xref: /freebsd/usr.sbin/bsdconfig/networking/share/resolv.subr (revision 7079fc4e0236ff334c2fb0f4367159be6df39332)

if [ ! "$_NETWORKING_RESOLV_SUBR" ]; then _NETWORKING_RESOLV_SUBR=1
#
# Copyright (c) 2006-2013 Devin Teske
# All Rights Reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
# $FreeBSD$
#
############################################################ INCLUDES

BSDCFG_SHARE="/usr/share/bsdconfig"
. $BSDCFG_SHARE/common.subr || exit 1
f_dprintf "%s: loading includes..." networking/resolv.subr
f_include $BSDCFG_SHARE/dialog.subr
f_include $BSDCFG_SHARE/media/tcpip.subr
f_include $BSDCFG_SHARE/networking/common.subr
f_include $BSDCFG_SHARE/networking/ipaddr.subr
f_include $BSDCFG_SHARE/strings.subr

BSDCFG_LIBE="/usr/libexec/bsdconfig" APP_DIR="120.networking"
f_include_lang $BSDCFG_LIBE/$APP_DIR/include/messages.subr

############################################################ CONFIGURATION

#
# When updating resolv.conf(5), should we populate the `search' directive with
# all possible sub-domains? In example, if the domain is "sub.domain.com", when
# the below option is set to 1, include both "sub.domain.com" and "domain.com"
# in the `search' directive, otherwise use only "sub.domain.com".
#
# When enabled (set to 1), specify the minimum number of dots required for each
# `search' domain by setting the second option below, `RESOLVER_SEARCH_NDOTS'.
#
: ${RESOLVER_SEARCH_DOMAINS_ALL:=1}
: ${RESOLVER_SEARCH_NDOTS:=1}

############################################################ FUNCTIONS

# f_resolv_conf_domain
#
# Returns the domain configured in resolv.conf(5).
#
f_resolv_conf_domain()
{
	tail -r "$RESOLV_CONF" 2> /dev/null | awk \
	'
		BEGIN { found = 0 }
		( tolower($1) == "domain" ) \
		{
			print $2
			found = 1
			exit
		}
		END { exit ! found }
	'
}

# f_resolv_conf_search
#
# Returns the search configured in resolv.conf(5).
#
f_resolv_conf_search()
{
	tail -r "$RESOLV_CONF" 2> /dev/null | awk \
	'
		BEGIN { found = 0 }
		{
			tl0 = tolower($0)
			if ( match(tl0, /^[[:space:]]*search[[:space:]]+/) ) {
				search = substr($0, RLENGTH + 1)
				sub(/[[:space:]]*#.*$/, "", search)
				gsub(/[[:space:]]+/, " ", search)
				print search
				found = 1
				exit
			}
		}
		END { exit ! found }
	'
}

# f_dialog_resolv_conf_update $hostname
#
# Updates the search/domain directives in resolv.conf(5) given a valid fully-
# qualified hostname.
#
# This function is a two-parter. Below is the awk(1) portion of the function,
# afterward is the sh(1) function which utilizes the below awk script.
#
f_dialog_resolv_conf_update_awk='
# Variables that should be defined on the invocation line:
# 	-v domain="domain"
# 	-v search_all="0|1"
# 	-v search_ndots="1+"
#
BEGIN {
	domain_found = search_found = 0

	if ( search_all ) {
		search = ""
		subdomain = domain
		if ( search_ndots < 1 )
			search_ndots = 1

		ndots = split(subdomain, labels, ".") - 1
		while ( ndots-- >= search_ndots ) {
			if ( length(search) ) search = search " "
			search = search subdomain
			sub(/[^.]*\./, "", subdomain)
		}
	}
	else search = domain
}
{
	if ( domain_found && search_found ) { print; next }

	tl0 = tolower($0)
	if ( ! domain_found && \
	     match(tl0, /^[[:space:]]*domain[[:space:]]+/) ) \
	{
		if ( length(domain) ) {
			printf "%s%s\n", substr($0, 0, RLENGTH), domain
			domain_found = 1
		}
	}
	else if ( ! search_found && \
	          match(tl0, /^[[:space:]]*search[[:space:]]+/) ) \
	{
		if ( length(search) ) {
			printf "%s%s\n", substr($0, 0, RLENGTH), search
			search_found = 1
		}
	}
	else print
}
END {
	if ( ! search_found && length(search) )
		printf "search\t%s\n", search
	if ( ! domain_found && length(domain) )
		printf "domain\t%s\n", domain
}
'
f_dialog_resolv_conf_update()
{
	local hostname="$1"

	#
	# Extrapolate the desired domain search parameter for resolv.conf(5)
	#
	local search ndots domain="${hostname#*.}"
	if [ "$RESOLVER_SEARCH_DOMAINS_ALL" = "1" ]; then
		search=""
		ndots=$( IFS=.; set -- $domain; echo $(( $# - 1 )) )
		while [ $ndots -ge ${RESOLVER_SEARCH_NDOTS:-1} ]; do
			search="$search${search:+ }$domain"
			domain="${domain#*.}"
			ndots=$(( $ndots - 1 ))
		done
		domain="${hostname#*.}"
	else
		search="$domain"
	fi

	#
	# Save domain/search information only if different from resolv.conf(5)
	#
	if [ "$domain" != "$( f_resolv_conf_domain )" -o \
	     "$search" != "$( f_resolv_conf_search )" ]
	then
		f_dialog_info "Saving new domain/search settings" \
		              "to resolv.conf(5)..."

