sdm845-common: Add and build trust HAL

Change-Id: I6ffdcd0cae2afb1b1e872152f7997da704ad74dc

trust/UsbRestrict.cpp

@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2019 The LineageOS 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 <fstream>
+
+#include "UsbRestrict.h"
+
+#include <android-base/logging.h>
+
+namespace vendor {
+namespace lineage {
+namespace trust {
+namespace V1_0 {
+namespace implementation {
+
+static constexpr const char* kControlPath = "/sys/class/power_supply/usb/otg_switch";
+
+// Methods from ::vendor::lineage::trust::V1_0::IUsbRestrict follow.
+Return<bool> UsbRestrict::isEnabled() {
+    std::ifstream file(kControlPath);
+    std::string content;
+    file >> content;
+    file.close();
+    return !file.fail() && !std::stoi(content);
+}
+
+Return<void> UsbRestrict::setEnabled(bool enabled) {
+    std::ofstream file(kControlPath);
+    if (file.is_open()) {
+        file << (!enabled ? "1" : "0");
+        file.close();
+    } else {
+        LOG(ERROR) << "Failed to open " << kControlPath << ", error=" << errno << " ("
+                   << strerror(errno) << ")";
+    }
+    return Void();
+}
+
+}  // namespace implementation
+}  // namespace V1_0
+}  // namespace trust
+}  // namespace lineage
+}  // namespace vendor