alternc-slavedns

#!/bin/bash
# Synchronize a dns server with alternc's remote server : 
# the configuration files contains definitions for remote masters.

CONFDIR=/etc/alternc/slavedns
CACHEDIR=/var/cache/slavedns
BINDDIR=/etc/bind/slavedns
BINDINCLUDE=/etc/bind/slavedns.conf
WGETRC=${HOME}/.wgetrc
WGET=wget
WGETFLAGS="-q"
NAMED="/etc/init.d/bind restart"
NAMED_CHECKCONF="/usr/sbin/named-checkconf"
DEFAULTS="defaults.conf"
DEFAULTSFILE="${CONFDIR}/${DEFAULTS}"
DEBUG=false

usage() {
    cat <<EOF
$0 [ -f ] [ -d ] [ -h ] [ config ]

Performs a sync of the list of domains to replicate from master.

Multiple master servers can be used, one per file in $CONFDIR
If a config file is specified on the command line, only that server
will be synced. The $BINDINCLUDE file will also be generated to include
the right configuration.

-f: refresh domain list even if it hasn't changed
-d: show everything we're doing
-h: this help
EOF
}

for i; do
    case "$i" in
        -f)
            FORCE=yes
            ;;
        -d)
            DEBUG=true
            ;;
        -h)
            usage
            exit 0
            ;;
        *)
            CONFIGS="${CONFIGS} ${i}"
            ;;
    esac
done

cd $CONFDIR

if [ -z "$CONFIGS" ]; then
    CONFIGS=`ls $CONFDIR | grep -v ~`
fi

TIMEOUT=5

CreateBindConf() {
    CFILE="$1"
    # create a new config for this host, in a tempfile
    while read domain; do
        # check if the data is valid, this will also display the domain in debug mode
        if echo $domain | grep -i '^\([a-z0-9]\([-a-z0-9]*[a-z0-9]\)\?\.\)*[a-z0-9]\([-a-z0-9]*[a-z0-9]\)$'; then
            echo "validated domain $domain" | MaybeCat
        else
            echo invalid domain listing: $domain, skipping file $CFILE >&2
            rm -f ${BINDDIR}/${CFILE}.$$
            return
        fi
        master=`grep -l "^$domain\$" ${CACHEDIR}/* | head -1`
        if [ "$master" != "${CACHEDIR}/${CFILE}" ]; then
            echo "domain $domain already present in another master ($master), skipping" >&2
            continue
        fi
        cat >> ${BINDDIR}/${CFILE}.$$ <<EOF
zone "$domain" {
    type slave;
    allow-query { any; };
    file "$domain";
    masters { ${MASTERIP}; };
};
EOF
    done < ${CACHEDIR}/${CFILE}
    mv ${BINDDIR}/${CFILE}.$$ ${BINDDIR}/${CFILE}
    INCLUDE_STR="include \"${BINDDIR}/${CFILE}\";"

    grep -q "${INCLUDE_STR}" ${BINDINCLUDE} || echo ${INCLUDE_STR} >>${BINDINCLUDE}
}

SetWgetPass() {
    USER="$1"
    PASS="$2"
    if [ -e ${WGETRC} ]; then
        mv ${WGETRC} ${WGETRC}.$$
    fi
    touch ${WGETRC}
    chmod og-r ${WGETRC}
    cat >> ${WGETRC} <<EOF
http_user = ${USER}
http_passwd = ${PASS}
EOF
}

ResetWgetConf() {
    mv -f ${WGETRC}.$$ ${WGETRC} 2>/dev/null || rm -f ${WGETRC}
}

MaybeCat() {
    if $DEBUG; then
        cat
    else
        cat > /dev/null
    fi
    return 0
}

# Main procedure : parse each config file and download the raw slave list.
# if something changed in a list, call CreateBindConf $i 

