#!/bin/bash
# 
# Script to control the bind-chroot ISC BIND named(8) server runtime environment.
#
# Usage:
#  [ -e | --enable ] [ -d | --disable ] | [ -s --sync ]
#
#  -e | --enable:   enable the bind-chroot environment
#  -d | --disable:  disable the bind-chroot environment
#  -s | --sync:     sync files between the bind chroot and / environments,
#                   so they are correct for the current state of the bind-chroot
#                   (enabled / disabled)
# $BIND_CHROOT_PREFIX, default /var/named/chroot, is the location of the chroot.
# $BIND_DIR, default /var/named, is the default un-chrooted bind directory.
#
# Copyright(C) 2006 Jason Vas Dias <jvdias@redhat.com>, Red Hat, Inc.
#
#    This software is provided under the terms of the GNU
#    General Public License (GPL), as published at: 
#    http://www.gnu.org/licenses/gpl.html .
#
#
BIND_CHROOT_PREFIX=${BIND_CHROOT_PREFIX:-@BIND_CHROOT_PREFIX@}
BIND_DIR=${BIND_DIR:-@BIND_DIR@}

function usage()
{
  echo 'Usage:
  -e | --enable:   enable the bind-chroot environment
  -d | --disable:  disable the bind-chroot environment
  -s | --sync:     sync files between the bind chroot and / environments,
                   so they are correct for the current state of the bind-chroot
                   (enabled / disabled)
  $BIND_CHROOT_PREFIX, default /var/named/chroot, is the location of the chroot.
  $BIND_DIR, default /var/named, is the default un-chrooted bind directory.
';
}

function rootdir()
{
    . /etc/sysconfig/named
    if [ -n "$ROOTDIR" ]; then
	BIND_CHROOT_PREFIX="$ROOTDIR";
	BIND_CHROOT_PREFIX=`echo $BIND_CHROOT_PREFIX | sed 's#//*#/#g;s#/$##'`;
	if [ -L "$BIND_CHROOT_PREFIX" ]; then
	    BIND_CHROOT_PREFIX=`/usr/bin/readlink "$BIND_CHROOT_PREFIX"`;
	fi
	return 0;
    fi;
    return 1;
}

function check_dirs()
{
    if [ -z "$BIND_CHROOT_PREFIX" ]; then
	rootdir;
	if [ -z "$BIND_CHROOT_PREFIX" ]; then
	    usage;
	    exit 1;
	fi;
    fi
    BIND_DIR=`echo $BIND_DIR | sed 's#//*#/#g;s#/$##'`;
    if [ -L "$BIND_DIR" ]; then
	BIND_DIR=`/usr/bin/readlink "$BIND_DIR"`;
    fi
    BIND_CHROOT_PREFIX=`echo $BIND_CHROOT_PREFIX | sed 's#//*#/#g;s#/$##'`;
    if [ -L "$BIND_CHROOT_PREFIX" ]; then
	BIND_CHROOT_PREFIX=`/usr/bin/readlink "$BIND_CHROOT_PREFIX"`;
    fi

    /bin/mkdir -p ${BIND_DIR}/{slaves,data};
    /bin/chown root:named ${BIND_DIR};
    /bin/chown named:named ${BIND_DIR}/{slaves,data};
    /bin/chmod 750 ${BIND_DIR}
    /bin/chmod 770 ${BIND_DIR}/{slaves,data};
        
    mkdir -p ${BIND_CHROOT_PREFIX}/{etc,dev,var/{run/named,named/{slaves,data}}};
    /bin/chown root:named ${BIND_CHROOT_PREFIX}/{etc,dev,var/{run,named/}};
    /bin/chmod 750 ${BIND_CHROOT_PREFIX}/{,etc,dev,var,var/{run,named/}};
    /bin/chown named:named ${BIND_CHROOT_PREFIX}/var/{run/named,named/{data,slaves}};
    /bin/chmod 770 ${BIND_CHROOT_PREFIX}/var/{run/named,named/{slaves,data}};        

