Merge pull request #3890 from leoetlino/evdev-hotplug

evdev: Add hotplug support

Source/Core/Core/HW/GCKeyboard.cpp

@@ -36,6 +36,7 @@ void Initialize(void* const hwnd)
   }
 
   g_controller_interface.Initialize(hwnd);
+  g_controller_interface.RegisterHotplugCallback(LoadConfig);
 
   // Load the saved controller config
   s_config.LoadConfig(true);

Source/Core/Core/HW/GCKeyboardEmu.cpp

@@ -86,6 +86,7 @@ std::string GCKeyboard::GetName() const
 
 void GCKeyboard::GetInput(KeyboardStatus* const kb)
 {
+  auto lock = ControllerEmu::GetStateLock();
   m_keys0x->GetState(&kb->key0x, keys0_bitmasks);
   m_keys1x->GetState(&kb->key1x, keys1_bitmasks);
   m_keys2x->GetState(&kb->key2x, keys2_bitmasks);

Source/Core/Core/HW/GCPad.cpp

@@ -35,6 +35,7 @@ void Initialize(void* const hwnd)
   }
 
   g_controller_interface.Initialize(hwnd);
+  g_controller_interface.RegisterHotplugCallback(LoadConfig);
 
   // Load the saved controller config
   s_config.LoadConfig(true);

Source/Core/Core/HW/GCPadEmu.cpp

@@ -81,6 +81,8 @@ std::string GCPad::GetName() const
 
 void GCPad::GetInput(GCPadStatus* const pad)
 {
+  auto lock = ControllerEmu::GetStateLock();
+
   ControlState x, y, triggers[2];
 
   // buttons
@@ -116,6 +118,7 @@ void GCPad::GetInput(GCPadStatus* const pad)
 
 void GCPad::SetOutput(const ControlState strength)
 {
+  auto lock = ControllerEmu::GetStateLock();
   m_rumble->controls[0]->control_ref->State(strength);
 }
 
@@ -190,5 +193,6 @@ void GCPad::LoadDefaults(const ControllerInterface& ciface)
 
 bool GCPad::GetMicButton() const
 {
+  auto lock = ControllerEmu::GetStateLock();
   return (0.0f != m_buttons->controls.back()->control_ref->State());
 }

Source/Core/Core/HW/Wiimote.cpp

@@ -37,6 +37,7 @@ void Initialize(void* const hwnd, InitializeMode init_mode)
   }
 
   g_controller_interface.Initialize(hwnd);
+  g_controller_interface.RegisterHotplugCallback(LoadConfig);
 
   s_config.LoadConfig(false);
 

Source/Core/Core/HW/WiimoteEmu/WiimoteEmu.cpp

@@ -623,8 +623,11 @@ void Wiimote::Update()
     return;
 
   // returns true if a report was sent
+  {
+    auto lock = ControllerEmu::GetStateLock();
     if (Step())
       return;
+  }
 
   u8 data[MAX_PAYLOAD];
   memset(data, 0, sizeof(data));
@@ -646,6 +649,8 @@ void Wiimote::Update()
     data[0] = 0xA1;
     data[1] = m_reporting_mode;
 
+    auto lock = ControllerEmu::GetStateLock();
+
     // core buttons
     if (rptf.core)
       GetButtonData(data + rptf.core);
@@ -876,6 +881,7 @@ void Wiimote::ConnectOnInput()
   }
 
   u16 buttons = 0;
+  auto lock = ControllerEmu::GetStateLock();
   m_buttons->GetState(&buttons, button_bitmasks);
   m_dpad->GetState(&buttons, dpad_bitmasks);
 

Source/Core/Core/HotkeyManager.cpp

@@ -186,6 +186,7 @@ void Initialize(void* const hwnd)
     s_config.CreateController<HotkeyManager>();
 
   g_controller_interface.Initialize(hwnd);
+  g_controller_interface.RegisterHotplugCallback(LoadConfig);
 
   // load the saved controller config
   s_config.LoadConfig(true);
@@ -239,6 +240,7 @@ std::string HotkeyManager::GetName() const
 
 void HotkeyManager::GetInput(HotkeyStatus* const kb)
 {
+  auto lock = ControllerEmu::GetStateLock();
   for (int set = 0; set < (NUM_HOTKEYS + 31) / 32; set++)
   {
     std::vector<u32> bitmasks;

