2 files changed, 512 insertions, 0 deletions

diff --git a/dom/gamepad/linux/LinuxGamepad.cpp b/dom/gamepad/linux/LinuxGamepad.cpp
new file mode 100644
index 0000000000..deee47b9d2
--- /dev/null
+++ b/dom/gamepad/linux/LinuxGamepad.cpp
@@ -0,0 +1,362 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+/*
+ * LinuxGamepadService: A Linux backend for the GamepadService.
+ * Derived from the kernel documentation at
+ * http://www.kernel.org/doc/Documentation/input/joystick-api.txt
+ */
+#include <algorithm>
+#include <cstddef>
+
+#include <glib.h>
+#include <linux/joystick.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+#include "nscore.h"
+#include "mozilla/dom/GamepadHandle.h"
+#include "mozilla/dom/GamepadPlatformService.h"
+#include "mozilla/Tainting.h"
+#include "mozilla/UniquePtr.h"
+#include "udev.h"
+
+namespace {
+
+using namespace mozilla::dom;
+using mozilla::MakeUnique;
+using mozilla::udev_device;
+using mozilla::udev_enumerate;
+using mozilla::udev_lib;
+using mozilla::udev_list_entry;
+using mozilla::udev_monitor;
+using mozilla::UniquePtr;
+
+static const float kMaxAxisValue = 32767.0;
+static const char kJoystickPath[] = "/dev/input/js";
+
+// TODO: should find a USB identifier for each device so we can
+// provide something that persists across connect/disconnect cycles.
+typedef struct {
+  GamepadHandle handle;
+  guint source_id;
+  int numAxes;
+  int numButtons;
+  char idstring[256];
+  char devpath[PATH_MAX];
+} Gamepad;
+
+class LinuxGamepadService {
+ public:
+  LinuxGamepadService() : mMonitor(nullptr), mMonitorSourceID(0) {}
+
+  void Startup();
+  void Shutdown();
+
+ private:
+  void AddDevice(struct udev_device* dev);
+  void RemoveDevice(struct udev_device* dev);
+  void ScanForDevices();
+  void AddMonitor();
+  void RemoveMonitor();
+  bool is_gamepad(struct udev_device* dev);
+  void ReadUdevChange();
+
+  // handler for data from /dev/input/jsN
+  static gboolean OnGamepadData(GIOChannel* source, GIOCondition condition,
+                                gpointer data);
+
+  // handler for data from udev monitor
+  static gboolean OnUdevMonitor(GIOChannel* source, GIOCondition condition,
+                                gpointer data);
+
+  udev_lib mUdev;
+  struct udev_monitor* mMonitor;
+  guint mMonitorSourceID;
+  // Information about currently connected gamepads.
+  AutoTArray<UniquePtr<Gamepad>, 4> mGamepads;
+};
+
+// singleton instance
+LinuxGamepadService* gService = nullptr;
+
+void LinuxGamepadService::AddDevice(struct udev_device* dev) {
+  RefPtr<GamepadPlatformService> service =
+      GamepadPlatformService::GetParentService();
+  if (!service) {
+    return;
+  }
+
+  const char* devpath = mUdev.udev_device_get_devnode(dev);
+  if (!devpath) {
+    return;
+  }
+
+  // Ensure that this device hasn't already been added.
+  for (unsigned int i = 0; i < mGamepads.Length(); i++) {
+    if (strcmp(mGamepads[i]->devpath, devpath) == 0) {
+      return;
+    }
+  }
+
+  auto gamepad = MakeUnique<Gamepad>();
+  snprintf(gamepad->devpath, sizeof(gamepad->devpath), "%s", devpath);
+  GIOChannel* channel = g_io_channel_new_file(devpath, "r", nullptr);
+  if (!channel) {
+    return;
+  }
+
+  g_io_channel_set_flags(channel, G_IO_FLAG_NONBLOCK, nullptr);
+  g_io_channel_set_encoding(channel, nullptr, nullptr);
+  g_io_channel_set_buffered(channel, FALSE);
+  int fd = g_io_channel_unix_get_fd(channel);
+  char name[128];
+  if (ioctl(fd, JSIOCGNAME(sizeof(name)), &name) == -1) {
+    strcpy(name, "unknown");
+  }
+  const char* vendor_id =
+      mUdev.udev_device_get_property_value(dev, "ID_VENDOR_ID");
+  const char* model_id =
+      mUdev.udev_device_get_property_value(dev, "ID_MODEL_ID");
+  if (!vendor_id || !model_id) {
+    struct udev_device* parent =
+        mUdev.udev_device_get_parent_with_subsystem_devtype(dev, "input",
+                                                            nullptr);
+    if (parent) {
+      vendor_id = mUdev.udev_device_get_sysattr_value(parent, "id/vendor");
+      model_id = mUdev.udev_device_get_sysattr_value(parent, "id/product");
+    }
+  }
+  snprintf(gamepad->idstring, sizeof(gamepad->idstring), "%s-%s-%s",
+           vendor_id ? vendor_id : "unknown", model_id ? model_id : "unknown",
+           name);
+
+  char numAxes = 0, numButtons = 0;
+  ioctl(fd, JSIOCGAXES, &numAxes);
+  gamepad->numAxes = numAxes;
+  ioctl(fd, JSIOCGBUTTONS, &numButtons);
+  gamepad->numButtons = numButtons;
+
+  gamepad->handle = service->AddGamepad(
+      gamepad->idstring, mozilla::dom::GamepadMappingType::_empty,
+      mozilla::dom::GamepadHand::_empty, gamepad->numButtons, gamepad->numAxes,
+      0, 0, 0);  // TODO: Bug 680289, implement gamepad haptics for Linux.
