[PATCH 16/17] meta-isar: deploy-image: Introduce auto-installation mode

[Jan Kiszka <jan.kiszka@siemens.com>]

From: Jan Kiszka <jan.kiszka@siemens.com>

If a special file called auto.install is found in the installation data
directory, parse this and attempt an unattended installation. The file
consists of 2 to 3 lines:

- source file name
- target device path
- optionally, "OVERWRITE" to ignore if the target device is non-empty

e.g.:
$ cat /install/auto.install
isar-image-base-debian-bookworm-qemuamd64.wic.zst
/dev/vda
OVERWRITE

Errors are still stopping the process, switching it back to interactive
mode.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 .../deploy-image/files/deploy-image-wic.sh       | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/meta-isar/recipes-installer/deploy-image/files/deploy-image-wic.sh b/meta-isar/recipes-installer/deploy-image/files/deploy-image-wic.sh
index 9df93fe7..8b25b1d2 100644
--- a/meta-isar/recipes-installer/deploy-image/files/deploy-image-wic.sh
+++ b/meta-isar/recipes-installer/deploy-image/files/deploy-image-wic.sh
@@ -7,8 +7,20 @@
 installdata=${INSTALL_DATA:-/install}
 
 AUTO_INSTALL=false
+OVERWRITE=
 
-if ! $AUTO_INSTALL; then
+if [ -f "$installdata/auto.install" ]; then
+    exec 3<"$installdata/auto.install"
+    read -r DISK_IMAGE <&3
+    read -r TARGET_DEVICE <&3
+    read -r OVERWRITE <&3
+    exec 3>&-
+    if [ ! -b ${TARGET_DEVICE} ]; then
+        dialog --msgbox "Target device is not a valid block device. Installation aborted." 6 60
+        exit 1
+    fi
+    AUTO_INSTALL=true
+else
     DISK_IMAGE=$(find "$installdata" -type f -iname "*.wic*" -a -not -iname "*.wic.bmap" -exec basename {} \;)
     if [ -z "$DISK_IMAGE" ] || [ ! -f "$installdata/$DISK_IMAGE" ]; then
         pushd "$installdata"
@@ -110,7 +122,7 @@ if ! $AUTO_INSTALL; then
     fi
 fi
 
-if ! cmp /dev/zero "$TARGET_DEVICE" -n 1M && \
+if [ "$OVERWRITE" != "OVERWRITE" ] && ! cmp /dev/zero "$TARGET_DEVICE" -n 1M && \
    ! dialog --defaultno \
             --yesno "WARNING: Target device is not empty! Continue anyway?" 5 60; then
     exit 0
-- 
2.43.0