rootfs: Add option to install local debs

Update README to document the option.

Author: lool

README.md

@@ -46,6 +46,7 @@ debos --fakemachine-backend qemu --memory 1GiB --scratchsize 4GiB debos-recipes/
 
 A few options are provided in the debos recipes; for the root filesystem recipe:
 - experimentalkernel: update the linux kernel to the version from experimental; default: don't update the kernel
+- localdebs: install this space separte list of local deb packages (NB: debos expects relative pathnames)
 - xfcedesktop: install a Xfce desktop environment; default: console only environment
 
 For the image recipe:

debos-recipes/qualcomm-linux-debian-rootfs.yaml

@@ -1,5 +1,9 @@
 {{- $xfcedesktop := or .xfcedesktop "false" }}
 {{- $experimentalkernel := or .experimentalkernel "false" }}
+{{- $localdebs := list -}}
+{{- if .localdebs -}}
+{{- $localdebs = split " " .localdebs }}
+{{- end -}}
 
 architecture: arm64
 
@@ -190,6 +194,21 @@ actions:
           /etc/apt/sources.list.d/debian-experimental.sources
 {{- end }}
 
+{{ range $deb := $localdebs }}
+  - action: overlay
+    description: Copy local deb "{{ $deb }}"
+    source: {{ $deb }}
+    destination: /local-debs/
+
+  - action: run
+    description: Install local deb "{{ $deb }}"
+    chroot: yes
+    command: |
+      set -eux
+      apt -y install /local-debs/*.deb
+      rm -rf /local-debs/
+{{ end }}
+
   - action: run
     description: Create DTBs tarball
     chroot: false