+  // TODO: Bug 1523355, implement gamepad lighindicator and touch for Linux.
+
+  gamepad->source_id =
+      g_io_add_watch(channel, GIOCondition(G_IO_IN | G_IO_ERR | G_IO_HUP),
+                     OnGamepadData, gamepad.get());
+  g_io_channel_unref(channel);
+
+  mGamepads.AppendElement(std::move(gamepad));
+}
+
+void LinuxGamepadService::RemoveDevice(struct udev_device* dev) {
+  RefPtr<GamepadPlatformService> service =
+      GamepadPlatformService::GetParentService();
+  if (!service) {
+    return;
+  }
+
+  const char* devpath = mUdev.udev_device_get_devnode(dev);
+  if (!devpath) {
+    return;
+  }
+
+  for (unsigned int i = 0; i < mGamepads.Length(); i++) {
+    if (strcmp(mGamepads[i]->devpath, devpath) == 0) {
+      auto gamepad = std::move(mGamepads[i]);
+      mGamepads.RemoveElementAt(i);
+
+      g_source_remove(gamepad->source_id);
+      service->RemoveGamepad(gamepad->handle);
+
+      break;
+    }
+  }
+}
+
+void LinuxGamepadService::ScanForDevices() {
+  struct udev_enumerate* en = mUdev.udev_enumerate_new(mUdev.udev);
+  mUdev.udev_enumerate_add_match_subsystem(en, "input");
+  mUdev.udev_enumerate_scan_devices(en);
+
+  struct udev_list_entry* dev_list_entry;
+  for (dev_list_entry = mUdev.udev_enumerate_get_list_entry(en);
+       dev_list_entry != nullptr;
+       dev_list_entry = mUdev.udev_list_entry_get_next(dev_list_entry)) {
+    const char* path = mUdev.udev_list_entry_get_name(dev_list_entry);
+    struct udev_device* dev =
+        mUdev.udev_device_new_from_syspath(mUdev.udev, path);
+    if (is_gamepad(dev)) {
+      AddDevice(dev);
+    }
+
+    mUdev.udev_device_unref(dev);
+  }
+
+  mUdev.udev_enumerate_unref(en);
+}
+
+void LinuxGamepadService::AddMonitor() {
+  // Add a monitor to watch for device changes
+  mMonitor = mUdev.udev_monitor_new_from_netlink(mUdev.udev, "udev");
+  if (!mMonitor) {
+    // Not much we can do here.
+    return;
+  }
+  mUdev.udev_monitor_filter_add_match_subsystem_devtype(mMonitor, "input",
+                                                        nullptr);
+
+  int monitor_fd = mUdev.udev_monitor_get_fd(mMonitor);
+  GIOChannel* monitor_channel = g_io_channel_unix_new(monitor_fd);
+  mMonitorSourceID = g_io_add_watch(monitor_channel,
+                                    GIOCondition(G_IO_IN | G_IO_ERR | G_IO_HUP),
+                                    OnUdevMonitor, nullptr);
+  g_io_channel_unref(monitor_channel);
+
+  mUdev.udev_monitor_enable_receiving(mMonitor);
+}
+
+void LinuxGamepadService::RemoveMonitor() {
+  if (mMonitorSourceID) {
+    g_source_remove(mMonitorSourceID);
+    mMonitorSourceID = 0;
+  }
+  if (mMonitor) {
+    mUdev.udev_monitor_unref(mMonitor);
+    mMonitor = nullptr;
+  }
+}
+
+void LinuxGamepadService::Startup() {
+  // Don't bother starting up if libudev couldn't be loaded or initialized.
