#!/bin/sh
# Define this variable _NOSPINDLE before calling this script if this script run through a systemd service
# if this variable _SAFESYNC is also defined, it will do a wd safe sync instead (when watchdog daemon is not used)

STAG=mbackup:
ENDSIG=/tmp/mbackup_sig
ERRSIG=/tmp/mbackup_err
PENDINGCHK=/tmp/.boot_pending
# lock wait time max 15mn * 60 = 900 secs (sufficient time to update)
LOCKWAIT=900
bname=mbackup
TMPBK=""
DEFBAKPATH=/mnt/storage/.sysbackup/
BAKPATH=$DEFBAKPATH
_curr_dir=""
BAKEXT=".tar.gz"
PREVEXT=".tar.gz.bk1"
TMPEXT=".tar.gz.tmp"
BAKMD5EXT=".md5"
PREVMD5EXT=".md5.bk1"
TMPMD5EXT=".md5.tmp"
mybasename=""
CREATEPBACK=1

sp="/-\|"
sc=0
spin() {
    if [ -z "$_NOSPINDLE" ]; then
        printf "\r${STAG} ${sp:sc++:1}"
        ((sc==${#sp})) && sc=0
    else
        printf "${STAG} ${sp:sc++:1} \n"
        ((sc==${#sp})) && sc=0
        if [ ! -z "$_SAFESYNC" ]; then
            dmesg -D
            echo 1 > /dev/watchdog
            dmesg -E
        fi
    fi
}
endspin() {
    if [ -z "$_NOSPINDLE" ]; then
        printf "\r"
    else
        if [ ! -z "$_SAFESYNC" ]; then
	    dmesg -E
	fi
    fi
}

readonly LOCKFILE_DIR=/var/lock
readonly LOCK_FD=980

lock() {
    local prefix=$1
    local fd=${2:-$LOCK_FD}
    local lock_file=$LOCKFILE_DIR/$prefix.lock

    # still allow to run unlocked if the lock dir does not exist
    if [ ! -d "${LOCKFILE_DIR}" ]; then
        return 0
    fi

    # create lock file
    eval "exec $fd>$lock_file"
    # still allow to run unlocked if the lock file cannot be created
    if [ $? -ne 0 ]; then
        return 0
    fi

    # acquier the lock
    flock -w ${LOCKWAIT} $fd \
        && return 0 \
        || return 1
}

unlock() {
    local prefix=$1
    local fd=${2:-$LOCK_FD}
    local lock_file=$LOCKFILE_DIR/$prefix.lock

    # release the lock
    flock -u $fd
    sync
}

function my_exit()
{
    sync
    if [ -f "$BAKPATH$mybasename$TMPEXT" ]; then
        rm -f $BAKPATH$mybasename$TMPEXT
    fi
    if [ -f "$BAKPATH$mybasename$TMPMD5EXT" ]; then
        rm -f $BAKPATH$mybasename$TMPMD5EXT
    fi
    if [ -d "${TMPBK}" ]; then
        TMPBKMNT_RES=$(mount | grep "${TMPBK}")
        TMPBKMNT_RET=$?
        if [ $TMPBKMNT_RET -eq 0 ]; then
            umount ${TMPBK}
        fi
        rmdir "${TMPBK}"
    fi
    sync
    cd "$_curr_dir"
    unlock $bname
    exit $*
}

function __sig_int {
    endspin
    log_write " "
    log_write "$STAG WARNING: SIGINT caught"
    my_exit 110
}

function __sig_quit {
    endspin
    log_write " "
    log_write "$STAG WARNING: SIGQUIT caught"
    my_exit 111
}

function __sig_term {
    endspin
    log_write " "
    log_write "$STAG WARNING: SIGTERM caught"
    my_exit 112
}

function __sig_hup {
    endspin
    log_write " "
    log_write "$STAG WARNING: SIGHUP caught"
    my_exit 113
}

function log_write()
{
	echo "$*"
}

function log_write_nr()
{
	echo -n "$*"
}

function show_help {
    log_write "mbackup help information:"
    log_write "Usage: mbackup [ [ [-f file] [-n] ] | [--help] ] <spath>"
    log_write " where: <spath>     # source directory path to backup recursively"
    log_write " options: -f file   # force output file name (will be appended with .tar.gz/.md5)"
    log_write "                    # specified file destination directory must exist!"
    log_write "                    # if -f not used, default dest. dir. is created: $BAKPATH"
    log_write "                    #    with auto generated filename according to <spath>"
    log_write "          -n        # do not create a previous backup (*.bk1) if one already exist"
    log_write "                    #    default is to create one"
    log_write "          --help    # displays this help information"
    log_write "example: mbackup /mnt/rom/user;            # backup user flash configuration to default dir"
    log_write "example: mbackup -f /tmp/qq /mnt/rom/user; # backup user flash configuration to /tmp/qq"
}

