webview-aad-helper/main.cpp

 
#include <webview.h>
 
#if defined(__linux__)
#include <gtk/gtk.h>
#endif
 
#include <atomic>
#include <chrono>
#include <condition_variable>
#include <cstdint>
#include <iostream>
#include <mutex>
#include <string>
#include <thread>
 
#include <winpr/file.h>
#include <winpr/handle.h>
#include <winpr/json.h>
 
#include "redirect_watcher.hpp"
 
namespace
{
 
  constexpr uint32_t kDefaultTimeoutMs = 180000;
 
  struct PendingResult
  {
    std::mutex mtx;
    std::condition_variable cv;
    bool done = false;
    bool ok = false;
    std::string redirectUrl;
    std::string errorMessage;
  };
 
  class Session
  {
    public:
    Session() : w(false, nullptr)
    {
      w.add_navigation_listener(&Session::onNavigateStatic, this);
    }
 
    void run()
    {
      w.run();
    }
 
    bool navigate(const std::string& title, const std::string& url,
                  const std::string& redirectUri, uint32_t timeoutMs, std::string& redirectUrl,
                  std::string& error)
    {
      PendingResult pending;
      {
        std::lock_guard<std::mutex> lock(stateMtx);
        if (current)
        {
          error = "navigate_already_in_progress";
          return false;
        }
        current = &pending;
        watcher = RedirectWatcher(redirectUri);
      }
 
      w.dispatch(
          [this, title, url]()
          {
#if defined(__linux__)
            /* the window may have been hidden (see below) by a previous navigate() on
             * this same reused webview - bring it back before showing new content. */
            auto handle = w.window();
            if (handle.ok())
              gtk_widget_show(GTK_WIDGET(handle.value()));
#endif
            w.set_title(title);
            w.set_size(800, 600, WEBVIEW_HINT_NONE);
            w.navigate(url);
          });
 
      const uint32_t timeout = timeoutMs ? timeoutMs : kDefaultTimeoutMs;
      bool signalled = false;
      {
        std::unique_lock<std::mutex> lock(pending.mtx);
        signalled = pending.cv.wait_for(lock, std::chrono::milliseconds(timeout),
                                        [&] { return pending.done; });
      }
 
      {
        std::lock_guard<std::mutex> lock(stateMtx);
        /* still ours: nobody finished it (timeout) - detach the now-invalid pointer to the
         * stack-local `pending` before it goes out of scope */
        if (current == &pending)
          current = nullptr;
      }
 
      /* the popup has served its purpose once this navigate() is done, whatever the
       * outcome - hide it now rather than leaving it sitting on screen until the next
       * navigate() (if any) reuses and re-shows it. webview has no portable hide(), so on
       * platforms without a native-handle-based fallback below, blanking the content is the
       * best available approximation. */
      w.dispatch(
          [this]()
          {
#if defined(__linux__)
            auto handle = w.window();
            if (handle.ok())
              gtk_widget_hide(GTK_WIDGET(handle.value()));
            else
              w.navigate("about:blank");
#else
            w.navigate("about:blank");
#endif
          });
 
      if (!signalled)
      {
        error = "timeout";
        return false;
      }
 
      if (!pending.ok)
      {
        error = pending.errorMessage.empty() ? "user_cancelled" : pending.errorMessage;
        return false;
      }
 
      redirectUrl = pending.redirectUrl;
      return true;
    }
 
    void cancel()
    {
      std::lock_guard<std::mutex> lock(stateMtx);
      finishCurrentLocked(false, "", "user_cancelled");
    }
 
    void quit()
    {
      {
        std::lock_guard<std::mutex> lock(stateMtx);
        finishCurrentLocked(false, "", "shutting_down");
      }
      w.dispatch([this]() { w.terminate(); });
    }
 
    private:
    static void onNavigateStatic(webview_t wv, const char* uri, webview_navigation_event_t type,
                                 void* arg)
    {
      (void)wv;
      if (type != WEBVIEW_LOAD_FINISHED)
        return;
      static_cast<Session*>(arg)->onNavigate(uri);
    }
 
    void onNavigate(const std::string& uri)
    {
      std::lock_guard<std::mutex> lock(stateMtx);
      if (!current || !watcher.matches(uri))
        return;
 
      std::string err;
      if (watcher.hasError(uri, err))
        finishCurrentLocked(false, "", err);
      else
        finishCurrentLocked(true, uri, "");
    }
 
