From f1060ff86c2b83e6e255db4989fa8e9d70920c58 Mon Sep 17 00:00:00 2001
From: Giulio De Pasquale <giulio@depasquale.eu>
Date: Sun, 14 May 2017 23:01:11 +0200
Subject: [PATCH] NULL pointers everywhere

---
 cpp/emulator.cpp |  3 ++-
 cpp/vm.cpp       |  2 +-
 cpp/vmas.cpp     | 13 +++++++++++++
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/cpp/emulator.cpp b/cpp/emulator.cpp
index e0535f0..1d1ebcf 100644
--- a/cpp/emulator.cpp
+++ b/cpp/emulator.cpp
@@ -8,7 +8,8 @@
 using namespace std;
 
 int main() {
-  VM vm((uint8_t*)"\x00\x00\x50\x50\x03\x10\x00\x00\x02\x04\x10\x00\x04\x04\x01\x00\x13", 107);
+  uint8_t bytecode[] = "\x00\x00\x00";
+  VM vm(bytecode, sizeof(bytecode));
   vm.run();
   printf("\n\n");
   vm.status();
diff --git a/cpp/vm.cpp b/cpp/vm.cpp
index 1f7c04e..1964901 100644
--- a/cpp/vm.cpp
+++ b/cpp/vm.cpp
@@ -177,7 +177,7 @@ void VM::run(void) {
       break;
     default:
       DBG_INFO(("WAT: 0x%x\n", opcode));
-      return;
+      finished = true;
       break;
     }
   }
diff --git a/cpp/vmas.cpp b/cpp/vmas.cpp
index c547f2b..1dd6cdb 100644
--- a/cpp/vmas.cpp
+++ b/cpp/vmas.cpp
@@ -5,6 +5,9 @@
 #include <string.h>
 
 VMAddrSpace::VMAddrSpace() {
+  stack = NULL;
+  code = NULL;
+  data = NULL;
   stacksize = DEFAULT_STACKSIZE;
   codesize = DEFAULT_CODESIZE;
   datasize = DEFAULT_DATASIZE;
@@ -12,6 +15,9 @@ VMAddrSpace::VMAddrSpace() {
 }
 
 VMAddrSpace::VMAddrSpace(uint32_t ss, uint32_t cs, uint32_t ds) {
+  stack = NULL;
+  code = NULL;
+  data = NULL;
   stacksize = ss;
   codesize = cs;
   datasize = ds;
@@ -21,12 +27,15 @@ VMAddrSpace::VMAddrSpace(uint32_t ss, uint32_t cs, uint32_t ds) {
 bool VMAddrSpace::allocate(void) {
   DBG_INFO(("Allocating sections...\n"));
   if (code == NULL) {
+    DBG_INFO(("\tcode...\n"));
     code = (uint8_t *)malloc(codesize);
   }
   if (data == NULL) {
+    DBG_INFO(("\tdata...\n"));
     data = (uint8_t *)malloc(datasize);
   }
   if (stack == NULL) {
+    DBG_INFO(("\tstack...\n"));
     stack = (uint8_t *)malloc(stacksize);
   }
   if (code == NULL) {
@@ -43,6 +52,10 @@ bool VMAddrSpace::allocate(void) {
     DBG_ERROR(("Couldn't allocate stack section.\n"));
     return false;
   }
+  memset(code, 0xff,
+         stacksize); // auto halt in case the assembly is not correct
+  memset(stack, 0x0, stacksize);
+  memset(data, 0x0, stacksize);
   DBG_SUCC(("Done!\n"));
   return true;
 }