#!/bin/bash
# name:         chkvac
# description:  utility in the manner of chkconfig for control of vacation.
# author:       G.R.Keech <richard.keech@gmail.com>
# Copyright (c) G.R.Keech 2003
# License: GPLv2
#--------------------------------------------------------------------------
# Test whether a user account exists.
userexists () {
    grep "^${1}:" /etc/passwd &> /dev/null
    return $?
}
#-------------------------------------------------------------------------
# Check is user has an interactive shell
userhasshell () {
	shell=$(grep $1 /etc/passwd | cut -d: -f 7)
	case $shell in
		"/bin/bash") return 0;;
		"/bin/rbash") return 0;;
		*) return 1 ;;
	esac
}
#-------------------------------------------------------------------------
# Fails if not running as root
testroot () {
    if [ "_${LOGNAME}" = "_" ]
	then
	LOGNAME=$(whoami)
    fi

    if [ "$LOGNAME" != "root" ]
    then
        return 1
    fi
}
#-------------------------------------------------------------------------
# Start of main block
ALIASES=/etc/aliases
VACATION=/usr/bin/vacation
PROG=$(basename $0)


if [ ! -x "$VACATION" -o ! -s "$VACATION" ]
then
  echo There appears to be no vacation executable
  exit 1
fi

if [ ! -f "$ALIASES" -o ! -s "$ALIASES" ]
then
  echo aliases file $ALIASES does not exist or is empty
  exit 1
fi

if [ $# -eq 0 -o $# -gt 2 ]
then
  echo "usage: $PROG user [on|off]"
  exit 1
fi

user=$1

if [ "$user" = "root" ]
then
  echo "It is not appropriate to set vacation for root."
  exit 1
fi

if [ $# -eq 2 ]
then
  operation=$2
  if [ "$operation" != "on" -a "$operation" != "off" ]
  then
  echo "usage: $PROG user [on|off]"
  exit 1
  fi
else
  operation=list
fi

if ! userexists "$user"
then
  echo user $user does not exist
  exit 1
fi
if ! userhasshell "$user"
then
  echo user $user does not have a shell
  exit 1
fi
FWD=/home/${user}/.forward
VACDB=/home/${user}/.vacation.db
# -------------------------------------------------------------
# If we've got this far then everything seems to be in order
# so lets actually do someting.

case "$operation" in

    "on")
	echo "\\${user}, \"|/usr/bin/vacation ${user}\"" > $FWD
	chmod 600 $FWD
	if testroot
	then
	  chown ${user}.${user} $FWD
	fi
	$VACATION -I ${user}
	chown ${user}.${user} $VACDB
	if [ ! -s /home/${user}/.vacation.msg ]
	then
	  cat > /home/${user}/.vacation.msg <<EOF
Subject: away from my mail

I will not be reading my mail for a while.
Your mail concerning "\$SUBJECT"
will be read when I'm back.
EOF
	  chown ${user}.${user} /home/${user}/.vacation.msg
	  echo default vacation message created
        fi
	;;

    "off")
	rm -f $VACDB &> /dev/null
	rm -f $FWD &> /dev/null
	;;

    "list")
	if [ -s $FWD -a -s $VACDB ]
	then
	  echo on
	else
	  if [ -s $FWD ]
	  then
	    echo forward file exists but no vacation database file
	  else
	    echo off
	  fi
	fi
	;;

    *)
	echo bogus operation
	exit 1
	;;
esac