build-ubuntu-rootfs.sh: Add support for injecting custom apt sources from package manifest

  - Extended script functionality to parse and add custom apt sources from the JSON
    package manifest, enabling installation from additional repositories during rootfs build.
  - Ensures each custom source line is written to a dedicated sources.list.d entry,
    preserving compatibility and flexibility for multi-repo configurations.
  - This enhancement improves package installation workflows, supports upstream and
    third-party repositories, and maintains backward compatibility with legacy and config-driven builds.

Signed-off-by: Bjordis Collaku <[email protected]>

Author: bjordiscollaku

rootfs/scripts/build-ubuntu-rootfs.sh

@@ -13,6 +13,7 @@
 #   - Supports Qualcomm product configuration file (.conf) for build parameters.
 #   - Supports JSON package manifest for additional package installation
 #     (via apt or local .deb) inside the rootfs.
+#   - Supports injecting custom apt sources from the package manifest.
 #   - Backward compatible with legacy 2-argument mode (kernel.deb, firmware.deb).
 #   - Parses qcom-product.conf (if provided) or uses defaults to determine the base image.
 #   - Runs target platform-specific image preprocessing to populate rootfs/.
@@ -265,6 +266,18 @@ case "$(echo "$TARGET_PLATFORM" | tr '[:upper:]' '[:lower:]')" in
     ;;
 esac
 
+# ==============================================================================
+# Step 3.5: Add custom apt sources from manifest (if provided)
+# ==============================================================================
+if [[ "$USE_MANIFEST" -eq 1 && -n "$MANIFEST" ]]; then
+    echo "[INFO] Adding custom apt sources from manifest..."
+    jq -c '.apt_sources[]?' "$MANIFEST" | while read -r row; do
+        NAME=$(echo "$row" | jq -r '.name // "customrepo"')
+        SRC_LINE=$(echo "$row" | jq -r '.source_line')
+        echo "$SRC_LINE" >> "$ROOTFS_DIR/etc/apt/sources.list.d/${NAME}.list"
+    done
+fi
+
 # ==============================================================================
 # Step 4: Inject Kernel, Firmware, and Working resolv.conf
 # ==============================================================================