remoting/host/curtain_mode_linux.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "remoting/host/curtain_mode.h"
   6
   7 #include <X11/extensions/XInput.h>
   8
   9 #include "base/callback.h"
  10 #include "base/single_thread_task_runner.h"
  11 #include "remoting/base/logging.h"
  12 #include "remoting/host/client_session_control.h"
  13
  14 namespace remoting {
  15
  16 class CurtainModeLinux : public CurtainMode {
  17  public:
  18   CurtainModeLinux();
  19
  20   // Overriden from CurtainMode.
  21   bool Activate() override;
  22
  23  private:
  24   // Returns true if the host is running under an Xvfb session.
  25   bool IsXvfbSession();
  26
  27   DISALLOW_COPY_AND_ASSIGN(CurtainModeLinux);
  28 };
  29
  30 CurtainModeLinux::CurtainModeLinux() {
  31 }
  32
  33 bool CurtainModeLinux::Activate() {
  34   // We can't curtain the session in run-time in Linux.
  35   // Either the session is running on Xvfb (i.e. always curtained), or it is
  36   // attached to the physical console (i.e. impossible to curtain).
  37   bool activated = IsXvfbSession();
  38   if (!activated) {
  39     LOG(ERROR) << "Curtain-mode is not supported when running on non-Xvfb "
  40                   "X server";
  41   }
  42
  43   return activated;
  44 }
  45
  46 bool CurtainModeLinux::IsXvfbSession() {
  47   // Try to identify an Xvfb session. There's no way to query what X server we
  48   // are running under, so we check for the Xvfb input devices.
  49   // TODO(rmsousa): Find a similar way to determine that the *output* is secure.
  50   Display* display = XOpenDisplay(nullptr);
  51   int opcode, event, error;
  52   if (!XQueryExtension(display, "XInputExtension", &opcode, &event, &error)) {
  53     // If XInput is not available, assume it is not an Xvfb session.
  54     LOG(ERROR) << "X Input extension not available: " << error;
  55     XCloseDisplay(display);
  56     return false;
  57   }
  58   int num_devices;
  59   XDeviceInfo* devices;
  60   bool found_xvfb_mouse = false;
  61   bool found_xvfb_keyboard = false;
  62   bool found_other_devices = false;
  63   devices = XListInputDevices(display, &num_devices);
  64   for (int i = 0; i < num_devices; i++) {
  65     XDeviceInfo* device_info = &devices[i];
  66     if (device_info->use == IsXExtensionPointer) {
  67       if (strcmp(device_info->name, "Xvfb mouse") == 0) {
  68         found_xvfb_mouse = true;
  69       } else if (strcmp(device_info->name, "Virtual core XTEST pointer") != 0) {
  70         found_other_devices = true;
  71         HOST_LOG << "Non Xvfb mouse found: " << device_info->name;
  72       }
  73     } else if (device_info->use == IsXExtensionKeyboard) {
  74       if (strcmp(device_info->name, "Xvfb keyboard") == 0) {
  75         found_xvfb_keyboard = true;
  76       } else if (strcmp(device_info->name,
  77                         "Virtual core XTEST keyboard") != 0) {
  78         found_other_devices = true;
  79         HOST_LOG << "Non Xvfb keyboard found: " << device_info->name;
  80       }
  81     } else if (device_info->use == IsXPointer) {
  82       if (strcmp(device_info->name, "Virtual core pointer") != 0) {
  83         found_other_devices = true;
  84         HOST_LOG << "Non Xvfb mouse found: " << device_info->name;
  85       }
  86     } else if (device_info->use == IsXKeyboard) {
  87       if (strcmp(device_info->name, "Virtual core keyboard") != 0) {
  88         found_other_devices = true;
  89         HOST_LOG << "Non Xvfb keyboard found: " << device_info->name;
  90       }
  91     } else {
  92       found_other_devices = true;
  93       HOST_LOG << "Non Xvfb device found: " << device_info->name;
  94     }
  95   }
  96   XFreeDeviceList(devices);
  97   XCloseDisplay(display);
  98   return found_xvfb_mouse && found_xvfb_keyboard && !found_other_devices;
  99 }
 100
 101 // static
 102 scoped_ptr<CurtainMode> CurtainMode::Create(
 103     scoped_refptr<base::SingleThreadTaskRunner> caller_task_runner,
 104     scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner,
 105     base::WeakPtr<ClientSessionControl> client_session_control) {
 106   return make_scoped_ptr(new CurtainModeLinux());
 107 }
 108
 109 }  // namespace remoting