#/bin/sh
set -e
+dkim_selector=$1
+if [ ! -n "${dkim_selector}" ]; then
+ echo "Give DKIM selector argument."
+ false
+fi
+
+# Set up DKIM key if necessary.
+mkdir -p /etc/dkimkeys/
+add_dkim_record=0
+if [ ! -f "/etc/dkimkeys/${dkim_selector}.private" ]; then
+ add_dkim_record=1
+ set +e
+ dpkg -s opendkim-tools &> /dev/null
+ preinstalled="$?"
+ set -e
+ if [ ! "${preinstalled}" -eq "0" ]; then
+ apt install -y opendkim-tools
+ fi
+ opendkim-genkey -s "${dkim_selector}"
+ mv "${dkim_selector}.private" /etc/dkimkeys/
+ if [ ! "${preinstalled}" -eq "0" ]; then
+ apt -y --purge autoremove opendkim-tools
+ fi
+fi
+
+# Link and adapt mail-server-specific /etc/ files.
+./hardlink_etc.sh mail
+sed -i "s/REPLACE_Domain_ECALPER/$(hostname -f)/g" /etc/opendkim.conf
+sed -i "s/REPLACE_Selector_ECALPER/${dkim_selector}/g" /etc/opendkim.conf
+
+# Some useful debconf selections.
echo "postfix postfix/main_mailer_type string 'Internet Site'" | debconf-set-selections
-echo "postfix postfix/mailname string $(hostname -f)" | debconf-set-selections
-echo "$(hostname -f)" > /etc/mailname
-apt install -y postfix
-mkdir -p /etc/dovecot/conf.d/
echo "ssl_cert = </etc/letsencrypt/live/$(hostname -f)/fullchain.pem" > /etc/dovecot/conf.d/99-ssl-certs.conf
echo "ssl_key = </etc/letsencrypt/live/$(hostname -f)/privkey.pem" >> /etc/dovecot/conf.d/99-ssl-certs.conf
-apt install -y dovecot-imapd
+
+# The second line should not be necessary due to the first line, but for
+# some reason the installation forgets to set up /etc/mailname early
+# enough to not (when running newaliases) stumble over its absence.
+echo "postfix postfix/mailname string $(hostname -f)" | debconf-set-selections
+echo "$(hostname -f)" > /etc/mailname
+
+# Everything should now be ready for installations.
+apt install -y -o Dpkg::Options::=--force-confold postfix dovecot-imapd opendkim
+echo "TODO: Ensure MX entry for your system in your DNS configuration."
+echo "TODO: Ensure a proper SPF entry for this system in your DNS configuration; something like 'v=spf1 a mx -all' mapped to your host."
+if [ "${add_dkim_record}" -eq "1" ]; then
+ echo "TODO: Add the following DKIM entry to your DNS configuration (possibly with slightly changed host entry – if your mail domain includes a subdomain, append that with a dot):"
+ cat "${dkim_selector}.txt"
+fi