OSDI Lab8

init

#!/sbin/busybox sh

set -e

/sbin/busybox --install -s

mount -t proc proc /proc
mount -t sysfs sysfs /sys

mknod -m 666 /dev/null c 1 3
mknod -m 666 /dev/zero c 1 5
mknod -m 666 /dev/ptmx c 5 2
mknod -m 666 /dev/tty c 5 0
mknod -m 444 /dev/random c 1 8
mknod -m 444 /dev/urandom c 1 9
mknod -m 620 /dev/tty1 c 4 1
mknod -m 620 /dev/tty2 c 4 2
mknod -m 620 /dev/tty3 c 4 3
mknod -m 620 /dev/tty4 c 4 4
mknod -m 620 /dev/tty5 c 4 5
mknod -m 620 /dev/tty6 c 4 6
mknod -m 620 /dev/tty7 c 4 7
mknod -m 620 /dev/tty8 c 4 8

ip link set eth0 up
ip link set lo up

exec /sbin/init

Makefile

ifneq ($(KERNELRELEASE),)
obj-m := lab8.o
else
KERNELDIR ?= linux-2.6.32.60
PWD := $(shell pwd)
SPACE :=
SPACE +=

eq = $(and $(findstring $(1),$(2)),$(findstring $(2),$(1)))

.SECONDEXPANSION:

.PHONY: all clean qemu

all: initramfs.cpio.gz

lab8.ko:
	$(MAKE) -C $(KERNELDIR) M=$(PWD) modules

qemu: all
	qemu-system-x86_64 -kernel $(KERNELDIR)/arch/x86_64/boot/bzImage -initrd initramfs.cpio.gz $(QEMUFLAGS)

malloc: malloc.c
	$(CC) $(CPPFLAGS) -static $(CFLAGS) $< -o $@

busybox:
	wget -nv http://www.busybox.net/downloads/binaries/latest/busybox-x86_64 -O $@
	chmod a+x $@

INITRAMFS := initramfs/
INITRAMFS_DIRS := $(INITRAMFS) $(addprefix $(INITRAMFS),bin/ dev/ etc/ lib/ proc/ sbin/ sys/ usr/ usr/bin/ usr/sbin/)
INITRAMFS_BINS := $(addprefix $(INITRAMFS),init sbin/busybox usr/bin/malloc lib/lab8.ko)

$(INITRAMFS_DIRS): %: | $$(if $$(call eq, $$(INITRAMFS), $$@),,$$(shell dirname $$@)/)
	mkdir $@

$(INITRAMFS_BINS): %: $$(notdir $$@) | $$(shell dirname $$@)/
	install -m755 $< $@

initramfs.cpio: $(INITRAMFS_DIRS) $(INITRAMFS_BINS)
	cd $(INITRAMFS) && \
	echo -e "$(subst $(SPACE),\n,$(^:$(INITRAMFS)%=./%))" | cpio -v -H newc -o > $(abspath $@)

%.gz: %
	gzip - < $< > $@

clean:
	-$(MAKE) -C $(KERNELDIR) M=$(PWD) clean
	-rm malloc
	-rm -r initramfs.cpio initramfs.cpio.gz $(INITRAMFS) 

distclean: clean
	-rm busybox

endif