Add read-only environment variable access.

runtime/bin/platform_linux.cc

-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// 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 "bin/platform.h"
 
 #include <signal.h>
 #include <string.h>
 #include <unistd.h>
 
 
@@ skipping 20 matching lines @@
 const char* Platform::OperatingSystem() {
   return "linux";
 }
 
 
 bool Platform::LocalHostname(char *buffer, intptr_t buffer_length) {
   return gethostname(buffer, buffer_length) == 0;
 }
 
 
+char** Platform::Environment(intptr_t* count) {
+  // Using environ directly is only safe as long as we do not
+  // provide access to modifying environment variables.
+  intptr_t i = 0;

[Søren Gjesse, 2012/04/17 16:10:47]

Why add i? Maybe just use *count instead.

[Mads Ager (google), 2012/04/17 16:20:14]

I wanted to have on clear assignment to count. Also, I found it easier to read
because of the occurrences of 'i' below as well.

+  char** tmp = environ;
+  while (*(tmp++) != NULL) i++;
+  *count = i;
+  char** result = new char*[i];
+  for (intptr_t current = 0; current < i; current++) {
+    result[current] = environ[current];
+  }
+  return result;
+}
+
+
 char* Platform::StrError(int error_code) {
   static const int kBufferSize = 1024;
   char* error = static_cast<char*>(malloc(kBufferSize));
   error[0] = '\0';
   char* error_str = strerror_r(error_code, error, kBufferSize);
   if (error_str != error) {
     size_t written = snprintf(error, kBufferSize, "%s", error_str);
     ASSERT(written == strlen(error_str));
   }
   return error;
 }