From ec48786180efe0ff984983b83e439417022ff8b3 Mon Sep 17 00:00:00 2001
From: Hussam <hussam@dominantstrategies.io>
Date: Tue, 17 Dec 2024 17:15:44 -0600
Subject: [PATCH] Sanity check to prevent common values mutating

---
 cmd/go-quai/start.go | 12 ++++++++++--
 common/big.go        | 44 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 2 deletions(-)

diff --git a/cmd/go-quai/start.go b/cmd/go-quai/start.go
index 4f611cfeab..9ec235563d 100644
--- a/cmd/go-quai/start.go
+++ b/cmd/go-quai/start.go
@@ -15,6 +15,7 @@ import (
 	"github.com/spf13/viper"
 
 	"github.com/dominant-strategies/go-quai/cmd/utils"
+	"github.com/dominant-strategies/go-quai/common"
 	"github.com/dominant-strategies/go-quai/log"
 	"github.com/dominant-strategies/go-quai/metrics_config"
 	"github.com/dominant-strategies/go-quai/p2p/node"
@@ -73,6 +74,7 @@ func runStart(cmd *cobra.Command, args []string) error {
 	// create a quit channel for services to signal for a clean shutdown
 	quitCh := make(chan struct{})
 
+	common.SanityCheck(quitCh)
 	// create a new p2p node
 	node, err := node.NewNode(ctx, quitCh)
 	if err != nil {
@@ -104,8 +106,14 @@ func runStart(cmd *cobra.Command, args []string) error {
 	// wait for a SIGINT or SIGTERM signal
 	ch := make(chan os.Signal, 1)
 	signal.Notify(ch, syscall.SIGINT, syscall.SIGTERM)
-	<-ch
-	log.Global.Warn("Received 'stop' signal, shutting down gracefully...")
+
+	select {
+	case <-ch:
+		log.Global.Warn("Received 'stop' signal, shutting down gracefully...")
+	case <-quitCh:
+		log.Global.Warn("Received 'quit' signal from child, shutting down...")
+	}
+
 	cancel()
 	// stop the hierarchical co-ordinator
 	hc.Stop()
diff --git a/common/big.go b/common/big.go
index 5efbe9e231..db6a04c9dc 100644
--- a/common/big.go
+++ b/common/big.go
@@ -18,7 +18,9 @@ package common
 
 import (
 	"math/big"
+	"time"
 
+	"github.com/dominant-strategies/go-quai/log"
 	"modernc.org/mathutil"
 )
 
@@ -80,3 +82,45 @@ func LogBig(diff *big.Int) *big.Int {
 	bigBits = new(big.Int).Add(bigBits, m)
 	return bigBits
 }
+
+// Continously verify that the common values have not been overwritten.
+func SanityCheck(quitCh chan struct{}) {
+	big0 := big.NewInt(0)
+	big1 := big.NewInt(1)
+	big2 := big.NewInt(2)
+	big3 := big.NewInt(3)
+	big8 := big.NewInt(8)
+	big32 := big.NewInt(32)
+	big99 := big.NewInt(99)
+	big100 := big.NewInt(100)
+	big101 := big.NewInt(101)
+	big256 := big.NewInt(256)
+	big257 := big.NewInt(257)
+	big2e256 := new(big.Int).Exp(big.NewInt(2), big.NewInt(256), big.NewInt(0))
+	big2e64 := new(big.Int).Exp(big.NewInt(2), big.NewInt(64), big.NewInt(0))
+
+	go func(quitCh chan struct{}) {
+		for {
+			time.Sleep(1 * time.Minute)
+
+			// Verify that none of the values have mutated.
+			if big0.Cmp(Big0) != 0 ||
+				big1.Cmp(Big1) != 0 ||
+				big2.Cmp(Big2) != 0 ||
+				big3.Cmp(Big3) != 0 ||
+				big8.Cmp(Big8) != 0 ||
+				big32.Cmp(Big32) != 0 ||
+				big99.Cmp(Big99) != 0 ||
+				big100.Cmp(Big100) != 0 ||
+				big101.Cmp(Big101) != 0 ||
+				big256.Cmp(Big256) != 0 ||
+				big257.Cmp(Big257) != 0 ||
+				big2e256.Cmp(new(big.Int).Exp(big.NewInt(2), big.NewInt(256), big.NewInt(0))) != 0 ||
+				big2e64.Cmp(new(big.Int).Exp(big.NewInt(2), big.NewInt(64), big.NewInt(0))) != 0 {
+				// Send a message to quitCh to abort.
+				log.Global.Fatal("A common value has mutated, exiting now")
+				quitCh <- struct{}{}
+			}
+		}
+	}(quitCh)
+}