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      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 struct UdevEnumerateDeleter {
     23   void operator()(udev_enumerate* enumerate) {
     24     udev_enumerate_unref(enumerate);
     25   }
     26 };
     27 
     28 struct UdevDeviceDeleter {
     29   void operator()(udev_device* device) { udev_device_unref(device); }
     30 };
     31 
     32 typedef scoped_ptr<udev_enumerate, UdevEnumerateDeleter> ScopedUdevEnumeratePtr;
     33 typedef scoped_ptr<udev_device, UdevDeviceDeleter> ScopedUdevDevicePtr;
     34 }
     35 
     36 // static
     37 scoped_ptr<SerialDeviceEnumerator> SerialDeviceEnumerator::Create() {
     38   return scoped_ptr<SerialDeviceEnumerator>(new SerialDeviceEnumeratorLinux());
     39 }
     40 
     41 SerialDeviceEnumeratorLinux::SerialDeviceEnumeratorLinux() {
     42   udev_.reset(udev_new());
     43 }
     44 
     45 SerialDeviceEnumeratorLinux::~SerialDeviceEnumeratorLinux() {}
     46 
     47 mojo::Array<serial::DeviceInfoPtr> SerialDeviceEnumeratorLinux::GetDevices() {
     48   mojo::Array<serial::DeviceInfoPtr> devices(0);
     49   ScopedUdevEnumeratePtr enumerate(udev_enumerate_new(udev_.get()));
     50   if (!enumerate) {
     51     LOG(ERROR) << "Serial device enumeration failed.";
     52     return devices.Pass();
     53   }
     54   if (udev_enumerate_add_match_subsystem(enumerate.get(), kSerialSubsystem)) {
     55     LOG(ERROR) << "Serial device enumeration failed.";
     56     return devices.Pass();
     57   }
     58   if (udev_enumerate_scan_devices(enumerate.get())) {
     59     LOG(ERROR) << "Serial device enumeration failed.";
     60     return devices.Pass();
     61   }
     62 
     63   udev_list_entry* entry = udev_enumerate_get_list_entry(enumerate.get());
     64   for (; entry != NULL; entry = udev_list_entry_get_next(entry)) {
     65     ScopedUdevDevicePtr device(udev_device_new_from_syspath(
     66         udev_.get(), udev_list_entry_get_name(entry)));
     67     // TODO(rockot): There may be a better way to filter serial devices here,
     68     // but it's not clear what that would be. Udev will list lots of virtual
     69     // devices with no real endpoint to back them anywhere. The presence of
     70     // a bus identifier (e.g., "pci" or "usb") seems to be a good heuristic
     71     // for detecting actual devices.
     72     const char* path =
     73         udev_device_get_property_value(device.get(), kHostPathKey);
     74     const char* bus = udev_device_get_property_value(device.get(), kHostBusKey);
     75     if (path != NULL && bus != NULL) {
     76       serial::DeviceInfoPtr info(serial::DeviceInfo::New());
     77       info->path = path;
     78 
     79       const char* vendor_id =
     80           udev_device_get_property_value(device.get(), kVendorIDKey);
     81       const char* product_id =
     82           udev_device_get_property_value(device.get(), kProductIDKey);
     83       const char* product_name =
     84           udev_device_get_property_value(device.get(), kProductNameKey);
     85 
     86       uint32 int_value;
     87       if (vendor_id && base::HexStringToUInt(vendor_id, &int_value)) {
     88         info->vendor_id = int_value;
     89         info->has_vendor_id = true;
     90       }
     91       if (product_id && base::HexStringToUInt(product_id, &int_value)) {
     92         info->product_id = int_value;
     93         info->has_product_id = true;
     94       }
     95       if (product_name)
     96         info->display_name = product_name;
     97       devices.push_back(info.Pass());
     98     }
     99   }
    100   return devices.Pass();
    101 }
    102 
    103 void SerialDeviceEnumeratorLinux::UdevDeleter::operator()(udev* handle) {
    104   udev_unref(handle);
    105 }
    106 
    107 }  // namespace device
    108