Source/Core/DolphinWX/InputConfigDiag.cpp

@@ -315,11 +315,12 @@ bool ControlDialog::Validate()
 {
   control_reference->expression = WxStrToStr(textctrl->GetValue());
 
+  auto lock = ControllerEmu::GetStateLock();
   g_controller_interface.UpdateReference(control_reference, m_parent->controller->default_device);
 
   UpdateGUI();
 
-  return (control_reference->parse_error == EXPRESSION_PARSE_SUCCESS);
+  return control_reference->parse_error == EXPRESSION_PARSE_SUCCESS;
 }
 
 void GamepadPage::SetDevice(wxCommandEvent&)
@@ -351,6 +352,7 @@ void ControlDialog::ClearControl(wxCommandEvent&)
 {
   control_reference->expression.clear();
 
+  auto lock = ControllerEmu::GetStateLock();
   g_controller_interface.UpdateReference(control_reference, m_parent->controller->default_device);
 
   UpdateGUI();
@@ -408,6 +410,7 @@ void ControlDialog::SetSelectedControl(wxCommandEvent&)
   textctrl->WriteText(expr);
   control_reference->expression = textctrl->GetValue();
 
+  auto lock = ControllerEmu::GetStateLock();
   g_controller_interface.UpdateReference(control_reference, m_parent->controller->default_device);
 
   UpdateGUI();
@@ -442,6 +445,7 @@ void ControlDialog::AppendControl(wxCommandEvent& event)
   textctrl->WriteText(expr);
   control_reference->expression = textctrl->GetValue();
 
+  auto lock = ControllerEmu::GetStateLock();
   g_controller_interface.UpdateReference(control_reference, m_parent->controller->default_device);
 
   UpdateGUI();
@@ -556,6 +560,7 @@ bool GamepadPage::DetectButton(ControlButton* button)
       wxString expr;
       GetExpressionForControl(expr, control_name);
       button->control_reference->expression = expr;
+      auto lock = ControllerEmu::GetStateLock();
       g_controller_interface.UpdateReference(button->control_reference, controller->default_device);
       success = true;
     }

Source/Core/DolphinWX/InputConfigDiagBitmaps.cpp

@@ -4,7 +4,6 @@
 
 #include <cstring>
 #include <memory>
-#include <mutex>
 #include <string>
 #include <vector>
 #include <wx/bitmap.h>
@@ -125,6 +124,7 @@ static void DrawButton(unsigned int* const bitmasks, unsigned int buttons, unsig
   }
   else
   {
+    auto lock = ControllerEmu::GetStateLock();
     unsigned char amt = 255 - g->control_group->controls[(row * 8) + n]->control_ref->State() * 128;
     dc.SetBrush(wxBrush(wxColour(amt, amt, amt)));
   }
@@ -232,7 +232,6 @@ static void DrawControlGroupBox(wxDC& dc, ControlGroupBox* g)
     }
 
     // raw dot
-    {
     ControlState xx, yy;
     xx = g->control_group->controls[3]->control_ref->State();
     xx -= g->control_group->controls[2]->control_ref->State();
@@ -242,7 +241,6 @@ static void DrawControlGroupBox(wxDC& dc, ControlGroupBox* g)
     dc.SetPen(*wxGREY_PEN);
     dc.SetBrush(*wxGREY_BRUSH);
     DrawCoordinate(dc, xx, yy);
-    }
 
     // adjusted dot
     if (x != 0 || y != 0)
@@ -403,6 +401,7 @@ static void DrawControlGroupBox(wxDC& dc, ControlGroupBox* g)
     for (unsigned int n = 0; n < trigger_count; ++n)
     {
       dc.SetBrush(*wxRED_BRUSH);
+
       ControlState trig_d = g->control_group->controls[n]->control_ref->State();
 
       ControlState trig_a =
@@ -465,6 +464,7 @@ void InputConfigDialog::UpdateBitmaps(wxTimerEvent& WXUNUSED(event))
   GamepadPage* const current_page =
       (GamepadPage*)m_pad_notebook->GetPage(m_pad_notebook->GetSelection());
 
