tinyramfs/init
2020-02-05 21:03:23 +03:00

139 lines
2.9 KiB
Plaintext

#!/sbin/busybox sh
#
# tiny init script
panic() {
printf "panic >> %s\n" "$@" && sh
}
# parse_cmdline() {
# TODO parse /proc/cmdline
#}
# mount pseudofs's
mnt_pseudofs() {
mount -t proc none /proc
mount -t sysfs none /sys
mount -t devtmpfs none /dev
}
# setup mdev
use_mdev() {
# setup hotplugger
if [ -e /proc/sys/kernel/hotplug ]; then
printf /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 ${u##*/} in
[0-9]*-[0-9]*)
printf add > "${u}/uevent"
;;
esac
done
# load drivers
find /sys -name "modalias" -type f -exec sort -u "{}" "+" | xargs modprobe -ba
}
# setup mdevd
use_mdevd() {
# setup daemon
mdevd &
# trigger uevents
mdevd-coldplug
# TODO investigate this
# avoid race condition
sleep 1.5
}
# setup udev
use_udev() {
udevd --daemon
udevadm trigger --action=add --type=subsystems
udevadm trigger --action=add --type=devices
udevadm settle
}
# unlock LUKS container
unlock_luks() {
# TODO implement POSIX findfs
# find device of luks root
luks_root="$(findfs $luks_root)"
# TODO improve mapper name ( crypttab or config option )
# unlock luks container
cryptsetup $luks_args luksOpen "$luks_root" luks_root || panic "failed to unlock luks container"
}
# manually trigger LVM if udev disabled
trigger_lvm() {
lvm vgchange --sysinit -a y
}
# mount rootfs to /mnt/root
mnt_rootfs() {
# 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 "failed to mount rootfs"
}
# kill and unmount
cleanup() {
# stop mdev
[ "$devmgr" = "mdev" ] && { printf "" >/proc/sys/kernel/hotplug || killall uevent; } >/dev/null 2>&1
# stop mdevd
[ "$devmgr" = "mdevd" ] && killall mdevd
# stop udev
[ "$devmgr" = "udev" ] && udevadm control --exit
# if debug mode off then restore kernel logging
[ "$debug" = 0 ] && printf 1 >/proc/sys/kernel/printk
umount /dev /sys /proc
}
# exec /mnt/root/sbin/init
boot_system() {
exec switch_root /mnt/root /sbin/init || panic "failed to boot system"
}
# install busybox
/sbin/busybox --install -s
# source config
. /config || panic "config doesn't exists"
if [ "$debug" = 1 ]; then
# debug shell commands
set -x
else
# silence is golden
printf 0 >/proc/sys/kernel/printk
fi
#parse_cmdline
mnt_pseudofs
case "$devmgr" in
mdev) use_mdev ;;
mdevd) use_mdevd ;;
udev) use_udev ;;
*) panic "devmgr option broken" ;;
esac
# TODO handle situations when LUKS on LVM
[ "$use_luks" = 1 ] && unlock_luks
[ "$use_lvm" = 1 ] && [ "$devmgr" != "udev" ] && trigger_lvm
mnt_rootfs
cleanup
boot_system