#!/usr/bin/env bash

function usage() {
   echo 
   [ -n  "$1" ] && echo -e "Error: $1\n"

cat<<EOF

   Usage: ` basename $0` < -a | -A |-p <program name to filter output> >


   Shows swap-usage either for all programs (-a/-A) or filtered for 
   a given program name (-p program_name).
   

   Options:

      -A
         Show swap-usage for all running processes, even if no swap
         is in use. Not realy useul, but gives a short overview about
         running processes.
      -a
         Show swap-usage for all running processes that have swap space allocated.

      -p <programm_name>
         Show swap-usage for all processes of the given program name.

      `basename $0` -p amavisd

EOF
exit 1
}

[ $# -eq "0" ] && usage "wrong number of arguments"

all=false
while getopts Aahp: opt ; do
   case $opt in
      A) all=true ;;
      a) ;;
      h) usage ;;
      p) filter_prog_name=$OPTARG ;;
      \?) usage
   esac
done

shift `expr $OPTIND - 1`
[ $# -eq "0" ] || usage "wrong number of arguments"

         

declare -i total_prog=0
declare -i total=0

for _dir in `find /proc/ -maxdepth 1 -type d | egrep "^/proc/[0-9]"` ; do
   #_pid=`basename $_dir`
   _pid=`echo $_dir | cut -d "/" -f 3`
   _prog_name=`ps -p $_pid -o comm --no-headers`
   if [ -n "$filter_prog_name" ]; then
      [ "$_prog_name" != "$filter_prog_name" ] && continue
   fi
   for _mem in `grep Swap $_dir/smaps 2>/dev/null| awk '{print$2}'` ; do
      [ $_mem -eq 0 ] && ! $all ] &&  continue 
      let total_prog=$total_prog+$_mem
      let tmp=$tmp+$_pid
   done

   [ $total_prog -eq 0 ] &&  ! $all  && continue
   echo "PID = $_pid - Swap used: $total_prog kb - ( $_prog_name )"
   let total=$total+$total_prog
   total_prog=0

done

if [ $total -eq 0 ]; then
   if [ -z $filter_prog_name ] ; then
      echo -e "\n\tNo swap space alocated.\n"
   else
      echo -e "\n\tNo swap space alocated by \"$filter_prog_name\" processes.\n"
   fi
else
   if [ -z $filter_prog_name ] ; then
      echo -e "\n\tTotal allocated swap space: $total kb\n"
   else
      echo -e "\n\tAllocated swap space by \"$filter_prog_name\" processes: $total kb\n"
   fi
fi

exit 0