#!/bin/sh

set -u

CMD=$(basename ${0})

. gettext.sh
TEXTDOMAIN="tails"
export TEXTDOMAIN

TORDATE_DIR=/var/run/tordate
TORDATE_DONE_FILE="${TORDATE_DIR}/done"
INOTIFY_TIMEOUT=60
MIN_REAL_MEMFREE=$((300 * 1024))
RUN_AS_USER=tails-upgrade-frontend

### Functions

error () {
    local cli_text="${CMD}: `gettext \"error:\"` ${@}"
    local dialog_text="<b><big>`gettext \"Error\"`</big></b>

${@}"
    echo "${cli_text}" >&2
    zenity --error --title "" --text "${dialog_text}"
    exit 1
}

check_free_memory () {
   local min_real_memfree memfree buffers cached real_memfree
   local errormsg

   min_real_memfree="$1"

   memfree=$(awk '/^MemFree:/{print $2}' /proc/meminfo)
   buffers=$(awk '/^Buffers:/{print $2}' /proc/meminfo)
   cached=$(awk '/^Cached:/{print $2}' /proc/meminfo)
   tmpfs=$(df --type=tmpfs --local --output=used --total | tail -n1)
   real_memfree=$(($memfree + $buffers + $cached - $tmpfs))

   errormsg="`gettext \"<b>Not enough memory available to check for upgrades.</b>

Make sure this system satisfies the requirements for running Tails.
See file:///usr/share/doc/tails/website/doc/about/requirements.en.html

Try to restart Tails to check for upgrades again.

Or do a manual upgrade.
See https://tails.boum.org/doc/first_steps/upgrade#manual\"`"

   if [ "$real_memfree" -lt "$MIN_REAL_MEMFREE" ] ; then
      echo "Only $real_memfree MemFree + Buffers + Cached - usage of tmpfs, while $MIN_REAL_MEMFREE is needed." >&2
      error "$errormsg"
   fi
}

### Main

sleep 30

check_free_memory "$MIN_REAL_MEMFREE"

# Go to a place where everyone, especially Archive::Tar::Wrapper called by
# tails-install-iuk, can chdir back after it has chdir'd elsewhere to do
# its job.
cd /

xhost +SI:localuser:"$RUN_AS_USER"
sudo -u "$RUN_AS_USER" /usr/bin/tails-upgrade-frontend $@
xhost -SI:localuser:"$RUN_AS_USER"