    /* caller must hold stateMtx */
    void finishCurrentLocked(bool ok, const std::string& redirectUrl, const std::string& err)
    {
      if (!current)
        return;
      {
        std::lock_guard<std::mutex> lock(current->mtx);
        current->done = true;
        current->ok = ok;
        current->redirectUrl = redirectUrl;
        current->errorMessage = err;
      }
      current->cv.notify_all();
      current = nullptr;
    }
 
    webview::webview w;
    std::mutex stateMtx;
    PendingResult* current = nullptr;
    RedirectWatcher watcher{ std::string() };
  };
 
  /* the JSON-RPC channel: handles imported from the --cmdInFd=/--cmdOutFd= command line arguments
   * (see main()), not stdin/stdout - so this helper's own stdio stays free for its normal
   * diagnostic output instead of colliding with the protocol. */
  HANDLE g_cmdIn = nullptr;
  HANDLE g_cmdOut = nullptr;
 
  bool writeLine(const std::string& line)
  {
    std::string data = line;
    data += "\n";
 
    size_t written = 0;
    while (written < data.size())
    {
      DWORD dwWritten = 0;
      if (!WriteFile(g_cmdOut, data.data() + written,
                     static_cast<DWORD>(data.size() - written), &dwWritten, nullptr) ||
          (dwWritten == 0))
        return false;
      written += dwWritten;
    }
    return true;
  }
 
  /* extracts one '\n'-terminated line already buffered in `buf`, if any */
  bool extractLine(std::string& buf, std::string& line)
  {
    const auto pos = buf.find('\n');
    if (pos == std::string::npos)
      return false;
    line = buf.substr(0, pos);
    buf.erase(0, pos + 1);
    return true;
  }
 
  bool readLine(std::string& buf, std::string& line)
  {
    if (extractLine(buf, line))
      return true;
 
    while (true)
    {
      char chunk[4096];
      DWORD dwRead = 0;
      if (!ReadFile(g_cmdIn, chunk, sizeof(chunk), &dwRead, nullptr) || (dwRead == 0))
        return false;
      buf.append(chunk, dwRead);
      if (extractLine(buf, line))
        return true;
    }
  }
 
  void sendLine(const std::string& line)
  {
    (void)writeLine(line);
  }
 
  void sendJson(WINPR_JSON* obj)
  {
    char* str = WINPR_JSON_PrintUnformatted(obj);
    if (str)
    {
      sendLine(str);
      free(str);
    }
    WINPR_JSON_Delete(obj);
  }
 
  void sendHelloResult(int64_t id)
  {
    WINPR_JSON* obj = WINPR_JSON_CreateObject();
    bool ok = WINPR_JSON_AddStringToObject(obj, "jsonrpc", "2.0") &&
              WINPR_JSON_AddNumberToObject(obj, "id", static_cast<double>(id));
    WINPR_JSON* result = ok ? WINPR_JSON_AddObjectToObject(obj, "result") : nullptr;
    if (result)
    {
      bool unused =
          WINPR_JSON_AddIntegerToObject(result, "protocol_version", 1) &&
          WINPR_JSON_AddStringToObject(result, "helper", "freerdp-webview-aad-helper/1.0");
      (void)unused;
    }
    sendJson(obj);
  }
 
  void sendNavigateResult(int64_t id, const std::string& redirectUrl)
  {
    WINPR_JSON* obj = WINPR_JSON_CreateObject();
    bool ok = WINPR_JSON_AddStringToObject(obj, "jsonrpc", "2.0") &&
              WINPR_JSON_AddNumberToObject(obj, "id", static_cast<double>(id));
    WINPR_JSON* result = ok ? WINPR_JSON_AddObjectToObject(obj, "result") : nullptr;
    if (result)
    {
      bool unused = WINPR_JSON_AddStringToObject(result, "status", "ok") &&
                    WINPR_JSON_AddStringToObject(result, "redirect_url", redirectUrl.c_str());
      (void)unused;
    }
    sendJson(obj);
  }
 
  void sendNullResult(int64_t id)
  {
    WINPR_JSON* obj = WINPR_JSON_CreateObject();
    bool ok = WINPR_JSON_AddStringToObject(obj, "jsonrpc", "2.0") &&
              WINPR_JSON_AddNumberToObject(obj, "id", static_cast<double>(id)) &&
              WINPR_JSON_AddNullToObject(obj, "result");
    (void)ok;
    sendJson(obj);
  }
 
