MEN-3172: [rpi3] Fill all available space on the memory card

This commit adds a systemd script which on boot runs parted to fill the
remaining space on the memory card into the data partition.

Changelog: None

Signed-off-by: Ole Petter <ole.orhagen@northern.tech>

configs/images/raspberrypi3_raspbian_config

@@ -12,3 +12,37 @@ IMAGE_OVERHEAD_FACTOR=1.0
 
 # Best compression there is!
 MENDER_COMPRESS_DISK_IMAGE=lzma
+
+#
+# Resize the data partition to fill the remaining space, using parted, with systemd
+#
+function grow_data_partition() {
+  log_info "Adding systemd init script to run parted and resize the data partition on boot"
+  log_info "to fill all the available space on the storage media"
+  run_and_log_cmd "sudo mkdir -p work/rpi/etc/systemd/system/"
+  run_and_log_cmd "sudo mkdir -p work/rootfs/etc/systemd/system/data.mount.wants/"
+  cat <<-EOF > work/rpi/etc/systemd/system/mender-grow-data.service
+  [Unit]
+  Description=Mender service to grow data partition size
+  DefaultDependencies=no
+  Before=data.mount
+  Before=systemd-growfs@data.service
+
+  [Service]
+  Type=oneshot
+  User=root
+  Group=root
+  ExecStart=/sbin/parted --script /dev/mmcblk0 resizepart ${MENDER_DATA_PART_NUMBER} 100%
+
+  [Install]
+  WantedBy=data.mount
+EOF
+
+  # Install
+  run_and_log_cmd "cp work/rpi/etc/systemd/system/mender-grow-data.service \
+                      work/rootfs/etc/systemd/system/"
+  run_and_log_cmd "ln -sf work/rootfs/etc/systemd/system/mender-grow-data.service \
+                          work/rootfs/etc/systemd/system/data.mount.wants/"
+}
+
+PLATFORM_MODIFY_HOOKS+=(grow_data_partition)