#!/bin/bash

SNAPSHOTFROMROOT=/etc/sysconfig/snapshot
SYSCONFIG="$( dirname $0 )/../../$SNAPSHOTFROMROOT"
SNAPSHOT=/opt/snapshot/snapshot
export PERLLIB=/opt/snapshot

# alternate way to write to standard error.
exec 3>&2

function printHelp 
{
  ( 
    echo "$*"
	echo ""
    echo "Usage: $0 <command>"
	echo "  Backup support script using LVM snapshots. "
	echo "  Configuration is in '$SNAPSHOTFROMROOT'" 
	echo ""
	ddecho "<command> is one of"
	echo "  login:       Login to iscsi target"
	echo "  activate:    Import and activate backup logical volumes"
	echo "  remove:      Remove backup logical volumes"
	echo "  backup:      Execute backup"
	echo "  deactivate:  Deactivate and export backup logical volumes"
	echo "  logout:      Logout from iscsi target"
	echo "  all:         All of the previous targets in order"
	echo ""	
  ) 1>&2
  exit 1 
}


if [[ ! -r "$SYSCONFIG" ]]
then
  printHelp "Config file '$SYSCONFIG' does not exist" 
fi


. "$SYSCONFIG"


if [[ $# -eq 0 ]] 
then 
  printHelp
fi

commands=""
while [[ $# -gt 0 ]]
do
  command="$1"
  case "$command" in 
    login|activate|remove|backup|deactivate|logout) 
	  commands="$commands $1"
    ;;
    all) commands="$commands login activate remove backup deactivate logout"
    ;;
	*) printHelp "Unknown command '$1'" 
	;;
  esac
  shift
done


# paths to LVM commands
VGS=$( which vgs )
VGCHANGE=$( which vgchange )
VGEXPORT=$( which vgexport )
VGIMPORT=$( which vgimport )
DMSETUP=$( which dmsetup )
LVREMOVE=$( which lvremove )

function execute
{
  echo "exec: $*"  
  if [[ -z "$DRYRUN" ]]
  then
      $* 2>&1 
      if [[ $? -ne 0 ]]
      then
        exit 1
      fi  
  fi
}

function show
{
  echo ""
  echo "========================================================================"
  echo "= $*"
  echo "========================================================================"
  echo ""
}

function login
{ 
  show "login"
  for target in $ISCSI_TARGETS
  do
    iqn="$( echo $target | sed 's@/.*$@@g' )"
	portal="$( echo $target | sed 's@^.*/@@g' )"
	ip="$( echo $portal | sed 's@:.*$@@'g )"
	execute iscsiadm -m discovery -t st -p $ip
	execute iscsiadm -m node --targetname $iqn --portal $portal --login
  done
  
  execute vgscan > /dev/null 2>&1 
}

function mustSucceed
{
  msg="$1"
  shift
  $* 
  if [[ $? -ne 0 ]]
  then
    echo "=== $msg" 1>&3
    exit 1
  fi
}

function lvmFilter
{
  grep -v "File descriptor.*leaked"
}

function vgs
{
  $VGS $* 2>&1 | lvmFilter
}

function vgimport
{
  $VGIMPORT $* 2>&1 | lvmFilter
}

function vgchange
{
  $VGCHANGE $* 2>&1 | lvmFilter
}

function expandDashes 
{
  echo $* | sed 's/-/@@/g' | sed 's/@@/--/g' 
}

function lvremove
{
  if [[ -b "$1" ]]
  then
    vglv=$( echo "$*" | sed 's@^/dev/@@g' )
    vg=$( echo $vglv | sed 's@/.*$@@g' )
    lv=$( echo $vglv | sed 's@^.*/@@g' )
    vg=$( expandDashes $vg )
    lv=$( expandDashes $lv )
    $DMSETUP -v remove $vg-$lv
    $LVREMOVE -f $* 2>&1 | lvmFilter
  else 
    echo "Volume $* already removed"
  fi
}

function vgexport
{
  $VGEXPORT $* 2>&1 | lvmFilter
}

function checkVg
{ 
  vg="$1"
  mustSucceed "Error getting volume group info for '$vg'" vgs "$vg" > /dev/null 2>&1
}


function backupVgs
{
   (
     override=""
     for backup in $BACKUP_VOLUMES
     do
       vg=$( echo $backup | sed 's@/.*$@@g' )
	   checkVg $vg
	   echo $vg
	   override="yes"
     done
	
     if [[ -z "$override" ]]
     then
       for source in $SOURCES
       do
         source="bak-$( echo $source | sed 's@/.*$@@g' )"
		 checkVg $source
	     echo $source
       done  
     fi
   ) | 
   sort | uniq
}

function backupLvs
{
   (
     override=""
     for backup in $BACKUP_VOLUMES
     do
       echo $backup 
	   override="yes"
     done
	
     if [[ -z "$override" ]]
     then
       for source in $SOURCES
       do
         source="bak-$( echo $source | sed 's@:.*$@@g' )"
	     echo $source
       done  
     fi
   ) | 
   sort | uniq
}


function activate
{
  show "activate" 
  for vg in $( backupVgs )
  do
    execute vgimport $vg
    execute vgchange -ay $vg
  done
  return 0
}

function remove
{ 
  show "remove"
  
  for lv in $( backupLvs ) 
  do
    execute lvremove /dev/$lv
  done
  return 0
  
}

function backup
{ 
  show "backup"
  
  sources=""
  empty="yes"
  for source in $SOURCES
  do
    sources="$sources /dev/$source"
    empty="no"
  done
  if [[ "$empty" = "yes" ]]
  then
    echo "No source volumes specified: edit $SNAPSHOTFROMROOT to specify volumes" 1>&2
    exit 1
  fi
  addopts=""
  if [[ -n "$VG_PATTERN" ]]
  then
    addopts="$addopts -b $VG_PATTERN"
  fi
  if [[ -n "$LV_PATTERN" ]]
  then
    addopts="$addopts -l $LV_PATTERN"
  fi
  (
    cd $( dirname $SNAPSHOT )
	exec 3>&-
    execute ./$( basename $SNAPSHOT ) $addopts -f "$BANDWIDTH" -s "$SNAPSHOTSIZE" $sources
  )
  return $?
}

function deactivate
{
  show "deactivate"
  
  for vg in $( backupVgs )
  do
    execute vgchange -an $vg
    execute vgexport $vg
  done
  return 0
}

function logout
{
  show "logout"
  for target in $ISCSI_TARGETS
  do
    iqn="$( echo $target | sed 's@/.*$@@g' )"
	execute iscsiadm -m node --targetname $iqn --logout
  done
  
  execute vgscan 1>/dev/null 2>&1 
  return 0 
}


for command in $commands
do
  $command
  if [[ $? -ne 0 ]]
  then
    (
      echo "Error executing $command"
    ) 1>&2
	exit 1
  fi
  echo ""
done

show "done"