#!/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
	ENABLED=0;
    else
	ENABLED=1;
    fi;
}

function selinux_enabled()
{
    if [ -x /usr/sbin/selinuxenabled ]; then
      /usr/sbin/selinuxenabled;
      return $?;
    fi;
    return 1;
}

function check_dirs()
{
    if [ -z "$BIND_CHROOT_PREFIX" ]; then
        usage;
        exit 1;
    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
    if [ -e /etc/sysconfig/named ]; then
	/bin/chown root:named /etc/sysconfig/named;
	/bin/chmod 0640 /etc/sysconfig/named;
    fi
    /bin/mkdir -p ${BIND_DIR}/{slaves,data,dynamic};
    /bin/chown --preserve-root root:named ${BIND_DIR};
    /bin/chown --preserve-root named:named ${BIND_DIR}/{slaves,data,dynamic};
    /bin/chmod --preserve-root 750 ${BIND_DIR}
    /bin/chmod --preserve-root 770 ${BIND_DIR}/{slaves,data,dynamic};
        
    mkdir -p ${BIND_CHROOT_PREFIX}/{etc,dev,var/{run/named,named/{slaves,data,dynamic}}};
    /bin/chown --preserve-root root:named ${BIND_CHROOT_PREFIX}/{etc,dev,var/{run,named/}};
    /bin/chown --preserve-root root:named ${BIND_CHROOT_PREFIX}/var;
    /bin/chmod --preserve-root 750 ${BIND_CHROOT_PREFIX}/{,etc,dev,var,var/{run,named/}};
    /bin/chown --preserve-root named:named ${BIND_CHROOT_PREFIX}/var/{run/named,named/{data,slaves,dynamic}};
    /bin/chmod --preserve-root 770 ${BIND_CHROOT_PREFIX}/var/{run/named,named/{slaves,data,dynamic}};        
    
