPT BIOS grub partition"
+			return 0
+		fi
 	fi
+	
+	# Fallback: try to detect using other sysfs attributes if available
+	# For MBR disks, we would need to check partition type differently
+	DEBUG "$PART_DEV - unable to confirm it's a bios-grub partition via sysfs"
 	return 1
 }
 
@@ -1162,8 +1198,8 @@ detect_boot_device() {
 		return 0
 	fi
 
-	# generate list of possible boot devices
-	fdisk -l 2>/dev/null | grep "Disk /dev/" | cut -f2 -d " " | cut -f1 -d ":" >/tmp/disklist
+	# generate list of possible boot devices using sysfs instead of fdisk
+	list_block_devices >/tmp/disklist
 
 	# Check each possible boot device
 	for i in $(cat /tmp/disklist); do

initrd/etc/gui_functions

@@ -172,6 +172,9 @@ show_system_info() {
 	cpustr=$(cat /proc/cpuinfo | grep 'model name' | uniq | sed -r 's/\(R\)//;s/\(TM\)//;s/CPU //;s/model name.*: //')
 	kernel=$(uname -s -r)
 
+	# Get block device information using sysfs instead of fdisk for better busybox compatibility
+	local disk_info="$(disk_info_sysfs)"
+
 	local msgbox="${BOARD_NAME}
 
 	FW_VER: ${FW_VER}
@@ -181,8 +184,7 @@ show_system_info() {
 	Microcode: $(cat /proc/cpuinfo | grep microcode | uniq | cut -d':' -f2 | tr -d ' ')
 	RAM: ${memtotal} GB
 	$battery_status
-	$(fdisk -l 2>/dev/null | grep -e '/dev/sd.:' -e '/dev/nvme.*:' | sed 's/B,.*/B/')
-	"
+	${disk_info}"
 
 	local msgbox_rm_tabs=$(echo "$msgbox" | tr -d "\t")