# Makefile for diskless network boot Linux

TEMP		?= /tmp

ARCH		= i386
CROSS_COMPILE	=

ROOTFSDIR	= $(shell pwd)/rootfs.d

KERNELVER	= linux-2.6.33.3
KERNELDIST	= $(KERNELVER).tar.bz2
KERNELURL	= ftp.kernel.org/pub/linux/kernel/v2.6/$(KERNELDIST)
KERNELSRC	= $(shell pwd)/$(KERNELVER)

BUSYBOX_VERSION	= 1.16.1
BUSYBOX_NAME	= busybox
BUSYBOX_SRC	= $(BUSYBOX_NAME)-$(BUSYBOX_VERSION)
BUSYBOX_DIST	= $(BUSYBOX_NAME)-$(BUSYBOX_VERSION).tar.bz2
BUSYBOX_SERVER	= http://www.busybox.net/downloads
BUSYBOX_URL	= $(BUSYBOX_SERVER)/$(BUSYBOX_DIST)

SYSLINUXVER	= syslinux-3.86
SYSLINUXDIST	= $(SYSLINUXVER).tar.bz2
SYSLINUXURL	= http://www.kernel.org/pub/linux/utils/boot/syslinux/$(SYSLINUXDIST)
SYSLINUXSRC	= $(shell pwd)/$(SYSLINUXVER)

.PHONY: kernel.menuconfig kernel busybox.menuconfig busybox pxelinux download install clean reallyclean distclean

default: linux.kernel linux.pxelinux linux.iso

###############################################################################

$(TEMP)/$(BUSYBOX_DIST):
	wget -nv -P $(TEMP) $(BUSYBOX_URL)

$(BUSYBOX_SRC): $(TEMP)/$(BUSYBOX_DIST)
	tar xjf $(TEMP)/$(BUSYBOX_DIST)

busybox.menuconfig: $(BUSYBOX_SRC)
	cp busybox.config $(BUSYBOX_SRC)/.config
	$(MAKE) -C $(BUSYBOX_SRC) menuconfig CROSS_COMPILE=$(CROSS_COMPILE)
	$(MAKE) -C $(BUSYBOX_SRC) oldconfig CROSS_COMPILE=$(CROSS_COMPILE)
	cp $(BUSYBOX_SRC)/.config busybox.config

$(BUSYBOX_SRC)/skeleton: $(BUSYBOX_SRC)
	cp busybox.config $(BUSYBOX_SRC)/.config
	$(MAKE) -C $(BUSYBOX_SRC) oldconfig CROSS_COMPILE=$(CROSS_COMPILE)
	$(MAKE) -C $(BUSYBOX_SRC) CROSS_COMPILE=$(CROSS_COMPILE)
	$(MAKE) -C $(BUSYBOX_SRC) install CROSS_COMPILE=$(CROSS_COMPILE) CONFIG_PREFIX=./skeleton
	touch $@

busybox: $(BUSYBOX_SRC)/skeleton

###############################################################################

# Build the root file system image

initramfs.cpio.gz: $(BUSYBOX_SRC)/skeleton
	rm -rf $(ROOTFSDIR)
	fakeroot sh -c "./populate.sh BUSYBOXSRC=$(BUSYBOX_SRC) ROOTFSDIR=$(ROOTFSDIR) ; cd $(ROOTFSDIR) ; find . -print0 | cpio -ov -0 --format=newc | gzip -9 >../$@"

initramfs: initramfs.cpio.gz

###############################################################################

# Download Linux kernel distribution tarball

$(TEMP)/$(KERNELDIST):
	wget -nv -P $(TEMP) $(KERNELURL)

$(KERNELSRC): $(TEMP)/$(KERNELDIST)
	tar xjf $(TEMP)/$(KERNELDIST)

