#!/bin/sh
#
# Track changes to enumerated pools for use in early-boot
set -ef

FSLIST_DIR="@sysconfdir@/zfs/zfs-list.cache"
FSLIST_TMP="@runstatedir@/zfs-list.cache.new"
FSLIST="${FSLIST_DIR}/${ZEVENT_POOL}"

# If the pool specific cache file is not writeable, abort
[ -w "${FSLIST}" ] || exit 0

[ -f "${ZED_ZEDLET_DIR}/zed.rc" ] && . "${ZED_ZEDLET_DIR}/zed.rc"
. "${ZED_ZEDLET_DIR}/zed-functions.sh"

zed_exit_if_ignoring_this_event
zed_check_cmd "${ZFS}" sort diff grep

# If we are acting on a snapshot, we have nothing to do
printf '%s' "${ZEVENT_HISTORY_DSNAME}" | grep '@' && exit 0

# We obtain a lock on zfs-list to avoid any simultaneous writes.
# If we run into trouble, log and drop the lock
abort_alter() {
  zed_log_msg "Error updating zfs-list.cache!"
  zed_unlock zfs-list
}

finished() {
  zed_unlock zfs-list
  trap - EXIT
  exit 0
}

case "${ZEVENT_HISTORY_INTERNAL_NAME}" in
    create|"finish receiving"|import|destroy|rename)
      ;;

    export)
        zed_lock zfs-list
        trap abort_alter EXIT
        echo > "${FSLIST}"
        finished
      ;;

    set|inherit)
        # Only act if the mountpoint or canmount setting is altered.
        case "${ZEVENT_HISTORY_INTERNAL_STR}" in
            canmount=*|mountpoint=*) ;;
            *) exit 0 ;;
        esac
      ;;

    *)
        # Ignore all other events.
        exit 0
      ;;
esac

zed_lock zfs-list
trap abort_alter EXIT

"${ZFS}" list -H -tfilesystem -oname,mountpoint,canmount -r "${ZEVENT_POOL}" \
    >"${FSLIST_TMP}"

# Sort the output so that it is stable
sort "${FSLIST_TMP}" -o "${FSLIST_TMP}"

# Don't modify the file if it hasn't changed
diff -q "${FSLIST_TMP}" "${FSLIST}" || mv "${FSLIST_TMP}" "${FSLIST}"
rm -f "${FSLIST_TMP}"

finished