function create_basename()
{
    local retval
    local retval2
    local repchr=-
    local srcchr=/
    local slen=${#1}
    local mystr
    local mystr2
    if [ "${1:$slen - 1:1}" == "/" ] ; then
        mystr=${1:0:$slen - 1}
        slen=$((slen-1))
    else
        mystr=$1
    fi
    if [ ${1:0:1} == "/" ] ; then
        mystr2=${mystr:1:$slen - 1}
        slen=$((slen-1))
    else
        mystr2=$mystr
    fi
    retval="bk-"${mystr2//$srcchr/$repchr}
    retval2=${retval// /$repchr}
    echo $retval2
}

# returns the file basename without directory and extension
function get_basename()
{
	echo ${1//+(*\/|.*)}
    return 0
}

function check_destpath()
{
	local retval=0
    local slen=${#1}
    local mystr
    if ! [ -d $1 ] ; then
        log_write "$STAG Destination directory does not exist ($1)!"
        retval=80
    else
        if [ "${1:$slen - 1:1}" == "/" ] ; then
            mystr=${1:0:$slen - 1}
            slen=$((slen-1))
        else
            mystr=$1
        fi
        BAKPATH=$mystr"/"
    fi
    return $retval
}

# corrects md5 associated source file
# param1=originalfilename
# param2=newfilename
# param3=md5 file to correct
function correct_md5_file()
{
    local name1
    local name2
    name1=`basename $1`
	if [ $? -ne 0 ]; then
		log_write "$STAG Getting basename of ($1) fail!"
		return 81
	fi
    name2=`basename $2`
	if [ $? -ne 0 ]; then
		log_write "$STAG Getting basename of ($2) fail!"
		return 82
	fi
    sed -i "s/$name1/$name2/g" $3
	if [ $? -ne 0 ]; then
		log_write "$STAG Sed md5 file ($3) fail!"
		return 83
	fi
    return 0
}

if [ -e "${PENDINGCHK}" ]; then
    log_write "$STAG Pending reboot, could not run!"
    exit 97
fi

_curr_dir=`pwd`

# Lock to test a single instance is running, and exit if wait timeout
log_write "$STAG Checking if allowed to run..."
lock $bname || ( log_write "$STAG Checking if allowed to run... failed"; exit 100 )
log_write "$STAG Checking if allowed to run... done"

# Set TRAPs to release lock if forced to exit
trap __sig_int SIGINT
trap __sig_quit SIGQUIT
trap __sig_term SIGTERM
trap __sig_hup SIGHUP

if [ -e "${PENDINGCHK}" ]; then
    log_write "$TAG Pending reboot, could not run!"
    my_exit 97
fi

TOTALARG=$#
while getopts :f:n- FLAG; do
    case $FLAG in
        f)
        #log_write "#Filename (-f)"
        check_destpath `dirname "$OPTARG"`
        valret=$?
        if [ $valret -ne 0 ]; then
            my_exit $valret
        fi
        mybasename=`basename "$OPTARG"`;;
        n)
        log_write "$STAG No previous backup option specified (-n)"
        CREATEPBACK=0;;
        '-')
        show_help
        my_exit 0;;
        \?)
        log_write "Invalid option: -$OPTARG" && my_exit 1;;
        \:)
        log_write "Required argument not found for option: -$OPTARG" && my_exit 2;;
  esac
done

# removes processed option(s) from the cmd line args
shift $((OPTIND-1))

if [ "$#" -ne 1 ]; then
    show_help
    my_exit 3
fi

if ! [ -d $1 ] ; then
    log_write "$STAG Source directory does not exist ($1)!"
    my_exit 4
fi
if [ "x$mybasename" == "x" ] ; then
    mybasename=$(create_basename $1)
    if ! [ -d "$BAKPATH" ]; then
        mkdir -p $BAKPATH
        if [ $? -ne 0 ]; then
            log_write "$STAG create dir ($BAKPATH) fail!"
            my_exit 5
        fi
    fi
fi

log_write "$STAG Creating backup to: "$BAKPATH$mybasename
TMPBK=$(mktemp -d)
if [ $? -ne 0 ]; then
	log_write "$STAG mktemp fail!"
	my_exit 6
fi

