help:
	@echo "Build a minimal Linux system"
	@echo ""
	@echo "source      - download source code"
	@echo ""
	@echo "all         - create all images"
	@echo "qemu        - create an image for QEMU"
	@echo "vdi         - create an image for VirtualBox"
	@echo "vmdk        - create an image for VMware"
	@echo ""
	@echo "clean       - cleanup build artifacts"
	@echo
	@echo "run-qemu    - run in QEMU"
	@echo ""
	@echo "run minimal Linux for example with 'qema -hda minilinux.img'"

.PHONY: help run-qemu all step1 step2 step3 step4 step5 mount-disk umount-disk mount-root umount-root

# software versions
SYSLINUX_VERSION=4.07
KERNEL_VERSION=3.1.4
UCLIBC_VERSION=0.9.32
BUSYBOX_VERSION=1.27.2
ACPID_VERSION=1.0.10
GPM_VERSION=1.20.7
PERL_VERSION=5.12.1
LUA_VERSION=5.1.4

PARALLEL=-j12

# TODO: make it a build option depending on the target
# architecture we want to build
#LIBDIR=lib
LIBDIR=lib64

all: qemu vdi vmdk zip-vdi zip-vmdk

vdi:
	-rm -f minilinux.vdi
	./vditool DD minilinux.vdi minilinux.img
	./vditool SHRINK minilinux.vdi
	chmod 666 minilinux.vdi
 
vmdk:
	qemu-img convert -f raw minilinux.img -O vmdk minilinux.vmdk
	chmod 666 minilinux.vmdk
	chmod 777 minilinux.vmx

zip-vdi:
	zip -9 -v -u minilinux.zip minilinux.vdi
	mv minilinux.zip minilinux-virtualbox.zip
	
zip-vmdk:
	zip -9 -v -u minilinux minilinux.vmx minilinux.vmdk
	mv minilinux.zip minilinux-vmware.zip
		
qemu: clean step1 step2 step3 step4 step5 umount-root

step1:

# step2: initial setup, image, directory layout, device inodes
step2: disk-image mount-root directory-layout initial-devices

# step3: boot loader
step3: syslinux syslinux-loader

# step4: kernel, uclibc C-library, busybox, basic tools, ACPI daemon
step4: kernel busybox acpid

# step5: additional user space tools:
# - GPM for mouse copy-pate
# - Miniperl
# - Lua
step5: gpm perl lua

# disk image and directories
	
directory-layout:
	cd target && mkdir bin boot dev etc home $(LIBDIR) mnt root sbin tmp usr var proc sys
	cd target/boot && mkdir extlinux
	cd target/var && mkdir lock log run spool
	cd target/usr && mkdir bin include lib local sbin share src
	cd target/usr/share && mkdir man
	cd target/usr/share/man && mkdir man1 man2 man3 man4 man5 man6 man7 man8 man9 
	cd target/usr && ln -s share/man man
	cd target/etc && mkdir init.d
	cp inittab passwd group nsswitch.conf hosts motd issue target/etc
	cp rcS target/etc/init.d

initial-devices:
	rm -rf target/dev/*
	mknod target/dev/console c 5 1
	mknod target/dev/null c 1 3
	mknod target/dev/zero c 1 5
	mknod target/dev/hda b 3 0
	mknod target/dev/hda1 b 3 1
	mknod target/dev/tty0 c 4 0
	mknod target/dev/tty1 c 4 1
	mknod target/dev/tty2 c 4 2
	mknod target/dev/tty3 c 4 3
	mknod target/dev/tty4 c 4 4
	mknod target/dev/tty5 c 4 5
	mknod target/dev/tty6 c 4 6
	mknod target/dev/ttyS0 c 4 64
	mknod target/dev/psaux c 10 1

disk-image:
	qemu-img create minilinux.img 16450560
	chmod 666 minilinux.img
	/sbin/losetup /dev/loop0 minilinux.img
	dd if=/dev/zero of=/dev/loop0 bs=512 count=32130
	echo ',2,L,*' | /sbin/sfdisk -H 255 -S 63 -C 2 --no-reread /dev/loop0
	sync && sleep 1
	/sbin/losetup -d /dev/loop0
	/sbin/losetup -o 512 /dev/loop0 minilinux.img
	/sbin/mke2fs /dev/loop0
	sync && sleep 1
	losetup -d /dev/loop0
	mkdir target