+  if (!mUdev) return;
+
+  AddMonitor();
+  ScanForDevices();
+}
+
+void LinuxGamepadService::Shutdown() {
+  for (unsigned int i = 0; i < mGamepads.Length(); i++) {
+    g_source_remove(mGamepads[i]->source_id);
+  }
+  mGamepads.Clear();
+  RemoveMonitor();
+}
+
+bool LinuxGamepadService::is_gamepad(struct udev_device* dev) {
+  if (!mUdev.udev_device_get_property_value(dev, "ID_INPUT_JOYSTICK"))
+    return false;
+
+  const char* devpath = mUdev.udev_device_get_devnode(dev);
+  if (!devpath) {
+    return false;
+  }
+  if (strncmp(kJoystickPath, devpath, sizeof(kJoystickPath) - 1) != 0) {
+    return false;
+  }
+
+  return true;
+}
+
+void LinuxGamepadService::ReadUdevChange() {
+  struct udev_device* dev = mUdev.udev_monitor_receive_device(mMonitor);
+  const char* action = mUdev.udev_device_get_action(dev);
+  if (is_gamepad(dev)) {
+    if (strcmp(action, "add") == 0) {
+      AddDevice(dev);
+    } else if (strcmp(action, "remove") == 0) {
+      RemoveDevice(dev);
+    }
+  }
+  mUdev.udev_device_unref(dev);
+}
+
+// static
+gboolean LinuxGamepadService::OnGamepadData(GIOChannel* source,
+                                            GIOCondition condition,
+                                            gpointer data) {
+  RefPtr<GamepadPlatformService> service =
+      GamepadPlatformService::GetParentService();
+  if (!service) {
+    return TRUE;
+  }
+  auto* gamepad = static_cast<Gamepad*>(data);
+
+  // TODO: remove gamepad?
+  if (condition & G_IO_ERR || condition & G_IO_HUP) return FALSE;
+
+  while (true) {
+    struct js_event event;
+    gsize count;
+    GError* err = nullptr;
+    if (g_io_channel_read_chars(source, (gchar*)&event, sizeof(event), &count,
+                                &err) != G_IO_STATUS_NORMAL ||
+        count == 0) {
+      break;
+    }
+
+    // TODO: store device state?
+    if (event.type & JS_EVENT_INIT) {
+      continue;
+    }
+
+    switch (event.type) {
+      case JS_EVENT_BUTTON:
+        service->NewButtonEvent(gamepad->handle, event.number, !!event.value);
+        break;
+      case JS_EVENT_AXIS:
+        service->NewAxisMoveEvent(gamepad->handle, event.number,
+                                  ((float)event.value) / kMaxAxisValue);
+        break;
+    }
+  }
+
+  return TRUE;
+}
+
+// static
+gboolean LinuxGamepadService::OnUdevMonitor(GIOChannel* source,
+                                            GIOCondition condition,
+                                            gpointer data) {
+  if (condition & G_IO_ERR || condition & G_IO_HUP) return FALSE;
+
+  gService->ReadUdevChange();
+  return TRUE;
+}
+
+}  // namespace
+
+namespace mozilla::dom {
+
+void StartGamepadMonitoring() {
+  if (gService) {
+    return;
+  }
+  gService = new LinuxGamepadService();
+  gService->Startup();
+}
+
+void StopGamepadMonitoring() {
+  if (!gService) {
+    return;
+  }
+  gService->Shutdown();
+  delete gService;
+  gService = nullptr;
+}
+
+void SetGamepadLightIndicatorColor(const Tainted<GamepadHandle>& aGamepadHandle,
+                                   const Tainted<uint32_t>& aLightColorIndex,
+                                   const uint8_t& aRed, const uint8_t& aGreen,
+                                   const uint8_t& aBlue) {
+  // TODO: Bug 1523355.
+  NS_WARNING("Linux doesn't support gamepad light indicator.");
+}
+
+}  // namespace mozilla::dom
diff --git a/dom/gamepad/linux/udev.h b/dom/gamepad/linux/udev.h
new file mode 100644
index 0000000000..4e3f0b7865
--- /dev/null
+++ b/dom/gamepad/linux/udev.h
@@ -0,0 +1,150 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+/*
+ * This file defines a wrapper around libudev so we can avoid
+ * linking directly to it and use dlopen instead.
+ */
+
+#ifndef HAL_LINUX_UDEV_H_
+#define HAL_LINUX_UDEV_H_
+
+#include <dlfcn.h>
+
+#include "mozilla/ArrayUtils.h"
+
+namespace mozilla {
+
+struct udev;
+struct udev_device;
+struct udev_enumerate;
+struct udev_list_entry;
+struct udev_monitor;
+
+class udev_lib {
+ public:
+  udev_lib() : lib(nullptr), udev(nullptr) {
+    // Be careful about ABI compat! 0 -> 1 didn't change any
+    // symbols this code relies on, per:
+    // https://lists.fedoraproject.org/pipermail/devel/2012-June/168227.html
+    const char* lib_names[] = {"libudev.so.0", "libudev.so.1"};
+    // Check whether a library is already loaded so we don't load two
+    // conflicting libs.
