1 files changed, 84 insertions, 5 deletions

diff --git a/remoting/host/curtain_mode_linux.cc b/remoting/host/curtain_mode_linux.cc
index 5c3f269..61a3d97 100644
--- a/remoting/host/curtain_mode_linux.cc
+++ b/remoting/host/curtain_mode_linux.cc
@@ -4,28 +4,107 @@
 
 #include "remoting/host/curtain_mode.h"
 
+#include <X11/extensions/XInput.h>
+
+#include "base/callback.h"
 #include "base/logging.h"
 
 namespace remoting {
 
 class CurtainModeLinux : public CurtainMode {
  public:
-  CurtainModeLinux() {}
+  CurtainModeLinux(const base::Closure& on_session_activate,
+                   const base::Closure& on_error);
+
   // Overriden from CurtainMode.
-  virtual void SetActivated(bool activated) OVERRIDE {
-    NOTIMPLEMENTED();
-  }
+  virtual void SetActivated(bool activated) OVERRIDE;
 
  private:
+  // Returns true if the host is running under an Xvfb session.
+  bool IsXvfbSession();
+
+  base::Closure on_session_activate_;
+  base::Closure on_error_;
+
   DISALLOW_COPY_AND_ASSIGN(CurtainModeLinux);
 };
 
+CurtainModeLinux::CurtainModeLinux(const base::Closure& on_session_activate,
+                                   const base::Closure& on_error)
+    : on_session_activate_(on_session_activate),
+      on_error_(on_error) {
+}
+
+bool CurtainModeLinux::IsXvfbSession() {
+  // Try to identify an Xvfb session. There's no way to query what X server we
+  // are running under, so we check for the Xvfb input devices.
+  // TODO(rmsousa): Find a similar way to determine that the *output* is secure.
+  Display* display = XOpenDisplay(NULL);
+  int opcode, event, error;
+  if (!XQueryExtension(display, "XInputExtension", &opcode, &event, &error)) {
+    // If XInput is not available, assume it is not an Xvfb session.
+    LOG(ERROR) << "X Input extension not available: " << error;
+    XCloseDisplay(display);
+    return false;
+  }
+  int num_devices;
+  XDeviceInfo* devices;
+  bool found_xvfb_mouse = false;
+  bool found_xvfb_keyboard = false;
+  bool found_other_devices = false;
+  devices = XListInputDevices(display, &num_devices);
+  for (int i = 0; i < num_devices; i++) {
+    XDeviceInfo* device_info = &devices[i];
+    if (device_info->use == IsXExtensionPointer) {
+      if (strcmp(device_info->name, "Xvfb mouse") == 0) {
+        found_xvfb_mouse = true;
+      } else if (strcmp(device_info->name, "Virtual core XTEST pointer") != 0) {
+        found_other_devices = true;
+        LOG(INFO) << "Non Xvfb mouse found: " << device_info->name;
+      }
+    } else if (device_info->use == IsXExtensionKeyboard) {
+      if (strcmp(device_info->name, "Xvfb keyboard") == 0) {
+        found_xvfb_keyboard = true;
+      } else if (strcmp(device_info->name,
+                        "Virtual core XTEST keyboard") != 0) {
+        found_other_devices = true;
+        LOG(INFO) << "Non Xvfb keyboard found: " << device_info->name;
+      }
+    } else if (device_info->use == IsXPointer) {
+      if (strcmp(device_info->name, "Virtual core pointer") != 0) {
+        found_other_devices = true;
+        LOG(INFO) << "Non Xvfb mouse found: " << device_info->name;
+      }
+    } else if (device_info->use == IsXKeyboard) {
+      if (strcmp(device_info->name, "Virtual core keyboard") != 0) {
+        found_other_devices = true;
+        LOG(INFO) << "Non Xvfb keyboard found: " << device_info->name;
+      }
+    } else {
+      found_other_devices = true;
+      LOG(INFO) << "Non Xvfb device found: " << device_info->name;
+    }
+  }
+  XFreeDeviceList(devices);
+  XCloseDisplay(display);
+  return found_xvfb_mouse && found_xvfb_keyboard && !found_other_devices;
+}
+
+void CurtainModeLinux::SetActivated(bool activated) {
+  // We can't curtain the session in run-time in Linux.
+  // Either the session is running on Xvfb (i.e. always curtained), or it is
+  // attached to the physical console (i.e. impossible to curtain).
+  if (activated && !IsXvfbSession()) {
+    on_error_.Run();
+  }
+}
+
 // static
 scoped_ptr<CurtainMode> CurtainMode::Create(
     const base::Closure& on_session_activate,
     const base::Closure& on_error) {
   return scoped_ptr<CurtainMode>(
-      new CurtainModeLinux());
+      new CurtainModeLinux(on_session_activate, on_error));
 }
 
 }  // namespace remoting