		#
		# Create a new temporary file to write our resolv.conf(5)
		# update with our new `domain' and `search' directives.
		#
		local tmpfile="$( mktemp -t "$pgm" )"
		[ "$tmpfile" ] || return $FAILURE

		#
		# Fixup permissions and ownership (mktemp(1) creates the
		# temporary file with 0600 permissions -- change the
		# permissions and ownership to match resolv.conf(5) before
		# we write it out and mv(1) it into place).
		#
		local mode="$( stat -f '%#Lp' "$RESOLV_CONF" 2> /dev/null )"
		local owner="$( stat -f '%u:%g' "$RESOLV_CONF" 2> /dev/null )"
		f_quietly chmod "${mode:-0644}" "$tmpfile"
		f_quietly chown "${owner:-root:wheel}" "$tmpfile"

		#
		# Operate on resolv.conf(5), replacing only the last
		# occurrences of `domain' and `search' directives (or add
		# them to the top if not found), in strict-adherence to the
		# following entry in resolver(5):
		#
		# 	The domain and search keywords are mutually exclusive.
		# 	If more than one instance of these keywords is present,
		# 	the last instance will override.
		#
		# NOTE: If RESOLVER_SEARCH_DOMAINS_ALL is set to `1' in the
		# environment, all sub-domains will be added to the `search'
		# directive, not just the FQDN.
		#
		local domain="${hostname#*.}" new_contents
		[ "$domain" = "$hostname" ] && domain=
		new_contents=$( tail -r "$RESOLV_CONF" 2> /dev/null )
		new_contents=$( echo "$new_contents" | awk \
			-v domain="$domain" \
			-v search_all="${RESOLVER_SEARCH_DOMAINS_ALL:-1}" \
			-v search_ndots="${RESOLVER_SEARCH_NDOTS:-1}" \
			"$f_dialog_resolv_conf_update_awk" )

		#
		# Write the temporary file contents and move the temporary
		# file into place.
		#
		echo "$new_contents" | tail -r > "$tmpfile" || return $FAILURE
		f_quietly mv "$tmpfile" "$RESOLV_CONF"

	fi
}

# f_dialog_input_nameserver [ $n $nameserver ]
#
# Allows the user to edit a given nameserver. The first argument is the
# resolv.conf(5) nameserver ``instance'' integer. For example, this will be one
# if editing the first nameserver instance, two if editing the second, three if
# the third, ad nauseum. If this argument is zero, null, or missing, the value
# entered by the user (if non-null) will be added to resolv.conf(5) as a new
# `nameserver' entry. The second argument is the IPv4 address of the nameserver
# to be edited -- this will be displayed as the initial value during the edit.
#
# Taint-checking is performed when editing an existing entry (when the second
# argument is one or higher) in that the first argument must match the current
# value of the Nth `nameserver' instance in resolv.conf(5) else an error is
# generated discarding any/all changes.
#
# This function is a two-parter. Below is the awk(1) portion of the function,
# afterward is the sh(1) function which utilizes the below awk script.
#
f_dialog_input_nameserver_edit_awk='
# Variables that should be defined on the invocation line:
# 	-v nsindex="1+"
# 	-v old_value="..."
# 	-v new_value="..."
#
BEGIN {
	if ( nsindex < 1 ) exit 1
	found = n = 0
}
{
	if ( found ) { print; next }

	if ( match(tolower($0), /^[[:space:]]*nameserver[[:space:]]+/)) {
		if ( ++n == nsindex ) {
			if ( $2 != old_value ) exit 2
			if ( new_value != "" ) printf "%s%s\n", \
				substr($0, 0, RLENGTH), new_value
			found = 1
		}
		else print
	}
	else print
}
END { if ( ! found ) exit 3 }
'
f_dialog_input_nameserver()
{
	local index="${1:-0}" old_ns="$2" new_ns
	local ns="$old_ns"

	#
	# Perform sanity checks
	#
	f_isinteger "$index" || return $FAILURE
	[ $index -ge 0 ] || return $FAILURE

	local msg
	if [ $index -gt 0 ]; then
		if [ "$USE_XDIALOG" ]; then
			msg="$xmsg_please_enter_nameserver_existing"
		else
			msg="$msg_please_enter_nameserver_existing"
		fi
	else
		msg="$msg_please_enter_nameserver"
	fi

	#
	# Loop until the user provides taint-free input.
	#
	while :; do
		f_dialog_input new_ns "$msg" "$ns" \
		               "$hline_num_punc_tab_enter" || return

