#!/bin/bash

export LANG=en_US

print_help() {
    echo "usage: oomguard [options] [command]" && echo && \
    echo "options: -l <limit>  set limit (relative)" && \
    echo "         -s <signal> set kill signal" && \
    echo "         -i <time>   set check time interval [s]" && \
    echo "         -h          display this help and exit" && echo
}

LIMIT=0.9
SIGNAL=15
INTERVAL=1
while getopts l:s:i:h OPT
do
  case $OPT in
  l) LIMIT=$OPTARG ;;
  s) SIGNAL=$OPTARG ;;
  i) INTERVAL=$OPTARG ;;
  h) print_help && exit 0 ;;
  \?) print_help && exit 1
  esac
done

COMMAND="${@:$#:$#}"

echo "oomguard: setting memory limit $LIMIT"
echo "oomguard: check time interval $INTERVAL s"
echo "oomguard: executing command '$COMMAND'"

$COMMAND &
PROC=$!

echo "oomguard: process started as pid $PROC"
trap "kill -s "$SIGNAL" "$PROC SIGHUP SIGINT SIGTERM

free -os1 | awk '{ \
  if ($1=="Mem:") { \
    if ($4/$2>'$LIMIT') { \
      system("kill -s '$SIGNAL' '$PROC'"); \
      exit(1); \
    } \
    if (system("test -d /proc/'$PROC'")) exit(0); \
  } \
}'