bupbanana

#!/bin/bash

# author: Marcus Schopen (marcus.schopen@uni-bielefeld.de)


__VERSION="0.1.1-6" # 06.06.2016

# turn on bash traces via command line
# DEBUG=1 bupbanana -c CONFIGFILE
if [ ${DEBUG:=0} == "1" ]; then
  export PS4='+ $LINENO: '
  set -x
fi;
    
# setting locale to POSIX C
export LC_ALL=C

set -o errexit
set -o pipefail
set -o nounset
set -o noclobber

# unalias
\unalias -a

# no file an directory permissions for others
umask o=

# set a secure path 
PATH='/usr/local/bin:/bin:/usr/bin:/sbin'
export PATH 

# set a secure IFS
IFS=$' \t\n'

# suppress leaked on lvs invocation warnings on 
# open stale lock file handle, see bug #591823
export LVM_SUPPRESS_FD_WARNINGS=1 


# --------------------------------------
# DEFAULTS
# --------------------------------------

# defaults and functions
PID=$$
PROG_NAME=$(basename "$0")
BANANA_PROFILE="/etc/bup/bupbanana.conf"
CMD_DISPLAY="1" # control cmd_run output
BACKUP_DIR="/vol/backup"
DOMAIN_LIST=""
LV_SNAP_NAME_PREFIX="backsnap"
LV_LIST=""
LV_LIST_IMAGE_DUMP=""
LOCK_DIR="/tmp/.bupbanana"
STALE_LOCK_FD=73
STOP_ON_STALE_LOCKFILE="1"
ROLLBACK_PREEXEC="1"
IS_ROLLBACK_PREEXEC="false"
IS_DELETE_STALE_LOCK_FILE="false"
        
readonly _VIRSH=$(which virsh)
readonly _DDRESCUE=$(which ddrescue)
readonly _LVS=$(which lvs)
readonly _LV_CREATE=$(which lvcreate)
readonly _LV_REMOVE=$(which lvremove)

# --------------------------------------
# BANANA LIBRARY
# --------------------------------------

source "$(dirname "$0")/libbupbanana" \
  || { echo "ERROR: cannot load bubbanana lib file";
       exit 1; 
     }


# --------------------------------------
# PREEXEC COMMANDS
# --------------------------------------

# prexec commands
function backup_preexec() {
  local arg=${1:-}

  # lockfile
  lockfile --preexec \
    || error_and_exit "${CMD_OUTPUT}"
        
  # create domain snapshots
  if [ -n "${DOMAIN_LIST}" ]; then
    domain_snapshot --create_as "${DOMAIN_LIST}" || return 1
  fi;
  
  # mount bind of /boot partiton
  mount_bind_partition "/boot"  || return 1
  
  # create LV snapshots
  lvm_snapshot --create "${LV_LIST}" || return 1

  # create ddrescue dump before mounting
  if [[ "$arg" == "with-image" ]]; then
    lvm_snapshot --dump "${LV_LIST_IMAGE_DUMP}" || return 1
  fi;

  # mount LV snapshots
  lvm_snapshot --mount "${LV_LIST}" || return 1
  
  # delete domain snapshots
  if [ -n "${DOMAIN_LIST}" ]; then
    domain_snapshot --delete "${DOMAIN_LIST}" || return 1
  fi;

  # cleanup pidfile and keep it to mark a successfull preexec run
  lockfile --pidfile_cleanup || return 1
                
  return 0
}


# --------------------------------------
# ROLLBACK COMMANDS
# --------------------------------------

# rollback preexec in case of failure
function backup_preexec_rollback() {
  IS_ROLLBACK_PREEXEC="true"

  banana_logger "CRITICAL: preexec some errors occurred"
  banana_logger "INFO: rollback preexec"

  # try to delete left domain snapshots from unclean preexec
  if [ -n "${DOMAIN_LIST}" ]; then
    banana_logger "INFO: try to delete left domain snapshots from unclean preexec"
    domain_snapshot --delete "${DOMAIN_LIST}" || exit_status=$?
  fi;