    [ ! -e "${BIND_CHROOT_PREFIX}/dev/random" ] && /bin/mknod "${BIND_CHROOT_PREFIX}/dev/random" c 1 8 
    [ ! -e "${BIND_CHROOT_PREFIX}/dev/zero" ] && /bin/mknod "${BIND_CHROOT_PREFIX}/dev/zero" c 1 5
    [ ! -e "${BIND_CHROOT_PREFIX}/dev/null" ] && /bin/mknod "${BIND_CHROOT_PREFIX}/dev/null" c 1 3
    [ ! -e "${BIND_CHROOT_PREFIX}/etc/localtime" ] &&  [ -e /etc/localtime ] && /bin/cp -fp /etc/localtime "${BIND_CHROOT_PREFIX}/etc/localtime";
    chmod 666 "${BIND_CHROOT_PREFIX}"/dev/{random,null,zero};
    if [ -d /selinux ] && [ -e /selinux/enforce ] && [ -x /usr/bin/chcon ]; then       
       for dev in random zero null; do
	   /usr/bin/chcon --reference=/dev/$dev ${BIND_CHROOT_PREFIX}/dev/$dev;
       done
    fi;
}

check_dirs;

function replace_with_link()
{ # replaces $dst second arg file  with link to $src first arg file
    if [ $# -lt 2 ]; then
	return 1;
    fi;
    src=$1
    dst=$2    
    if [ -z "$src" ] || [ -z "$dst" ] || [ "$src" = "$dst" ]; then
       return 1;
    fi
    if [ ! -e "$src" ]; then
       if [ ! -e "$dst" ]; then
	   return 1;
       else
	   if [ -L "$dst" ]; then
	       dstlnk=`/usr/bin/readlink "$dst"`;
	       if [ ! -e "$dstlnk" ] ; then
		   return 1;
	       fi	       
	       rm -f "$dst";
	       /bin/cp -fp "$dstlnk" "$dst";
	   fi;
	   /bin/mv "$dst" "$src";
       fi
    fi
    if [ -e "$dst" ]; then
       if [ ! -L "$dst" ]; then
	  if [ ! -s "$dst" ]; then
	     /bin/rm -f "$dst";
	  else	     
	     if [ "$src" -nt "$dst" ] || [ ! "$dst" -nt "$src" ] ; then
	        /bin/mv "$dst" "$dst".`/bin/date +'%Y-%m-%d_%H-%M-%S.%N'`;
	     else # [ "$dst" -nt "$src" ]
	        /bin/mv "$src" "$src".`/bin/date +'%Y-%m-%d_%H-%M-%S.%N'`;
	        /bin/mv "$dst" "$src";
	     fi;
	  fi;
       else
          dstlnk=`/usr/bin/readlink "$dst"`
	  if [ "$dstlnk" != $src ]; then
	     /bin/rm -f $dst;
	     if [ "$dstlnk" != "$dst" ] && [ -s $dstlnk ]; then
		 if [ "$dstlnk" -nt "$src" ] || [ ! "$dstlnk" -nt "$src" ] ; then		     
		     /bin/cp -fp "$dstlnk" "$dst".`/bin/date +'%Y-%m-%d_%H-%M-%S.%N'`;
		 else
		     /bin/mv "$src" "$src".`/bin/date +'%Y-%m-%d_%H-%M-%S.%N'`;
		     /bin/cp -fp "$dstlnk" "$src";
		 fi;
	     fi;
	  else
	     return 0;
	  fi;
       fi;
    fi; 
    /bin/ln -sf "$src" "$dst";
    return $?;
}

function replace_with_file()
{
    if [ $# -lt 2 ]; then
	return 1;
    fi;
    src=$1;
    dst=$2;
    if [ -z "$src" ] || [ -z "$dst" ] || [ "$src" = "$dst" ]; then
       return 1;
    fi
    if [ ! -e "$src" ]; then
       if [ -e "$dst" ]; then
	  /bin/rm -f $dst;
       fi;
       return 1;
    fi;
    if [ -e "$dst" ]; then
       if [ ! -L "$dst" ]; then
	   /bin/mv "$dst" "$dst".`/bin/date +'%Y-%m-%d_%H-%M-%S.%N'`;
       else
	   /bin/rm -f "$dst";
       fi;
    fi;
    /bin/mv -f "$src" "$dst";
}

