#!/bin/sh

# SPDX-License-Identifier: GPL-2.0-or-later
# Copyright (C) 2009-2014 Stephan Raue (stephan@openelec.tv)

. /etc/swap.conf
. /etc/profile

if [ -f /storage/.config/swap.conf ]; then
  . /storage/.config/swap.conf
fi

if [ -f "$SWAPFILE" ]; then
  # Clean up existing swap file if it is smaller than desired or swap type is zram
  if [ $(ls -l "$SWAPFILE" | awk '{print  $5}') -lt $(($SWAPSIZE*1024*1024)) -o "$SWAP_TYPE" = "zram" ]; then
    [[ $(swapon | grep "$SWAPFILE") ]] && swapoff "$SWAPFILE"
    rm -rf "$SWAPFILE"
  fi
fi

if [ -e /dev/.storage_netboot ] ; then
  logger -t Boot "### netbooting... swap disabled ###"
  exit 0
fi

if [ ! "$SWAP_ENABLED" = yes ] ; then
  logger -t Boot "### swap disabled via configfile ###"
  exit 0
fi

SWAP=`blkid -t TYPE="swap" -o device`

case $1 in
  create)
    logger -t Boot "### creating swap type ${SWAP_TYPE} ###"

    if [ "$SWAP_TYPE" = "file" ]; then
      if [ -z "$SWAP" -a ! -f "$SWAPFILE" ]; then
        mkdir -p `dirname $SWAPFILE`
        dd if=/dev/zero of=$SWAPFILE bs=1M count=$SWAPSIZE
        chmod 0600 $SWAPFILE
        mkswap $SWAPFILE
      fi
    elif [ "$SWAP_TYPE" = "zram" ]; then
      # Load zram module
      modprobe zram

      # Set up zram device of desired size
      zramctl --find --size ${SWAPSIZE}M --algorith zstd
    fi
    ;;
  mount)
    logger -t Boot "### mounting swap type ${SWAP_TYPE} ###"

    if [ "$SWAP_TYPE" = "file" ]; then
      [ -z "$SWAP" -a -f "$SWAPFILE" ] && SWAP=$SWAPFILE
      for i in $SWAP; do
        swapon -p 10000 $i
      done
    elif [ "$SWAP_TYPE" = "zram" ]; then
      ZRAM_DEV=$(zramctl -o NAME | grep zram)

      if [ ! -z "$ZRAM_DEV" ]; then
        mkswap ${ZRAM_DEV}
        swapon ${ZRAM_DEV}
      fi
    fi
    ;;
  unmount)
    swapoff -a
    ;;
esac