1// Copyright (c) 2012 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 "rlz/lib/machine_id.h"
6
7#include "base/sha1.h"
8#include "rlz/lib/assert.h"
9#include "rlz/lib/crc8.h"
10#include "rlz/lib/string_utils.h"
11
12namespace rlz_lib {
13
14bool GetMachineId(std::string* machine_id) {
15  if (!machine_id)
16    return false;
17
18  static std::string calculated_id;
19  static bool calculated = false;
20  if (calculated) {
21    *machine_id = calculated_id;
22    return true;
23  }
24
25  base::string16 sid_string;
26  int volume_id;
27  if (!GetRawMachineId(&sid_string, &volume_id))
28    return false;
29
30  if (!testing::GetMachineIdImpl(sid_string, volume_id, machine_id))
31    return false;
32
33  calculated = true;
34  calculated_id = *machine_id;
35  return true;
36}
37
38namespace testing {
39
40bool GetMachineIdImpl(const base::string16& sid_string,
41                      int volume_id,
42                      std::string* machine_id) {
43  machine_id->clear();
44
45  // The ID should be the SID hash + the Hard Drive SNo. + checksum byte.
46  static const int kSizeWithoutChecksum = base::kSHA1Length + sizeof(int);
47  std::basic_string<unsigned char> id_binary(kSizeWithoutChecksum + 1, 0);
48
49  if (!sid_string.empty()) {
50    // In order to be compatible with the old version of RLZ, the hash of the
51    // SID must be done with all the original bytes from the unicode string.
52    // However, the chromebase SHA1 hash function takes only an std::string as
53    // input, so the unicode string needs to be converted to std::string
54    // "as is".
55    size_t byte_count = sid_string.size() * sizeof(base::string16::value_type);
56    const char* buffer = reinterpret_cast<const char*>(sid_string.c_str());
57    std::string sid_string_buffer(buffer, byte_count);
58
59    // Note that digest can have embedded nulls.
60    std::string digest(base::SHA1HashString(sid_string_buffer));
61    VERIFY(digest.size() == base::kSHA1Length);
62    std::copy(digest.begin(), digest.end(), id_binary.begin());
63  }
64
65  // Convert from int to binary (makes big-endian).
66  for (size_t i = 0; i < sizeof(int); i++) {
67    int shift_bits = 8 * (sizeof(int) - i - 1);
68    id_binary[base::kSHA1Length + i] = static_cast<unsigned char>(
69        (volume_id >> shift_bits) & 0xFF);
70  }
71
72  // Append the checksum byte.
73  if (!sid_string.empty() || (0 != volume_id))
74    rlz_lib::Crc8::Generate(id_binary.c_str(),
75                            kSizeWithoutChecksum,
76                            &id_binary[kSizeWithoutChecksum]);
77
78  return rlz_lib::BytesToString(
79      id_binary.c_str(), kSizeWithoutChecksum + 1, machine_id);
80}
81
82}  // namespace testing
83
84}  // namespace rlz_lib
85