2 files changed, 62 insertions, 23 deletions

diff --git a/Makefile b/Makefile
index 68a7de1..6b670a3 100644
--- a/Makefile
+++ b/Makefile
@@ -167,6 +167,10 @@ FORCE:
 $(btrfs_images): FORCE
         $(MAKE) -C rootfs $(notdir $@)
 
+.PHONY: usb
+usb: rootfs
+        USB=$$(./src/usb.sh) && sudo ROOTFS=rootfs/$(rootfs) ./src/parted-usb.sh $$USB
+
 boot: rootfs
         sudo ./src/mkinitramfs-samizdat
         sudo ROOTFS=rootfs/$(rootfs) ./src/parted-usb.sh
diff --git a/src/parted-usb.sh b/src/parted-usb.sh
index fff003c..af56c8c 100755
--- a/src/parted-usb.sh
+++ b/src/parted-usb.sh
@@ -234,6 +234,38 @@ boot_vm()
         -drive file="$installer_target",format=raw
 }
 
+do_build()
+{
+    if [ -b "$target" ]
+    then
+        globalize
+        individualize
+        release_target_block_devices
+    elif [ -f "$target" -o ! -e "$target" ]
+    then
+         template=${target%.img}.template.img
+         final=$target
+         (
+             target=$target.tmp
+             if [ ! -e "$template" ]
+             then
+                 target="$template".tmp globalize
+                 release_target_block_devices
+                 mv -T "$template".tmp "$template"
+             fi
+
+             cp -T --reflink=always "$template" "$target"
+             acquire_target_block_devices
+             individualize
+             release_target_block_devices
+
+             mv -T "$target" "$final"
+         )
+    else
+        die "Target must be a file or block device."
+    fi
+}
+
 . samizdat-paths.sh || die 'samizdat-paths.sh not found'
 samizdat_linux_dir=/
 
@@ -270,33 +302,36 @@ fi
 sanity_checks
 set -e
 
-if [ "$1" = boot ]
-then
-    boot_vm boot-disk.img
-elif [ "$1" ]
+if [ "$1" = -n ]
 then
-    [ -b "$1" ] || die "Not a block device: $1"
-    target=$1
-    globalize
-    individualize
-    release_target_block_devices
+    shift
+    DO_BUILD=
 else
-    template=boot-disk.template.img
-    if [ ! -e "$template" ]
+    DO_BUILD=y
+fi
+
+default_target=boot-disk.img
+
+if [ "$1" ]
+then
+
+    if [ "$1" = USB ]
     then
-        target="$template".tmp globalize
-        release_target_block_devices
-        mv -T "$template".tmp "$template"
+        target=$(./src/usb.sh) || exit 1
+    elif [ -f "$1" ]
+    then
+        case "$1" in
+            *.img) ;;
+            *) die "Invalid image filename.  Use *.img";;
+        esac
     fi
+    target=$1
+else
+    target=$default_target
+fi
 
-    target=boot-disk.img.tmp
-    cp -T --reflink=always "$template" "$target"
-    acquire_target_block_devices
-    individualize
-    release_target_block_devices
-
-    final=${target%.tmp}
-    mv -T "$target" "$final"
-    target=$final
+if [ "$DO_BUILD" ]
+then
+    do_build
 fi
 boot_vm "$target"