  banana_logger "INFO: run postexec"
  backup_postexec || return 1
 
  return 0
}


# --------------------------------------
# POSTEXEC COMMANDS
# --------------------------------------

# postexec commands
function backup_postexec() {
  local exit_status=0
  local pidfile_isclean=true

  # check if preexec finished clean
  if ! lockfile --pidfile_isclean; then
    pidfile_isclean=false
  fi;

  # lockfile
  lockfile --postexec \
    || error_and_exit "${CMD_OUTPUT}"

  # umount lvm snapshot of / partition
  lvm_snapshot --umount "${LV_LIST}" || exit_status=$?
  
  # delete lvm snapshots
  lvm_snapshot --delete "${LV_LIST}" || exit_status=$?
  
  # umount bind of /boot
  umount_partition "${BACKUP_DIR}/boot" || exit_status=$?

  # delete pidfile on non erros to mark a completely successful run set
  if [ "${exit_status}" == "0" ]; then 
    lockfile --pidfile_delete \
      || error_and_exit "cannot cleanup pidfile"
  else
    banana_logger "ERROR: postexec some errors occurred"; 
  fi;
  
  return ${exit_status}
}


# --------------------------------------
# MAIN
# --------------------------------------
        
function main() {

  # check if profile exists and is readable
  [ -r "${BANANA_PROFILE}" ] \
    || { echo "ERROR: no such config file or not readable" >&2; exit 1; };

  # load profile
  load_banana_profile "${BANANA_PROFILE}" \
    || { echo "ERROR: ${CMD_OUTPUT}" >&2; exit 1; };

  # run preexec
  if [ "${arg_command}" == "preexec" ]; then
    backup_preexec \
      || { if [ "${ROLLBACK_PREEXEC}" == "0" ]; then
	     banana_logger "INFO: rollback disabled";
             error_and_exit "cannot execute preexec";
           else
             backup_preexec_rollback \
               || banana_logger "ERROR: cannot execute preexec rollback";
             error_and_exit "cannot execute preexec";
           fi;
         }

  # run preexec with image dump
  elif [ "${arg_command}" == "preexec-with-image" ]; then
    backup_preexec with-image \
      || { if [ "${ROLLBACK_PREEXEC}" == "0" ]; then
	     banana_logger "INFO: rollback disabled";
             error_and_exit "cannot execute preexec with image";
           else
             backup_preexec_rollback \
               || banana_logger "ERROR: cannot execute preexec rollback";
             error_and_exit "cannot execute preexec with image";
           fi;
         }

  # run postexec
  elif [ "${arg_command}" == "postexec" ]; then
      backup_postexec \
        || false;
  fi;

}


# --------------------------------------
# COMMAND LINE
# --------------------------------------

# usage info
function display_help() {
  # don't display help without a terminal
  [ "$TERM" == "dumb" ] && return 0
    
  cat << EOF
Version: bupbanana ${__VERSION}

Usage: ${0##*/} [-h] [--preexec|--preexec-with-image|--postexec] [CONFIGFILE]

    -h|--help               display this help and exit
    --preexec               run preexec commands
    --preexec-with-image    run preexec commands with image dump
    --postexec              run postexec commans

    CONFIGFILE		    the default is /etc/bup/bupbanana.conf
            
For full debug trace use DEBUG=1 ${0##*/}

EOF
}


# check empty parameters
if [ "$#" -eq 0 ]; then
  echo "ERROR: missing arguments"
  display_help
  exit 1
fi


CMD_OPTIONS=$(getopt --options h --longoptions \
    "help,preexec,preexec-with-image,postexec" --name "$0" -- "$@" 2>&1 ) \
  || { echo "ERROR: wrong option or argument"; 
       display_help; 
       exit 1; }

eval set -- "${CMD_OPTIONS}"


# check command line parameters
preexec_flag=false
postexec_flag=false
arg_command=""

while [ $# -gt 0 ] ; 
do
  case "$1" in
    -h|--help)
        display_help;
        exit 0
    ;;
    --preexec)
        preexec_flag=true
        arg_command="preexec"
    ;;
    --preexec-with-image)
        preexec_flag=true
        arg_command="preexec-with-image"
    ;;
    --postexec)
        postexec_flag=true
        arg_command="postexec"
    ;;
    --)  # end of all options
        shift
        break
    ;;
    *)
        echo "internal error"
        exit 1
    ;;

  esac
  shift

done  

# post checking given arguments and options
if [ $preexec_flag == true ] && [ $postexec_flag == true ]; then
  echo "ERROR: excluding arguments"
  display_help
  exit 1
elif [ $preexec_flag == false ] && [ $postexec_flag == false ]; then
  echo "ERROR: missing arguments"
  display_help
  exit 1
fi

# overwrite default config file location
if [ -n "${1:-}" ]; then
   BANANA_PROFILE="${1}"
fi

main;

exit $?