  void sendError(int64_t id, int code, const std::string& message)
  {
    WINPR_JSON* obj = WINPR_JSON_CreateObject();
    bool ok = WINPR_JSON_AddStringToObject(obj, "jsonrpc", "2.0") &&
              WINPR_JSON_AddNumberToObject(obj, "id", static_cast<double>(id));
    WINPR_JSON* error = ok ? WINPR_JSON_AddObjectToObject(obj, "error") : nullptr;
    if (error)
    {
      bool unused = WINPR_JSON_AddIntegerToObject(error, "code", code) &&
                    WINPR_JSON_AddStringToObject(error, "message", message.c_str());
      (void)unused;
    }
    sendJson(obj);
  }
 
  std::string getStringField(WINPR_JSON* obj, const char* name)
  {
    if (!obj)
      return {};
    WINPR_JSON* item = WINPR_JSON_GetObjectItemCaseSensitive(obj, name);
    if (!item || !WINPR_JSON_IsString(item))
      return {};
    const char* v = WINPR_JSON_GetStringValue(item);
    return v ? v : "";
  }
 
  uint32_t getUintField(WINPR_JSON* obj, const char* name, uint32_t def)
  {
    if (!obj)
      return def;
    WINPR_JSON* item = WINPR_JSON_GetObjectItemCaseSensitive(obj, name);
    if (!item || !WINPR_JSON_IsNumber(item))
      return def;
    return static_cast<uint32_t>(WINPR_JSON_GetNumberValue(item));
  }
 
  void readerLoop(Session& session)
  {
    std::string buf;
    std::string line;
    while (readLine(buf, line))
    {
      if (line.empty())
        continue;
 
      WINPR_JSON* msg = WINPR_JSON_Parse(line.c_str());
      if (!msg)
        continue;
 
      WINPR_JSON* idItem = WINPR_JSON_GetObjectItemCaseSensitive(msg, "id");
      const bool hasId = idItem && WINPR_JSON_IsNumber(idItem);
      const int64_t id = hasId ? static_cast<int64_t>(WINPR_JSON_GetNumberValue(idItem)) : 0;
      const std::string method = getStringField(msg, "method");
      WINPR_JSON* params = WINPR_JSON_GetObjectItemCaseSensitive(msg, "params");
 
      if (method == "hello")
      {
        sendHelloResult(id);
      }
      else if (method == "navigate")
      {
        const std::string title = getStringField(params, "title");
        const std::string url = getStringField(params, "url");
        const std::string redirectUri = getStringField(params, "redirect_uri");
        const uint32_t timeoutMs = getUintField(params, "timeout_ms", kDefaultTimeoutMs);
 
        std::string redirectUrl;
        std::string error;
        if (session.navigate(title, url, redirectUri, timeoutMs, redirectUrl, error))
          sendNavigateResult(id, redirectUrl);
        else
          sendError(id, 1, error);
      }
      else if (method == "cancel")
      {
        session.cancel();
      }
      else if (method == "shutdown")
      {
        sendNullResult(id);
      }
      else if (method == "exit")
      {
        WINPR_JSON_Delete(msg);
        break;
      }
 
      WINPR_JSON_Delete(msg);
    }
 
    session.quit();
  }
 
} // namespace
 
int main(int argc, char* argv[])
{
  std::string cmdInArg;
  std::string cmdOutArg;
  for (int i = 1; i < argc; i++)
  {
    const std::string arg = argv[i];
    if (arg.rfind("--cmdInFd=", 0) == 0)
      cmdInArg = arg;
    else if (arg.rfind("--cmdOutFd=", 0) == 0)
      cmdOutArg = arg;
  }
 
  if (cmdInArg.empty() || cmdOutArg.empty())
  {
    std::cerr << "usage: " << (argc > 0 ? argv[0] : "freerdp-webview-aad-helper")
              << " --cmdInFd=<handle> --cmdOutFd=<handle>" << std::endl;
    return 1;
  }
 
  g_cmdIn = winpr_importHandleFromString(cmdInArg.c_str(), "--cmdInFd={}");
  g_cmdOut = winpr_importHandleFromString(cmdOutArg.c_str(), "--cmdOutFd={}");
  if (!g_cmdIn || (g_cmdIn == INVALID_HANDLE_VALUE) || !g_cmdOut ||
      (g_cmdOut == INVALID_HANDLE_VALUE))
  {
    std::cerr << "failed to import the cmdIn/cmdOut channel handles" << std::endl;
    return 1;
  }
 
  Session session;
  std::thread reader(readerLoop, std::ref(session));
 
  session.run();
  reader.join();
 
  (void)CloseHandle(g_cmdIn);
  (void)CloseHandle(g_cmdOut);
  return 0;
}