#!/bin/sh
# Copyright (c) 2007-2019 Roy Marples
# All rights reserved
# libc subscriber for resolvconf
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * 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 COPYRIGHT HOLDERS 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 COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 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.
SYSCONFDIR=@SYSCONFDIR@
LIBEXECDIR=@LIBEXECDIR@
VARDIR=@VARDIR@
IFACEDIR="$VARDIR/interfaces"
NL="
"
# sed may not be available, and this is faster on small files
key_get_value()
{
key="$1"
shift
if [ $# -eq 0 ]; then
while read -r line; do
case "$line" in
"$key"*) echo "${line##$key}";;
esac
done
else
for x do
while read -r line; do
case "$line" in
"$key"*) echo "${line##$key}";;
esac
done < "$x"
done
fi
}
keys_remove()
{
while read -r line; do
found=false
for key do
case "$line" in
"$key"*|"#"*|" "*|" "*|"") found=true;;
esac
$found && break
done
$found || echo "$line"
done
}
local_nameservers="127.* 0.0.0.0 255.255.255.255 ::1"
# Support original resolvconf configuration layout
# as well as the openresolv config file
if [ -f "$SYSCONFDIR"/resolvconf.conf ]; then
. "$SYSCONFDIR"/resolvconf.conf
elif [ -d "$SYSCONFDIR"/resolvconf ]; then
SYSCONFDIR="$SYSCONFDIR/resolvconf"
base="$SYSCONFDIR/resolv.conf.d/base"
if [ -f "$base" ]; then
prepend_nameservers="$(key_get_value "nameserver " "$base")"
domain="$(key_get_value "domain " "$base")"
prepend_search="$(key_get_value "search " "$base")"
resolv_conf_options="$(key_get_value "options " "$base")"
resolv_conf_sortlist="$(key_get_value "sortlist " "$base")"
fi
if [ -f "$SYSCONFDIR"/resolv.conf.d/head ]; then
resolv_conf_head="$(cat "${SYSCONFDIR}"/resolv.conf.d/head)"
fi
if [ -f "$SYSCONFDIR"/resolv.conf.d/tail ]; then
resolv_conf_tail="$(cat "$SYSCONFDIR"/resolv.conf.d/tail)"
fi
fi
: ${resolv_conf:=/etc/resolv.conf}
: ${libc_service:=nscd}
: ${list_resolv:=@SBINDIR@/resolvconf -l}
if [ "${resolv_conf_head-x}" = x ] && [ -f "$SYSCONFDIR"/resolv.conf.head ]
then
resolv_conf_head="$(cat "${SYSCONFDIR}"/resolv.conf.head)"
fi
if [ "${resolv_conf_tail-x}" = x ] && [ -f "$SYSCONFDIR"/resolv.conf.tail ]
then
resolv_conf_tail="$(cat "$SYSCONFDIR"/resolv.conf.tail)"
fi
backup=true
signature="# Generated by resolvconf"
uniqify()
{
result=
while [ -n "$1" ]; do
case " $result " in
*" $1 "*);;
*) result="$result $1";;
esac
shift
done
echo "${result# *}"
}
case "${resolv_conf_passthrough:-NO}" in
[Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]|[Oo][Nn]|1)
backup=false
newest=
for conf in "$IFACEDIR"/*; do
if [ -z "$newest" ] || [ "$conf" -nt "$newest" ]; then
newest="$conf"
fi
done
[ -z "$newest" ] && exit 0
newconf="$(cat "$newest")$NL"
;;
/dev/null|[Nn][Uu][Ll][Ll])
: ${resolv_conf_local_only:=NO}
if [ "$local_nameservers" = "127.* 0.0.0.0 255.255.255.255 ::1" ]; then
local_nameservers=
fi
# Need to overwrite our variables.
eval "$(@SBINDIR@/resolvconf -V)"
;;
*)
[ -z "$RESOLVCONF" ] && eval "$(@SBINDIR@/resolvconf -v)"
;;
esac
case "${resolv_conf_passthrough:-NO}" in
[Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]|[Oo][Nn]|1) ;;
*)
: ${domain:=$DOMAIN}
newsearch="$(uniqify $prepend_search $SEARCH $append_search)"
NS="$LOCALNAMESERVERS $NAMESERVERS"
newns=
gotlocal=false
for n in $(uniqify $prepend_nameservers $NS $append_nameservers); do
add=true
islocal=false
for l in $local_nameservers; do
case "$n" in
$l) islocal=true; gotlocal=true; break;;
esac
done
if ! $islocal; then
case "${resolv_conf_local_only:-YES}" in
[Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]|[Oo][Nn]|1)
$gotlocal && add=false;;
esac
fi
$add && newns="$newns $n"
done
# Hold our new resolv.conf in a variable to save on temporary files
newconf="$signature$NL"
if [ -n "$resolv_conf_head" ]; then
newconf="$newconf$resolv_conf_head$NL"
fi
[ -n "$domain" ] && newconf="${newconf}domain $domain$NL"
if [ -n "$newsearch" ] && [ "$newsearch" != "$domain" ]; then
newconf="${newconf}search $newsearch$NL"
fi
for n in $newns; do
newconf="${newconf}nameserver $n$NL"
done
# Now add anything we don't care about such as sortlist and options
stuff="$($list_resolv | keys_remove nameserver domain search)"
if [ -n "$stuff" ]; then
newconf="$newconf$stuff$NL"
fi
# Append any user defined ones
if [ -n "$resolv_conf_options" ]; then
newconf="${newconf}options $resolv_conf_options$NL"
fi
if [ -n "$resolv_conf_sortlist" ]; then
newconf="${newconf}sortlist $resolv_conf_sortlist$NL"
fi
if [ -n "$resolv_conf_tail" ]; then
newconf="$newconf$resolv_conf_tail$NL"
fi
;;
esac
# Check if the file has actually changed or not
if [ -e "$resolv_conf" ]; then
[ "$(cat "$resolv_conf")" = "$(printf %s "$newconf")" ] && exit 0
fi
# Change is good.
# If the old file does not have our signature, back it up.
# If the new file just has our signature, restore the backup.
if $backup; then
if [ "$newconf" = "$signature$NL" ]; then
if [ -e "$resolv_conf.bak" ]; then
newconf="$(cat "$resolv_conf.bak")$NL"
fi
elif [ -e "$resolv_conf" ]; then
read line <"$resolv_conf"
if [ "$line" != "$signature" ]; then
cp "$resolv_conf" "$resolv_conf.bak"
fi
fi
fi
# Create our resolv.conf now
(umask 022; echo "$newconf" >"$resolv_conf")
if [ -n "$libc_restart" ]; then
eval $libc_restart
elif [ -n "$RESTARTCMD" ]; then
set -- ${libc_service}
eval "$RESTARTCMD"
else
@SBINDIR@/resolvconf -r ${libc_service}
fi
retval=0
# Notify users of the resolver
for script in "$LIBEXECDIR"/libc.d/*; do
if [ -f "$script" ]; then
if [ -x "$script" ]; then
"$script" "$@"
else
(. "$script")
fi
retval=$(($retval + $?))
fi
done
exit $retval
