+
+# * initial dns config & daemon setup
+#
+# use systemd-resolved for glibc resolutions, setup symlinks
+
+pi libnss-resolve
+
+# if this link gets replaced with a normal file we will get exim log
+# errors on MAIL_HOST like so:
+#
+# R=fsfsmarthost defer (-36) DT=0s: host lookup for mail.fsf.org did not complete (DNS timeout?)
+
+if [[ ! -L /etc/nsswitch.conf ]]; then
+ sudo mkdir -p /etc/resolved-nsswitch
+ sudo mv /etc/nsswitch.conf /etc/resolved-nsswitch
+ sudo ln -sf /etc/resolved-nsswitch/nsswitch.conf /etc
+fi
+
+f=/etc/basic-nsswitch/nsswitch.conf
+if [[ ! -e $f ]]; then
+ sudo mkdir -p ${f%/*}
+ sudo cp /etc/nsswitch.conf $f
+ sudo sed -i --follow-symlinks 's/^ *hosts:.*/hosts: files dns myhostname/' $f
+fi
+case $HOSTNAME in
+ bk|je)
+ # je should be able to get along systemd-resolved, but ive had some odd
+ # very intermittent dns failures with spamassassin, it seems it might only
+ # be happening with systemd-resolved, so just use unbound
+ # to make it consistent with the other hosts.
+ sudo sed -i --follow-symlinks 's/^ *hosts:.*/hosts: files dns myhostname/' /etc/nsswitch.conf
+ soff systemd-resolved
+ sudo ln -sf 127.0.0.1-resolv/stub-resolv.conf /etc/resolv.conf
+ sgo unbound
+ # cautious measure to make sure resolution is working
+ sleep 1
+ ;;
+ *)
+ # default is
+ # files mdns4_minimal [NOTFOUND=return] dns myhostname
+ # mdns4 is needed for my printer and for bbb webrtc, not sure exactly why.
+ # https://www.freedesktop.org/software/systemd/man/nss-resolve.html#
+ # seems more important than some potential use case.
+ # Interestingly, t9/t10 man page says use files before resolve, debian 10 says the opposite.
+ # removing files makes hostname -f not actually give the fully qualified domain name.
+ sudo sed -i --follow-symlinks 's/^ *hosts:.*/hosts: files resolve [!UNAVAIL=return] mdns4_minimal [NOTFOUND=return] myhostname/' /etc/resolved-nsswitch/nsswitch.conf
+ ;;
+esac
+
+case $HOSTNAME in
+ bk)
+ sgo named
+ ;;
+esac
+
+
+lines=(
+ "/etc/resolved-nsswitch/nsswitch.conf r,"
+ "/etc/basic-nsswitch/nsswitch.conf r,"
+ # Aug 06 23:09:11 kd audit[3995]: AVC apparmor="DENIED" operation="connect" profile="/usr/bin/freshclam" name="/run/systemd/resolve/io.systemd.Resolve" pid=3995 comm="freshclam" requested_mask="wr" denied_mask="wr" fsuid=109 ouid=101
+ # I dont know if this is quite the right fix, but I saw other sockets
+ # in the nameservice files that were rw, so figured it was ok to add this and it worked.
+ "/run/systemd/resolve/io.systemd.Resolve rw,"
+)
+f=/etc/apparmor.d/abstractions/nameservice
+apparmor_reload=false
+if [[ -e $f ]]; then
+ for l in "${lines[@]}"; do
+ if ! grep -qF "$l" $f; then
+ sudo sed -i "/\/nsswitch.conf/a $l" $f
+ apparmor_reload=true
+ if ! grep -qF "$l" $f; then
+ echo "$0: failed editing $f. investigate"
+ exit 1
+ fi
+ fi
+ done
+ if $apparmor_reload && systemctl is-active apparmor; then
+ m ser reload apparmor
+ fi
+fi
+
+
+