cmd/utils: open db in readonly when dev datadir exists (#24298)

cmd/utils/flags.go

@@ -1673,9 +1673,15 @@ func SetEthConfig(ctx *cli.Context, stack *node.Node, cfg *ethconfig.Config) {
 		// Create a new developer genesis block or reuse existing one
 		cfg.Genesis = core.DeveloperGenesisBlock(uint64(ctx.GlobalInt(DeveloperPeriodFlag.Name)), ctx.GlobalUint64(DeveloperGasLimitFlag.Name), developer.Address)
 		if ctx.GlobalIsSet(DataDirFlag.Name) {
+			// If datadir doesn't exist we need to open db in write-mode
+			// so leveldb can create files.
+			readonly := true
+			if !common.FileExist(stack.ResolvePath("chaindata")) {
+				readonly = false
+			}
 			// Check if we have an already initialized chain and fall back to
 			// that if so. Otherwise we need to generate a new genesis spec.
-			chaindb := MakeChainDatabase(ctx, stack, false)
+			chaindb := MakeChainDatabase(ctx, stack, readonly)
 			if rawdb.ReadCanonicalHash(chaindb, 0) != (common.Hash{}) {
 				cfg.Genesis = nil // fallback to db content
 			}