From 0d627c947f5b137170f23827b8f251dab8ed29c3 Mon Sep 17 00:00:00 2001
From: Roman Khimov <roman@nspcc.ru>
Date: Sat, 2 Jul 2022 15:48:35 +0300
Subject: [PATCH] notary: control start/stop state

Don't start/stop twice, don't do anything in callbacks if not started.
---
 pkg/services/notary/notary.go | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/pkg/services/notary/notary.go b/pkg/services/notary/notary.go
index bc567055c..f270d2a71 100644
--- a/pkg/services/notary/notary.go
+++ b/pkg/services/notary/notary.go
@@ -22,6 +22,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/vm"
 	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
 	"github.com/nspcc-dev/neo-go/pkg/wallet"
+	"go.uber.org/atomic"
 	"go.uber.org/zap"
 )
 
@@ -47,6 +48,8 @@ type (
 		// newTxs is a channel where new transactions are sent
 		// to be processed in an `onTransaction` callback.
 		newTxs chan txHashPair
+		// started is a status bool to protect from double start/shutdown.
+		started *atomic.Bool
 
 		// reqMtx protects requests list.
 		reqMtx sync.RWMutex
@@ -142,6 +145,7 @@ func NewNotary(cfg Config, net netmode.Magic, mp *mempool.Pool, onTransaction fu
 		requests:      make(map[util.Uint256]*request),
 		Config:        cfg,
 		Network:       net,
+		started:       atomic.NewBool(false),
 		wallet:        wallet,
 		onTransaction: onTransaction,
 		newTxs:        make(chan txHashPair, defaultTxChannelCapacity),
@@ -159,6 +163,9 @@ func (n *Notary) Name() string {
 
 // Start runs a Notary module in a separate goroutine.
 func (n *Notary) Start() {
+	if !n.started.CAS(false, true) {
+		return
+	}
 	n.Config.Log.Info("starting notary service")
 	n.Config.Chain.SubscribeForBlocks(n.blocksCh)
 	n.mp.SubscribeForTransactions(n.reqCh)
@@ -203,11 +210,17 @@ drainLoop:
 
 // Shutdown stops the Notary module.
 func (n *Notary) Shutdown() {
+	if !n.started.CAS(true, false) {
+		return
+	}
 	close(n.stopCh)
 }
 
 // OnNewRequest is a callback method which is called after a new notary request is added to the notary request pool.
 func (n *Notary) OnNewRequest(payload *payload.P2PNotaryRequest) {
+	if !n.started.Load() {
+		return
+	}
 	acc := n.getAccount()
 	if acc == nil {
 		return
@@ -314,7 +327,7 @@ func (n *Notary) OnNewRequest(payload *payload.P2PNotaryRequest) {
 // OnRequestRemoval is a callback which is called after fallback transaction is removed
 // from the notary payload pool due to expiration, main tx appliance or any other reason.
 func (n *Notary) OnRequestRemoval(pld *payload.P2PNotaryRequest) {
-	if n.getAccount() == nil {
+	if !n.started.Load() || n.getAccount() == nil {
 		return
 	}
 
@@ -338,6 +351,9 @@ func (n *Notary) OnRequestRemoval(pld *payload.P2PNotaryRequest) {
 // PostPersist is a callback which is called after a new block event is received.
 // PostPersist must not be called under the blockchain lock, because it uses finalization function.
 func (n *Notary) PostPersist() {
+	if !n.started.Load() {
+		return
+	}
 	acc := n.getAccount()
 	if acc == nil {
 		return