+  auto lock = ControllerEmu::GetStateLock();
   for (ControlGroupBox* g : current_page->control_groups)
   {
     // if this control group has a bitmap

Source/Core/InputCommon/ControllerEmu.cpp

@@ -6,8 +6,19 @@
 #include <memory>
 #include "Common/Common.h"
 
+// This should be called before calling GetState() or State() on a control reference
+// to prevent a race condition.
+// This is a recursive mutex because UpdateReferences is recursive.
+static std::recursive_mutex s_get_state_mutex;
+std::unique_lock<std::recursive_mutex> ControllerEmu::GetStateLock()
+{
+  std::unique_lock<std::recursive_mutex> lock(s_get_state_mutex);
+  return lock;
+}
+
 void ControllerEmu::UpdateReferences(ControllerInterface& devi)
 {
+  auto lock = ControllerEmu::GetStateLock();
   for (auto& ctrlGroup : groups)
   {
     for (auto& control : ctrlGroup->controls)

Source/Core/InputCommon/ControllerEmu.h

@@ -7,6 +7,7 @@
 #include <algorithm>
 #include <cmath>
 #include <memory>
+#include <mutex>
 #include <string>
 #include <vector>
 
@@ -444,6 +445,12 @@ public:
 
   void UpdateReferences(ControllerInterface& devi);
 
+  // This returns a lock that should be held before calling State() on any control
+  // references and GetState(), by extension. This prevents a race condition
+  // which happens while handling a hotplug event because a control reference's State()
+  // could be called before we have finished updating the reference.
+  static std::unique_lock<std::recursive_mutex> GetStateLock();
+
   std::vector<std::unique_ptr<ControlGroup>> groups;
 
   ciface::Core::DeviceQualifier default_device;

Source/Core/InputCommon/ControllerInterface/ControllerInterface.cpp

@@ -106,17 +106,6 @@ void ControllerInterface::Shutdown()
   if (!m_is_init)
     return;
 
-  std::lock_guard<std::mutex> lk(m_devices_mutex);
-
-  for (const auto& d : m_devices)
-  {
-    // Set outputs to ZERO before destroying device
-    for (ciface::Core::Device::Output* o : d->Outputs())
-      o->SetState(0);
-  }
-
-  m_devices.clear();
-
 #ifdef CIFACE_USE_XINPUT
   ciface::XInput::DeInit();
 #endif
@@ -136,6 +125,20 @@ void ControllerInterface::Shutdown()
 #ifdef CIFACE_USE_ANDROID
 // nothing needed
 #endif
+#ifdef CIFACE_USE_EVDEV
+  ciface::evdev::Shutdown();
+#endif
+
+  std::lock_guard<std::mutex> lk(m_devices_mutex);
+
+  for (const auto& d : m_devices)
+  {
+    // Set outputs to ZERO before destroying device
+    for (ciface::Core::Device::Output* o : d->Outputs())
+      o->SetState(0);
+  }
+
+  m_devices.clear();
 
   m_is_init = false;
 }
@@ -160,6 +163,14 @@ void ControllerInterface::AddDevice(std::shared_ptr<ciface::Core::Device> device
   m_devices.emplace_back(std::move(device));
 }
 
+void ControllerInterface::RemoveDevice(std::function<bool(const ciface::Core::Device*)> callback)
+{
+  std::lock_guard<std::mutex> lk(m_devices_mutex);
+  m_devices.erase(std::remove_if(m_devices.begin(), m_devices.end(),
+                                 [&callback](const auto& dev) { return callback(dev.get()); }),
+                  m_devices.end());
+}
+
 //
 // UpdateInput
 //
@@ -167,9 +178,35 @@ void ControllerInterface::AddDevice(std::shared_ptr<ciface::Core::Device> device
 //
 void ControllerInterface::UpdateInput()
 {
-  std::lock_guard<std::mutex> lk(m_devices_mutex);
+  // Don't block the UI or CPU thread (to avoid a short but noticeable frame drop)
+  if (m_devices_mutex.try_lock())
+  {
+    std::lock_guard<std::mutex> lk(m_devices_mutex, std::adopt_lock);
     for (const auto& d : m_devices)
       d->UpdateInput();
+  }
+}
+
+//
+// RegisterHotplugCallback
+//
+// Register a callback to be called from the input backends' hotplug thread
+// when there is a new device
+//
+void ControllerInterface::RegisterHotplugCallback(std::function<void()> callback)
+{
+  m_hotplug_callbacks.emplace_back(std::move(callback));
+}
+
+//
+// InvokeHotplugCallbacks
+//
+// Invoke all callbacks that were registered
+//
+void ControllerInterface::InvokeHotplugCallbacks() const
+{
+  for (const auto& callback : m_hotplug_callbacks)
+    callback();
 }
 
