#!/bin/bash
# Name: sw_reboot-check.sh
# Description: Check running kernel vs newest installed to see if the system needs a reboot.
# Last Modified: 2016-10-07
# Recent Changes:-header format
#                -Minor spelling correction and added comments
####################################################################################

##### Customize These Variables #####
# Spacecmd command and any default arguments
spacecmd_cmd="spacecmd -q"

##### End of Customize Variables #####

#=====================================
# Functions; Main starts after
#=====================================
function show_usage
{
  echo -e "\n==== Reboot Check ===="
  echo -e "\nDescription: Check running kernel vs newest installed to see if the system needs a reboot."
  echo -e "\n--Usage--"
  echo -e "-h                    => Display usage."
  echo -e "-s system             => Check a single system's kernel."
  echo -e "-g system-group       => Check a system groups' kernel."
  echo -e "-a                    => Check all systems' kernel."
  echo -e "\n--Other Requirements--"
  echo -e "-> Spacecmd and config file setup required."
  echo -e "-> Run as a user with admin privileges on the Spacewalk server."
  echo -e
}

#=======================
# Get Script Arguments
#=======================
# Reset POSIX variable in case it has been used previously in this shell
OPTIND=1

## Default settings ##
# Do not assume we want to check all systems
all_systems="no"

## Get command line arguments ##
while getopts "hs:g:a" opt; do
  case "${opt}" in
    h) # -h (help) argument
      show_usage
      exit 0
    ;;
    s) # -s system
      single_system=${OPTARG}
      check_type="single"
    ;;
    g) # -g system-group
      system_group=${OPTARG}
      check_type="group"
    ;;
    a) # -a (all systems)
      all_systems="yes"
      check_type="all"
    ;;
    *) # invalid argument
      show_usage
      exit 0
    ;;
  esac
done

## Argument Sanity Checks ##
# Scenario: No arguments set
if [[ ${all_systems} == "no" ]]; then
  if [[ -z ${single_system} && -z ${system_group} ]]; then
    echo -e "\n>> ERROR! You must decide on something to check."
    show_usage
    exit 1
  fi
fi

# Scenario: All systems AND single system set
if [[ ${all_systems} == "yes" && ${single_system} ]]; then
  echo -e "\n>> ERROR! Incompatible arguments (check all systems and a single system)."
  show_usage
  exit 1
fi

# Scenario: All systems AND system group set
if [[ ${all_systems} == "yes" && ${system_group} ]]; then
  echo -e "\n>> ERROR! Incompatible arguments (check all systems and a system group)."
  show_usage
  exit 1
fi

# Scenario: Single system AND system group set
if [[ ${single_system} && ${system_group} ]]; then
  echo -e "\n>> ERROR! Incompatible arguments (check a single system and a system group)."
  show_usage
  exit 1
fi

#===================
# Pre-checks: Ensure dependencies exist
#===================

# Check for Spacecmd
which spacecmd &> /dev/null
if [[ $? -ne 0 ]]; then
  echo "\n>> Error! The command 'spacecmd' is not found or not in PATH. Exiting..."
  exit 1
fi

# Check to see if a spacecmd config file exists
if [[ ! -f ${HOME}/.spacecmd/config ]]; then
  echo -e "\n>> Error! No spacecmd config file found at: ${HOME}/.spacecmd/config. Exiting..."
  exit 1
fi

#===================
# Main starts here
#===================

echo -e "========================================"
echo -e "####=== Spacewalk: Reboot Check ====####"
echo -e "========================================"
echo
echo -e "Check the following systems to see if they need a reboot..."
if [[ ${single_system} ]]; then
  echo -e "Checking system: ${single_system}"
elif [[ ${system_group} ]]; then
  echo -e "Checking system group: ${system_group}"
else
  echo -e "Checking ALL systems registered with Spacewalk."
fi
echo -e "\n=>Continue?[y/n]:\c"
read run_script

if [[ ${run_script} != "y" ]]; then
  echo -e "\n>> Will not run the Reboot Check script. Exiting..."
  exit 1
fi

### Kernel Variable Intent ###
## kernel_running -> Get reported running kernel and filter output with sed to remove x86_64 
#  (leaving version number only)
## kernel_latest -> Get installed kernels, filter kernel- and x86_64 from the name 
#  (leaving version number only). Then, sort list (field sep = '.') using fields 1-5 with version format (-V)
#   tail -1 to get the highest version installed

## Check System Running and Installed Kernels ##
case ${check_type} in
  single)
  ## Single system ##
    echo -e "\n>> Checking the system '${single_system}'...\n"
    kernel_running="$(${spacecmd_cmd} system_details ${single_system} | awk '/Kernel/ {print $2}' | sed 's/.x86_64//')"
    kernel_latest="$(${spacecmd_cmd} system_listinstalledpackages ${single_system} | grep ^kernel-[0-9] | sed 's/kernel-//' | sed 's/.x86_64//' | sort -t '.' -k1,5 -V | tail -1)"

    if [[ ${kernel_running} != ${kernel_latest} ]]; then
      echo -e "--> Reboot Required: ${node} (Running kernel: ${kernel_running}, Latest Installed: ${kernel_latest})"
    fi
  ;;

  group)
  ## Group of systems (Spacewalk Group) ##
    echo -e "\n>> Checking the group '${system_group}'...\n"

    for node in $(${spacecmd_cmd} group_listsystems ${system_group}); do
      echo -e "-> Checking ${node}..."
      kernel_running="$(${spacecmd_cmd} system_details ${node} | awk '/Kernel/ {print $2}' | sed 's/.x86_64//')"
      kernel_latest="$(${spacecmd_cmd} system_listinstalledpackages ${node} | grep ^kernel-[0-9] | sed 's/kernel-//' | sed 's/.x86_64//' | sort -t '.' -k1,5 -V | tail -1)"

      if [[ ${kernel_running} != ${kernel_latest} ]]; then
        echo -e "--> Reboot Required: ${node} (Running kernel: ${kernel_running}, Latest Installed: ${kernel_latest})"
      fi
    done
  ;;

  all)
  ## All Systems ##
    echo -e "\n>> Checking all systems...\n"

    for node in $(${spacecmd_cmd} system_list); do
      echo -e "-> Checking ${node}..."
      kernel_running="$(${spacecmd_cmd} system_details ${node} | awk '/Kernel/ {print $2}' | sed 's/.x86_64//')"
      kernel_latest="$(${spacecmd_cmd} system_listinstalledpackages ${node} | grep ^kernel-[0-9] | sed 's/kernel-//' | sed 's/.x86_64//' | sort -t '.' -k1,5 -V | tail -1)"

      if [[ ${kernel_running} != ${kernel_latest} ]]; then
        echo -e "--> Reboot Required: ${node} (Running kernel: ${kernel_running}, Latest Installed: ${kernel_latest})"
      fi
    done
  ;;
esac

echo -e "\n============================="
echo -e "=- Reboot Check Completed. -="
echo -e "============================="