From d374a4ba23315c8b1ef949396879cc210071eb46 Mon Sep 17 00:00:00 2001
From: Tim Coulter <tim@Tims-MacBook-Pro.local>
Date: Thu, 24 Mar 2016 10:15:30 -0700
Subject: [PATCH] Merge #24. Add -s/--seed option to see the addresses that are
 created. Add -a/--accounts options to specify how many accounts you want to
 create.

---
 bin/testrpc       |  2 ++
 lib/blockchain.js |  6 ++++--
 lib/manager.js    |  3 ++-
 lib/random.js     | 16 ++++++++++++++++
 package.json      |  1 +
 5 files changed, 25 insertions(+), 3 deletions(-)
 create mode 100644 lib/random.js

diff --git a/bin/testrpc b/bin/testrpc
index 871cfa22c..a533978ae 100755
--- a/bin/testrpc
+++ b/bin/testrpc
@@ -23,5 +23,7 @@ function parseAccounts(accounts) {
 TestRPC.startServer(console, {
   port: argv.p || argv.port,
   debug: argv.d || argv.debug,
+  seed: argv.s || argv.seed,
+  total_accounts: argv.a || argv.accounts,
   accounts: parseAccounts(argv.account)
 });
diff --git a/lib/blockchain.js b/lib/blockchain.js
index 55491da45..86a3e1718 100644
--- a/lib/blockchain.js
+++ b/lib/blockchain.js
@@ -4,7 +4,8 @@ var VM = require('ethereumjs-vm');
 var Trie = require('merkle-patricia-tree');
 var FakeTransaction = require('ethereumjs-tx/fake.js');
 var utils = require('ethereumjs-util');
-var crypto = require('crypto');
+var seedrandom = require('seedrandom');
+var random = require('./random');
 
 Blockchain = function(logger, options) {
   this.stateTrie = new Trie();
@@ -23,6 +24,7 @@ Blockchain = function(logger, options) {
   this.lastBlockHash = "0x0000000000000000000000000000000000000000000000000000000000000000";
   this.snapshots = [];
   this.logger = logger || console;
+  this.rng = seedrandom(options.seed);
 
   if (options.debug == true) {
     this.vm.on('step', function(info){
@@ -54,7 +56,7 @@ Blockchain.prototype.toHex = function(val) {
 Blockchain.prototype.addAccount = function(opts, callback) {
   var self = this;
 
-  var secretKey = opts.secretKey || crypto.randomBytes(32);
+  var secretKey = opts.secretKey || random.randomBytes(32, this.rng);
   var publicKey = utils.privateToPublic(new Buffer(secretKey));
   var address = utils.pubToAddress(new Buffer(publicKey));
 
diff --git a/lib/manager.js b/lib/manager.js
index 88351baea..9d4c0a8e8 100644
--- a/lib/manager.js
+++ b/lib/manager.js
@@ -14,6 +14,7 @@ function Manager(logger, options) {
   this.blockchain = new Blockchain(logger, options);
   this.initialized = false;
   this.accounts = options.accounts;
+  this.total_accounts = options.total_accounts || 10;
 }
 
 Manager.prototype.initialize = function(callback) {
@@ -27,7 +28,7 @@ Manager.prototype.initialize = function(callback) {
     });
   } else {
     // Add 10 accounts, for testing purposes.
-    async.times(10, function(n, next) {
+    async.times(this.total_accounts, function(n, next) {
       self.blockchain.addAccount({}, next);
     }, function() {
       self.initialized = true;
diff --git a/lib/random.js b/lib/random.js
new file mode 100644
index 000000000..0098bb5ff
--- /dev/null
+++ b/lib/random.js
@@ -0,0 +1,16 @@
+module.exports = {
+  // Mimics crypto.random bytes, but takes in a random number generator
+  // as its second parameter. rng is expected to be a function that takes
+  // no parameters and returns a result like Math.random().
+  // This is important because it allows for a seeded random number generator.
+  // Since this is a mock RPC library, the rng doesn't need to be cryptographically secure.
+  randomBytes: function(length, rng) {
+    var buf = [];
+
+    for (var i = 0; i < length; i++) {
+      buf.push(rng()*255);
+    }
+
+    return new Buffer(buf);
+  }
+}
diff --git a/package.json b/package.json
index 391be6f0e..727e10d23 100644
--- a/package.json
+++ b/package.json
@@ -21,6 +21,7 @@
     "ethereumjs-util": "^4.0.1",
     "ethereumjs-vm": "^1.2.1",
     "merkle-patricia-tree": "2.1.2",
+    "seedrandom": "^2.4.2",
     "shelljs": "^0.6.0",
     "web3": "^0.15.1",
     "web3-provider-engine": "^6.0.1",