# temporarily bind mount dir to backup to TMPBK
mount --bind -o ro $1 ${TMPBK}
if [ $? -ne 0 ]; then
    log_write "$STAG mount $1 to temp folder fail!"
    my_exit 7
fi

rm -f $BAKPATH$mybasename$TMPEXT
if [ $? -ne 0 ]; then
	log_write "$STAG cannot remove ($BAKPATH$mybasename$TMPEXT)!"
	my_exit 8
fi
rm -f $BAKPATH$mybasename$TMPMD5EXT
if [ $? -ne 0 ]; then
	log_write "$STAG cannot remove ($BAKPATH$mybasename$TMPMD5EXT)!"
	my_exit 9
fi
rm -f ${ENDSIG}
rm -f ${ERRSIG}
log_write "$STAG Creating files backup..."
(
tar -zcf $BAKPATH$mybasename$TMPEXT -C ${TMPBK} .
if [ $? -ne 0 ]; then
    log_write " $STAG tar ($BAKPATH$mybasename$TMPEXT) fail!"
    touch ${ERRSIG}
    exit 10
fi
touch ${ENDSIG}
) &
until [ -f ${ENDSIG} ]; do
    spin
    if [ -f ${ERRSIG} ]; then
        my_exit 11
    fi
    if [ ! -f ${ENDSIG} ]; then
        sleep 1s
    fi
done
endspin
log_write "$STAG Creating files backup... done"

# create md5
cd $BAKPATH
if [ $? -ne 0 ]; then
    log_write "$STAG cannot change dir to ($BAKPATH)!"
    my_exit 12
fi
md5sum ./$mybasename$TMPEXT > ./$mybasename$TMPMD5EXT
if [ $? -ne 0 ]; then
    log_write "$STAG cannot create md5 for ($BAKPATH$mybasename$TMPEXT)!"
    my_exit 13
fi

# create a previous backup if one already exit
if [ $CREATEPBACK -eq 1 ]; then
    if [ -f "$BAKPATH$mybasename$BAKEXT" ] && [ -f "$BAKPATH$mybasename$BAKMD5EXT" ]; then
        log_write "$STAG Copy prev. backup to: "$BAKPATH$mybasename$PREVEXT
        cp -f $BAKPATH$mybasename$BAKEXT $BAKPATH$mybasename$PREVEXT
        if [ $? -ne 0 ]; then
            log_write "$STAG Creating previous backup ($BAKPATH$mybasename$PREVEXT) fail!"
            my_exit 14
        fi
        log_write "$STAG Copy prev. MD5 to: "$BAKPATH$mybasename$PREVMD5EXT
        cp -f $BAKPATH$mybasename$BAKMD5EXT $BAKPATH$mybasename$PREVMD5EXT
        if [ $? -ne 0 ]; then
            log_write "$STAG Creating previous backup ($BAKPATH$mybasename$PREVMD5EXT) fail!"
            my_exit 15
        fi
        correct_md5_file $BAKPATH$mybasename$BAKEXT $BAKPATH$mybasename$PREVEXT $BAKPATH$mybasename$PREVMD5EXT
        if [ $? -ne 0 ]; then
            my_exit $?
        fi
    fi
fi

# create current backup from temporary files
rm -f $BAKPATH$mybasename$BAKEXT
if [ $? -ne 0 ]; then
    log_write " $STAG cannot remove ($BAKPATH$mybasename$BAKEXT) fail!"
    my_exit 16
fi
rm -f $BAKPATH$mybasename$BAKMD5EXT
if [ $? -ne 0 ]; then
    log_write " $STAG cannot remove ($BAKPATH$mybasename$BAKMD5EXT) fail!"
    my_exit 17
fi
log_write "$STAG Move backup to: "$BAKPATH$mybasename$BAKEXT
mv $BAKPATH$mybasename$TMPEXT $BAKPATH$mybasename$BAKEXT
if [ $? -ne 0 ]; then
    log_write " $STAG cannot move to ($BAKPATH$mybasename$BAKEXT) fail!"
    my_exit 18
fi
log_write "$STAG Move MD5 to: "$BAKPATH$mybasename$BAKMD5EXT
mv $BAKPATH$mybasename$TMPMD5EXT $BAKPATH$mybasename$BAKMD5EXT
if [ $? -ne 0 ]; then
    log_write " $STAG cannot move to ($BAKPATH$mybasename$BAKMD5EXT) fail!"
    my_exit 19
fi
correct_md5_file $BAKPATH$mybasename$TMPEXT $BAKPATH$mybasename$BAKEXT $BAKPATH$mybasename$BAKMD5EXT
if [ $? -ne 0 ]; then
	my_exit $?
fi
rm -f ${ENDSIG}
rm -f ${ERRSIG}
log_write "$STAG System sync..."
(
sync
if [ $? -ne 0 ]; then
    log_write " $STAG sync fail!"
    touch ${ERRSIG}
    exit 20
fi
touch ${ENDSIG}
) &
until [ -f ${ENDSIG} ]; do
    spin
    if [ -f ${ERRSIG} ]; then
        my_exit 21
    fi
    if [ ! -f ${ENDSIG} ]; then
        sleep 1s
    fi
done
endspin
log_write "$STAG System sync... done"
my_exit 0