Leave resolv.conf to resolvd if it learned nameservers

During install (not upgrade) the installer parses resolv.conf looking for
nameservers, FQDN and domain information;  it also prompts for nameservers
if none were found.

If DHCP is used and nameservers were found, resolv.conf gets recreated from
scratch.

Under dhclient(8) this was fine, but resolvd(8) persists learned proposals
across such file modifications and resolv.conf will thus contain a mix
between managed and manual entries -- stale duplicates which users have to
remove manually.

Do not touch resolv.conf anymore in case resolvd knows better and thus
provide a clean file for installations.

OK florian

diff --git a/distrib/miniroot/install.sub b/distrib/miniroot/install.sub
index fb95222..757b95a 100644 (file)
--- a/distrib/miniroot/install.sub
+++ b/distrib/miniroot/install.sub
@@ -1,5 +1,5 @@
 #!/bin/ksh
-#      $OpenBSD: install.sub,v 1.1169 2021/07/20 11:20:09 kn Exp $
+#      $OpenBSD: install.sub,v 1.1170 2021/08/02 01:29:26 kn Exp $
 #
 # Copyright (c) 1997-2015 Todd Miller, Theo de Raadt, Ken Westerback
 # Copyright (c) 2015, Robert Peichaer <rpe@openbsd.org>
@@ -2052,7 +2052,7 @@ set_term() {
 
 # Configure the network.
 donetconfig() {
-       local _dn _ns _f1 _f2 _f3
+       local _dn _ns _f1 _f2 _f3 _autoconf_ns=false
 
        configure_ifs
        v4_defroute
@@ -2065,6 +2065,7 @@ donetconfig() {
                # domain given on *last* search or domain statement.
                while read -r -- _f1 _f2 _f3; do
                        [[ $_f1 == nameserver ]] && _ns="${_ns:+$_ns }$_f2"
+                       [[ $_f3 == '# resolvd: '* ]] && _autoconf_ns=true
                        [[ $_f1 == @(domain|search) ]] && _dn=$_f2
                done </etc/resolv.conf
        fi
@@ -2086,6 +2087,11 @@ donetconfig() {
        fi
        hostname "$(hostname -s).$resp"
 
+       if $_autoconf_ns && [[ -n $_ns ]]; then
+               echo "Using DNS nameservers at $_ns"
+               return
+       fi
+
        # Get & add nameservers to /tmp/resolv.conf. Don't ask if there's only
        # one configured interface and if it's managed by dhcp and if the
        # nameserver is configured via dhcp too.