1 files changed, 105 insertions, 0 deletions
diff --git a/toolkit/mozapps/defaultagent/RemoteSettings.cpp b/toolkit/mozapps/defaultagent/RemoteSettings.cpp
new file mode 100644
index 0000000000..37a376ff90
--- /dev/null
+++ b/toolkit/mozapps/defaultagent/RemoteSettings.cpp
@@ -0,0 +1,105 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "RemoteSettings.h"
+
+#include <iostream>
+#include <string>
+#include <windows.h>
+#include <shlwapi.h>
+
+#include "common.h"
+#include "EventLog.h"
+#include "Registry.h"
+
+#include "mozilla/Maybe.h"
+#include "mozilla/Result.h"
+#include "mozilla/Unused.h"
+
+// All strings cross the C/C++ <-> Rust FFI boundary as
+// null-terminated UTF-8.
+extern "C" {
+HRESULT IsAgentRemoteDisabledRust(const char* szUrl, DWORD* lpdwDisabled);
+}
+
+#define PROD_ENDPOINT "https://firefox.settings.services.mozilla.com/v1"
+#define PROD_BID "main"
+#define PROD_CID "windows-default-browser-agent"
+#define PROD_ID "state"
+
+#define PATH "buckets/" PROD_BID "/collections/" PROD_CID "/records/" PROD_ID
+
+using BoolResult = mozilla::WindowsErrorResult<bool>;
+
+// Use Rust library to query remote service endpoint to determine if
+// WDBA is disabled.
+//
+// Pass through errors.
+static BoolResult IsAgentRemoteDisabledInternal() {
+  // Fetch remote settings server root from registry.
+  auto serverResult =
+      RegistryGetValueString(IsPrefixed::Prefixed, L"ServicesSettingsServer");
+
+  // Unconfigured?  Fallback to production.
+  std::string url =
+      serverResult.unwrapOr(mozilla::Some(std::string(PROD_ENDPOINT)))
+          .valueOr(std::string(PROD_ENDPOINT));
+
+  if (url.length() > 0 && url[url.length() - 1] != '/') {
+    url += '/';
+  }
+  url += PATH;
+
+  std::cerr << "default-browser-agent: Remote service disabled state URL: '"
+            << url << "'" << std::endl;
+
+  // Invoke Rust to query remote settings.
+  DWORD isRemoteDisabled;
+  HRESULT hr = IsAgentRemoteDisabledRust(url.c_str(), &isRemoteDisabled);
+
+  std::cerr << "default-browser-agent: HRESULT: 0x" << std::hex << hr
+            << std::endl;
+
+  if (SUCCEEDED(hr)) {
+    return (0 != isRemoteDisabled);
+  }
+
+  LOG_ERROR(hr);
+  return mozilla::Err(mozilla::WindowsError::FromHResult(hr));
+}
+
+// Query remote service endpoint to determine if WDBA is disabled.
+//
+// Handle errors, failing to the last state witnessed without error.
+bool IsAgentRemoteDisabled() {
+  // Fetch last witnessed state from registry.  If we can't get the last
+  // state, or there is no last state, assume we're not disabled.
+  bool lastRemoteDisabled =
+      RegistryGetValueBool(IsPrefixed::Prefixed,
+                           L"DefaultAgentLastRemoteDisabled")
+          .unwrapOr(mozilla::Some(false))
+          .valueOr(false);
+
+  std::cerr << "default-browser-agent: Last remote disabled: "
+            << lastRemoteDisabled << std::endl;
+
+  auto remoteDisabledResult = IsAgentRemoteDisabledInternal();
+  if (remoteDisabledResult.isErr()) {
+    // Fail to the last state witnessed without error.
+    return lastRemoteDisabled;
+  }
+
+  bool remoteDisabled = remoteDisabledResult.unwrap();
+
+  std::cerr << "default-browser-agent: Next remote disabled: " << remoteDisabled
+            << std::endl;
+
+  // Update last witnessed state in registry.
+  mozilla::Unused << RegistrySetValueBool(
+      IsPrefixed::Prefixed, L"DefaultAgentLastRemoteDisabled", remoteDisabled);
+
+  return remoteDisabled;
+}