# syslinux boot loeader

syslinux:
	tar jxf tarballs/syslinux-$(SYSLINUX_VERSION).tar.gz
	cd syslinux-$(SYSLINUX_VERSION) && make $(PARALLEL)
	syslinux-$(SYSLINUX_VERSION)/extlinux/extlinux -i target/boot/extlinux/.
	cp extlinux.conf target/boot/extlinux/.

syslinux-loader:
	/sbin/losetup /dev/loop1 minilinux.img
	cat syslinux-$(SYSLINUX_VERSION)/mbr/mbr.bin > /dev/loop1
	sync && sleep 1
	/sbin/losetup -d /dev/loop1

syslinux-clean:
	-rm -rf syslinux-build
	-rm -rf syslinux-$(SYSLINUX_VERSION)

# Linux kernel

kernel:
	-rm -rf linux-$(KERNEL_VERSION)
	tar jxf tarballs/linux-$(KERNEL_VERSION).tar.bz2
	cp kernel-config.`uname -m` linux-$(KERNEL_VERSION)/.config
	cd linux-$(KERNEL_VERSION) && ( yes '' | make $(PARALLEL) bzImage )
	cp linux-$(KERNEL_VERSION)/arch/x86/boot/bzImage target/boot/bzImage-$(KERNEL_VERSION)

kernel-clean:
	-rm -rf linux-$(KERNEL_VERSION)

# micro C library

uclibc:
	-rm -rf uClibc-$(UCLIBC_VERSION)
	tar jxf tarballs/uClibc-$(UCLIBC_VERSION).tar.bz2
	cp uclibc-config uClibc-$(UCLIBC_VERSION)/.config
	cd uClibc-$(UCLIBC_VERSION) && make $(PARALLEL) CROSS=i486-pc-linux-gnu-
	cd uClibc-$(UCLIBC_VERSION) && make install DESTDIR=/tools

uclibc-clean:
	-rm -rf uClibc-$(UCLIBC_VERSION)

# busybox

busybox:
	-rm -rf busybox-$(BUSYBOX_VERSION)
	tar jxf tarballs/busybox-$(BUSYBOX_VERSION).tar.bz2
	cp busybox-config busybox-$(BUSYBOX_VERSION)/.config
	cd busybox-$(BUSYBOX_VERSION) && make $(PARALLEL)
	cd busybox-$(BUSYBOX_VERSION) && make install
	cp /$(LIBDIR)/libcrypt.so.1 target/$(LIBDIR)
	cp /$(LIBDIR)/ld-linux-x86-64.so.2 target/$(LIBDIR)
	cp /$(LIBDIR)/libm.so.6 target/$(LIBDIR)
	cp /$(LIBDIR)/libc.so.6 target/$(LIBDIR)
	cp /$(LIBDIR)/libdl.so.2 target/$(LIBDIR)
	cp /$(LIBDIR)/libpthread.so.0 target/$(LIBDIR)
	-cp /$(LIBDIR)/libpcre.so.0 target/$(LIBDIR)
#???
#	-cp /usr/$(LIBDIR)/libpcre.so.3 target/$(LIBDIR)

	
busybox-clean:
	-rm -rf busybox-$(BUSYBOX_VERSION)

gpm:
	-rm -rf gpm-$(GPM_VERSION)
	tar jxf tarballs/gpm-$(GPM_VERSION).tar.bz2
	cd gpm-$(GPM_VERSION) && ./autogen.sh
	cd gpm-$(GPM_VERSION) && ./configure --prefix=/usr --without-curses
	cd gpm-$(GPM_VERSION) && make LDFLAGS="-lm" $(PARALLEL)
	cd gpm-$(GPM_VERSION) && cp src/gpm ../target/usr/sbin

gpm-clean:
	-rm -rf gpm-$(GPM_VERSION)

acpid:
	-rm -rf acpid-$(ACPID_VERSION)
	-rm -rf target/etc/acpi
	tar zxf tarballs/acpid-$(ACPID_VERSION).tar.gz	
	cd acpid-$(ACPID_VERSION) && make $(PARALLEL)
	cd acpid-$(ACPID_VERSION) && cp acpid ../target/usr/sbin/acpid
	mkdir target/etc/acpi
	mkdir target/etc/acpi/events
	cp acpid-anything target/etc/acpi/events
	cp acpid-handler.sh target/etc/acpi/handler.sh
	chmod 775 target/etc/acpi/handler.sh
	
