device/hid/hid_service_linux.cc

   1 // Copyright 2014 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 <linux/hidraw.h>
   6 #include <sys/ioctl.h>
   7
   8 #include <stdint.h>
   9
  10 #include <string>
  11
  12 #include "base/bind.h"
  13 #include "base/files/file_path.h"
  14 #include "base/logging.h"
  15 #include "base/platform_file.h"
  16 #include "base/stl_util.h"
  17 #include "base/strings/string_number_conversions.h"
  18 #include "base/strings/string_piece.h"
  19 #include "base/strings/string_split.h"
  20 #include "device/hid/hid_connection_linux.h"
  21 #include "device/hid/hid_device_info.h"
  22 #include "device/hid/hid_report_descriptor.h"
  23 #include "device/hid/hid_service_linux.h"
  24 #include "device/hid/udev_common.h"
  25
  26 namespace device {
  27
  28 namespace {
  29
  30 const char kHIDSubSystem[] = "hid";
  31 const char kHidrawSubsystem[] = "hidraw";
  32 const char kHIDID[] = "HID_ID";
  33 const char kHIDName[] = "HID_NAME";
  34 const char kHIDUnique[] = "HID_UNIQ";
  35
  36 } // namespace
  37
  38 HidServiceLinux::HidServiceLinux() {
  39   DeviceMonitorLinux* monitor = DeviceMonitorLinux::GetInstance();
  40   monitor->AddObserver(this);
  41   monitor->Enumerate(
  42       base::Bind(&HidServiceLinux::OnDeviceAdded, base::Unretained(this)));
  43 }
  44
  45 scoped_refptr<HidConnection> HidServiceLinux::Connect(
  46     const HidDeviceId& device_id) {
  47   HidDeviceInfo device_info;
  48   if (!GetDeviceInfo(device_id, &device_info))
  49     return NULL;
  50
  51   ScopedUdevDevicePtr device =
  52       DeviceMonitorLinux::GetInstance()->GetDeviceFromPath(
  53           device_info.device_id);
  54
  55   if (device) {
  56     std::string dev_node;
  57     if (!FindHidrawDevNode(device.get(), &dev_node)) {
  58       LOG(ERROR) << "Cannot open HID device as hidraw device.";
  59       return NULL;
  60     }
  61     return new HidConnectionLinux(device_info, dev_node);
  62   }
  63
  64   return NULL;
  65 }
  66
  67 HidServiceLinux::~HidServiceLinux() {
  68   if (DeviceMonitorLinux::HasInstance())
  69     DeviceMonitorLinux::GetInstance()->RemoveObserver(this);
  70 }
  71
  72 void HidServiceLinux::OnDeviceAdded(udev_device* device) {
  73   if (!device)
  74     return;
  75
  76   const char* device_path = udev_device_get_syspath(device);
  77   if (!device_path)
  78     return;
  79   const char* subsystem = udev_device_get_subsystem(device);
  80   if (!subsystem || strcmp(subsystem, kHIDSubSystem) != 0)
  81     return;
  82
  83   HidDeviceInfo device_info;
  84   device_info.device_id = device_path;
  85
  86   uint32_t int_property = 0;
  87   const char* str_property = NULL;
  88
  89   const char* hid_id = udev_device_get_property_value(device, kHIDID);
  90   if (!hid_id)
  91     return;
  92
  93   std::vector<std::string> parts;
  94   base::SplitString(hid_id, ':', &parts);
  95   if (parts.size() != 3) {
  96     return;
  97   }
  98
  99   if (HexStringToUInt(base::StringPiece(parts[1]), &int_property)) {
 100     device_info.vendor_id = int_property;
 101   }
 102
 103   if (HexStringToUInt(base::StringPiece(parts[2]), &int_property)) {
 104     device_info.product_id = int_property;
 105   }
 106
 107   str_property = udev_device_get_property_value(device, kHIDUnique);
 108   if (str_property != NULL)
 109     device_info.serial_number = str_property;
 110
 111   str_property = udev_device_get_property_value(device, kHIDName);
 112   if (str_property != NULL)
 113     device_info.product_name = str_property;
 114
 115   std::string dev_node;
 116   if (!FindHidrawDevNode(device, &dev_node)) {
 117     LOG(ERROR) << "Cannot open HID device as hidraw device.";
 118     return;
 119   }
 120
 121   int flags = base::File::FLAG_OPEN | base::File::FLAG_READ;
 122
 123   base::File device_file(base::FilePath(dev_node), flags);
 124   if (!device_file.IsValid()) {
 125     LOG(ERROR) << device_file.error_details();
 126     return;
 127   }
 128
 129   int desc_size = 0;
 130   int res = ioctl(device_file.GetPlatformFile(), HIDIOCGRDESCSIZE, &desc_size);
 131   if (res < 0) {
 132     LOG(ERROR) << "HIDIOCGRDESCSIZE failed.";
 133     device_file.Close();
 134     return;
 135   }
 136
 137   hidraw_report_descriptor rpt_desc;
 138   rpt_desc.size = desc_size;
 139
 140   res = ioctl(device_file.GetPlatformFile(), HIDIOCGRDESC, &rpt_desc);
 141   if (res < 0) {
 142     LOG(ERROR) << "HIDIOCGRDESC failed.";
 143     device_file.Close();
 144     return;
 145   }
 146
 147   device_file.Close();
 148
 149   HidReportDescriptor report_descriptor(rpt_desc.value, rpt_desc.size);
 150   report_descriptor.GetTopLevelCollections(&device_info.usages);
 151
 152   AddDevice(device_info);
 153 }
 154
 155 void HidServiceLinux::OnDeviceRemoved(udev_device* device) {
 156   const char* device_path = udev_device_get_syspath(device);;
 157   if (device_path)
 158     RemoveDevice(device_path);
 159 }
 160
 161 bool HidServiceLinux::FindHidrawDevNode(udev_device* parent,
 162                                         std::string* result) {
 163   udev* udev = udev_device_get_udev(parent);
 164   if (!udev) {
 165     return false;
 166   }
 167   ScopedUdevEnumeratePtr enumerate(udev_enumerate_new(udev));
 168   if (!enumerate) {
 169     return false;
 170   }
 171   if (udev_enumerate_add_match_subsystem(enumerate.get(), kHidrawSubsystem)) {
 172     return false;
 173   }
 174   if (udev_enumerate_scan_devices(enumerate.get())) {
 175     return false;
 176   }
 177   std::string parent_path(udev_device_get_devpath(parent));
 178   if (parent_path.length() == 0 || *parent_path.rbegin() != '/')
 179     parent_path += '/';
 180   udev_list_entry* devices = udev_enumerate_get_list_entry(enumerate.get());
 181   for (udev_list_entry* i = devices; i != NULL;
 182        i = udev_list_entry_get_next(i)) {
 183     ScopedUdevDevicePtr hid_dev(
 184         udev_device_new_from_syspath(udev, udev_list_entry_get_name(i)));
 185     const char* raw_path = udev_device_get_devnode(hid_dev.get());
 186     std::string device_path = udev_device_get_devpath(hid_dev.get());
 187     if (raw_path &&
 188         !device_path.compare(0, parent_path.length(), parent_path)) {
 189       std::string sub_path = device_path.substr(parent_path.length());
 190       if (sub_path.substr(0, sizeof(kHidrawSubsystem) - 1) ==
 191           kHidrawSubsystem) {
 192         *result = raw_path;
 193         return true;
 194       }
 195     }
 196   }
 197
 198   return false;
 199 }
 200
 201 } // namespace dev