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 #ifndef TRUSTY_NVRAM_TRUSTY_NVRAM_IMPLEMENTATION_H_
18 #define TRUSTY_NVRAM_TRUSTY_NVRAM_IMPLEMENTATION_H_
19 
20 #include <stdint.h>
21 
22 #include <nvram/hal/nvram_device_adapter.h>
23 #include <nvram/messages/nvram_messages.h>
24 
25 namespace nvram {
26 
27 // |TrustyNvramImplementation| proxies requests to the Trusty NVRAM app. It
28 // serializes the request objects, sends it to the Trusty app and finally reads
29 // back the result and decodes it.
30 class TrustyNvramImplementation : public nvram::NvramImplementation {
31  public:
32   ~TrustyNvramImplementation() override;
33 
34   void Execute(const nvram::Request& request,
35                nvram::Response* response) override;
36 
37  private:
38   // Connects the IPC channel to the Trusty app if it is not already open.
39   // Returns true if the channel is open, false on errors.
40   bool Connect();
41 
42   // Dispatches a command to the trust app. Returns true if successful (note
43   // that the response may still indicate an error on the Trusty side), false if
44   // there are any I/O or encoding/decoding errors.
45   bool SendRequest(const nvram::Request& request,
46                    nvram::Response* response);
47 
48   // The file descriptor for the IPC connection to the Trusty app.
49   int tipc_nvram_fd_ = -1;
50 
51   // Response buffer. This puts a hard size limit on the responses from the
52   // Trusty app. 4096 matches the maximum IPC message size currently supported
53   // by Trusty.
54   uint8_t response_buffer_[4096];
55 };
56 
57 }  // namespace nvram
58 
59 #endif  // TRUSTY_NVRAM_TRUSTY_NVRAM_IMPLEMENTATION_H_
60