 //

Source/Core/InputCommon/ControllerInterface/ControllerInterface.h

@@ -122,12 +122,17 @@ public:
   void Reinitialize();
   void Shutdown();
   void AddDevice(std::shared_ptr<ciface::Core::Device> device);
+  void RemoveDevice(std::function<bool(const ciface::Core::Device*)> callback);
   bool IsInit() const { return m_is_init; }
   void UpdateReference(ControlReference* control,
                        const ciface::Core::DeviceQualifier& default_device) const;
   void UpdateInput();
 
+  void RegisterHotplugCallback(std::function<void(void)> callback);
+  void InvokeHotplugCallbacks() const;
+
 private:
+  std::vector<std::function<void()>> m_hotplug_callbacks;
   bool m_is_init;
   void* m_hwnd;
 };

Source/Core/InputCommon/ControllerInterface/Device.h

@@ -98,6 +98,7 @@ public:
   virtual std::string GetName() const = 0;
   virtual std::string GetSource() const = 0;
   virtual void UpdateInput() {}
+  virtual bool IsValid() const { return true; }
   const std::vector<Input*>& Inputs() const { return m_inputs; }
   const std::vector<Output*>& Outputs() const { return m_outputs; }
   Input* FindInput(const std::string& name) const;

Source/Core/InputCommon/ControllerInterface/ExpressionParser.cpp

@@ -235,8 +235,9 @@ public:
   ControlQualifier qualifier;
   Device::Control* control;
 
-  ControlExpression(ControlQualifier qualifier_, Device::Control* control_)
-      : qualifier(qualifier_), control(control_)
+  ControlExpression(ControlQualifier qualifier_, std::shared_ptr<Device> device,
+                    Device::Control* control_)
+      : qualifier(qualifier_), control(control_), m_device(device)
   {
   }
 
@@ -244,6 +245,8 @@ public:
   void SetValue(ControlState value) override { control->ToOutput()->SetGatedState(value); }
   int CountNumControls() override { return 1; }
   operator std::string() override { return "`" + (std::string)qualifier + "`"; }
+private:
+  std::shared_ptr<Device> m_device;
 };
 
 class BinaryExpression : public ExpressionNode
@@ -393,6 +396,7 @@ private:
     {
     case TOK_CONTROL:
     {
+      std::shared_ptr<Device> device = finder.FindDevice(tok.qualifier);
       Device::Control* control = finder.FindControl(tok.qualifier);
       if (control == nullptr)
       {
@@ -400,7 +404,7 @@ private:
         return EXPRESSION_PARSE_SUCCESS;
       }
 
-      *expr_out = new ControlExpression(tok.qualifier, control);
+      *expr_out = new ControlExpression(tok.qualifier, device, control);
       return EXPRESSION_PARSE_SUCCESS;
     }
     case TOK_LPAREN:
@@ -550,10 +554,11 @@ ExpressionParseStatus ParseExpression(const std::string& str, ControlFinder& fin
   qualifier.control_name = str;
   qualifier.has_device = false;
 
+  std::shared_ptr<Device> device = finder.FindDevice(qualifier);
   Device::Control* control = finder.FindControl(qualifier);
   if (control)
   {
-    *expr_out = new Expression(new ControlExpression(qualifier, control));
+    *expr_out = new Expression(new ControlExpression(qualifier, device, control));
     return EXPRESSION_PARSE_SUCCESS;
   }
 

