#!/bin/bash
# time-and-mem-limit
# Ralph Becket <rafe@csse.unimelb.edu.au>
# Tue Feb 10 12:21:58 EST 2009
#
# usage: time-and-mem-limit N M cmd ...
#
# Kill cmd ... if it does not terminate after N seconds of wallclock time or if
# it uses more than M megabytes of memory.  Either "EXCEEDED TIME LIMIT" or
# "EXCEEDED MEMORY LIMIT" is printed on stderr as appropriate if cmd ... is
# killed for one of these reasons.

USAGE="usage: time-and-mem-limit num-seconds num-megabytes cmd ..."

if [ "$*" = "-h" -o "$*" = "--help" ]
then
	echo $USAGE >&2
	exit 0
fi

if [ $# -lt 3 ]
then
	echo $USAGE >&2
	exit 1
fi

# CMDPID: we exec the command so it gets the current PID.
CMDPID=$$
# TIMELIMIT: the time limit in seconds.
TIMELIMIT=$1
# MEMLIMIT: the memory limit in megabytes.
MEMLIMITMB=$2
MEMLIMITKB=$(($MEMLIMITMB << 10))
shift 2
# CMD: anything else on the command line is the command to be executed.
CMD=$@

declare TimeoutOrig=$(ulimit -t)
declare MemoryOrig=$(ulimit -v)

# Using ulimit like this doesn't work on Cygwin.
#
if test ! -e /bin/cygpath.exe
then
    ulimit -S -t ${TIMELIMIT}
    ulimit -S -v ${MEMLIMITKB}
else   ### Only on Cygwin: Ubuntu 15 does not allow to delete output files and reports wrong exit result
  # Check the time and memory limits every ten seconds in a background
  # process.  If either limit is reached, kill the process.
  (
    for (( i=0 ; i<$TIMELIMIT ; i+=1 ))
    do
      # Sleep for 1 seconds.
      sleep 1
      # Obtain the process memory usage in kilobytes.
      # (We use this form of ps arguments for portability).
      CMDMEMUSAGEKB=`ps -p $CMDPID -o vsize=""`
      # Quit if the process has already terminated.
      if [ -z $CMDMEMUSAGEKB ]
      then
        exit 0
      fi
      # Kill the process if it has exceeded its memory limit.
      if [ $CMDMEMUSAGEKB -gt $MEMLIMITKB ]
      then
        kill -KILL $CMDPID >/dev/null 2>&1
        echo "" >&2
        echo "EXCEEDED MEMORY LIMIT OF $MEMLIMITMB Mbytes" >&2
        exit 1
      fi
    done
    # Kill the process if it has exceeded its time limit.
    if ps -p $CMDPID >/dev/null 2>&1
    then
      kill -KILL $CMDPID >/dev/null 2>&1
      echo "" >&2
      echo "EXCEEDED TIME LIMIT OF $TIMELIMIT s" >&2
      exit 1
    fi
  ) &

  # The background process above sometimes does not seem to fire or does not
  # kill all subprocesses.  "ulimit" is more reliable, but it is not clear how
  # to get useful, specific error messages.  Thus for now we use both methods.
fi

# Run the command.
exec $CMD

if test ! -e /bin/cygpath.exe
then
    ulimit -S -t ${TimeoutOrig}
    ulimit -S -v ${MemoryOrig}
fi