Add support for MaraDNS

MaraDNS is a lightweight self-hosting DNS server. This patch adds
support for adding records to zone files stored on the server in the
format expected by MaraDNS. Path to the file should be exported in
MARA_ZONE_FILE environment variable. To reload the configuration
automatically, the user must provide path to the pid file of duende (the
daemonization tool that ships with MaraDNS) in MARA_DUENDE_PID_PATH
(--pid argument to duende).

dnsapi/dns_maradns.sh

@@ -0,0 +1,69 @@
+#!/usr/bin/env sh
+
+#Usage: dns_maradns_add _acme-challenge.www.domain.com "token"
+dns_maradns_add() {
+  fulldomain="$1"
+  txtvalue="$2"
+
+  MARA_ZONE_FILE="${MARA_ZONE_FILE:-$(_readaccountconf_mutable MARA_ZONE_FILE)}"
+  MARA_DUENDE_PID_PATH="${MARA_DUENDE_PID_PATH:-$(_readaccountconf_mutable MARA_DUENDE_PID_PATH)}"
+
+  _check_zone_file "$MARA_ZONE_FILE" || return 1
+  _check_duende_pid_path "$MARA_DUENDE_PID_PATH" || return 1
+
+  _saveaccountconf_mutable MARA_ZONE_FILE "$MARA_ZONE_FILE"
+  _saveaccountconf_mutable MARA_DUENDE_PID_PATH "$MARA_DUENDE_PID_PATH"
+
+  printf "%s. TXT '%s' ~\n" "$fulldomain" "$txtvalue" >>"$MARA_ZONE_FILE"
+  _reload_maradns "$MARA_DUENDE_PID_PATH" || return 1
+}
+
+#Usage: dns_maradns_rm _acme-challenge.www.domain.com "token"
+dns_maradns_rm() {
+  fulldomain="$1"
+  txtvalue="$2"
+
+  MARA_ZONE_FILE="${MARA_ZONE_FILE:-$(_readaccountconf_mutable MARA_ZONE_FILE)}"
+  MARA_DUENDE_PID_PATH="${MARA_DUENDE_PID_PATH:-$(_readaccountconf_mutable MARA_DUENDE_PID_PATH)}"
+
+  _check_zone_file "$MARA_ZONE_FILE" || return 1
+  _check_duende_pid_path "$MARA_DUENDE_PID_PATH" || return 1
+
+  _saveaccountconf_mutable MARA_ZONE_FILE "$MARA_ZONE_FILE"
+  _saveaccountconf_mutable MARA_DUENDE_PID_PATH "$MARA_DUENDE_PID_PATH"
+
+  _sed_i "/^$fulldomain.\+TXT '$txtvalue' ~/d" "$MARA_ZONE_FILE"
+  _reload_maradns "$MARA_DUENDE_PID_PATH" || return 1
+}
+
+_check_zone_file() {
+  zonefile="$1"
+  if [ -z "$zonefile" ]; then
+    _err "MARA_ZONE_FILE not passed!"
+    return 1
+  elif [ ! -w "$zonefile" ]; then
+    _err "MARA_ZONE_FILE not writable: $zonefile"
+    return 1
+  fi
+}
+
+_check_duende_pid_path() {
+  pidpath="$1"
+  if [ -z "$pidpath" ]; then
+    _err "MARA_DUENDE_PID_PATH not passed!"
+    return 1
+  fi
+  if [ ! -r "$pidpath" ]; then
+    _err "MARA_DUENDE_PID_PATH not readable: $pidpath"
+    return 1
+  fi
+}
+
+_reload_maradns() {
+  pidpath="$1"
+  kill -s HUP -- "$(cat "$pidpath")"
+  if [ $? -ne 0 ]; then
+    _err "Unable to reload MaraDNS, kill returned $?"
+    return 1
+  fi
+}