src/chrome/browser/extensions/api/image_writer_private/removable_storage_provider_linux.cc

   1 // Copyright 2013 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 <libudev.h>
   6
   7 #include "base/file_util.h"
   8 #include "base/strings/string_number_conversions.h"
   9 #include "chrome/browser/extensions/api/image_writer_private/removable_storage_provider.h"
  10 #include "content/public/browser/browser_thread.h"
  11
  12 namespace extensions {
  13 // TODO(haven): Udev code may be duplicated in the Chrome codebase.
  14 // https://code.google.com/p/chromium/issues/detail?id=284898
  15
  16 // Returns the integer contained in |attr|.  Returns 0 on error.
  17 static uint64 get_int_attr(const char* attr){
  18   uint64 result = 0;
  19   // In error cases, StringToInt will set result to 0
  20   base::StringToUint64(attr, &result);
  21   return result;
  22 }
  23
  24 static int get_device_blk_size(const std::string& path) {
  25   base::FilePath file_path(path);
  26   std::string device = file_path.BaseName().value();
  27
  28   base::FilePath info_file_path = base::FilePath("/sys/block")
  29                                   .Append(device)
  30                                   .Append("queue/logical_block_size");
  31
  32   std::string file_contents;
  33   int blk_size;
  34
  35   if (!base::ReadFileToString(info_file_path, &file_contents)) {
  36     return 0;
  37   }
  38   // In error cases, StringToInt will set blk_size to 0
  39   base::StringToInt(file_contents, &blk_size);
  40
  41   return blk_size;
  42 }
  43
  44 bool RemovableStorageProvider::PopulateDeviceList(
  45     scoped_refptr<StorageDeviceList> device_list) {
  46   struct udev* udev;
  47   struct udev_enumerate* enumerate;
  48   struct udev_list_entry* devices, *dev_list_entry;
  49   struct udev_device* dev, *parent;
  50
  51   udev = udev_new();
  52   if (!udev) {
  53     DLOG(ERROR) << "Can't create udev";
  54     return false;
  55   }
  56
  57   /* Create a list of the devices in the 'block' subsystem. */
  58   enumerate = udev_enumerate_new(udev);
  59
  60   udev_enumerate_add_match_subsystem(enumerate, "block");
  61   udev_enumerate_scan_devices(enumerate);
  62   devices = udev_enumerate_get_list_entry(enumerate);
  63
  64   udev_list_entry_foreach(dev_list_entry, devices) {
  65     const char* path = udev_list_entry_get_name(dev_list_entry);
  66     dev = udev_device_new_from_syspath(udev, path);
  67
  68     const char* partition = udev_device_get_sysattr_value(dev, "partition");
  69     if (partition && get_int_attr(partition)){
  70       // This is a partition of a device, not the device itself
  71       continue;
  72     }
  73
  74     const char* removable = udev_device_get_sysattr_value(dev, "removable");
  75     if (!removable || !get_int_attr(removable)) {
  76       // This is not a removable storage device.
  77       continue;
  78     }
  79
  80     /* Get the parent SCSI device that contains the model
  81        and manufacturer.  You can look at the hierarchy with
  82        udevadm info -a -n /dev/<device> */
  83     parent = udev_device_get_parent_with_subsystem_devtype(
  84            dev,
  85            "scsi",
  86            NULL);
  87     if (!parent) {
  88       // this is not a usb device
  89       continue;
  90     }
  91
  92     linked_ptr<api::image_writer_private::RemovableStorageDevice> device(
  93       new api::image_writer_private::RemovableStorageDevice());
  94     device->vendor = udev_device_get_sysattr_value(parent, "vendor");
  95     device->model = udev_device_get_sysattr_value(parent, "model");
  96     // TODO (smaskell): Don't expose raw device path
  97     device->storage_unit_id = udev_device_get_devnode(dev);
  98     device->capacity = get_int_attr(udev_device_get_sysattr_value(dev, "size"))
  99       * get_device_blk_size(device->storage_unit_id);
 100     device->removable = removable;
 101
 102     device_list->data.push_back(device);
 103
 104     udev_device_unref(dev);
 105   }
 106   /* Free the enumerator object */
 107   udev_enumerate_unref(enumerate);
 108   udev_unref(udev);
 109
 110   return true;
 111 }
 112
 113 } // namespace extensions