| /* |
| * Copyright (C) 2016 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include <errno.h> |
| #include <string.h> |
| |
| #include <hardware/nvram.h> |
| #include <trusty/tipc.h> |
| |
| #define LOG_TAG "TrustyNVRAM" |
| #include <log/log.h> |
| |
| #include <nvram/hal/nvram_device_adapter.h> |
| #include <nvram/messages/blob.h> |
| #include <nvram/messages/nvram_messages.h> |
| |
| namespace { |
| |
| // Character device to open for Trusty IPC connections. |
| const char kTrustyDeviceName[] = "/dev/trusty-ipc-dev0"; |
| |
| // App identifier of the NVRAM app. |
| const char kTrustyNvramAppId[] = "com.android.trusty.nvram"; |
| |
| // |TrustyNvramImplementation| proxies requests to the Trusty NVRAM app. It |
| // serializes the request objects, sends it to the Trusty app and finally reads |
| // back the result and decodes it. |
| class TrustyNvramImplementation : public nvram::NvramImplementation { |
| public: |
| ~TrustyNvramImplementation() override; |
| |
| void Execute(const nvram::Request& request, |
| nvram::Response* response) override; |
| |
| private: |
| // Connects the IPC channel to the Trusty app if it is not already open. |
| // Returns true if the channel is open, false on errors. |
| bool Connect(); |
| |
| // Dispatches a command to the trust app. Returns true if successful (note |
| // that the response may still indicate an error on the Trusty side), false if |
| // there are any I/O or encoding/decoding errors. |
| bool SendRequest(const nvram::Request& request, |
| nvram::Response* response); |
| |
| // The file descriptor for the IPC connection to the Trusty app. |
| int tipc_nvram_fd_ = -1; |
| |
| // Response buffer. This puts a hard size limit on the responses from the |
| // Trusty app. 4096 matches the maximum IPC message size currently supported |
| // by Trusty. |
| uint8_t response_buffer_[4096]; |
| }; |
| |
| TrustyNvramImplementation::~TrustyNvramImplementation() { |
| if (tipc_nvram_fd_ != -1) { |
| tipc_close(tipc_nvram_fd_); |
| tipc_nvram_fd_ = -1; |
| } |
| } |
| |
| void TrustyNvramImplementation::Execute(const nvram::Request& request, |
| nvram::Response* response) { |
| if (!SendRequest(request, response)) { |
| response->result = NV_RESULT_INTERNAL_ERROR; |
| } |
| } |
| |
| bool TrustyNvramImplementation::Connect() { |
| if (tipc_nvram_fd_ != -1) { |
| return true; |
| } |
| |
| int rc = tipc_connect(kTrustyDeviceName, kTrustyNvramAppId); |
| if (rc < 0) { |
| ALOGE("Failed to connect to Trusty NVRAM app: %s\n", strerror(-rc)); |
| return false; |
| } |
| |
| tipc_nvram_fd_ = rc; |
| return true; |
| } |
| |
| bool TrustyNvramImplementation::SendRequest(const nvram::Request& request, |
| nvram::Response* response) { |
| if (!Connect()) { |
| return false; |
| } |
| |
| nvram::Blob request_buffer; |
| if (!nvram::Encode(request, &request_buffer)) { |
| ALOGE("Failed to encode NVRAM request.\n"); |
| return false; |
| } |
| |
| ssize_t rc = |
| write(tipc_nvram_fd_, request_buffer.data(), request_buffer.size()); |
| if (rc < 0) { |
| ALOGE("Failed to send NVRAM request: %s\n", strerror(-rc)); |
| return false; |
| } |
| if (static_cast<size_t>(rc) != request_buffer.size()) { |
| ALOGE("Failed to send full request buffer: %zd\n", rc); |
| return false; |
| } |
| |
| rc = read(tipc_nvram_fd_, response_buffer_, sizeof(response_buffer_)); |
| if (rc < 0) { |
| ALOGE("Failed to read NVRAM response: %s\n", strerror(-rc)); |
| return false; |
| } |
| |
| if (static_cast<size_t>(rc) >= sizeof(response_buffer_)) { |
| ALOGE("NVRAM response exceeds response buffer size.\n"); |
| return false; |
| } |
| |
| if (!nvram::Decode(response_buffer_, static_cast<size_t>(rc), response)) { |
| ALOGE("Failed to decode NVRAM response.\n"); |
| return false; |
| } |
| |
| return true; |
| } |
| |
| } // namespace |
| |
| extern "C" int trusty_nvram_open(const hw_module_t* module, |
| const char* device_id, |
| hw_device_t** device_ptr) { |
| if (strcmp(NVRAM_HARDWARE_DEVICE_ID, device_id) != 0) { |
| return -EINVAL; |
| } |
| |
| nvram::NvramDeviceAdapter* adapter = |
| new nvram::NvramDeviceAdapter(module, new TrustyNvramImplementation); |
| *device_ptr = adapter->as_device(); |
| return 0; |
| } |