content/browser/gamepad/gamepad_platform_data_fetcher_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 "content/browser/gamepad/gamepad_platform_data_fetcher_linux.h"
   6
   7 #include <fcntl.h>
   8 #include <linux/joystick.h>
   9 #include <string.h>
  10 #include <sys/stat.h>
  11 #include <sys/types.h>
  12 #include <unistd.h>
  13
  14 #include "base/message_loop/message_loop.h"
  15 #include "base/posix/eintr_wrapper.h"
  16 #include "base/strings/string_number_conversions.h"
  17 #include "base/strings/string_util.h"
  18 #include "base/strings/stringprintf.h"
  19 #include "base/strings/utf_string_conversions.h"
  20 #include "base/trace_event/trace_event.h"
  21 #include "content/browser/udev_linux.h"
  22 #include "device/udev_linux/scoped_udev.h"
  23
  24 namespace {
  25
  26 const char kInputSubsystem[] = "input";
  27 const char kUsbSubsystem[] = "usb";
  28 const char kUsbDeviceType[] = "usb_device";
  29 const float kMaxLinuxAxisValue = 32767.0;
  30
  31 void CloseFileDescriptorIfValid(int fd) {
  32   if (fd >= 0)
  33     close(fd);
  34 }
  35
  36 bool IsGamepad(udev_device* dev, int* index, std::string* path) {
  37   if (!device::udev_device_get_property_value(dev, "ID_INPUT_JOYSTICK"))
  38     return false;
  39
  40   const char* node_path = device::udev_device_get_devnode(dev);
  41   if (!node_path)
  42     return false;
  43
  44   static const char kJoystickRoot[] = "/dev/input/js";
  45   bool is_gamepad = base::StartsWith(node_path, kJoystickRoot,
  46                                      base::CompareCase::SENSITIVE);
  47   if (!is_gamepad)
  48     return false;
  49
  50   int tmp_idx = -1;
  51   const int base_len = sizeof(kJoystickRoot) - 1;
  52   base::StringPiece str(&node_path[base_len], strlen(node_path) - base_len);
  53   if (!base::StringToInt(str, &tmp_idx))
  54     return false;
  55   if (tmp_idx < 0 ||
  56       tmp_idx >= static_cast<int>(blink::WebGamepads::itemsLengthCap)) {
  57     return false;
  58   }
  59   *index = tmp_idx;
  60   *path = node_path;
  61   return true;
  62 }
  63
  64 }  // namespace
  65
  66 namespace content {
  67
  68 using blink::WebGamepad;
  69 using blink::WebGamepads;
  70
  71 GamepadPlatformDataFetcherLinux::GamepadPlatformDataFetcherLinux() {
  72   for (size_t i = 0; i < arraysize(device_fds_); ++i)
  73     device_fds_[i] = -1;
  74   memset(mappers_, 0, sizeof(mappers_));
  75
  76   std::vector<UdevLinux::UdevMonitorFilter> filters;
  77   filters.push_back(UdevLinux::UdevMonitorFilter(kInputSubsystem, NULL));
  78   udev_.reset(
  79       new UdevLinux(filters,
  80                     base::Bind(&GamepadPlatformDataFetcherLinux::RefreshDevice,
  81                                base::Unretained(this))));
  82
  83   EnumerateDevices();
  84 }
  85
  86 GamepadPlatformDataFetcherLinux::~GamepadPlatformDataFetcherLinux() {
  87   for (size_t i = 0; i < WebGamepads::itemsLengthCap; ++i)
  88     CloseFileDescriptorIfValid(device_fds_[i]);
  89 }
  90
  91 void GamepadPlatformDataFetcherLinux::GetGamepadData(WebGamepads* pads, bool) {
  92   TRACE_EVENT0("GAMEPAD", "GetGamepadData");
  93
  94   data_.length = WebGamepads::itemsLengthCap;
  95
  96   // Update our internal state.
