cmd added unsafe shutdown detection

Author: muhammednagy

cmd/geth/main.go

@@ -19,6 +19,7 @@ package main
 
 import (
 	"fmt"
+	"github.com/ethereum/go-ethereum/ethdb/leveldb"
 	"math"
 	"os"
 	"runtime"
@@ -257,6 +258,16 @@ func init() {
 		return debug.Setup(ctx)
 	}
 	app.After = func(ctx *cli.Context) error {
+		unsafeShutdownDb, err := leveldb.New(utils.DataDirFlag.Value.String()+"/unsafe-shutdown", 0, 0, "")
+		if err != nil {
+			log.Warn("failed to access unsafe shutdown database", "time", err)
+		}
+		// safe shutdown deletes unsafe shutdown from unsafe-shutdown-db
+		err = unsafeShutdownDb.Delete([]byte("unsafe-shutdown"))
+		if err != nil {
+			log.Error("err", err)
+		}
+		unsafeShutdownDb.Close()
 		debug.Exit()
 		prompt.Stdin.Close() // Resets terminal mode.
 		return nil
@@ -361,6 +372,21 @@ func geth(ctx *cli.Context) error {
 func startNode(ctx *cli.Context, stack *node.Node) {
 	debug.Memsize.Add("node", stack)
 
+	// Create a db to hold invalid shutdowns
+	unsafeShutdownDb, err := leveldb.New(utils.DataDirFlag.Value.String()+"/unsafe-shutdown", 0, 0, "")
+	if err != nil {
+		log.Warn("failed to access unsafe shutdown database", "time", err)
+	}
+	// Check for invalid shutdown
+	invalidShutdown, _ := unsafeShutdownDb.Get([]byte("unsafe-shutdown"))
+	if invalidShutdown != nil {
+		log.Error("unsafe shutdown detected", "time", string(invalidShutdown))
+	}
+	// Create an invalid shutdown in database in case the app crashed
+	if err = unsafeShutdownDb.Put([]byte("unsafe-shutdown"), []byte(time.Now().String())); err != nil {
+		log.Warn("Failed to record possible future unsafe shutdown", "err", err)
+	}
+	unsafeShutdownDb.Close()
 	// Start up the node itself
 	utils.StartNode(stack)