Source/Core/InputCommon/ControllerInterface/ExpressionParser.h

@@ -37,10 +37,10 @@ public:
       : container(container_), default_device(default_), is_input(is_input_)
   {
   }
+  std::shared_ptr<Core::Device> FindDevice(ControlQualifier qualifier);
   Core::Device::Control* FindControl(ControlQualifier qualifier);
 
 private:
-  std::shared_ptr<Core::Device> FindDevice(ControlQualifier qualifier);
   const Core::DeviceContainer& container;
   const Core::DeviceQualifier& default_device;
   bool is_input;

Source/Core/InputCommon/ControllerInterface/evdev/evdev.cpp

@@ -5,12 +5,17 @@
 #include <fcntl.h>
 #include <libudev.h>
 #include <map>
+#include <memory>
 #include <unistd.h>
 
+#include <sys/eventfd.h>
+
 #include "Common/Assert.h"
+#include "Common/Flag.h"
 #include "Common/Logging/Log.h"
 #include "Common/MathUtil.h"
 #include "Common/StringUtil.h"
+#include "Common/Thread.h"
 #include "InputCommon/ControllerInterface/ControllerInterface.h"
 #include "InputCommon/ControllerInterface/evdev/evdev.h"
 
@@ -18,6 +23,15 @@ namespace ciface
 {
 namespace evdev
 {
+static std::thread s_hotplug_thread;
+static Common::Flag s_hotplug_thread_running;
+static int s_wakeup_eventfd;
+
+// There is no easy way to get the device name from only a dev node
+// during a device removed event, since libevdev can't work on removed devices;
+// sysfs is not stable, so this is probably the easiest way to get a name for a node.
+static std::map<std::string, std::string> s_devnode_name_map;
+
 static std::string GetName(const std::string& devnode)
 {
   int fd = open(devnode.c_str(), O_RDWR | O_NONBLOCK);
@@ -28,20 +42,110 @@ static std::string GetName(const std::string& devnode)
     close(fd);
     return std::string();
   }
-  std::string res = libevdev_get_name(dev);
+  std::string res = StripSpaces(libevdev_get_name(dev));
   libevdev_free(dev);
   close(fd);
   return res;
 }
 
+static void HotplugThreadFunc()
+{
+  Common::SetCurrentThreadName("evdev Hotplug Thread");
+  NOTICE_LOG(SERIALINTERFACE, "evdev hotplug thread started");
+
+  udev* udev = udev_new();
+  _assert_msg_(PAD, udev != nullptr, "Couldn't initialize libudev.");
+
+  // Set up monitoring
+  udev_monitor* monitor = udev_monitor_new_from_netlink(udev, "udev");
+  udev_monitor_filter_add_match_subsystem_devtype(monitor, "input", nullptr);
+  udev_monitor_enable_receiving(monitor);
+  const int monitor_fd = udev_monitor_get_fd(monitor);
+
+  while (s_hotplug_thread_running.IsSet())
+  {
+    fd_set fds;
+
+    FD_ZERO(&fds);
+    FD_SET(monitor_fd, &fds);
+    FD_SET(s_wakeup_eventfd, &fds);
+
+    int ret = select(monitor_fd + 1, &fds, nullptr, nullptr, nullptr);
+    if (ret < 1 || !FD_ISSET(monitor_fd, &fds))
+      continue;
+
+    udev_device* dev = udev_monitor_receive_device(monitor);
+
+    const char* action = udev_device_get_action(dev);
+    const char* devnode = udev_device_get_devnode(dev);
+    if (!devnode)
+      continue;
+
+    if (strcmp(action, "remove") == 0)
+    {
+      const auto it = s_devnode_name_map.find(devnode);
+      if (it == s_devnode_name_map.end())
+        continue;  // we don't know the name for this device, so it is probably not an evdev device
+      const std::string& name = it->second;
+      g_controller_interface.RemoveDevice([&name](const auto& device) {
+        return device->GetSource() == "evdev" && device->GetName() == name && !device->IsValid();
+      });
+      NOTICE_LOG(SERIALINTERFACE, "Removed device: %s", name.c_str());
+      s_devnode_name_map.erase(devnode);
+      g_controller_interface.InvokeHotplugCallbacks();
+    }
+    // Only react to "device added" events for evdev devices that we can access.
+    else if (strcmp(action, "add") == 0 && access(devnode, W_OK) == 0)
+    {
+      const std::string name = GetName(devnode);
+      if (name.empty())
+        continue;  // probably not an evdev device
+      auto device = std::make_shared<evdevDevice>(devnode);
+      if (device->IsInteresting())
+      {
+        g_controller_interface.AddDevice(std::move(device));
+        s_devnode_name_map.insert(std::pair<std::string, std::string>(devnode, name));
+        NOTICE_LOG(SERIALINTERFACE, "Added new device: %s", name.c_str());
+        g_controller_interface.InvokeHotplugCallbacks();
+      }
+    }
+    udev_device_unref(dev);
+  }
+  NOTICE_LOG(SERIALINTERFACE, "evdev hotplug thread stopped");
+}
+
+static void StartHotplugThread()
+{
+  if (s_hotplug_thread_running.IsSet())
+    return;
+
+  s_wakeup_eventfd = eventfd(0, 0);
+  _assert_msg_(PAD, s_wakeup_eventfd != -1, "Couldn't create eventfd.");
+  s_hotplug_thread_running.Set(true);
+  s_hotplug_thread = std::thread(HotplugThreadFunc);
+}
+
+static void StopHotplugThread()
+{
+  if (s_hotplug_thread_running.TestAndClear())
+  {
+    // Write something to efd so that select() stops blocking.
+    uint64_t value = 1;
+    write(s_wakeup_eventfd, &value, sizeof(uint64_t));
+    s_hotplug_thread.join();
+  }
+}
+
 void Init()
 {
-  // We use Udev to find any devices. In the future this will allow for hotplugging.
-  // But for now it is essentially iterating over /dev/input/event0 to event31. However if the
-  // naming scheme is ever updated in the future, this *should* be forwards compatable.
+  s_devnode_name_map.clear();
 
