Make rootfs dir and output image customizable for rootfs target

Author: gsingh93

Makefile

@@ -84,6 +84,9 @@ help:
 	@echo '   Environment Variables:'
 	@echo '      EXT4_SIZE                     - TODO'
 	@echo '      INITRAMFS_DIR                 - TODO'
+	@echo '      ROOTFS                        - TODO'
+	@echo '      ROOTFS_DIR                    - TODO'
+	@echo '      ROOTFS_FORMAT                 - TODO'
 	@echo ''
 	@echo '$(GREEN)Miscellaneous:$(NC)'
 	@echo '   Targets:'
@@ -225,29 +228,30 @@ tools-vm_clean:
 ## Generate rootfs images
 ##
 
-ROOTFS_DIR := $(ROOT_DIR)/rootfs
-ROOTFS_IMG := $(ROOTFS_DIR)/rootfs-$(ARCH).img
-ALPINE_ROOTFS_DIR := $(ROOTFS_DIR)/alpine-$(ARCH)
-INITRAMFS_DIR ?= $(ALPINE_ROOTFS_DIR)
-CPIO_FILE := $(ROOTFS_DIR)/$$(basename $(INITRAMFS_DIR)).cpio.gz
+ROOTFS_PARENT_DIR := $(ROOT_DIR)/rootfs
+ROOTFS ?= $(ROOTFS_PARENT_DIR)/rootfs-$(ARCH).img
+ROOTFS_FORMAT ?= qcow2
+ROOTFS_DIR := $(ROOTFS_PARENT_DIR)/alpine-$(ARCH)
+INITRAMFS_DIR ?= $(ROOTFS_DIR)
+CPIO_FILE := $(ROOTFS_PARENT_DIR)/$$(basename $(INITRAMFS_DIR)).cpio.gz
 EXT4_SIZE ?= 1G
 
-$(ALPINE_ROOTFS_DIR):
-	mkdir -p $(ALPINE_ROOTFS_DIR)
+$(ROOTFS_DIR):
+	mkdir -p $(ROOTFS_DIR)
 
 .PHONY: rootfs-init
-rootfs-init: | $(ALPINE_ROOTFS_DIR)
-	tar -xf $(ROOTFS_DIR)/alpine-minirootfs-*-$(ARCH).tar.gz -C $(ALPINE_ROOTFS_DIR)
-	cp -f -r $(CONFIG_DIR)/rootfs-overlay/. $(ALPINE_ROOTFS_DIR)
-	$(SCRIPT_DIR)/arch_specific.sh $(ARCH) $(ALPINE_ROOTFS_DIR)
+rootfs-init: | $(ROOTFS_DIR)
+	tar -xf $(ROOTFS_PARENT_DIR)/alpine-minirootfs-*-$(ARCH).tar.gz -C $(ROOTFS_DIR)
+	cp -f -r $(CONFIG_DIR)/rootfs-overlay/. $(ROOTFS_DIR)
+	$(SCRIPT_DIR)/arch_specific.sh $(ARCH) $(ROOTFS_DIR)
 	$(MAKE) ext4
 
 .PHONY: ext4
-ext4: | $(INITRAMFS_DIR)
-	dd if=/dev/zero of=$(ROOTFS_IMG) bs=1 count=0 seek=$(EXT4_SIZE)
-	mkfs.ext4 -b 4096 -d $(ALPINE_ROOTFS_DIR) -F $(ROOTFS_IMG)
-	qemu-img convert -O qcow2 $(ROOTFS_IMG) $(ROOTFS_IMG).qcow2
-	mv $(ROOTFS_IMG).qcow2 $(ROOTFS_IMG)
+ext4: | $(ROOTFS_DIR)
+	dd if=/dev/zero of=$(ROOTFS) bs=1 count=0 seek=$(EXT4_SIZE)
+	mkfs.ext4 -b 4096 -d $(ROOTFS_DIR) -F $(ROOTFS)
+	qemu-img convert -O $(ROOTFS_FORMAT) $(ROOTFS) $(ROOTFS).tmp
+	mv $(ROOTFS).tmp $(ROOTFS)
 
 .PHONY: cpio
 cpio: | $(INITRAMFS_DIR)
@@ -271,9 +275,9 @@ rootfs-unmount:
 
 .PHONY: rootfs_clean
 rootfs_clean:
-	rm -rf $(ALPINE_ROOTFS_DIR)
+	rm -rf $(ROOTFS_DIR)
 	rm -f $(CPIO_FILE)
-	rm -f $(ROOTFS_IMG)
+	rm -f $(ROOTFS)
 
 ##
 ## Run QEMU
@@ -284,8 +288,6 @@ MEM ?= 1024
 QEMU_EXTRA_ARGS ?=
 QEMU_EXTRA_KERNEL_CMDLINE ?=
 GDB ?= 0
-ROOTFS ?= $(ROOTFS_IMG)
-ROOTFS_FORMAT ?= qcow2
 INITRD ?=
 RDINIT ?= /sbin/init