1 files changed, 176 insertions, 0 deletions
diff --git a/libs/binder/ServiceManagerHost.cpp b/libs/binder/ServiceManagerHost.cpp
new file mode 100644
index 0000000000..07f5778deb
--- /dev/null
+++ b/libs/binder/ServiceManagerHost.cpp
@@ -0,0 +1,176 @@
+/*
+ * Copyright (C) 2021 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 "ServiceManagerHost.h"
+
+#include <android-base/parseint.h>
+#include <android-base/strings.h>
+#include <binder/IServiceManager.h>
+#include <binder/RpcSession.h>
+
+#include "UtilsHost.h"
+
+namespace android {
+
+namespace {
+
+const void* kDeviceServiceExtraId = "DeviceServiceExtra";
+
+// Parse stdout of program execution to string. If any error, return 0.
+unsigned int parsePortNumber(const std::string& out, const std::string& what) {
+    auto trimmed = android::base::Trim(out);
+    unsigned int port = 0;
+    if (!android::base::ParseUint(trimmed, &port)) {
+        int savedErrno = errno;
+        ALOGE("%s is not a valid %s: %s", trimmed.c_str(), what.c_str(), strerror(savedErrno));
+        return 0;
+    }
+    if (port == 0) {
+        ALOGE("0 is not a valid %s", what.c_str());
+        return 0; // explicitly
+    }
+    return port;
+}
+
+// RAII object for adb forwarding
+class AdbForwarder {
+public:
+    AdbForwarder() = default;
+    static std::optional<AdbForwarder> forward(unsigned int devicePort);
+    AdbForwarder(AdbForwarder&& other) noexcept { (*this) = std::move(other); }
+    AdbForwarder& operator=(AdbForwarder&&) noexcept;
+    ~AdbForwarder();
+    [[nodiscard]] const std::optional<unsigned int>& hostPort() const { return mPort; }
+
+private:
+    DISALLOW_COPY_AND_ASSIGN(AdbForwarder);
+    explicit AdbForwarder(unsigned int port) : mPort(port) {}
+    std::optional<unsigned int> mPort;
+};
+std::optional<AdbForwarder> AdbForwarder::forward(unsigned int devicePort) {
+    auto result =
+            execute({"adb", "forward", "tcp:0", "tcp:" + std::to_string(devicePort)}, nullptr);
+    if (!result.ok()) {
+        ALOGE("Unable to run `adb forward tcp:0 tcp:%d`: %s", devicePort,
+              result.error().message().c_str());
+        return std::nullopt;
+    }
+    // Must end with exit code 0 (`has_value() && value() == 0`)
+    if (result->exitCode.value_or(1) != 0) {
+        ALOGE("Unable to run `adb forward tcp:0 tcp:%d`, command exits with %s", devicePort,
+              result->toString().c_str());
+        return std::nullopt;
+    }
+    if (!result->stderr.empty()) {
+        LOG_HOST("`adb forward tcp:0 tcp:%d` writes to stderr: %s", devicePort,
+                 result->stderr.c_str());
+    }
+
+    unsigned int hostPort = parsePortNumber(result->stdout, "host port");
+    if (hostPort == 0) return std::nullopt;
+
+    return AdbForwarder(hostPort);
+}
+
+AdbForwarder& AdbForwarder::operator=(AdbForwarder&& other) noexcept {
+    std::swap(mPort, other.mPort);
+    return *this;
+}
+
+AdbForwarder::~AdbForwarder() {
+    if (!mPort.has_value()) return;
+
+    auto result = execute({"adb", "forward", "--remove", "tcp:" + std::to_string(*mPort)}, nullptr);
+    if (!result.ok()) {
+        ALOGE("Unable to run `adb forward --remove tcp:%d`: %s", *mPort,
+              result.error().message().c_str());
+        return;
+    }
+    // Must end with exit code 0 (`has_value() && value() == 0`)
+    if (result->exitCode.value_or(1) != 0) {
+        ALOGE("Unable to run `adb forward --remove tcp:%d`, command exits with %s", *mPort,
+              result->toString().c_str());
+        return;
+    }
+    if (!result->stderr.empty()) {
+        LOG_HOST("`adb forward --remove tcp:%d` writes to stderr: %s", *mPort,
+                 result->stderr.c_str());
+    }
+
+    LOG_HOST("Successfully run `adb forward --remove tcp:%d`", *mPort);
+}
+
+void cleanupCommandResult(const void* id, void* obj, void* /* cookie */) {
+    LOG_ALWAYS_FATAL_IF(id != kDeviceServiceExtraId,
+                        "cleanupCommandResult invoked with mismatched ID %p, "
+                        "expected %p",
+                        id, kDeviceServiceExtraId);
+    auto ptr = static_cast<CommandResult*>(obj);
+    delete ptr;
+}
+
+} // namespace
+
+sp<IBinder> getDeviceService(std::vector<std::string>&& serviceDispatcherArgs) {
+    std::vector<std::string> prefix{"adb", "shell", "servicedispatcher"};
+    serviceDispatcherArgs.insert(serviceDispatcherArgs.begin(), prefix.begin(), prefix.end());
+
+    auto result = execute(std::move(serviceDispatcherArgs), &CommandResult::stdoutEndsWithNewLine);
+    if (!result.ok()) {
+        ALOGE("%s", result.error().message().c_str());
+        return nullptr;
+    }
+
+    // `servicedispatcher` process must be alive to keep the port open.
+    if (result->exitCode.has_value()) {
+        ALOGE("Command exits with: %s", result->toString().c_str());
+        return nullptr;
+    }
+    if (!result->stderr.empty()) {
+        LOG_HOST("servicedispatcher writes to stderr: %s", result->stderr.c_str());
+    }
+
+    if (!result->stdoutEndsWithNewLine()) {
+        ALOGE("Unexpected command result: %s", result->toString().c_str());
+        return nullptr;
+    }
+
+    unsigned int devicePort = parsePortNumber(result->stdout, "device port");
+    if (devicePort == 0) return nullptr;
+
+    auto forwardResult = AdbForwarder::forward(devicePort);
+    if (!forwardResult.has_value()) {
+        return nullptr;
+    }
+    LOG_ALWAYS_FATAL_IF(!forwardResult->hostPort().has_value());
+
+    auto rpcSession = RpcSession::make();
+    if (!rpcSession->setupInetClient("127.0.0.1", *forwardResult->hostPort())) {
+        ALOGE("Unable to set up inet client on host port %u", *forwardResult->hostPort());
+        return nullptr;
+    }
+    auto binder = rpcSession->getRootObject();
+    if (binder == nullptr) {
+        ALOGE("RpcSession::getRootObject returns nullptr");
+        return nullptr;
+    }
+    binder->attachObject(kDeviceServiceExtraId,
+                         static_cast<void*>(new CommandResult(std::move(*result))), nullptr,
+                         &cleanupCommandResult);
+    return binder;
+}
+
+} // namespace android