build-vm, pack: implement tar, tar.gz, tar.xz support for vm/* target

build-vm ceases to be a target for building only virtual machine images.
Now it can be used to build tarballs designed for installation on real
machines.

This commit is the result of transferring the required functionality from
build-mr (mipsel rootfs) by Ivan Melnikov <iv@altlinux.org>.

NB: mike@ strongly objected to this dilution but gave up eventually;
    the whole kernel/build-vm/tar2fs/pack mess should be split into
    distinct layers busy with their own responsibilities:

    1) a tarball with kernel is done without tar2fs at all
       (and no build-vm bits should be needed either, maybe
       it's worth splitting and renaming as "vm" meaning
       disk image for some armh board is grossly misleading);

    2) a tarball with kernel can be further (multi-)packed
       as, well, (compressed) tarball and a disk image
       (only the latter one should employ build-vm/tar2fs);

    3) compression should be done in pack feature style,
       preferably described once and not duplicated all over
       the profile for every single new kind of its output.

    In the mean time, running into this and moving no further
    starts to hurt more than it could help.

features.in/build-vm/README

@@ -1,3 +1,6 @@
-Эта фича конфигурирует создание образа виртуальной машины (VM).
+Эта фича конфигурирует создание образа виртуальной машины (VM)
+или тарбола rootfs для использования его на реальном компьютере.
 Дополняет финальную стадию сборки (lib/, image-scripts.d/).
-Требует для работы sudo(8) -- см. тж. doc/vm.txt
+Для создания образа виртуальной машины требуется sudo(8)
+Для создания тарбола sudo не требуется.
+-- см. тж. doc/vm.txt

features.in/build-vm/lib/90-build-vm.mk

@@ -22,18 +22,22 @@ VM_RAWDISK := $(IMAGE_OUTDIR)/$(IMAGE_NAME).raw
 VM_FSTYPE ?= ext4
 VM_SIZE ?= 0
 
+VM_GZIP_COMMAND ?= gzip
+VM_XZ_COMMAND ?= xz -T0
+
 check-sudo:
 	@if ! type -t sudo >&/dev/null; then \
 		echo "** error: sudo not available, see doc/vm.txt" >&2; \
+	fi
+
+check-qemu:
+	@if ! type -t qemu-img >&/dev/null; then \
+		echo "** error: qemu-img not available" >&2; \
 		exit 1; \
 	fi
 
-prepare-image: check-sudo
-	@# need to copy $(BUILDDIR)/.work/chroot/.host/qemu* into chroot
-	@#if qemu is used
-	@(cd "$(BUILDDIR)/.work/chroot/"; \
-		tar -rf "$(VM_TARBALL)" ./.host/qemu*) ||:; \
-	if [ -x /usr/share/mkimage-profiles/bin/tar2fs ]; then \
+tar2fs: check-sudo
+	@if [ -x /usr/share/mkimage-profiles/bin/tar2fs ]; then \
 		TOPDIR=/usr/share/mkimage-profiles; \
 	fi; \
 	if ! sudo $$TOPDIR/bin/tar2fs \
@@ -43,26 +47,40 @@ prepare-image: check-sudo
 		exit 1; \
 	fi
 
-convert-image: prepare-image
+prepare-image:
+	@# need to copy $(BUILDDIR)/.work/chroot/.host/qemu* into chroot
+	@#if qemu is used
+	@(cd "$(BUILDDIR)/.work/chroot/"; \
+		tar -rf "$(VM_TARBALL)" ./.host/qemu*) ||:
+
+convert-image/tar:
+	mv "$(VM_TARBALL)" "$(IMAGE_OUTPATH)"
+
+convert-image/tar.gz:
+	$(VM_GZIP_COMMAND) < "$(VM_TARBALL)" > "$(IMAGE_OUTPATH)"
+
+convert-image/tar.xz:
+	$(VM_XZ_COMMAND) < "$(VM_TARBALL)" > "$(IMAGE_OUTPATH)"
+
+convert-image/img: tar2fs
+	mv "$(VM_RAWDISK)" "$(IMAGE_OUTPATH)"
+
+convert-image/qcow2 convert-image/qcow2c convert-image/vmdk \
+	convert-image/vdi convert-image/vhd: check-qemu tar2fs
 	@VM_COMPRESS=; \
 	case "$(IMAGE_TYPE)" in \
-	"img") \
-		mv "$(VM_RAWDISK)" "$(IMAGE_OUTPATH)"; \
-		if [ "0$(DEBUG)" -le 1 ]; then rm "$(VM_TARBALL)"; fi; \
-		exit 0;; \
 	"vhd") VM_FORMAT="vpc";; \
 	"qcow2c") VM_FORMAT="qcow2"; VM_COMPRESS="-c";; \
 	*) VM_FORMAT="$(IMAGE_TYPE)"; \
 	esac; \
-	if ! type -t qemu-img >&/dev/null; then \
-		echo "** error: qemu-img not available" >&2; \
-		exit 1; \
-	else \
-		qemu-img convert $$VM_COMPRESS -O "$$VM_FORMAT" \
-			"$(VM_RAWDISK)" "$(IMAGE_OUTPATH)"; \
-		rm "$(VM_RAWDISK)"; \
-		if [ "0$(DEBUG)" -le 1 ]; then rm "$(VM_TARBALL)"; fi; \
-	fi
+	qemu-img convert $$VM_COMPRESS -O "$$VM_FORMAT" \
+		"$(VM_RAWDISK)" "$(IMAGE_OUTPATH)"
+
+post-convert:
+	@rm -f "$(VM_RAWDISK)"; \
+	if [ "0$(DEBUG)" -le 1 ]; then rm -f "$(VM_TARBALL)"; fi
+
+convert-image: prepare-image convert-image/$(IMAGE_TYPE) post-convert; @:
 
 run-image-scripts: GLOBAL_CLEANUP_PACKAGES := $(CLEANUP_PACKAGES)
 

features.in/pack/config.mk

@@ -29,12 +29,18 @@ use/pack/$(1).$(2): use/pack/$(1)
 	@$$(call set,IMAGE_COMPRESS,$(2))
 endef
 
+ifeq (ve,$(IMAGE_CLASS))
 $(foreach c,$(VE_ARCHIVES), \
 	$(eval $(call PACK_containers,$(c))) \
 	$(foreach z,$(VE_COMPRESSORS), \
 		$(eval $(call PACK_compressors,$(c),$(z)))))
+endif
 
-# virtual machines
-VM_EXTS := .img .qcow2 .qcow2c .vdi .vmdk .vhd
+# extensions for buld-vm
+VM_EXTS := .tar .tar.gz .tar.xz .img .qcow2 .qcow2c .vdi .vmdk .vhd
+
+ifeq (vm,$(IMAGE_CLASS))
 
 $(VM_EXTS:.%=use/pack/%): use/pack; @:
+
+endif