  97   for (size_t i = 0; i < WebGamepads::itemsLengthCap; ++i) {
  98     if (device_fds_[i] >= 0) {
  99       ReadDeviceData(i);
 100     }
 101   }
 102
 103   // Copy to the current state to the output buffer, using the mapping
 104   // function, if there is one available.
 105   pads->length = data_.length;
 106   for (size_t i = 0; i < WebGamepads::itemsLengthCap; ++i) {
 107     if (mappers_[i])
 108       mappers_[i](data_.items[i], &pads->items[i]);
 109     else
 110       pads->items[i] = data_.items[i];
 111   }
 112 }
 113
 114 // Used during enumeration, and monitor notifications.
 115 void GamepadPlatformDataFetcherLinux::RefreshDevice(udev_device* dev) {
 116   int index;
 117   std::string node_path;
 118   if (IsGamepad(dev, &index, &node_path)) {
 119     int& device_fd = device_fds_[index];
 120     WebGamepad& pad = data_.items[index];
 121     GamepadStandardMappingFunction& mapper = mappers_[index];
 122
 123     CloseFileDescriptorIfValid(device_fd);
 124
 125     // The device pointed to by dev contains information about the logical
 126     // joystick device. In order to get the information about the physical
 127     // hardware, get the parent device that is also in the "input" subsystem.
 128     // This function should just walk up the tree one level.
 129     dev = device::udev_device_get_parent_with_subsystem_devtype(
 130         dev, kInputSubsystem, NULL);
 131     if (!dev) {
 132       // Unable to get device information, don't use this device.
 133       device_fd = -1;
 134       pad.connected = false;
 135       return;
 136     }
 137
 138     device_fd = HANDLE_EINTR(open(node_path.c_str(), O_RDONLY | O_NONBLOCK));
 139     if (device_fd < 0) {
 140       // Unable to open device, don't use.
 141       pad.connected = false;
 142       return;
 143     }
 144
 145     const char* vendor_id =
 146         device::udev_device_get_sysattr_value(dev, "id/vendor");
 147     const char* product_id =
 148         device::udev_device_get_sysattr_value(dev, "id/product");
 149     mapper = GetGamepadStandardMappingFunction(vendor_id, product_id);
 150
 151     // Driver returns utf-8 strings here, so combine in utf-8 first and
 152     // convert to WebUChar later once we've picked an id string.
 153     const char* name = device::udev_device_get_sysattr_value(dev, "name");
 154     std::string name_string(name);
 155
 156     // In many cases the information the input subsystem contains isn't
 157     // as good as the information that the device bus has, walk up further
 158     // to the subsystem/device type "usb"/"usb_device" and if this device
 159     // has the same vendor/product id, prefer the description from that.
 160     struct udev_device* usb_dev =
 161         device::udev_device_get_parent_with_subsystem_devtype(
 162             dev, kUsbSubsystem, kUsbDeviceType);
 163     if (usb_dev) {
 164       const char* usb_vendor_id =
 165           device::udev_device_get_sysattr_value(usb_dev, "idVendor");
 166       const char* usb_product_id =
 167           device::udev_device_get_sysattr_value(usb_dev, "idProduct");
 168
 169       if (strcmp(vendor_id, usb_vendor_id) == 0 &&
 170           strcmp(product_id, usb_product_id) == 0) {
 171         const char* manufacturer =
 172             device::udev_device_get_sysattr_value(usb_dev, "manufacturer");
 173         const char* product =
 174             device::udev_device_get_sysattr_value(usb_dev, "product");
 175
 176         // Replace the previous name string with one containing the better
 177         // information, again driver returns utf-8 strings here so combine
 178         // in utf-8 for conversion to WebUChar below.
 179         name_string = base::StringPrintf("%s %s", manufacturer, product);
 180       }
 181     }
 182
 183     // Append the vendor and product information then convert the utf-8
 184     // id string to WebUChar.
