4 files changed, 77 insertions, 11 deletions
diff --git a/cmd/puppeth/wizard.go b/cmd/puppeth/wizard.go
index 518741279..3fdd639f8 100644
--- a/cmd/puppeth/wizard.go
+++ b/cmd/puppeth/wizard.go
@@ -161,6 +161,28 @@ func (w *wizard) readDefaultInt(def int) int {
 	}
 }
 
+// readDefaultBigInt reads a single line from stdin, trimming if from spaces,
+// enforcing it to parse into a big integer. If an empty line is entered, the
+// default value is returned.
+func (w *wizard) readDefaultBigInt(def *big.Int) *big.Int {
+	for {
+		fmt.Printf("> ")
+		text, err := w.in.ReadString('\n')
+		if err != nil {
+			log.Crit("Failed to read user input", "err", err)
+		}
+		if text = strings.TrimSpace(text); text == "" {
+			return def
+		}
+		val, ok := new(big.Int).SetString(text, 0)
+		if !ok {
+			log.Error("Invalid input, expected big integer")
+			continue
+		}
+		return val
+	}
+}
+
 /*
 // readFloat reads a single line from stdin, trimming if from spaces, enforcing it
 // to parse into a float.
diff --git a/cmd/puppeth/wizard_genesis.go b/cmd/puppeth/wizard_genesis.go
index 43dae9c20..222fc2a7c 100644
--- a/cmd/puppeth/wizard_genesis.go
+++ b/cmd/puppeth/wizard_genesis.go
@@ -18,7 +18,9 @@ package main
 
 import (
 	"bytes"
+	"encoding/json"
 	"fmt"
+	"io/ioutil"
 	"math/big"
 	"math/rand"
 	"time"
@@ -135,3 +137,53 @@ func (w *wizard) makeGenesis() {
 	// All done, store the genesis and flush to disk
 	w.conf.genesis = genesis
 }
+
+// manageGenesis permits the modification of chain configuration parameters in
+// a genesis config and the export of the entire genesis spec.
+func (w *wizard) manageGenesis() {
+	// Figure out whether to modify or export the genesis
+	fmt.Println()
+	fmt.Println(" 1. Modify existing fork rules")
+	fmt.Println(" 2. Export genesis configuration")
+
+	choice := w.read()
+	switch {
+	case choice == "1":
+		// Fork rule updating requested, iterate over each fork
+		fmt.Println()
+		fmt.Printf("Which block should Homestead come into effect? (default = %v)\n", w.conf.genesis.Config.HomesteadBlock)
+		w.conf.genesis.Config.HomesteadBlock = w.readDefaultBigInt(w.conf.genesis.Config.HomesteadBlock)
+
+		fmt.Println()
+		fmt.Printf("Which block should EIP150 come into effect? (default = %v)\n", w.conf.genesis.Config.EIP150Block)
+		w.conf.genesis.Config.EIP150Block = w.readDefaultBigInt(w.conf.genesis.Config.EIP150Block)
+
+		fmt.Println()
+		fmt.Printf("Which block should EIP155 come into effect? (default = %v)\n", w.conf.genesis.Config.EIP155Block)
+		w.conf.genesis.Config.EIP155Block = w.readDefaultBigInt(w.conf.genesis.Config.EIP155Block)
+
+		fmt.Println()
+		fmt.Printf("Which block should EIP158 come into effect? (default = %v)\n", w.conf.genesis.Config.EIP158Block)
+		w.conf.genesis.Config.EIP158Block = w.readDefaultBigInt(w.conf.genesis.Config.EIP158Block)
+
+		fmt.Println()
+		fmt.Printf("Which block should Byzantium come into effect? (default = %v)\n", w.conf.genesis.Config.ByzantiumBlock)
+		w.conf.genesis.Config.ByzantiumBlock = w.readDefaultBigInt(w.conf.genesis.Config.ByzantiumBlock)
+
+		out, _ := json.MarshalIndent(w.conf.genesis.Config, "", "  ")
+		fmt.Printf("Chain configuration updated:\n\n%s\n", out)
+
+	case choice == "2":
+		// Save whatever genesis configuration we currently have
+		fmt.Println()
+		fmt.Printf("Which file to save the genesis into? (default = %s.json)\n", w.network)
+		out, _ := json.MarshalIndent(w.conf.genesis, "", "  ")
+		if err := ioutil.WriteFile(w.readDefaultString(fmt.Sprintf("%s.json", w.network)), out, 0644); err != nil {
+			log.Error("Failed to save genesis file", "err", err)
+		}
+		log.Info("Exported existing genesis block")
+
+	default:
+		log.Error("That's not something I can do")
+	}
+}
diff --git a/cmd/puppeth/wizard_intro.go b/cmd/puppeth/wizard_intro.go
index c3eaf5324..2d9a097ee 100644
--- a/cmd/puppeth/wizard_intro.go
+++ b/cmd/puppeth/wizard_intro.go
@@ -98,7 +98,7 @@ func (w *wizard) run() {
 		if w.conf.genesis == nil {
 			fmt.Println(" 2. Configure new genesis")
 		} else {
-			fmt.Println(" 2. Save existing genesis")
+			fmt.Println(" 2. Manage existing genesis")
 		}
 		if len(w.servers) == 0 {
 			fmt.Println(" 3. Track new remote server")
@@ -118,18 +118,10 @@ func (w *wizard) run() {
 			w.networkStats(false)
 
 		case choice == "2":
-			// If we don't have a genesis, make one
 			if w.conf.genesis == nil {
 				w.makeGenesis()
 			} else {
-				// Otherwise just save whatever we currently have
-				fmt.Println()
-				fmt.Printf("Which file to save the genesis into? (default = %s.json)\n", w.network)
-				out, _ := json.MarshalIndent(w.conf.genesis, "", "  ")
-				if err := ioutil.WriteFile(w.readDefaultString(fmt.Sprintf("%s.json", w.network)), out, 0644); err != nil {
-					log.Error("Failed to save genesis file", "err", err)
-				}
-				log.Info("Exported existing genesis block")
+				w.manageGenesis()
 			}
 		case choice == "3":
 			if len(w.servers) == 0 {
diff --git a/cmd/puppeth/wizard_netstats.go b/cmd/puppeth/wizard_netstats.go
index ab8078698..c06972198 100644
--- a/cmd/puppeth/wizard_netstats.go
+++ b/cmd/puppeth/wizard_netstats.go
@@ -129,7 +129,7 @@ func (w *wizard) networkStats(tips bool) {
 		}
 	}
 	// If a genesis block was found, load it into our configs
-	if protips.genesis != "" {
+	if protips.genesis != "" && w.conf.genesis == nil {
 		genesis := new(core.Genesis)
 		if err := json.Unmarshal([]byte(protips.genesis), genesis); err != nil {
 			log.Error("Failed to parse remote genesis", "err", err)