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/memory/linked_ptr.h"
   9 #include "base/strings/string_number_conversions.h"
  10
  11 namespace device {
  12
  13 namespace {
  14
  15 const char kSerialSubsystem[] = "tty";
  16
  17 const char kHostPathKey[] = "DEVNAME";
  18 const char kHostBusKey[] = "ID_BUS";
  19 const char kVendorIDKey[] = "ID_VENDOR_ID";
  20 const char kProductIDKey[] = "ID_MODEL_ID";
  21 const char kProductNameKey[] = "ID_MODEL";
  22
  23 struct UdevEnumerateDeleter {
  24   void operator()(udev_enumerate* enumerate) {
  25     udev_enumerate_unref(enumerate);
  26   }
  27 };
  28
  29 struct UdevDeviceDeleter {
  30   void operator()(udev_device* device) { udev_device_unref(device); }
  31 };
  32
  33 typedef scoped_ptr<udev_enumerate, UdevEnumerateDeleter> ScopedUdevEnumeratePtr;
  34 typedef scoped_ptr<udev_device, UdevDeviceDeleter> ScopedUdevDevicePtr;
  35 }
  36
  37 // static
  38 scoped_ptr<SerialDeviceEnumerator> SerialDeviceEnumerator::Create() {
  39   return scoped_ptr<SerialDeviceEnumerator>(new SerialDeviceEnumeratorLinux());
  40 }
  41
  42 SerialDeviceEnumeratorLinux::SerialDeviceEnumeratorLinux() {
  43   udev_.reset(udev_new());
  44 }
  45
  46 SerialDeviceEnumeratorLinux::~SerialDeviceEnumeratorLinux() {}
  47
  48 void SerialDeviceEnumeratorLinux::GetDevices(SerialDeviceInfoList* devices) {
  49   devices->clear();
  50
  51   ScopedUdevEnumeratePtr enumerate(udev_enumerate_new(udev_.get()));
  52   if (!enumerate) {
  53     LOG(ERROR) << "Serial device enumeration failed.";
  54     return;
  55   }
  56   if (udev_enumerate_add_match_subsystem(enumerate.get(), kSerialSubsystem)) {
  57     LOG(ERROR) << "Serial device enumeration failed.";
  58     return;
  59   }
  60   if (udev_enumerate_scan_devices(enumerate.get())) {
  61     LOG(ERROR) << "Serial device enumeration failed.";
  62     return;
  63   }
  64
  65   udev_list_entry* entry = udev_enumerate_get_list_entry(enumerate.get());
  66   for (; entry != NULL; entry = udev_list_entry_get_next(entry)) {
  67     ScopedUdevDevicePtr device(udev_device_new_from_syspath(
  68         udev_.get(), udev_list_entry_get_name(entry)));
  69     // TODO(rockot): There may be a better way to filter serial devices here,
  70     // but it's not clear what that would be. Udev will list lots of virtual
  71     // devices with no real endpoint to back them anywhere. The presence of
  72     // a bus identifier (e.g., "pci" or "usb") seems to be a good heuristic
  73     // for detecting actual devices.
  74     const char* path =
  75         udev_device_get_property_value(device.get(), kHostPathKey);
  76     const char* bus = udev_device_get_property_value(device.get(), kHostBusKey);
  77     if (path != NULL && bus != NULL) {
  78       linked_ptr<SerialDeviceInfo> info(new SerialDeviceInfo());
  79       info->path = std::string(path);
  80
  81       const char* vendor_id =
  82           udev_device_get_property_value(device.get(), kVendorIDKey);
  83       const char* product_id =
  84           udev_device_get_property_value(device.get(), kProductIDKey);
  85       const char* product_name =
  86           udev_device_get_property_value(device.get(), kProductNameKey);
  87
  88       uint32 int_value;
  89       if (vendor_id && base::HexStringToUInt(vendor_id, &int_value))
  90         info->vendor_id.reset(new uint16(int_value));
  91       if (product_id && base::HexStringToUInt(product_id, &int_value))
  92         info->product_id.reset(new uint16(int_value));
  93       if (product_name)
  94         info->display_name.reset(new std::string(product_name));
  95
  96       devices->push_back(info);
  97     }
  98   }
  99 }
 100
 101 void SerialDeviceEnumeratorLinux::UdevDeleter::operator()(udev* handle) {
 102   udev_unref(handle);
 103 }
 104
 105 }  // namespace device