+    for (unsigned i = 0; i < ArrayLength(lib_names); i++) {
+      lib = dlopen(lib_names[i], RTLD_NOLOAD | RTLD_LAZY | RTLD_GLOBAL);
+      if (lib) {
+        break;
+      }
+    }
+    // If nothing loads the first time through, it means no version of libudev
+    // was already loaded.
+    if (!lib) {
+      for (unsigned i = 0; i < ArrayLength(lib_names); i++) {
+        lib = dlopen(lib_names[i], RTLD_LAZY | RTLD_GLOBAL);
+        if (lib) {
+          break;
+        }
+      }
+    }
+    if (lib && LoadSymbols()) {
+      udev = udev_new();
+    }
+  }
+
+  ~udev_lib() {
+    if (udev) {
+      udev_unref(udev);
+    }
+
+    if (lib) {
+      dlclose(lib);
+    }
+  }
+
+  explicit operator bool() { return udev; }
+
+ private:
+#define DLSYM(s)                       \
+  do {                                 \
+    (s) = (decltype(s))dlsym(lib, #s); \
+    if (!(s)) return false;            \
+  } while (0)
+
+  bool LoadSymbols() {
+    DLSYM(udev_new);
+    DLSYM(udev_unref);
+    DLSYM(udev_device_unref);
+    DLSYM(udev_device_new_from_syspath);
+    DLSYM(udev_device_get_devnode);
+    DLSYM(udev_device_get_parent_with_subsystem_devtype);
+    DLSYM(udev_device_get_property_value);
+    DLSYM(udev_device_get_action);
+    DLSYM(udev_device_get_sysattr_value);
+    DLSYM(udev_enumerate_new);
+    DLSYM(udev_enumerate_unref);
+    DLSYM(udev_enumerate_add_match_subsystem);
+    DLSYM(udev_enumerate_scan_devices);
+    DLSYM(udev_enumerate_get_list_entry);
+    DLSYM(udev_list_entry_get_next);
+    DLSYM(udev_list_entry_get_name);
+    DLSYM(udev_monitor_new_from_netlink);
+    DLSYM(udev_monitor_filter_add_match_subsystem_devtype);
+    DLSYM(udev_monitor_enable_receiving);
+    DLSYM(udev_monitor_get_fd);
+    DLSYM(udev_monitor_receive_device);
+    DLSYM(udev_monitor_unref);
+
+    return true;
+  }
+
+#undef DLSYM
+
+  void* lib;
+
+ public:
+  struct udev* udev;
+
+  // Function pointers returned from dlsym.
+  struct udev* (*udev_new)(void);
+  void (*udev_unref)(struct udev*);
+
+  void (*udev_device_unref)(struct udev_device*);
+  struct udev_device* (*udev_device_new_from_syspath)(struct udev*,
+                                                      const char*);
+  const char* (*udev_device_get_devnode)(struct udev_device*);
+  struct udev_device* (*udev_device_get_parent_with_subsystem_devtype)(
+      struct udev_device*, const char*, const char*);
+  const char* (*udev_device_get_property_value)(struct udev_device*,
+                                                const char*);
+  const char* (*udev_device_get_action)(struct udev_device*);
+  const char* (*udev_device_get_sysattr_value)(struct udev_device*,
+                                               const char*);
+
+  struct udev_enumerate* (*udev_enumerate_new)(struct udev*);
+  void (*udev_enumerate_unref)(struct udev_enumerate*);
+  int (*udev_enumerate_add_match_subsystem)(struct udev_enumerate*,
+                                            const char*);
+  int (*udev_enumerate_scan_devices)(struct udev_enumerate*);
+  struct udev_list_entry* (*udev_enumerate_get_list_entry)(
+      struct udev_enumerate*);
+
+  struct udev_list_entry* (*udev_list_entry_get_next)(struct udev_list_entry*);
+  const char* (*udev_list_entry_get_name)(struct udev_list_entry*);
+
+  struct udev_monitor* (*udev_monitor_new_from_netlink)(struct udev*,
+                                                        const char*);
+  int (*udev_monitor_filter_add_match_subsystem_devtype)(struct udev_monitor*,
+                                                         const char*,
+                                                         const char*);
+  int (*udev_monitor_enable_receiving)(struct udev_monitor*);
+  int (*udev_monitor_get_fd)(struct udev_monitor*);
+  struct udev_device* (*udev_monitor_receive_device)(struct udev_monitor*);
+  void (*udev_monitor_unref)(struct udev_monitor*);
+};
+
+}  // namespace mozilla
+
+#endif  // HAL_LINUX_UDEV_H_