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