Automount all block devices that do not include the boot partition

Rather than filter by usb subsystems, just ensure that the parent
block device does not include the boot partition provided to the kernel.
All other block devices are fair game to mount.

Change-type: patch
Signed-off-by: Kyle Harding <kyle@balena.io>

30-mount.sh

@@ -1,21 +1,22 @@
 #!/usr/bin/with-contenv bash
 # shellcheck shell=bash
 
-mapfile -t usb_devices < <(lsblk -J -O | jq -r '.blockdevices[] | 
-    select(.subsystems=="block:scsi:usb:platform" or .subsystems=="block:scsi:usb:pci:platform") | 
-    .path, .children[].path')
+# list all block devices that do not include the kernel boot partition
+root_uuid="$(cat /proc/cmdline | sed -rn 's/.*root=UUID=([^ ]+).*/\1/p')"
+mapfile -t block_devs < <(lsblk -J -O | jq -r --arg UUID "${root_uuid}" '.blockdevices[] | 
+    select(.children) | select( all(.children[]; .uuid != $UUID )) | .children[].path')
 
-# automount USB device partitions at /media/{UUID}
-if [ ${#usb_devices[@]} -gt 0 ]
+# automount block device partitions at /media/{UUID}
+if [ ${#block_devs[@]} -gt 0 ]
 then
-    echo "Found USB storage block devices: ${usb_devices[*]}"
-    for uuid in $(blkid -sUUID -ovalue "${usb_devices[@]}")
+    echo "Found block storage devices: ${block_devs[*]}"
+    for uuid in $(blkid -sUUID -ovalue "${block_devs[@]}")
     do
         {
             mkdir -pv /media/"${uuid}"
             mount -v UUID="${uuid}" /media/"${uuid}"
         } || continue
     done
 else
-    echo "No USB block storage devices found."
+    echo "No block storage devices found."
 fi