did lots of work

Makefile

@@ -3,7 +3,7 @@ KERNEL_URL=https://cdn.kernel.org/pub/linux/kernel/v4.x/linux-$(KERNEL_VERSION).
 BUSYBOX_VERSION=1.24.2
 BUSYBOX_URL=https://www.busybox.net/downloads/busybox-$(BUSYBOX_VERSION).tar.bz2
 
-all: bzImage
+all: fs.tar
 
 linux-$(KERNEL_VERSION).tar.xz:
 	wget $(KERNEL_URL)
@@ -33,3 +33,5 @@ fs.tar: bzImage busybox
 
 mdos.img: fs.tar gen_image.sh
 	./gen_image.sh
+
+.PHONY: fs.tar

filesystem/Makefile

@@ -1,4 +1,4 @@
-FS_FILES=build.sh crypttab filesystem.install fstab group gshadow host.conf hosts inittab issue ld.so.conf locale.sh modprobe.d.usb-load-ehci-first motd nsswitch.conf os-release passwd profile rcS resolv.conf securetty shadow shells
+FS_FILES=build.sh crypttab filesystem.install fstab group gshadow host.conf hosts inittab issue ld.so.conf locale.sh modprobe.d.usb-load-ehci-first motd nsswitch.conf os-release passwd profile systemctl resolv.conf securetty shadow shells
 
-all: build.sh $(FS_FILES)
+../fs.tar: build.sh $(FS_FILES)
 	fakeroot ./build.sh

filesystem/build.sh

@@ -89,6 +89,6 @@ busybox --install -s usr/bin
 
 install -m644 "$srcdir/inittab" etc/inittab
 install -d -m755 etc/init.d
-install -m755 "$srcdir/rcS" etc/init.d/rcS
+install -m755 "$srcdir/systemctl" sbin/systemctl
 
 tar --xattrs -cpf ../../fs.tar *

filesystem/inittab

@@ -1,3 +1,4 @@
-::sysinit:/etc/init.d/rcS
-::respawn:-/bin/sh
+::sysinit:/sbin/systemctl init
+::askfirst:-/bin/sh
 ::ctrlaltdel:/bin/umount -a -r
+::shutdown:/usr/bin/umount -a -r

filesystem/passwd

@@ -1,4 +1,4 @@
-root:x:0:0:root:/root:/bin/bash
+root:x:0:0:root:/root:/bin/sh
 bin:x:1:1:bin:/bin:/usr/bin/nologin
 daemon:x:2:2:daemon:/:/usr/bin/nologin
 mail:x:8:12:mail:/var/spool/mail:/usr/bin/nologin
@@ -7,8 +7,3 @@ http:x:33:33:http:/srv/http:/usr/bin/nologin
 uuidd:x:68:68:uuidd:/:/usr/bin/nologin
 dbus:x:81:81:dbus:/:/usr/bin/nologin
 nobody:x:99:99:nobody:/:/usr/bin/nologin
-systemd-journal-gateway:x:191:191:systemd-journal-gateway:/:/usr/bin/nologin
-systemd-timesync:x:192:192:systemd-timesync:/:/usr/bin/nologin
-systemd-network:x:193:193:systemd-network:/:/usr/bin/nologin
-systemd-bus-proxy:x:194:194:systemd-bus-proxy:/:/usr/bin/nologin
-systemd-resolve:x:195:195:systemd-resolve:/:/usr/bin/nologin

filesystem/rcS

@@ -1,2 +0,0 @@
-#!/bin/sh
-/usr/bin/mount -a

filesystem/systemctl

@@ -0,0 +1,27 @@
+#!/bin/sh
+
+init() {
+  # TODO options
+  /usr/bin/mount -t proc proc /proc
+  /usr/bin/mount -t sysfs sys /sys
+  /usr/bin/mount -t devtmpfs dev /dev
+  mkdir -p /dev/pts /dev/shm # TODO check if in filesystem
+  /usr/bin/mount -t devpts devpts /dev/pts
+  /usr/bin/mount -t tmpfs tmpfs /dev/shm
+
+  if [[ -f /etc/hostname ]]; then
+    echo "$(cat /etc/hostname)" > /proc/sys/kernel/hostname
+  fi
+
+  /sbin/mdev -s
+  echo /sbin/mdev > /proc/sys/kernel/hotplug
+
+  /usr/bin/mount -a
+  /usr/bin/mount -o remount,rw /
+}
+
+case $1 in
+  init)
+    init
+    ;;
+esac

gen_image.sh

@@ -5,10 +5,12 @@ if [[ $(id -u) -ne 0 ]]; then
   exit 1
 fi
 
-rm -f mdos.img
-fallocate -l 100M mdos.img
-echo -e "o\nn\n\n\n\n\nw\n" | fdisk mdos.img
-loopdevice="$(losetup -P --show -f mdos.img)"
+image=mdos.img
+
+rm -f $image
+fallocate -l 100M $image
+echo -e "o\nn\n\n\n\n\nw\n" | fdisk $image
+loopdevice="$(losetup -P --show -f $image)"
 looppart=${loopdevice}p1
 mkfs.ext4 $looppart
 
@@ -16,9 +18,18 @@ mkdir -p mountdir
 mount $looppart mountdir
 cd mountdir
 tar --xattrs -xpf ../fs.tar
-grub-install --target=i386-pc --boot-directory="$PWD/boot/grub" $loopdevice
+grub-install --target=i386-pc --boot-directory="$PWD/boot" $loopdevice
 cd ..
+
+## generate grub.cfg (since linux 3.8 32-bit MBR "NT disk signatures" are allowed)
+uuid=$(fdisk -l $image | grep "Disk identifier" | cut -d " " -f 3 | cut --complement -c 1,2)-01
+echo -e "linux /boot/bzImage root=PARTUUID=$uuid\nboot" > "mountdir/boot/grub/grub.cfg"
+
 umount mountdir
 sync
 rm -rf mountdir
 losetup -d $loopdevice
+
+if [[ -n $SUDO_UID ]]; then
+  chown $SUDO_UID:$SUDO_GID $image
+fi