1//
2// Copyright (C) 2015 The Android Open Source Project
3//
4// Licensed under the Apache License, Version 2.0 (the "License");
5// you may not use this file except in compliance with the License.
6// You may obtain a copy of the License at
7//
8//      http://www.apache.org/licenses/LICENSE-2.0
9//
10// Unless required by applicable law or agreed to in writing, software
11// distributed under the License is distributed on an "AS IS" BASIS,
12// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13// See the License for the specific language governing permissions and
14// limitations under the License.
15//
16
17#include "tpm_manager/server/local_data_store_impl.h"
18
19#include <fcntl.h>
20
21#include <string>
22
23#include <base/files/file_path.h>
24#include <base/files/file_util.h>
25#include <base/files/important_file_writer.h>
26
27using base::FilePath;
28
29namespace tpm_manager {
30
31const char kTpmLocalDataFile[] = "/var/lib/tpm_manager/local_tpm_data";
32const mode_t kLocalDataPermissions = 0600;
33
34bool LocalDataStoreImpl::Read(LocalData* data) {
35  CHECK(data);
36  FilePath path(kTpmLocalDataFile);
37  if (!base::PathExists(path)) {
38    data->Clear();
39    return true;
40  }
41  int permissions = 0;
42  if (base::GetPosixFilePermissions(path, &permissions) &&
43      (permissions & ~kLocalDataPermissions) != 0) {
44    base::SetPosixFilePermissions(path, kLocalDataPermissions);
45  }
46  std::string file_data;
47  if (!ReadFileToString(path, &file_data)) {
48    LOG(ERROR) << "Error reading data store file.";
49    return false;
50  }
51  if (!data->ParseFromString(file_data)) {
52    LOG(ERROR) << "Error parsing file data into protobuf.";
53    return false;
54  }
55  return true;
56}
57
58bool LocalDataStoreImpl::Write(const LocalData& data) {
59  std::string file_data;
60  if (!data.SerializeToString(&file_data)) {
61    LOG(ERROR) << "Error serializing file to string.";
62    return false;
63  }
64  FilePath path(kTpmLocalDataFile);
65  if (!base::CreateDirectory(path.DirName())) {
66    LOG(ERROR) << "Cannot create directory: " << path.DirName().value();
67    return false;
68  }
69  if (!base::ImportantFileWriter::WriteFileAtomically(path, file_data)) {
70    LOG(ERROR) << "Failed to write file: " << path.value();
71    return false;
72  }
73  if (!base::SetPosixFilePermissions(path, kLocalDataPermissions)) {
74    LOG(ERROR) << "Failed to set permissions for file: " << path.value();
75    return false;
76  }
77  // Sync the parent directory.
78  std::string dir_name = path.DirName().value();
79  int dir_fd = HANDLE_EINTR(open(dir_name.c_str(), O_RDONLY|O_DIRECTORY));
80  if (dir_fd < 0) {
81    PLOG(WARNING) << "Could not open " << dir_name << " for syncing";
82    return false;
83  }
84  // POSIX specifies EINTR as a possible return value of fsync().
85  int result = HANDLE_EINTR(fsync(dir_fd));
86  if (result < 0) {
87    PLOG(WARNING) << "Failed to sync " << dir_name;
88    close(dir_fd);
89    return false;
90  }
91  // close() may not be retried on error.
92  result = IGNORE_EINTR(close(dir_fd));
93  if (result < 0) {
94    PLOG(WARNING) << "Failed to close after sync " << dir_name;
95    return false;
96  }
97  return true;
98}
99
100}  // namespace tpm_manager
101