[PATCH] installer: hide device-mapper root partitions from target device list

["'Kasturi Shekar' via isar-users" <isar-users@googlegroups.com>]

Root filesystems exposed through device-mapper paths (e.g.,
/dev/mapper/verityroot or /dev/dm-0) were being included in the list of
installable block devices. Since these mapper devices represent the
active root filesystem, they must not appear as installation targets.
This change resolves the issue by detecting the underlying physical
device of the current root and skipping it during block device enumeration.

Signed-off-by: Kasturi Shekar <kasturi.shekar@siemens.com>
---
 .../files/usr/bin/deploy-image-wic.sh         | 61 +++++++++++++------
 1 file changed, 41 insertions(+), 20 deletions(-)

diff --git a/meta-isar/recipes-installer/deploy-image/files/usr/bin/deploy-image-wic.sh b/meta-isar/recipes-installer/deploy-image/files/usr/bin/deploy-image-wic.sh
index b5ea8119..a4e38876 100755
--- a/meta-isar/recipes-installer/deploy-image/files/usr/bin/deploy-image-wic.sh
+++ b/meta-isar/recipes-installer/deploy-image/files/usr/bin/deploy-image-wic.sh
@@ -36,22 +36,39 @@ if ! $installer_unattended; then
     # inspired by poky/meta/recipes-core/initrdscripts/files/install-efi.sh
     target_device_list=""
     current_root_dev_type=$(findmnt / -o fstype -n)
+    exclude_list=()
+
     if [ "$current_root_dev_type" = "nfs" ]; then
         current_root_dev="nfs"
+        exclude_list+=("nfs")
     else
-        current_root_dev=$(readlink -f "$(findmnt / -o source -n)")
-        current_root_dev=${current_root_dev#\/dev/}
-    fi
+    # For normal or immutable systems, get the backing device of '/'
+        root_source=$(findmnt / -o source -n)
+        root_source_resolved=$(readlink -f "$root_source" 2>/dev/null || echo "$root_source")
+        current_root_dev=${root_source_resolved#/dev/}
+
+        # Always exclude the exact device mounted as /
+        exclude_list+=("$current_root_dev")
 
-    case $current_root_dev in
-        mmcblk*)
-            ;;
-        nvme*)
-            ;;
-        *)
-            current_root_dev=${current_root_dev%%[0-9]*}
-            ;;
-    esac
+        base_no_part=${current_root_dev%%[0-9]*}
+        if [ -n "$base_no_part" ]; then
+            exclude_list+=("$base_no_part")
+        fi
+
+        # If root is coming through a dm-* device (e.g., dm-verity),
+        # the actual physical devices appear under /sys/block/<dm>/slaves/.
+        # We must exclude those slaves as well, otherwise the installer
+        # might show the live USB stick as a valid target.
+        if [ -d "/sys/block/$current_root_dev/slaves" ]; then
+            for slave in /sys/block/"$current_root_dev"/slaves/*; do
+                [ -e "$slave" ] || continue
+                slave_dev=$(basename "$slave")
+                exclude_list+=("$slave_dev")
+                slave_base=${slave_dev%%[0-9]*}
+                [ -n "$slave_base" ] && exclude_list+=("$slave_base")
+            done
+        fi
+    fi
 
     echo "Searching for target device..."
 
@@ -102,14 +119,18 @@ if ! $installer_unattended; then
                 # skip ram device
                 ;;
             *)
-                case $device in
-                    $current_root_dev*)
-                    # skip the device we are running from
-                    ;;
-                    *)
-                        target_device_list="$target_device_list $device"
-                    ;;
-                esac
+                #skip any excluded devices (root and its slaves)
+                skip_device=0
+                for ex in "${exclude_list[@]}"; do
+                    if [[ "$device" == "$ex"* ]]; then
+                        skip_device=1
+                        break
+                    fi
+                done
+
+                if [ "$skip_device" -eq 0 ]; then
+                    target_device_list="$target_device_list $device"
+                fi
                 ;;
         esac
     done
-- 
2.39.5

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