[Win] Implement core mechanism to honor Windows Group Policy

chrome/browser/configuration_policy_provider_win.cc

+// Copyright (c) 2010 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.
+
+#include "chrome/browser/configuration_policy_provider_win.h"
+
+#include <algorithm>
+
+#include "base/logging.h"
+#include "base/registry.h"
+#include "base/scoped_ptr.h"
+#include "base/sys_string_conversions.h"
+#include "base/values.h"
+
+const wchar_t WinConfigurationPolicyProvider::kHomepageRegistryValueName[] =
+    L"Homepage";
+const wchar_t WinConfigurationPolicyProvider::
+    kHomepageIsNewTabPageRegistryValueName[] = L"HomepageIsNewTabPage";
+const wchar_t WinConfigurationPolicyProvider::kCookiesModeRegistryValueName[] =
+    L"CookiesMode";
+
+#if defined(GOOGLE_CHROME_BUILD)
+const wchar_t WinConfigurationPolicyProvider::kPolicyRegistrySubKey[] =
+    L"SOFTWARE\\Policies\\Google\\Google Chrome";
+#else
+const wchar_t WinConfigurationPolicyProvider::kPolicyRegistrySubKey[] =
+    L"SOFTWARE\\Policies\\Chromium";
+#endif
+
+WinConfigurationPolicyProvider::WinConfigurationPolicyProvider() {
+}
+
+bool WinConfigurationPolicyProvider::GetRegistryPolicyString(
+    const wchar_t* value_name, string16* result) {
+  DWORD value_size = 0;
+  DWORD key_type = 0;
+  scoped_array<uint8> buffer;
+  RegKey hkcu_policy_key(HKEY_LOCAL_MACHINE, kPolicyRegistrySubKey);
+  if (hkcu_policy_key.ReadValue(value_name, 0, &value_size, &key_type)) {
+    if (key_type != REG_SZ)
+      return false;
+    // According to the Microsoft documentation, the string
+    // buffer may not be explicitly 0-terminated. Allocate a
+    // slightly larger buffer and prefill to zeros to guarantee
+    // the 0-termination.
+    buffer.reset(new uint8[value_size + 2]);
+    memset(buffer.get(), 0, value_size + 2);
+    hkcu_policy_key.ReadValue(value_name, buffer.get(), &value_size);
+  } else {
+    RegKey hklm_policy_key(HKEY_CURRENT_USER, kPolicyRegistrySubKey);
+    if (hklm_policy_key.ReadValue(value_name, 0, &value_size, &key_type)) {
+      if (key_type != REG_SZ)
+        return false;
+      // According to the Microsoft documentation, the string
+      // buffer may not be explicitly 0-terminated. Allocate a
+      // slightly larger buffer and prefill to zeros to guarantee
+      // the 0-termination.
+      buffer.reset(new uint8[value_size + 2]);
+      memset(buffer.get(), 0, value_size + 2);
+      hklm_policy_key.ReadValue(value_name, buffer.get(), &value_size);
+    } else {
+      return false;
+    }
+  }
+
+  result->assign(reinterpret_cast<const wchar_t*>(buffer.get()));
+  return true;
+}
+
+bool WinConfigurationPolicyProvider::GetRegistryPolicyBoolean(
+    const wchar_t* value_name, bool* result) {
+  DWORD value;
+  RegKey hkcu_policy_key(HKEY_LOCAL_MACHINE, kPolicyRegistrySubKey);
+  if (hkcu_policy_key.ReadValueDW(value_name, &value)) {
+    *result = value != 0;
+    return true;
+  }
+
+  RegKey hklm_policy_key(HKEY_CURRENT_USER, kPolicyRegistrySubKey);
+  if (hklm_policy_key.ReadValueDW(value_name, &value)) {
+    *result = value != 0;
+    return true;
+  }
+  return false;
+}
+
+bool WinConfigurationPolicyProvider::GetRegistryPolicyInteger(
+    const wchar_t* value_name, uint32* result) {
+  DWORD value;
+  RegKey hkcu_policy_key(HKEY_LOCAL_MACHINE, kPolicyRegistrySubKey);
+  if (hkcu_policy_key.ReadValueDW(value_name, &value)) {
+    *result = value;
+    return true;
+  }
+
+  RegKey hklm_policy_key(HKEY_CURRENT_USER, kPolicyRegistrySubKey);
+  if (hklm_policy_key.ReadValueDW(value_name, &value)) {
+    *result = value;
+    return true;
+  }
+  return false;
+}
+
+const WinConfigurationPolicyProvider::RegistryPolicyMapEntry
+    WinConfigurationPolicyProvider::registry_to_policy_map_[] = {
+    { Value::TYPE_STRING,
+      ConfigurationPolicyStore::kPolicyHomePage,
+      kHomepageRegistryValueName },
+    { Value::TYPE_BOOLEAN,
+      ConfigurationPolicyStore::kPolicyHomepageIsNewTabPage,
+      kHomepageIsNewTabPageRegistryValueName },
+    { Value::TYPE_INTEGER,
+      ConfigurationPolicyStore::kPolicyCookiesMode,
+      kCookiesModeRegistryValueName },
+};
+
+bool WinConfigurationPolicyProvider::Provide(
+    ConfigurationPolicyStore* store) {
+  const RegistryPolicyMapEntry* current;
+  const RegistryPolicyMapEntry* end = registry_to_policy_map_ +
+      arraysize(registry_to_policy_map_);
+
+  for (current = registry_to_policy_map_; current != end; ++current) {
+    std::wstring string_value;
+    uint32 int_value;
+    bool bool_value;
+    switch (current->value_type) {
+      case Value::TYPE_STRING:
+        if (GetRegistryPolicyString(current->registry_value_name,
+                                    &string_value)) {
+          store->Apply(
+              current->policy_type,
+              Value::CreateStringValueFromUTF16(string_value));
+        }
+        break;
+      case Value::TYPE_BOOLEAN:
+        if (GetRegistryPolicyBoolean(current->registry_value_name,
+                                     &bool_value)) {
+          store->Apply(current->policy_type,
+                       Value::CreateBooleanValue(bool_value));
+        }
+        break;
+      case Value::TYPE_INTEGER:
+        if (GetRegistryPolicyInteger(current->registry_value_name,
+                                     &int_value)) {
+          store->Apply(current->policy_type,
+                       Value::CreateIntegerValue(int_value));
+        }
+        break;
+      default:
+        NOTREACHED();
+        return false;
+    }
+  }
+
+  return true;
+}
+