#!/bin/bash

print_help() {
    echo "Usage: $0 -h <host> -s <shares>"
    echo "Checks if the specified NFS shares are exported on the given host."
    echo ""
    echo "-h    The IP address or hostname of the NFS server."
    echo "-s    A comma-separated list of NFS shares to check. For example: '/mnt/test,/mnt/export'"
    echo ""
    echo "You can list the exported shares on an NFS server using the command 'showmount -e <host>'"
    echo "This script assumes that 'showmount' is installed on the system where it is run."
    exit 1
}

if ! command -v showmount &> /dev/null; then
    echo "UNKNOWN - 'showmount' is not installed. Try installing 'nfs-common'"
    exit 3
fi

if [ "$#" -ne 4 ] || [ "$1" == "--help" ]; then
    print_help
fi

while getopts "h:s:" opt; do
  case ${opt} in
    h )
      host=$OPTARG
      ;;
    s )
      shares=$OPTARG
      ;;
    \? )
      print_help
      ;;
  esac
done

share_count=0
all_ok=true

IFS=',' read -r -a share_array <<< "$shares"

for share in "${share_array[@]}"; do
    output=$(showmount -e $host | grep $share)
    if [[ $output != *"$share"* ]]; then
        echo "CRITICAL - $share is not exported on $host"
        exit 2
    fi
    share_count=$((share_count+1))
done

if $all_ok; then
    echo "OK - All $share_count shares are exported on $host | share_count=$share_count"
fi

exit 0