# Configure the Linux kernel

kernel.menuconfig: $(KERNELSRC)
	make -C $(KERNELSRC) mrproper ARCH=$(ARCH) CROSS_COMPILE=$(CROSS_COMPILE)
	cp kernel.config $(KERNELSRC)/.config
	make -C $(KERNELSRC) menuconfig ARCH=$(ARCH) CROSS_COMPILE=$(CROSS_COMPILE)
	make -C $(KERNELSRC) oldconfig ARCH=$(ARCH) CROSS_COMPILE=$(CROSS_COMPILE)
	cp $(KERNELSRC)/.config kernel.config
	touch kernel.configured

kernel.configured: $(KERNELSRC) kernel.config
	make -C $(KERNELSRC) mrproper ARCH=$(ARCH) CROSS_COMPILE=$(CROSS_COMPILE)
	cp kernel.config $(KERNELSRC)/.config
	make -C $(KERNELSRC) oldconfig ARCH=$(ARCH) CROSS_COMPILE=$(CROSS_COMPILE)
	touch kernel.configured

# Build the Linux kernel

$(KERNELSRC)/arch/i386/boot/bzImage: kernel.configured initramfs.cpio.gz
	make -C $(KERNELSRC) bzImage ARCH=$(ARCH) CROSS_COMPILE=$(CROSS_COMPILE)

linux.kernel: $(KERNELSRC)/arch/$(ARCH)/boot/bzImage
	cp $< $@

kernel: linux.kernel

###############################################################################

# Download Syslinux distribution

$(TEMP)/$(SYSLINUXDIST):
	wget -nv -P $(TEMP) $(SYSLINUXURL)

$(SYSLINUXSRC): $(TEMP)/$(SYSLINUXDIST)
	tar xjf $(TEMP)/$(SYSLINUXDIST)
	cp $(SYSLINUXSRC)/core/pxelinux.asm $(SYSLINUXSRC)/core/pxelinux.asm.original
	cd $(SYSLINUXSRC) ; patch -p0 <../pxelinux.patch
	$(MAKE) -C $(SYSLINUXSRC)/core spotless

# Compile pxelinux and isolinux

$(SYSLINUXSRC)/core/pxelinux.0: $(SYSLINUXSRC)
	$(MAKE) -C $(SYSLINUXSRC)/core pxelinux.0 isolinux.bin
	touch $?
	touch $@

linux.pxelinux: $(SYSLINUXSRC)/core/pxelinux.0
	cp $(SYSLINUXSRC)/core/pxelinux.0 linux.pxelinux

pxelinux: linux.pxelinux

###############################################################################

# Build ISO image with isolinux and kernel

linux.iso: linux.kernel linux.pxelinux linux.config
	mkdir -p cdrom/isolinux
	install -cm 0644 $(SYSLINUXSRC)/core/isolinux.bin cdrom/isolinux
	install -cm 0444 linux.config cdrom/isolinux/isolinux.cfg
	install -cm 0444 linux.kernel cdrom/isolinux
	mkisofs -l -o linux.iso -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table cdrom

###############################################################################

# download source distributions

download: $(KERNELDIST) $(BUSYBOX_DIST) $(SYSLINUXDIST)

# Install to /tftpboot

install: linux.kernel linux.pxelinux linux.config
	scp linux.kernel linux.pxelinux linux.config $(TFTPSERVER)/tftpboot

# Clean out working files, except the kernel

clean:
	-rm initramfs.cpio.gz
	-rm linux.pxelinux
	-rm linux.kernel
	-rm linux.iso
	-rm -rf $(ROOTFSDIR)
	-rm -rf cdrom

# Clean out all working files

reallyclean: clean
	-rm kernel.configured
	-rm -rf $(KERNELSRC)
	-rm -rf $(BUSYBOX_SRC)
	-rm -rf $(SYSLINUXSRC)

# Return source tree to pristine state

distclean: reallyclean
	-rm $(KERNELDIST)
	-rm $(BUSYBOX_DIST)
	-rm $(SYSLINUXDIST)