tinyramfs/init

#!/sbin/busybox sh

# debugging
set -x

# install busybox
/sbin/busybox --install -s

panic() { echo "bruh moment :(" && sh; }

# silence is golden
#echo 0 >/proc/sys/kernel/printk

# TODO parse /proc/cmdline

# check config
[ -f /config ] && . /config || panic

# mount pseudofs's
mount -t proc none /proc
mount -t sysfs none /sys
mount -t devtmpfs none /dev

# handle device managers
if [ "$use_mdevd" = 1 ]; then
    # setup mdevd
    mdevd &
    # trigger uevents
    mdevd-coldplug

    # TODO investigate this
    # avoid race condition
    sleep 1.5
elif [ "$use_mdev" = 1 ]; then
    # setup mdev
    if [ -e /proc/sys/kernel/hotplug ]; then
	echo /sbin/mdev >/proc/sys/kernel/hotplug
    else
	uevent mdev &
    fi

    # trigger mdev
    mdev -s

    # trigger uevent for usb devices
    for u in /sys/bus/usb/devices/*; do
	case ${u##*/} in
	    [0-9]*-[0-9]*)
	    echo add > "$u/uevent"
            ;;
        esac
    done

    # load drivers
    find /sys -name 'modalias' -type f -exec cat '{}' + | sort -u | xargs modprobe -ba
elif [ "$use_udev" = 1 ]; then
    # setup udev
    udevd --daemon
    udevadm trigger --action=add --type=subsystems
    udevadm trigger --action=add --type=devices
    udevadm settle
else
    panic
fi

# TODO handle situations when LUKS on LVM

# unlock cryptsetup container
[ "$use_luks" = 1 ] && {
    luks_root="$(findfs $luks_root)"
    # TODO improve mapper name ( crypttab or config option )
    cryptsetup $luks_args luksOpen "$luks_root" luks_root || panic
}

# manually trigger LVM if udev disabled
[ "$use_lvm" = 1 ] && [ "$use_udev" = 0 ] && {
    lvm vgchange --sysinit -a y
}

# merge mount flags
[ -n "$root_args" ] && mount_args="$root_args"
[ -n "$root_type" ] && mount_args="$mount_args -t $root_type"

# mount rootfs
mount $mount_args "$root" /mnt/root || panic

# clean up
[ "$use_mdevd" = 1 ] && killall mdevd
[ "$use_mdev" = 1 ] && { echo "" >/proc/sys/kernel/hotplug || killall uevent; }
[ "$use_udev" = 1 ] && udevadm control --exit
umount /dev /sys /proc

# boot system
echo SUCCESS
exec switch_root /mnt/root /sbin/init