1/*
2 * Copyright (C) 2016 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#define LOG_TAG "TrustyNVRAM"
18
19#include "trusty_nvram_implementation.h"
20
21#include <errno.h>
22#include <string.h>
23#include <unistd.h>
24
25#include <hardware/nvram.h>
26#include <log/log.h>
27#include <trusty/tipc.h>
28
29#include <nvram/messages/blob.h>
30
31namespace nvram {
32namespace {
33
34// Character device to open for Trusty IPC connections.
35const char kTrustyDeviceName[] = "/dev/trusty-ipc-dev0";
36
37// App identifier of the NVRAM app.
38const char kTrustyNvramAppId[] = "com.android.trusty.nvram";
39
40}  // namespace
41
42TrustyNvramImplementation::~TrustyNvramImplementation() {
43  if (tipc_nvram_fd_ != -1) {
44    tipc_close(tipc_nvram_fd_);
45    tipc_nvram_fd_ = -1;
46  }
47}
48
49void TrustyNvramImplementation::Execute(const nvram::Request& request,
50                                        nvram::Response* response) {
51  if (!SendRequest(request, response)) {
52    response->result = NV_RESULT_INTERNAL_ERROR;
53  }
54}
55
56bool TrustyNvramImplementation::Connect() {
57  if (tipc_nvram_fd_ != -1) {
58    return true;
59  }
60
61  int rc = tipc_connect(kTrustyDeviceName, kTrustyNvramAppId);
62  if (rc < 0) {
63    ALOGE("Failed to connect to Trusty NVRAM app: %s\n", strerror(-rc));
64    return false;
65  }
66
67  tipc_nvram_fd_ = rc;
68  return true;
69}
70
71bool TrustyNvramImplementation::SendRequest(const nvram::Request& request,
72                                            nvram::Response* response) {
73  if (!Connect()) {
74    return false;
75  }
76
77  nvram::Blob request_buffer;
78  if (!nvram::Encode(request, &request_buffer)) {
79    ALOGE("Failed to encode NVRAM request.\n");
80    return false;
81  }
82
83  ssize_t rc =
84      write(tipc_nvram_fd_, request_buffer.data(), request_buffer.size());
85  if (rc < 0) {
86    ALOGE("Failed to send NVRAM request: %s\n", strerror(-rc));
87    return false;
88  }
89  if (static_cast<size_t>(rc) != request_buffer.size()) {
90    ALOGE("Failed to send full request buffer: %zd\n", rc);
91    return false;
92  }
93
94  rc = read(tipc_nvram_fd_, response_buffer_, sizeof(response_buffer_));
95  if (rc < 0) {
96    ALOGE("Failed to read NVRAM response: %s\n", strerror(-rc));
97    return false;
98  }
99
100  if (static_cast<size_t>(rc) >= sizeof(response_buffer_)) {
101    ALOGE("NVRAM response exceeds response buffer size.\n");
102    return false;
103  }
104
105  if (!nvram::Decode(response_buffer_, static_cast<size_t>(rc), response)) {
106    ALOGE("Failed to decode NVRAM response.\n");
107    return false;
108  }
109
110  return true;
111}
112
113}  // namespace nvram
114