function enable_bind_chroot()
{
    if /bin/egrep -q '^ROOTDIR=' /etc/sysconfig/named; then
	/bin/sed -i -e 's#^ROOTDIR=.*$#ROOTDIR='${BIND_CHROOT_PREFIX}'#' /etc/sysconfig/named ;
    else
	echo 'ROOTDIR='${BIND_CHROOT_PREFIX} >> /etc/sysconfig/named;
    fi
}

function disable_bind_chroot()
{
    /bin/sed -i -e '/^ROOTDIR=/d' /etc/sysconfig/named;    
}

function sync_files()
{
    shopt -q nullglob;
    ng=$?
    shopt -s nullglob;
    pfx=''
    changed=`/bin/mktemp /tmp/XXXXXX`;
    rm -f $changed
    if rootdir ; then # chroot is enabled
	/usr/bin/find /{etc/{named.*,rndc.*},${BIND_DIR#/}{/*,/data/*,/slaves/*}}  -maxdepth 0 -type f |
	while read f;
        do
	    replace_with_link ${BIND_CHROOT_PREFIX}/$f $f;
	    [ ! -e $changed ] && touch $changed;
	done;
	pfx=${BIND_CHROOT_PREFIX}
    else              # chroot is disabled	
	/usr/bin/find /var/named/chroot/{etc/{named.*,rndc.*},var/named{/*,/data/*,/slaves/*}} -maxdepth 0 |
	while read f; 
	do
	    if [ ! -d "$f" ]; then
		replace_with_file $f ${f#$BIND_CHROOT_PREFIX};
		[ ! -e $changed ] && touch $changed;
	    fi;
	done
    fi;
    if [ ! -e ${pfx}/etc/rndc.key ]; then
	   echo 'key "rndckey" {
	algorithm	hmac-md5;
	secret		"'`/usr/sbin/dns-keygen`'";
};'     > /etc/rndc.key;
    elif /bin/egrep -q '@KEY@' /etc/rndc.key; then
	/bin/sed -i -e 's^@KEY@^'`/usr/sbin/dns-keygen`'^' /etc/rndc.key ;
    fi
    chown root:named ${pfx}/var/named/* >/dev/null 2>&1;
    chmod 750 ${pfx}/var/named  >/dev/null 2>&1;
    chmod 640 ${pfx}/var/named/* >/dev/null 2>&1;
    chown named:named ${pfx}/var/named/{data{,/*},slaves{,*/}} >/dev/null 2>&1;
    chmod 770 ${pfx}/var/named/{data,slaves} >/dev/null 2>&1;
    chmod 640 ${pfx}/var/named/{data/*,slaves/*} >/dev/null 2>&1;
    if [ -e $changed ]; then
	if [ -e /selinux/enforce ] && [ -x /sbin/restorecon ]; then
	    if [ -n "$pfx" ]; then
		/sbin/restorecon -R $pfx/etc $pfx/var/named $pfx/var/run/named >/dev/null 2>&1;
		if [ -e $pfx/etc/localtime ] && [ -e /etc/localtime ] ; then 
		   /usr/bin/chcon --reference=/etc/localtime $pfx/etc/localtime >/dev/null 2>&1;
		fi;		
	    else
		/sbin/restorecon /etc/{named,rndc}.* >/dev/null 2>&1;
		/usr/bin/chcon --reference=/etc/named.conf /etc/named.* >/dev/null 2>&1;
		/sbin/restorecon -e /var/named/chroot /var/named{/,/data/,/slaves/}* >/dev/null 2>&1;
	    fi;
	fi;
	/sbin/service named condrestart
	rm -f $changed;
    fi;
    if [ $ng -eq 1 ]; then
	shopt -u nullglob;
    fi;
}

case $1 in 
    -e|--enable)
	enable_bind_chroot;
	sync_files;
	exit $?;
	;;
    -d|--disable)
	disable_bind_chroot;
	sync_files;
	/bin/umount ${BIND_CHROOT_PREFIX}/proc >/dev/null 2>&1 || :;
	/bin/umount ${BIND_CHROOT_PREFIX}/var/run/dbus >/dev/null 2>&1 || :;
	exit $?;
	;;
    -s|--sync)
        sync_files;
	exit $?;
	;;
    -q)
	;;
    *)
	usage;
	exit 1;
esac