#!/usr/bin/env bash

get_devtype() {
  local typ
  typ=$(udevadm info --query=property --name="$1" | grep "^ID_FS_TYPE=" | sed 's|^ID_FS_TYPE=||')
  if [ "$typ" = "" ] ; then
     typ=$(blkid -c /dev/null "$1" -o value -s TYPE)
  fi
  echo "$typ"
}

get_pool_devices() {
  # also present in 99zfssystemd
  local poolconfigtemp
  local poolconfigoutput
  local pooldev
  local prefix
  local resolved
  poolconfigtemp=`mktemp`
  @sbindir@/zpool list -v -H -P "$1" > "$poolconfigtemp" 2>&1
  if [ "$?" != "0" ] ; then
    poolconfigoutput=$(cat "$poolconfigtemp")
    dinfo "zfsexpandknowledge: pool $1 cannot be listed: $poolconfigoutput"
  else
    cat "$poolconfigtemp" |  awk -F '\t' '/\t\/dev/ { print $2 }' | \
    while read pooldev ; do
        if [ -n "$pooldev" -a -e "$pooldev" ] ; then
          if [ -h "$pooldev" ] ; then
              resolved=`readlink -f "$pooldev"`
          else
              resolved="$pooldev"
          fi
          dinfo "zfsexpandknowledge: pool $1 has device $pooldev (which resolves to $resolved)"
          echo "$resolved"
        fi
    done
  fi
  rm -f "$poolconfigtemp"
}

find_zfs_block_devices() {
    local dev
    local blockdev
    local mp
    local fstype
    local pool
    local key
    local n
    local poolconfigoutput
    numfields=`head -1 /proc/self/mountinfo | awk '{print NF}'`
    if [ "$numfields" == "10" ] ; then
        fields="n n n n mp n n fstype dev n"
    else
        fields="n n n n mp n n n fstype dev n"
    fi
    while read $fields ; do
       if [ "$fstype" != "zfs" ]; then continue ; fi
       if [ "$mp" == "$1" ]; then
           pool=$(echo "$dev" | cut -d / -f 1)
           get_pool_devices "$pool"
       fi
    done < /proc/self/mountinfo
}

array_contains () {
  local e
  for e in "${@:2}"; do [[ "$e" == "$1" ]] && return 0; done
  return 1
}

check() {
    local mp
    local dev
    local blockdevs
    local fstype
    local majmin
    local _slavedev
    local _slavedevname
    local _slavedevtype
    local _slavemajmin
    local _dev

if [[ $hostonly ]]; then

    for mp in \
        "/" \
        "/etc" \
        "/bin" \
        "/sbin" \
        "/lib" \
        "/lib64" \
        "/usr" \
        "/usr/bin" \
        "/usr/sbin" \
        "/usr/lib" \
        "/usr/lib64" \
        "/boot";
    do
        mp=$(readlink -f "$mp")
        mountpoint "$mp" >/dev/null 2>&1 || continue
        blockdevs=$(find_zfs_block_devices "$mp")
        if [ -z "$blockdevs" ] ; then continue ; fi
        dinfo "zfsexpandknowledge: block devices backing ZFS dataset $mp: $blockdevs"
        for dev in $blockdevs
        do
            array_contains "$dev" "${host_devs[@]}" || host_devs+=("$dev")
            fstype=$(get_devtype "$dev")
            host_fs_types["$dev"]="$fstype"
            majmin=$(get_maj_min "$dev")
            if [[ -d /sys/dev/block/$majmin/slaves ]] ; then
                for _slavedev in /sys/dev/block/$majmin/slaves/*; do
                    [[ -f $_slavedev/dev ]] || continue
                    _slavedev=/dev/$(basename "$_slavedev")
                    _slavedevname=$(udevadm info --query=property --name="$_slavedev" | grep "^DEVNAME=" | sed 's|^DEVNAME=||')
                    _slavedevtype=$(get_devtype "$_slavedevname")
                    _slavemajmin=$(get_maj_min "$_slavedevname")
                    dinfo "zfsexpandknowledge: slave block device backing ZFS dataset $mp: $_slavedevname"
                    array_contains "$_slavedevname" "${host_devs[@]}" || host_devs+=("$_slavedevname")
                    host_fs_types["$_slavedevname"]="$_slavedevtype"
                done
            fi
        done
    done
    for a in "${host_devs[@]}"
        do
        dinfo "zfsexpandknowledge: host device $a"
    done
    for a in "${!host_fs_types[@]}"
        do
        dinfo "zfsexpandknowledge: device $a of type ${host_fs_types[$a]}"
    done

fi

return 1
}