From 7dcb836a255f6d849537c8770a06823939a782b1 Mon Sep 17 00:00:00 2001
From: Luca Beltrame <lbeltrame@kde.org>
Date: Sun, 5 Jun 2022 22:41:30 +0200
Subject: [PATCH] Scripts to check and restart kresd if it does not respond

---
 sysadmin/dnscheck.config           |  7 ++++
 sysadmin/dnscheck.init             | 41 +++++++++++++++++++
 sysadmin/turrisos-restart-kresd.sh | 64 ++++++++++++++++++++++++++++++
 3 files changed, 112 insertions(+)
 create mode 100644 sysadmin/dnscheck.config
 create mode 100644 sysadmin/dnscheck.init
 create mode 100644 sysadmin/turrisos-restart-kresd.sh

diff --git a/sysadmin/dnscheck.config b/sysadmin/dnscheck.config
new file mode 100644
index 0000000..a6144fa
--- /dev/null
+++ b/sysadmin/dnscheck.config
@@ -0,0 +1,7 @@
+# Place this in /etc/config/dnscheck
+
+config setup 'check_service'
+    option host 'CHANGEME'
+    option server '127.0.0.1'
+    option timeout '5'
+    option maxfailures '3'
diff --git a/sysadmin/dnscheck.init b/sysadmin/dnscheck.init
new file mode 100644
index 0000000..23325fe
--- /dev/null
+++ b/sysadmin/dnscheck.init
@@ -0,0 +1,41 @@
+#!/bin/sh /etc/rc.common
+#
+# start dnscheck
+#
+# https://openwrt.org/docs/guide-developer/procd-init-script-example
+
+# Init sequence
+START=99
+STOP=10
+
+# PROCD
+USE_PROCD=1
+
+start_service() {
+	procd_open_instance dnscheck
+	procd_set_param command /bin/sh "/usr/lib/dnscheck/dnscheck.sh"
+
+	procd_set_param respawn ${respawn_threshold:-3600} ${respawn_timeout:-5} ${respawn_retry:-5}
+
+	procd_set_param stdout 1 # forward stdout of the command to logd
+	procd_set_param stderr 1 # same for stderr
+
+	procd_set_param pidfile /var/run/dnscheck.pid
+
+	procd_close_instance
+}
+
+stop_service() {
+	logger -t "dnscheck" "kresd monitoring stopped"
+}
+
+service_triggers()
+{
+	procd_add_reload_trigger "dnscheck"
+}
+
+reload_service()
+{
+	stop
+	start
+}
diff --git a/sysadmin/turrisos-restart-kresd.sh b/sysadmin/turrisos-restart-kresd.sh
new file mode 100644
index 0000000..3593dfa
--- /dev/null
+++ b/sysadmin/turrisos-restart-kresd.sh
@@ -0,0 +1,64 @@
+# Checks DNS and restarts kresd if necessary
+
+# check prerequisites
+
+. /lib/functions.sh
+
+if [ ! -x "$(command -v host)" ]; then
+	echo 'dnscheck error: host is not installed, exiting' >&2
+	exit 1
+fi
+
+perform_check() {
+
+    local host
+    local server
+    local timeout
+    local maxfailures
+    local failure=0
+
+    config_get host check_service host "CHANGEME"
+    config_get server check_service server "10.64.0.1"
+    config_get timeout check_service timeout "5"
+    config_get maxfailures check_service maxfailures "3"
+
+    # check DNS
+    host -w "${timeout}" "${host}" "${server}" &> /dev/null
+    if [ $? -ne 0 ]; then
+        failure=1
+        logger -p err -t "dnscheck" "kresd failed to respond, ${failcount} of ${maxfailures}"
+        let "failcount++"
+    else
+        if [ $failcount -ge 0 ]; then
+            logger -p info -t "dnscheck" "kresd is responding again"
+        fi
+
+        failcount=0
+    fi
+
+    if [ $failcount -ge $maxfailures ]; then
+        failcount=0
+        logger -p err -t "dnscheck" "kresd not responding, restarting"
+
+        # restart service
+        /etc/init.d/resolver restart
+    fi
+
+    return $failure
+}
+
+
+# read configuration
+config_load dnscheck
+
+# check loop
+logger -p info -t "dnscheck" "Starting kresd monitoring"
+failcount=0
+while sleep 10; do
+    perform_check ${job}
+    if [ $? -ne 0 ]; then
+        logger -p err -t "dnscheck" "kresd did not respond and was restarted"
+    fi
+done
+
+exit 0