tinyramfs/files/init
2020-02-25 22:43:25 +03:00

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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 -- $(cat /proc/cmdline)
for line in "$@"; do
value="${line##*=}"
case "${line%%=*}" in
debug) debug="$value" ;;
init) init="$value" ;;
root) root="$value" ;;
root.type) root_type="$value" ;;
root.opts) root_opts="$value" ;;
lvm) lvm="$value" ;;
lvm.name) lvm_name="$value" ;;
lvm.group) lvm_group="$value" ;;
lvm.args) lvm_args="$value" ;;
luks) luks="$value" ;;
luks.root) luks_root="$value" ;;
luks.name) luks_name="$value" ;;
luks.discard) luks_discard="$value" ;;
luks.args) luks_args="$value" ;;
# TODO implement
#lvm.discard) ;;
#lvm.conf) ;;
#luks_header) ;;
#luks_keyfile) ;;
esac
done
}
mount_pseudofs() {
mount -t proc none /proc
mount -t sysfs none /sys
mount -t devtmpfs none /dev
}
setup_devmgr() {
case "$devmgr" in
udev)
udevd -d
udevadm trigger -c add -t subsystems
udevadm trigger -c add -t devices
udevadm settle
;;
mdev)
uevent mdev &
mdev -s
for device in /sys/bus/usb/devices/*; do
case "${device##*/}" in [0-9]*-[0-9]*)
printf add > "${device}/uevent" ;;
esac
done
find /sys -name modalias -type f -exec sort -u {} + |
xargs modprobe -b > /dev/null 2>&1
;;
mdevd)
mdevd &
mdevd-coldplug
;;
*)
panic "devmgr option broken"
;;
esac
}
findfs_sh() {
value="${1##*=}"
case "${1%%=*}" in
LABEL) device="/dev/disk/by-label/${value}" ;;
UUID) device="/dev/disk/by-uuid/${value}" ;;
PARTUUID) device="/dev/disk/by-partuuid/${value}" ;;
/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 $lvm_args --sysinit -q -a y "${lvm_group}/${lvm_name}" > /dev/null
elif [ "$lvm_group" ]; then
lvm vgchange $lvm_args --sysinit -q -a y "$lvm_group" > /dev/null
else
lvm vgchange $lvm_args --sysinit -q -a y > /dev/null
fi
}
mount_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
udev) udevadm control -e ;;
mdev) killall uevent ;;
mdevd) killall mdevd ;;
esac
# unmount pseudofs's
umount /dev /sys /proc
}
boot_system() {
exec switch_root /mnt/root ${init:-/sbin/init} ||
panic "failed to boot system"
}
/sbin/busybox --install -s
. /config ||
panic "failed to source config"
mount_pseudofs
parse_cmdline
[ "$debug" = 1 ] && set -x
setup_devmgr
# TODO handle situations when LUKS on LVM
[ "$luks" = 1 ] && command -v cryptsetup > /dev/null 2>&1 &&
unlock_luks
[ "$lvm" = 1 ] && command -v lvm > /dev/null 2>&1 &&
trigger_lvm
mount_rootfs
[ "$debug" = 1 ] &&
panic "dropping to shell"
cleanup
boot_system