 185     std::string id =
 186         name_string + base::StringPrintf(" (%sVendor: %s Product: %s)",
 187                                          mapper ? "STANDARD GAMEPAD " : "",
 188                                          vendor_id,
 189                                          product_id);
 190     base::TruncateUTF8ToByteSize(id, WebGamepad::idLengthCap - 1, &id);
 191     base::string16 tmp16 = base::UTF8ToUTF16(id);
 192     memset(pad.id, 0, sizeof(pad.id));
 193     tmp16.copy(pad.id, arraysize(pad.id) - 1);
 194
 195     if (mapper) {
 196       std::string mapping = "standard";
 197       base::TruncateUTF8ToByteSize(
 198           mapping, WebGamepad::mappingLengthCap - 1, &mapping);
 199       tmp16 = base::UTF8ToUTF16(mapping);
 200       memset(pad.mapping, 0, sizeof(pad.mapping));
 201       tmp16.copy(pad.mapping, arraysize(pad.mapping) - 1);
 202     } else {
 203       pad.mapping[0] = 0;
 204     }
 205
 206     pad.connected = true;
 207   }
 208 }
 209
 210 void GamepadPlatformDataFetcherLinux::EnumerateDevices() {
 211   device::ScopedUdevEnumeratePtr enumerate(
 212       device::udev_enumerate_new(udev_->udev_handle()));
 213   if (!enumerate)
 214     return;
 215   int ret = device::udev_enumerate_add_match_subsystem(enumerate.get(),
 216                                                        kInputSubsystem);
 217   if (ret != 0)
 218     return;
 219   ret = device::udev_enumerate_scan_devices(enumerate.get());
 220   if (ret != 0)
 221     return;
 222
 223   udev_list_entry* devices =
 224       device::udev_enumerate_get_list_entry(enumerate.get());
 225   for (udev_list_entry* dev_list_entry = devices; dev_list_entry != NULL;
 226        dev_list_entry = device::udev_list_entry_get_next(dev_list_entry)) {
 227     // Get the filename of the /sys entry for the device and create a
 228     // udev_device object (dev) representing it
 229     const char* path = device::udev_list_entry_get_name(dev_list_entry);
 230     device::ScopedUdevDevicePtr dev(
 231         device::udev_device_new_from_syspath(udev_->udev_handle(), path));
 232     if (!dev)
 233       continue;
 234     RefreshDevice(dev.get());
 235   }
 236 }
 237
 238 void GamepadPlatformDataFetcherLinux::ReadDeviceData(size_t index) {
 239   // Linker does not like CHECK_LT(index, WebGamepads::itemsLengthCap). =/
 240   if (index >= WebGamepads::itemsLengthCap) {
 241     CHECK(false);
 242     return;
 243   }
 244
 245   const int& fd = device_fds_[index];
 246   WebGamepad& pad = data_.items[index];
 247   DCHECK_GE(fd, 0);
 248
 249   js_event event;
 250   while (HANDLE_EINTR(read(fd, &event, sizeof(struct js_event))) > 0) {
 251     size_t item = event.number;
 252     if (event.type & JS_EVENT_AXIS) {
 253       if (item >= WebGamepad::axesLengthCap)
 254         continue;
 255       pad.axes[item] = event.value / kMaxLinuxAxisValue;
 256       if (item >= pad.axesLength)
 257         pad.axesLength = item + 1;
 258     } else if (event.type & JS_EVENT_BUTTON) {
 259       if (item >= WebGamepad::buttonsLengthCap)
 260         continue;
 261       pad.buttons[item].pressed = event.value;
 262       pad.buttons[item].value = event.value ? 1.0 : 0.0;
 263       if (item >= pad.buttonsLength)
 264         pad.buttonsLength = item + 1;
 265     }
 266     pad.timestamp = event.time;
 267   }
 268 }
 269
 270 }  // namespace content