    [ ! -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";
    /bin/chown --preserve-root root:named "${BIND_CHROOT_PREFIX}"/dev/{random,null,zero};
    /bin/chmod --preserve-root 660 "${BIND_CHROOT_PREFIX}"/dev/{random,null,zero};
    if selinux_enabled && [ -x /sbin/restorecon ]; then       
       for dev in random zero null; do
	   /sbin/restorecon ${BIND_CHROOT_PREFIX}/dev/$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" ] || /usr/bin/cmp "$dst" "$src" > /dev/null 2>&1; 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 $dst;
	     if ! /usr/bin/cmp "$dstlnk" "$src" > /dev/null 2>&1; then
		if [ "$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" "$src";
		  fi;
	        fi;
	     fi;
	  else
	     return 0;
	  fi;
       fi;
    fi; 
    /bin/ln -sf "$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()
{
    rootdir;
    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()
{
    rootdir;
    shopt -q nullglob;
    ng=$?
    shopt -s nullglob;
    pfx=''
    changed=`/bin/mktemp /tmp/XXXXXX`;
    rm -f $changed
    if [ $ENABLED -eq 0 ] ; then # chroot is enabled
	/usr/bin/find /{etc/{named.*,rndc.*},${BIND_DIR#/}{/*,/data/*,/slaves/*,/dynamic/*}} /var/log/named.log  -maxdepth 0 -type f |
	while read f;
        do
	    replace_with_link ${BIND_CHROOT_PREFIX}$f $f;
	    [ ! -e $changed ] && touch $changed;
	done;
	/usr/bin/find /etc/{named.*,rndc.*}.rpmsave ${BIND_DIR}/*.rpmsave  -maxdepth 0 -type l 2>/dev/null |
	while read f;
	do
	    /bin/rm -f $f >/dev/null 2>&1;
	done
	pfx=${BIND_CHROOT_PREFIX}
    else              # chroot is disabled	
	/usr/bin/find /var/named/chroot/{etc/{named.*,rndc.*},var/{named{/*,/data/*,/slaves/*,/dynamic/*},log/named.log}} -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 -h root:named /var/named/* >/dev/null 2>&1;
    chown -h root:named ${BIND_CHROOT_PREFIX}/var/named/* >/dev/null 2>&1;
    chown -h root:named /etc/{named,rndc}.* >/dev/null 2>&1;
    chown -h root:named ${BIND_CHROOT_PREFIX}/etc/{named,rndc}.* >/dev/null 2>&1;
    chown -h named:named /var/log/named.log >/dev/null 2>&1;
    chown -h named:named ${BIND_CHROOT_PREFIX}/var/log/named.log >/dev/null 2>&1;
    chmod 750 ${pfx}/var/named  >/dev/null 2>&1;
    chmod 640 ${pfx}/var/named/* >/dev/null 2>&1;
    chmod 750 ${pfx}/var/named/*/. >/dev/null 2>&1;
    chmod 660 ${pfx}/var/log/named.log >/dev/null 2>&1;
    chown -h named:named /var/named/{data{,/*},slaves{,/*},dynamic{,/*}} >/dev/null 2>&1;
    chown -h named:named ${BIND_CHROOT_PREFIX}/var/named/{data{,/*},slaves{,/*},dynamic{,/*}} >/dev/null 2>&1;
    chmod 770 ${pfx}/var/named/{data,slaves,dynamic} >/dev/null 2>&1;
    chmod 660 ${pfx}/var/named/{data/*,slaves/*,dynamic/*} >/dev/null 2>&1;
    chmod 770 ${pfx}/var/named/{data/*/.,slaves/*/.,dynamic/*/.} >/dev/null 2>&1;
    if [ -e $changed ]; then
	if selinux_enabled && [ -x /sbin/restorecon ]; then
	   /sbin/restorecon -R ${BIND_CHROOT_PREFIX}/{dev,etc,var} >/dev/null 2>&1;
	   /sbin/restorecon /etc/named.*    >/dev/null 2>&1;
	   /sbin/restorecon /etc/rndc.key   >/dev/null 2>&1;
	   /sbin/restorecon /etc/rndc.conf  >/dev/null 2>&1;
	   for all in `ls /var/named`; do
		if [ "x$all" != "xchroot" ]; then
		    restorecon -R /var/named/"$all" > /dev/null 2>&1;
		fi
	   done
	fi;
	/sbin/service named try-restart
	rm -f $changed;
    fi;
    if [ $ng -eq 1 ]; then
	shopt -u nullglob;
    fi;
}

function clean_root()
{
    if [ $ENABLED -eq 0 ] ; then # chroot is disabled, clean it up
        if [ -n "${BIND_CHROOT_PREFIX}" -a "x${BIND_CHROOT_PREFIX}" != "x/" ]; then
            rm -r ${BIND_CHROOT_PREFIX}/dev  >/dev/null 2>&1 || :;
	    rmdir ${BIND_CHROOT_PREFIX}/etc  >/dev/null 2>&1 || :;
	    rmdir ${BIND_CHROOT_PREFIX}/var/run/named  >/dev/null 2>&1 || :;
	    rmdir ${BIND_CHROOT_PREFIX}/var/run/dbus  >/dev/null 2>&1 || :;
	    rmdir ${BIND_CHROOT_PREFIX}/var/run  >/dev/null 2>&1 || :;
	    rmdir ${BIND_CHROOT_PREFIX}/var/named/slaves  >/dev/null 2>&1 || :;
	    rmdir ${BIND_CHROOT_PREFIX}/var/named/data  >/dev/null 2>&1 || :;
	    rmdir ${BIND_CHROOT_PREFIX}/var/named/dynamic >/dev/null 2>&1 || :;
	    rmdir ${BIND_CHROOT_PREFIX}/var/named  >/dev/null 2>&1 || :;
	    rmdir ${BIND_CHROOT_PREFIX}/var/tmp  >/dev/null 2>&1 || :;
	    rmdir ${BIND_CHROOT_PREFIX}/var  >/dev/null 2>&1 || :;
        fi;
    fi;
}

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