RELOAD=""

for conf in ${CONFIGS}; do
    [ "${DEFAULTS}" = "${conf}" -o "slavedns.conf" = "${conf}" ] && continue
    URL=""
    # source defaults
    . ${DEFAULTSFILE}
    # source this site's config
    . $CONFDIR/${conf}
    if [ -z "$URL" ]; then
        if [ -z "$PROTOCOL" ]; then
            if [ "$SSL" ]; then
                PROTOCOL=https
            else
                PROTOCOL=http
            fi
        fi
        URL=${PROTOCOL}://${HOST}/admin/domlist.php
    fi

    if [ ! -z "$INTEGRITY" ] ; then
      if [ $INTEGRITY -eq 1 ] ; then
        URL="$URL?integrity=1"
      fi
    fi

    if [ -z "$URL" -a -z "$HOST" -o -z "$MASTERIP" ]; then
        echo "error in the config file '${conf}'" >&2
    else
        touch ${CACHEDIR}/${conf}
        rm -f ${CACHEDIR}/${conf}.temp
        [ "${LOGIN}" ] && SetWgetPass ${LOGIN} ${PASSWORD}
        ${WGET} ${URL} ${WGETFLAGS} -O ${CACHEDIR}/${conf}.temp -t 1 -T ${TIMEOUT} 2>&1 | MaybeCat
        [ "${LOGIN}" ] && ResetWgetConf
        if [ -s "${CACHEDIR}/${conf}.temp" ]; then
            # If there are integrity check setup, 
            # Get of the checksum of the file and compare it
            if [ ! -z "$INTEGRITY" ] ; then
              if [ $INTEGRITY -eq 1 ] ; then
                # Get the checksum
                checksum="$( tail -1 "${CACHEDIR}/${conf}.temp" )"
                echo "$checksum  ${CACHEDIR}/${conf}.temp" > "${CACHEDIR}/${conf}.temp.md5sum"
                # Get it of the file
                tmpff="$( cat "${CACHEDIR}/${conf}.temp" |grep -v "$checksum")"
                echo -e "$tmpff" > "${CACHEDIR}/${conf}.temp"
                # Calculate checksum
                md5sum --warn --check --status "${CACHEDIR}/${conf}.temp.md5sum"
                checkmd=$?
                if [ "x$checkmd" != "x0" ] ; then
                  echo "Error: bad checksum for $conf"
                  echo "+++ BEGIN +++"
                  echo -e "$tmpff"
                  echo "+++  END  +++"
                  echo -n "Local checksum: "
                  cat "${CACHEDIR}/${conf}.temp.md5sum" 
                  # Clean the file and do the next conf file
                  rm "${CACHEDIR}/${conf}.temp.md5sum" "${CACHEDIR}/${conf}.temp"
                  continue
                fi
              fi
            fi

            test -e "${CACHEDIR}/${conf}.temp.md5sum" && rm "${CACHEDIR}/${conf}.temp.md5sum"


            # If the slave file has changed, synchronize it.
            if ! [ "${FORCE}" ] && cmp ${CACHEDIR}/${conf}.temp ${CACHEDIR}/${conf} > /dev/null; then
                echo "no change found for '${conf}'"
            else
                echo "change detected for '${conf}', applying"
                mv -f ${CACHEDIR}/${conf}.temp ${CACHEDIR}/${conf}
                # Now parse the slave file and send it to /etc/bind/slavedns
                CreateBindConf ${conf}
                if /usr/sbin/named-checkconf ${BINDDIR}/${conf}; then
                    RELOAD="yes"
                else
                    echo "error: file ${conf} is not correct" >&2
                fi
            fi
        else
            echo "downloaded file for '${conf}' has zero size" >&2
            rm -f ${CACHEDIR}/${conf}.temp
        fi
    fi
done # Main loop on config files

if [ "$RELOAD" ]; then
    if $NAMED_CHECKCONF >&2 ; then
        ${NAMED} >/dev/null
    else
        echo "Error in named configuration - bind not reloaded" >&2
    fi
fi