Add automatic mount of USB devices for minimal images

Minimal images have no automatic mounts of mass storage devices.
Allow to mount USB storage devices automatically in R/O mode to
prevent accidental corruption of filesystem on device.

This feature is needed for mass storage upgrades.

Signed-off-by: Denis Pynkin <denis.pynkin@collabora.com>

apertis-ospack-minimal.yaml

@@ -37,6 +37,7 @@ actions:
       - apt-transport-https
       - apertis-customizations
       - initramfs-tools
+      - udisks2
 
   - action: apt
     description: "Base packages"
@@ -100,6 +101,9 @@ actions:
   - action: overlay
     source: overlays/minimal-ribchester-polkit-rules
 
+  - action: overlay
+    source: overlays/minimal-automount-rules
+
   - action: run
     chroot: true
     script: scripts/add-xdg-user-metadata.sh

overlays/minimal-automount-rules/etc/udev/rules.d/99-udisks2.rules

+ENV{ID_FS_USAGE}=="filesystem", ENV{UDISKS_FILESYSTEM_SHARED}="1"
+
+KERNEL=="sd*", SUBSYSTEMS=="usb", ACTION=="add", ATTR{partition}=="1", PROGRAM="/bin/systemd-escape -p --template=usbmount@.service $env{DEVNAME}", ENV{SYSTEMD_WANTS}+="%c"
+KERNEL=="sd*", SUBSYSTEMS=="usb", ACTION=="remove", RUN+="/usr/bin/udisksctl unmount -f -b $env{DEVNAME}"

overlays/minimal-automount-rules/lib/systemd/system/default.target.wants/usbmount@.service

+../usbmount@.service
\ No newline at end of file

overlays/minimal-automount-rules/lib/systemd/system/usbmount@.service

+[Unit]
+BindTo=%i.device
+After=%i.device
+
+[Service]
+Type=oneshot
+TimeoutStartSec=0
+ExecStart=/usr/bin/udisksctl mount -o ro -b /%I 
+RemainAfterExit=yes
+StandardOutput=syslog