tinyramfs/init
2020-02-22 20:46:57 +03:00

163 lines
4.2 KiB
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#!/sbin/busybox sh
#
# tiny init script
panic() {
printf "panic >> %s\n" "$1"
# TODO fix job control
sh -l
}
parse_cmdline() {
# turn output into list
set -- $(cat /proc/cmdline)
# parse line by line
for line in "$@"; do
# parse options
case "${line%%=*}" in
debug) debug="${line##*=}" ;;
init) init="${line##*=}" ;;
root) root="${line##*=}" ;;
root.type) root_type="${line##*=}" ;;
root.opts) root_opts="${line##*=}" ;;
lvm) lvm="${line##*=}" ;;
lvm.name) lvm_name="${line##*=}" ;;
lvm.group) lvm_group="${line##*=}" ;;
lvm.args) lvm_args="${line##*=}" ;;
luks) luks="${line##*=}" ;;
luks.root) luks_root="${line##*=}" ;;
luks.name) luks_name="${line##*=}" ;;
luks.discard) luks_discard="${line##*=}" ;;
luks.args) luks_args="${line##*=}" ;;
# TODO implement
#lvm.discard) ;;
#lvm.conf) ;;
#luks_header) ;;
#luks_keyfile) ;;
esac
done
}
mnt_pseudofs() {
mount -t proc none /proc
mount -t sysfs none /sys
mount -t devtmpfs none /dev
mount -t tmpfs none /tmp
}
setup_mdev() {
# setup hotplugger
if [ -e /proc/sys/kernel/hotplug ]; then
printf /sbin/mdev > /proc/sys/kernel/hotplug
else
uevent mdev &
fi
# trigger mdev
mdev -s
# trigger uevent for usb devices
for device in /sys/bus/usb/devices/*; do
case "${device##*/}" in
[0-9]*-[0-9]*) printf add > "${device}/uevent" ;;
esac
done
# load drivers
find /sys -name modalias -type f -exec sort -u "{}" "+" | xargs modprobe -qba
}
setup_mdevd() {
# setup daemon
mdevd &
# trigger uevents
mdevd-coldplug
}
setup_udev() {
udevd --daemon
udevadm trigger --action=add --type=subsystems
udevadm trigger --action=add --type=devices
udevadm settle
}
findfs_sh() {
case "${1%%=*}" in
LABEL) device="/dev/disk/by-label/${1##*=}" ;;
UUID) device="/dev/disk/by-uuid/${1##*=}" ;;
PARTUUID) device="/dev/disk/by-partuuid/${1##*=}" ;;
/dev/*) device="$1" ;;
*) panic "findfs option broken" ;;
esac
# avoid race condition
while [ ! -e "$device" ]; do
sleep 0.5
[ "$increment" ] || increment=0
increment=$(( increment + 1 ))
[ "$increment" = 10 ] && panic "failed to lookup partition"
done
printf "%s\n" "$device"
}
unlock_luks() {
[ "$luks_discard" = 1 ] && luks_args="--allow-discards $luks_args"
cryptsetup $luks_args luksOpen $(findfs_sh "$luks_root") ${luks_name:-luks_root} || panic "failed to unlock luks container"
}
trigger_lvm() {
if [ "$lvm_group" ] && [ "$lvm_name" ]; then
lvm lvchange $lvm_args --quiet --sysinit -a y "${lvm_group}/${lvm_name}" > /dev/null
elif [ "$lvm_group" ]; then
lvm vgchange $lvm_args --quiet --sysinit -a y "$lvm_group" > /dev/null
else
lvm vgchange $lvm_args --quiet --sysinit -a y > /dev/null
fi
}
mnt_rootfs() {
mount ${root_type:+-t $root_type} ${root_opts:+-o $root_opts} $(findfs_sh "$root") /mnt/root || panic "failed to mount rootfs"
}
cleanup() {
case "$devmgr" in
mdev) { printf "" > /proc/sys/kernel/hotplug || killall uevent; } > /dev/null 2>&1 ;;
mdevd) killall mdevd ;;
udev) udevadm control --exit ;;
esac
# unmount pseudofs's
umount /dev /sys /proc /tmp
}
boot_system() {
exec switch_root /mnt/root ${init:-/sbin/init} || panic "failed to boot system"
}
/sbin/busybox --install -s
. /config || panic "failed to source config"
mnt_pseudofs
parse_cmdline
# debug mode
[ "$debug" = 1 ] && set -x
case "$devmgr" in
mdev) setup_mdev ;;
mdevd) setup_mdevd ;;
udev) setup_udev ;;
*) panic "devmgr option broken" ;;
esac
# TODO handle situations when LUKS on LVM
[ "$luks" = 1 ] && [ -x "$(command -v cryptsetup)" ] && unlock_luks
[ "$lvm" = 1 ] && [ -x "$(command -v lvm)" ] && trigger_lvm
mnt_rootfs
[ "$debug" = 1 ] && panic "dropping to shell"
cleanup
boot_system