#!/bin/sh

set -u

PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin

MOUNTPOINT="${F3S_KEYS_MOUNTPOINT:-/keys}"
LABEL="${F3S_KEYS_LABEL:-F3S_KEYS}"
DEVICES="${F3S_KEYS_DEVICES:-/dev/ufs/${LABEL} /dev/da0}"
WAIT_SECONDS="${F3S_KEYS_WAIT_SECONDS:-10}"
MOUNT_OPTIONS="${F3S_KEYS_MOUNT_OPTIONS:-ro}"
LOGTAG="f3s-mount-keys"
STRICT="NO"

if [ "${1:-}" = "--strict" ]; then
    STRICT="YES"
fi

log()
{
    logger -t "$LOGTAG" "$*"
    echo "$LOGTAG: $*"
}

fail()
{
    log "$*"
    if [ "$STRICT" = "YES" ]; then
        exit 1
    fi
    exit 0
}

is_mounted()
{
    mount | grep -Eq " on ${MOUNTPOINT} \\("
}

find_device()
{
    for dev in $DEVICES; do
        if [ -e "$dev" ]; then
            echo "$dev"
            return 0
        fi
    done
    return 1
}

validate_keys()
{
    missing="$(
        zfs get -H -t filesystem,volume -s local -o value,name keylocation 2>/dev/null |
        while IFS="$(printf '\t')" read -r keylocation dataset; do
            case "$keylocation" in
                file://"$MOUNTPOINT"/*)
                    keyfile="${keylocation#file://}"
                    if [ ! -s "$keyfile" ] || [ ! -r "$keyfile" ]; then
                        echo "${dataset}:${keyfile}"
                    fi
                    ;;
            esac
        done
    )"

    if [ -n "$missing" ]; then
        echo "$missing" | while IFS=: read -r dataset keyfile; do
            log "key file for ${dataset} is missing or unreadable: ${keyfile}"
        done
        return 1
    fi

    return 0
}

if is_mounted; then
    log "$MOUNTPOINT is already mounted"
    validate_keys || true
    exit 0
fi

mkdir -p "$MOUNTPOINT" || fail "could not create $MOUNTPOINT"
chmod 700 "$MOUNTPOINT" 2>/dev/null || true

i=0
dev=""
while [ "$i" -le "$WAIT_SECONDS" ]; do
    if dev="$(find_device)"; then
        break
    fi
    sleep 1
    i=$((i + 1))
done

if [ -z "$dev" ]; then
    fail "no USB key device found; checked: $DEVICES"
fi

if ! fsck_ufs -p "$dev"; then
    fail "fsck_ufs failed for $dev; leaving $MOUNTPOINT unmounted"
fi

if ! mount -t ufs -o "$MOUNT_OPTIONS" "$dev" "$MOUNTPOINT"; then
    fail "could not mount $dev on $MOUNTPOINT"
fi

log "mounted $dev on $MOUNTPOINT with options $MOUNT_OPTIONS"
validate_keys || true

exit 0