Fixes leak of duplicate command line environment strings

runtime/bin/main.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
 
 #include "include/dart_api.h"
 #include "include/dart_tools_api.h"
@@ skipping 264 matching lines @@
   ASSERT(arg != NULL);
   if (*arg == '\0') {
     // Ignore empty -D option.
     Log::PrintErr("No arguments given to -D option\n");
     return true;
   }
   if (environment == NULL) {
     environment = new HashMap(&HashMap::SameStringValue, 4);
   }
   // Split the name=value part of the -Dname=value argument.
-  char* name;
-  char* value = NULL;
   const char* equals_pos = strchr(arg, '=');
   if (equals_pos == NULL) {
     // No equal sign (name without value) currently not supported.
     Log::PrintErr("No value given to -D option\n");
     return false;
-  } else {
-    int name_len = equals_pos - arg;
-    if (name_len == 0) {
-      Log::PrintErr("No name given to -D option\n");
-      return false;
-    }
-    // Split name=value into name and value.
-    name = reinterpret_cast<char*>(malloc(name_len + 1));
-    strncpy(name, arg, name_len);
-    name[name_len] = '\0';
-    value = strdup(equals_pos + 1);
   }
+
+  char* name;
+  char* value = NULL;
+  int name_len = equals_pos - arg;
+  if (name_len == 0) {
+    Log::PrintErr("No name given to -D option\n");
+    return false;
+  }
+  // Split name=value into name and value.
+  name = reinterpret_cast<char*>(malloc(name_len + 1));
+  strncpy(name, arg, name_len);
+  name[name_len] = '\0';
+  value = strdup(equals_pos + 1);
   HashMap::Entry* entry = environment->Lookup(
       GetHashmapKeyFromString(name), HashMap::StringHash(name), true);
   ASSERT(entry != NULL);  // Lookup adds an entry if key not found.
+  if (entry->value != NULL) {
+    free(name);
+    free(entry->value);
+  }
   entry->value = value;
   return true;
 }
 
 
 static bool ProcessCompileAllOption(const char* arg,
                                     CommandLineOptions* vm_options) {
   ASSERT(arg != NULL);
   if (*arg != '\0') {
     return false;
@@ skipping 1470 matching lines @@
   Platform::Exit(Process::GlobalExitCode());
 }
 
 }  // namespace bin
 }  // namespace dart
 
 int main(int argc, char** argv) {
   dart::bin::main(argc, argv);
   UNREACHABLE();
 }