-  struct udev* udev = udev_new();
-  _assert_msg_(PAD, udev != 0, "Couldn't initilize libudev.");
+  // During initialization we use udev to iterate over all /dev/input/event* devices.
+  // Note: the Linux kernel is currently limited to just 32 event devices. If this ever
+  //            changes, hopefully udev will take care of this.
+
+  udev* udev = udev_new();
+  _assert_msg_(PAD, udev != nullptr, "Couldn't initialize libudev.");
 
   // List all input devices
   udev_enumerate* enumerate = udev_enumerate_new(udev);
@@ -69,12 +173,20 @@ void Init()
       if (input->IsInteresting())
       {
         g_controller_interface.AddDevice(std::move(input));
+        s_devnode_name_map.insert(std::pair<std::string, std::string>(devnode, name));
       }
     }
     udev_device_unref(dev);
   }
   udev_enumerate_unref(enumerate);
   udev_unref(udev);
+
+  StartHotplugThread();
+}
+
+void Shutdown()
+{
+  StopHotplugThread();
 }
 
 evdevDevice::evdevDevice(const std::string& devnode) : m_devfile(devnode)
@@ -152,6 +264,22 @@ void evdevDevice::UpdateInput()
   } while (rc >= 0);
 }
 
+bool evdevDevice::IsValid() const
+{
+  int current_fd = libevdev_get_fd(m_dev);
+  if (current_fd == -1)
+    return false;
+
+  libevdev* device;
+  if (libevdev_new_from_fd(current_fd, &device) != 0)
+  {
+    close(current_fd);
+    return false;
+  }
+  libevdev_free(device);
+  return true;
+}
+
 std::string evdevDevice::Button::GetName() const
 {
   // Buttons below 0x100 are mostly keyboard keys, and the names make sense

Source/Core/InputCommon/ControllerInterface/evdev/evdev.h

@@ -8,11 +8,14 @@
 #include <string>
 #include <vector>
 
+#include "InputCommon/ControllerInterface/ControllerInterface.h"
+
 namespace ciface
 {
 namespace evdev
 {
 void Init();
+void Shutdown();
 
 class evdevDevice : public Core::Device
 {
@@ -62,6 +65,7 @@ private:
 
 public:
   void UpdateInput() override;
+  bool IsValid() const override;
 
   evdevDevice(const std::string& devnode);
   ~evdevDevice();