acpid-clean:
	-rm -rf acpid-$(ACPID_VERSION)

perl:
	-rm -rf perl-$(PERL_VERSION)
	tar zxf tarballs/perl-$(PERL_VERSION).tar.gz
	cp {Makefile.micro,miniperlmain.c} perl-$(PERL_VERSION)
	cd perl-$(PERL_VERSION) && make -f Makefile.micro $(PARALLEL)
	cd perl-$(PERL_VERSION) && cp microperl ../target/usr/bin/perl

perl-clean:
	-rm -rf perl-$(PERL_VERSION)

lua:
	-rm -rf lua-$(LUA_VERSION)
	tar zxf tarballs/lua-$(LUA_VERSION).tar.gz
	cd lua-$(LUA_VERSION) && make posix $(PARALLEL)
	cd lua-$(LUA_VERSION) && cp src/lua ../target/usr/bin/lua

lua-clean:
	-rm -rf lua-$(LUA_VERSION)
	
# helpers

mount-disk:
	/sbin/losetup /dev/loop0 minilinux.img

umount-disk:
	/sbin/losetup -d /dev/loop0

mount-root:
	/sbin/losetup -o 512 /dev/loop0 minilinux.img
	mount /dev/loop0 target

umount-root:
	umount target
	/sbin/losetup -d /dev/loop0

# global clean

clean: syslinux-clean uclibc-clean kernel-clean busybox-clean acpid-clean gpm-clean perl-clean
	-umount target
	-/sbin/losetup -d /dev/loop0
	-rm minilinux.img
	-rm minilinux.vdi *-vditool-*.log
	-rm minilinux.vmdk minilinux.nvram minilinux.vmem minilinux.vmsd minilinux.vmss vmware*.log minilinux.vmxf minilinux*.zip
	-rm -rf target

# download sources to tarballs

source:
	-test -d tarballs || mkdir tarballs
	-test -r tarballs/syslinux-$(SYSLINUX_VERSION).tar.gz || \
		wget -O tarballs/syslinux-$(SYSLINUX_VERSION).tar.gz \
		http://www.kernel.org/pub/linux/utils/boot/syslinux/4.xx//syslinux-$(SYSLINUX_VERSION).tar.bz2
	-test -r tarballs/linux-$(KERNEL_VERSION).tar.bz2 || \
		wget -O tarballs/linux-$(KERNEL_VERSION).tar.bz2 \
		http://www.kernel.org/pub/linux/kernel/v3.0//linux-$(KERNEL_VERSION).tar.bz2
	-test -r tarballs/uClibc-$(UCLIBC_VERSION).tar.bz2 || \
		wget -O tarballs/uClibc-$(UCLIBC_VERSION).tar.bz2 \
		http://www.uclibc.org/downloads/uClibc-$(UCLIBC_VERSION).tar.bz2
	-test -r tarballs/busybox-$(BUSYBOX_VERSION).tar.bz2 || \
		wget -O tarballs/busybox-$(BUSYBOX_VERSION).tar.bz2 \
		http://www.busybox.net/downloads/busybox-$(BUSYBOX_VERSION).tar.bz2
	-test -r tarballs/acpid-$(ACPID_VERSION).tar.gz || \
		wget -O tarballs/acpid-$(ACPID_VERSION).tar.gz \
		http://downloads.sourceforge.net/sourceforge/acpid/acpid-$(ACPID_VERSION).tar.gz
	-test -r tarballs/gpm-$(GPM_VERSION).tar.bz2 || \
		wget -O tarballs/gpm-$(GPM_VERSION).tar.bz2 \
		http://www.nico.schottelius.org/software/gpm/archives/gpm-$(GPM_VERSION).tar.bz2
	-test -r tarballs/perl-$(PERL_VERSION).tar.gz || \
		wget -O tarballs/perl-$(PERL_VERSION).tar.gz \
		http://www.cpan.org/src/perl-$(PERL_VERSION).tar.gz
	-test -r tarballs/lua-$(LUA_VERSION).tar.gz || \
		wget -O tarballs/lua-$(LUA_VERSION).tar.gz \
		http://www.lua.org/ftp/lua-$(LUA_VERSION).tar.gz

run-qemu:
	/usr/libexec/qemu-kvm -hda minilinux.img &
	vncviewer localhost &
	
run-qemu: minilinux.img
	qemu-system-x86_64 -curses -enable-kvm -hda minilinux.img