Check-in rlz code to src\rlz from http://code.google.com/p/rlz/.

rlz/win/lib/registry_util.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// A helper library to keep track of a user's key by SID.
+// Used by RLZ libary. Also to be used by SearchWithGoogle library.
+
+#include "rlz/win/lib/registry_util.h"
+
+#include "base/process_util.h"
+#include "base/utf_string_conversions.h"
+#include "base/win/registry.h"
+#include "base/win/windows_version.h"
+#include "rlz/lib/assert.h"
+#include "rlz/win/lib/process_info.h"
+
+namespace rlz_lib {
+
+bool RegKeyReadValue(base::win::RegKey& key, const wchar_t* name,
+                     char* value, size_t* value_size) {
+  value[0] = 0;
+
+  std::wstring value_string;
+  if (key.ReadValue(name, &value_string) != ERROR_SUCCESS) {
+    return false;
+  }
+
+  if (value_string.length() > *value_size) {
+    *value_size = value_string.length();
+    return false;
+  }
+
+  // Note that RLZ string are always ASCII by design.
+  strncpy(value, WideToUTF8(value_string).c_str(), *value_size);
+  value[*value_size - 1] = 0;
+  return true;
+}
+
+bool RegKeyWriteValue(base::win::RegKey& key, const wchar_t* name,
+                      const char* value) {
+  std::wstring value_string(ASCIIToWide(value));
+  return key.WriteValue(name, value_string.c_str()) == ERROR_SUCCESS;
+}
+
+bool HasUserKeyAccess(bool write_access) {
+  // The caller is trying to access HKEY_CURRENT_USER.  Test to see if we can
+  // read from there.  Don't try HKEY_CURRENT_USER because this will cause
+  // problems in the unit tests: if we open HKEY_CURRENT_USER directly here,
+  // the overriding done for unit tests will no longer work.  So we try subkey
+  // "Software" which is known to always exist.
+  base::win::RegKey key;
+  if (key.Open(HKEY_CURRENT_USER, L"Software", KEY_READ) != ERROR_SUCCESS)
+    ASSERT_STRING("Could not open HKEY_CURRENT_USER");
+
+  if (ProcessInfo::IsRunningAsSystem()) {
+    ASSERT_STRING("UserKey::HasAccess: No access as SYSTEM without SID set.");
+    return false;
+  }
+
+  if (write_access) {
+    if (base::win::GetVersion() < base::win::VERSION_VISTA) return true;
+    base::ProcessHandle process_handle = base::GetCurrentProcessHandle();
+    base::IntegrityLevel level = base::INTEGRITY_UNKNOWN;
+
+    if (!base::GetProcessIntegrityLevel(process_handle, &level)) {
+      ASSERT_STRING("UserKey::HasAccess: Cannot determine Integrity Level.");
+      return false;
+    }
+    if (level <= base::LOW_INTEGRITY) {
+      ASSERT_STRING("UserKey::HasAccess: Cannot write from Low Integrity.");
+      return false;
+    }
+  }
+  return true;
+}
+
+}  // namespace rlz_lib