		# Take only the first "word" of the user's input
		new_ns="${new_ns%%[$IFS]*}"

		# Taint-check the user's input
		[ "$new_ns" ] || break
		f_dialog_validate_ipaddr "$new_ns" && break

		# Update prompt to allow user to re-edit previous entry
		ns="$new_ns"
	done

	#
	# Save only if the user changed the nameserver.
	#
	if [ $index -eq "0" -a "$new_ns" ]; then
		f_dialog_info "$msg_saving_nameserver"
		printf "nameserver\t%s\n" "$new_ns" >> "$RESOLV_CONF"
		return $SUCCESS
	elif [ $index -gt 0 -a "$old_ns" != "$new_ns" ]; then
		if [ "$new_ns" ]; then
			msg="$msg_saving_nameserver_existing"
		else
			msg="$msg_removing_nameserver"
		fi
		f_dialog_info "$msg"

		#
		# Create a new temporary file to write our new resolv.conf(5)
		#
		local tmpfile="$( mktemp -t "$pgm" )"
		[ "$tmpfile" ] || return $FAILURE

		#
		# Quietly fixup permissions and ownership
		#
		local mode owner
		mode=$( stat -f '%#Lp' "$RESOLV_CONF" 2> /dev/null )
		owner=$( stat -f '%u:%g' "$RESOLV_CONF" 2> /dev/null )
		f_quietly chmod "${mode:-0644}" "$tmpfile"
		f_quietly chown "${owner:-root:wheel}" "$tmpfile"

		#
		# Operate on resolv.conf(5)
		#
		local new_contents
		new_contents=$( awk -v nsindex="$index"    \
		                    -v old_value="$old_ns" \
		                    -v new_value="$new_ns" \
		                    "$f_dialog_input_nameserver_edit_awk" \
		                    "$RESOLV_CONF" )

		#
		# Produce an appropriate error message if necessary.
		#
		local retval=$?
		case $retval in
		1) f_die 1 "$msg_internal_error_nsindex_value" "$nsindex" ;;
		2) f_show_msg "$msg_resolv_conf_changed_while_editing"
		   return $retval ;;
		3) f_show_msg "$msg_resolv_conf_entry_no_longer_exists"
		   return $retval ;;
		esac

		#
		# Write the temporary file contents and move the temporary
		# file into place.
		#
		echo "$new_contents" > "$tmpfile" || return $FAILURE
		f_quietly mv "$tmpfile" "$RESOLV_CONF"
	fi
}

# f_dialog_menu_nameservers
#
# Edit the nameservers in resolv.conf(5).
#
f_dialog_menu_nameservers()
{
	local prompt="$msg_dns_configuration"
	local menu_list # Calculated below
	local hline="$hline_arrows_tab_enter"
	local defaultitem=

	local height width rows
	local opt_exit="$msg_return_to_previous_menu"
	local opt_add="$msg_add_nameserver"

	#
	# Loop forever until the user has finished configuring nameservers
	#
	while :; do
		#
		# Re/Build list of nameservers
		#
		local nameservers="$( f_resolv_conf_nameservers )"
		menu_list=$(
			index=1

			echo "'X $msg_exit' '$opt_exit'"
			index=$(( $index + 1 ))

			echo "'A $msg_add'  '$opt_add'"
			index=$(( $index + 1 ))

			for ns in $nameservers; do
				[ $index -lt ${#DIALOG_MENU_TAGS} ] || break
				tag=$( f_substr "$DIALOG_MENU_TAGS" $index 1 )
				echo "'$tag nameserver' '$ns'"
				index=$(( $index + 1 ))
			done
		)

		#
		# Display configuration-edit menu
		#
		eval f_dialog_menu_size height width rows \
		                        \"\$DIALOG_TITLE\"     \
		                        \"\$DIALOG_BACKTITLE\" \
		                        \"\$prompt\"           \
		                        \"\$hline\"            \
		                        $menu_list
		local tag
		tag=$( eval $DIALOG \
			--title \"\$DIALOG_TITLE\"         \
			--backtitle \"\$DIALOG_BACKTITLE\" \
			--hline \"\$hline\"                \
			--ok-label \"\$msg_ok\"            \
			--cancel-label \"\$msg_cancel\"    \
			--default-item \"\$defaultitem\"   \
			--menu \"\$prompt\"                \
			$height $width $rows               \
			$menu_list                         \
			2>&1 >&$DIALOG_TERMINAL_PASSTHRU_FD
		)
		local retval=$?
		f_dialog_data_sanitize tag

		# Return if "Cancel" was chosen (-1) or ESC was pressed (255)
		if [ $retval -ne $SUCCESS ]; then
			return $retval
		else
			# Only update default-item on success
			defaultitem="$tag"
		fi

		case "$tag" in
		"X $msg_exit") break ;;
		"A $msg_add")
			f_dialog_input_nameserver
			;;
		*)
			local n ns
			n=$( eval f_dialog_menutag2index \"\$tag\" $menu_list )
			ns=$( eval f_dialog_menutag2item \"\$tag\" $menu_list )
			f_dialog_input_nameserver $(( $n - 2 )) "$ns"
			;;
		esac
	done
}

############################################################ MAIN

f_dprintf "%s: Successfully loaded." networking/resolv.subr

fi # ! $_NETWORKING_RESOLV_SUBR