device/serial/serial_device_enumerator_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 "device/serial/serial_device_enumerator_linux.h"
   6
   7 #include "base/logging.h"
   8 #include "base/strings/string_number_conversions.h"
   9
  10 namespace device {
  11
  12 namespace {
  13
  14 const char kSerialSubsystem[] = "tty";
  15
  16 const char kHostPathKey[] = "DEVNAME";
  17 const char kHostBusKey[] = "ID_BUS";
  18 const char kVendorIDKey[] = "ID_VENDOR_ID";
  19 const char kProductIDKey[] = "ID_MODEL_ID";
  20 const char kProductNameKey[] = "ID_MODEL";
  21
  22 }  // namespace
  23
  24 // static
  25 scoped_ptr<SerialDeviceEnumerator> SerialDeviceEnumerator::Create() {
  26   return scoped_ptr<SerialDeviceEnumerator>(new SerialDeviceEnumeratorLinux());
  27 }
  28
  29 SerialDeviceEnumeratorLinux::SerialDeviceEnumeratorLinux() {
  30   udev_.reset(udev_new());
  31 }
  32
  33 SerialDeviceEnumeratorLinux::~SerialDeviceEnumeratorLinux() {}
  34
  35 mojo::Array<serial::DeviceInfoPtr> SerialDeviceEnumeratorLinux::GetDevices() {
  36   mojo::Array<serial::DeviceInfoPtr> devices(0);
  37   ScopedUdevEnumeratePtr enumerate(udev_enumerate_new(udev_.get()));
  38   if (!enumerate) {
  39     LOG(ERROR) << "Serial device enumeration failed.";
  40     return devices.Pass();
  41   }
  42   if (udev_enumerate_add_match_subsystem(enumerate.get(), kSerialSubsystem)) {
  43     LOG(ERROR) << "Serial device enumeration failed.";
  44     return devices.Pass();
  45   }
  46   if (udev_enumerate_scan_devices(enumerate.get())) {
  47     LOG(ERROR) << "Serial device enumeration failed.";
  48     return devices.Pass();
  49   }
  50
  51   udev_list_entry* entry = udev_enumerate_get_list_entry(enumerate.get());
  52   for (; entry != NULL; entry = udev_list_entry_get_next(entry)) {
  53     ScopedUdevDevicePtr device(udev_device_new_from_syspath(
  54         udev_.get(), udev_list_entry_get_name(entry)));
  55     // TODO(rockot): There may be a better way to filter serial devices here,
  56     // but it's not clear what that would be. Udev will list lots of virtual
  57     // devices with no real endpoint to back them anywhere. The presence of
  58     // a bus identifier (e.g., "pci" or "usb") seems to be a good heuristic
  59     // for detecting actual devices.
  60     const char* path =
  61         udev_device_get_property_value(device.get(), kHostPathKey);
  62     const char* bus = udev_device_get_property_value(device.get(), kHostBusKey);
  63     if (path != NULL && bus != NULL) {
  64       serial::DeviceInfoPtr info(serial::DeviceInfo::New());
  65       info->path = path;
  66
  67       const char* vendor_id =
  68           udev_device_get_property_value(device.get(), kVendorIDKey);
  69       const char* product_id =
  70           udev_device_get_property_value(device.get(), kProductIDKey);
  71       const char* product_name =
  72           udev_device_get_property_value(device.get(), kProductNameKey);
  73
  74       uint32 int_value;
  75       if (vendor_id && base::HexStringToUInt(vendor_id, &int_value)) {
  76         info->vendor_id = int_value;
  77         info->has_vendor_id = true;
  78       }
  79       if (product_id && base::HexStringToUInt(product_id, &int_value)) {
  80         info->product_id = int_value;
  81         info->has_product_id = true;
  82       }
  83       if (product_name)
  84         info->display_name = product_name;
  85       devices.push_back(info.Pass());
  86     }
  87   }
  88   return devices.Pass();
  89 }
  90
  91 }  // namespace device