1 files changed, 152 insertions, 0 deletions
diff --git a/trusty/nvram/trusty_nvram_implementation.cpp b/trusty/nvram/trusty_nvram_implementation.cpp
new file mode 100644
index 000000000..39496b417
--- /dev/null
+++ b/trusty/nvram/trusty_nvram_implementation.cpp
@@ -0,0 +1,152 @@
+/*
+ * 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;
+}