mini_snmpd: fix bugs and automatically reload daemon if one of monitored interfaces goes up/down

This commit fixes bugs, cleans and enhances init.d script:
1. The first disk and interface was passed to mini_snmpd with extra
   leading space.
   This bug caused the first monitored disk and interface to be
   inaccessible by SNMP daemon.
2. Automatically reload deamon if one of monitored interfaces goes
   up/down.
   Since mini_snmpd reads interface list only at startup, it won't
   detect any interface which appeared after the daemon was started.
   Fortunately we can use procd interface triggers to automatically
   restart the daemon.
3. Replace hand-written direct ubus calls and json data filtering with
   standard network functions.

Signed-off-by: Marcin Jurkowski <marcin1j@gmail.com>

net/mini_snmpd/Makefile

@@ -9,8 +9,8 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=mini_snmpd
 PKG_VERSION:=1.4-rc1
-PKG_RELEASE:=2
+PKG_RELEASE:=3
-PKG_MAINTAINER:=Luke McKee <hojuruku@gmail.com>
+PKG_MAINTAINER:=Marcin Jurkowski <marcin1j@gmail.com>
 PKG_LICENSE:=GPL-2.0
 PKG_LICENSE_FILES:=COPYING
 

net/mini_snmpd/files/mini_snmpd.init

@@ -71,7 +71,7 @@ append_interface() {
 	local name="$1" netdev netdev_count
 	[ -z $netdev_count ] && netdev_count=0
 	# for the purposes of snmp monitoring it doesn't need to be up, it just needs to exist in /proc/net/dev
-	netdev=$(ubus -S call network.interface dump|jsonfilter -e "@.interface[@.interface=\"$name\"].l3_device")  
+	network_get_device netdev "$name"
 	if [ -n "$netdev" ] && grep -qF "$netdev" /proc/net/dev ]; then 
 		[ $netdev_count -ge 4 ] && {
 			_err "$cfg: too many network interfaces configured, ignoring $name"
@@ -84,7 +84,7 @@ append_interface() {
 			append interfaces_arg "$netdev"
 		fi
 	else
-		 _err "$cfg: physical interface for network $name not found in uci or kernel so not monitoring"
+		 _log "$cfg: physical interface for network $name not found in uci or kernel so not monitoring"
 	fi
 }
 
@@ -100,10 +100,12 @@ watch_interfaces() {
 	config_get_bool enabled "$cfg" "enabled" '1'
 	[ "$enabled" -gt 0 ] || return 0
 	config_get listen_interface "$cfg" listen_interface
-	# listen_interface_up=$(ubus -S call network.interface dump | jsonfilter -e "@.interface[@.interface=\"$listen_interface\"].up")
 	# If the interface is up & instance is running we'll watch at the instance level and only restart that instance if it's bound interface changes
 	# Regardless of ubus knowing about an interface (in the case it's not yet configured)
 	[ -n "$listen_interface" ] && trigger_interfaces="${listen_interface} ${trigger_interfaces} "
+	# Restart daemon if one of monitored interfaces changes
+	config_get reload_interfaces "$cfg" interfaces
+
 }
 
 validate_mini_snmpd_section() {
@@ -126,6 +128,11 @@ service_triggers() {
 			procd_add_interface_trigger "interface.*" $n /etc/init.d/mini_snmpd start
                 done
         }
+	[ -n "$reload_interfaces" ] && {
+		for n in $reload_interfaces; do
+			procd_add_reload_interface_trigger $n
+		done
+	}
         procd_close_trigger
 	procd_add_validation validate_mini_snmpd_section
 }
@@ -146,35 +153,19 @@ start_instance() {
 		 return 1
 	}
 	
-	local listen_interface_json listen_interface_ip listen_interface_device listen_interface_up ubus_exit ubus_err
+	local listen_interface_json listen_interface_ip listen_interface_device listen_interface_up
 	[ -n "$listen_interface" ] && {
-		listen_interface_json=$(ubus -S call network.interface.$listen_interface status)
-		ubus_exit=$?
-		[ $ubus_exit = 4 ] && {
-			_err "$cfg: listen_interface $listen_interface not properly configured in ubus network.interface.* not starting this instance "
-			return 1
-		}
-		[ $ubus_exit = 255 -a -z "$listen_interface_json" ] && { 
-			_log "$cfg: ubusd not yet up, will try to start mini_snmpd shorlty when procd detects $listen_interface comes up"
-			return 1
-		}
-		[ -z "$listen_interface_json" ] && { 
-			ubus_err=`ubus call network.interface.$listen_interface status 2>&1 >/dev/null`
-			_err "$cfg: unknown ubus error. exit: $ubus_exit errormsg: $ubus_err "
-			return 1
-		}
-		listen_interface_up=$(jsonfilter -s "$listen_interface_json" -e '@.up')
 		if [ "$ipv6" = 1 ]; then
-			listen_interface_ip=$(jsonfilter -s "$listen_interface_json" -e "@['ipv6-address'][0].address")
+			network_get_ipaddrs6 listen_interface_ip "$listen_interface"
 		else
-			listen_interface_ip=$(jsonfilter -s "$listen_interface_json" -e "@['ipv4-address'][0].address")
+			network_get_ipaddrs listen_interface_ip "$listen_interface"
 		fi
-		[ -n "$listen_interface_ip" -a "$listen_interface_up" = 'true' ] || {
+		network_is_up "$listen_interface" && [ -n "$listen_interface_ip" ] || {
 			_log "$cfg:listen interface $listen_interface not up yet / not configured properly"
 			_log "$cfg:procd will try again when interface state changes"
 			return 1
 		}
-		listen_interface_device=$(jsonfilter -s "$listen_interface_json" -e '@.l3_device')
+		network_get_physdev listen_interface_device "$listen_interface"
 	}
 
 	[ $validation_failed ] && {  
@@ -223,17 +214,23 @@ start_instance() {
 	# uci_validate_section() aka /sbin/validate_data can only cast default values not defined in /etc/config/* to string 
 	# e.g. ="1" however it sets bools defined in /etc/config/* to =1 / =0
 	[ "$auth" = 1 -o "$auth" = "1" ] && procd_append_param command "-a"
-	[ -n "$disks_arg" ] && procd_append_param command "-d $disks_arg" 
+	[ -n "$disks_arg" ] && procd_append_param command "-d" "$disks_arg"
-	[ -n "$interfaces_arg" ] && procd_append_param command "-i $interfaces_arg"
+	[ -n "$interfaces_arg" ] && {
+		procd_append_param netdev ${interfaces_arg//,/ }
+		procd_append_param command "-i" "$interfaces_arg"
+	}
 	[ -n "$listen_interface_device" ] && {
 		 procd_append_param command "-I" "$listen_interface_device"
 		 # and this monitors the hardware device for changes outside of ubus - just a guess
-		 procd_set_param netdev $listen_interface_device
+		 procd_append_param netdev $listen_interface_device
 	}
 	procd_close_instance
 }
 
 start_service() {
+	. /lib/functions.sh
+	. /lib/functions/network.sh
+
 	config_load 'mini_snmpd'
 	config_foreach start_instance 'mini_snmpd'
 }