#!/bin/sh --

#

# CDDL HEADER START

#

# The contents of this file are subject to the terms of the

# Common Development and Distribution License (the "License").

# You may not use this file except in compliance with the License.

#

# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE

# or http://www.opensolaris.org/os/licensing.

# See the License for the specific language governing permissions

# and limitations under the License.

#

# When distributing Covered Code, include this CDDL HEADER in each

# file and include the License file at usr/src/OPENSOLARIS.LICENSE.

# If applicable, add the following below this CDDL HEADER, with the

# fields enclosed by brackets "[]" replaced with your own identifying

# information: Portions Copyright [yyyy] [name of copyright owner]

#

# CDDL HEADER END

#

# Check hostname configuration as per the sendmail code.

#

#

#

PATH=/bin:/usr/sbin

# If $1 has a ".", accept it and exit.

accept_if_fully_qualified() {

	case $1 in

	*.*)

		echo "Hostname $myhostname OK: fully qualified as $1"

		exit 0

		;;

	esac

}

# Check the `getent hosts $1` output, skipping the 1st entry (IP address).

check_gethostbyname() {

	for host in `getent hosts $1 | awk '{for (f=2; f <= NF; f++) print $f}'`

	do

		accept_if_fully_qualified $host

	done

}

# Parse /etc/hosts, looking for $1 as an entry by itself, and try to find

# a long name on the same line.  First kill all comments, then check for

# $1 as a word by itself, then take just the first such line, then skip

# its first entry (IP address).

check_hosts_file() {

	for entry in `sed -e 's/#.*$//' /etc/hosts | \

		awk '/[ 	]'$1'([ 	]|$)/ \

			{for (f=2; f <= NF; f++) print $f; exit}'`

	do

		accept_if_fully_qualified $entry

	done

}

# Parse the output of `nslookup $1`, checking the Name and Aliases.

check_dns() {

	for host in `nslookup $1 2>/dev/null | \

		awk '$1 == "Name:" || $1 == "Aliases:"{print $2}'`

	do

		accept_if_fully_qualified $host

	done

}

# Check the `ypmatch $1 hosts` output, skipping the 1st entry (IP address).

check_nis() {

	for hst in `ypmatch $1 hosts | awk '{for (f=2; f <= NF; f++) print $f}'`

	do

		accept_if_fully_qualified $hst

	done

}

# Recommend how to reconfigure to get $1.$2 as the FQHN.

# $3 is the first entry for hosts in /etc/nsswitch.conf . 

suggest_fix_and_exit() {

	myhost=$1

	suggested_domain=$2

	fhe=$3

	myipaddr=`getent hosts $myhost | head -1 | awk '{print $1}'`

	# aliases: skip the 1st & 2nd entries: IP address & canonical name

	set -- '' '' '[ aliases ... ]'

	set -- `grep "^$myipaddr[	 ]" /etc/hosts 2>/dev/null`

	result=$?

	shift 2

	echo "We recommend \c"

	if [ "x$fhe" != "xfiles" ] ; then

		echo "listing files first for hosts in /etc/nsswitch.conf"

		echo "and then \c"

	fi

	if [ $result = 0 ] ; then

		echo "changing the /etc/hosts entry:\n"

		echo "$myipaddr $myhost $*\n"

		echo "to:\n"

	else

		echo "adding the /etc/hosts entry:\n"

	fi

	echo "$myipaddr $myhost $myhost.$suggested_domain $*"

}

# Fall back to the NIS domain, minus the first label.  If it is non-null,

# use it but recommend against it.  $2 is just informative, indicating whether

# we're checking the NIS domain.  $3 is to pass on.

check_nis_domain() {

	nisdomain=`domainname`

	realdomain=`echo $nisdomain | sed 's/[^.]*\.//'`

	if [ "x$realdomain" != "x" ] ; then

		echo "Hostname $1 can be fully qualified using NIS$2 domain"

		echo "	$nisdomain"

		echo "resulting in the name"

		echo "	$1.$realdomain"

		echo "but this is bad practice.\n"

		suggest_fix_and_exit $1 $realdomain $3

	fi

}

# Goal: try to fully qualify `hostname` as sendmail would.

# Algorithm (stop as soon as a name with a dot is found):

#    1. gethostbyname (simulate with getent hosts)

#    2. fall back to individual hosts: methods in nsswitch.conf, using

#       only those that are configured, in their configured order

#       * files (parse /etc/hosts directly)

#       * dns (parse nslookup output)

#       * nis (parse ypmatch output)

#    3. fall back to the NIS domain name.

# If none of the above succeed, give up.  Recommend:

#    a. the domain entry in /etc/resolv.conf, if one exists

#    b. "pick.some.domain"

myhostname=`hostname`

check_gethostbyname $myhostname

hosts_line=`sed -n -e 's/^hosts:\([^#]*\).*/\1/p' /etc/nsswitch.conf`

first_hosts_entry=`echo $hosts_line | awk '{print $1}'`

nis_domains=""

for entry in $hosts_line

do

	case $entry in

	files)

		check_hosts_file $myhostname

		;;

	dns)

		check_dns $myhostname

		;;

	nis)

		check_nis $myhostname

		nis_domains="$nis_domains nis"

		;;

	esac

done

for entry in $nis_domains

do

	case $entry in

	nis)

		check_nis_domain $myhostname "" $first_hosts_entry

		;;

	esac

done

realdomain=`awk '$1 ~ /^domain/ {print $2}' 2>/dev/null < /etc/resolv.conf`

case $realdomain in

*.*)

	# OK

	;;

*)

	realdomain="pick.some.domain"

	;;

esac

echo "Hostname $myhostname could not be fully qualified."

suggest_fix_and_exit $myhostname $realdomain $first_hosts_entry