1 files changed, 81 insertions, 0 deletions
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/snapuserd_client.h b/fs_mgr/libsnapshot/include/libsnapshot/snapuserd_client.h
new file mode 100644
index 000000000..280e85730
--- /dev/null
+++ b/fs_mgr/libsnapshot/include/libsnapshot/snapuserd_client.h
@@ -0,0 +1,81 @@
+// Copyright (C) 2020 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.
+
+#pragma once
+
+#include <unistd.h>
+
+#include <chrono>
+#include <cstring>
+#include <iostream>
+#include <string>
+#include <thread>
+#include <vector>
+
+#include <android-base/unique_fd.h>
+
+namespace android {
+namespace snapshot {
+
+static constexpr uint32_t PACKET_SIZE = 512;
+
+static constexpr char kSnapuserdSocket[] = "snapuserd";
+
+// Ensure that the second-stage daemon for snapuserd is running.
+bool EnsureSnapuserdStarted();
+
+class SnapuserdClient {
+  private:
+    android::base::unique_fd sockfd_;
+
+    bool Sendmsg(const std::string& msg);
+    std::string Receivemsg();
+
+    bool ValidateConnection();
+
+  public:
+    explicit SnapuserdClient(android::base::unique_fd&& sockfd);
+
+    static std::unique_ptr<SnapuserdClient> Connect(const std::string& socket_name,
+                                                    std::chrono::milliseconds timeout_ms);
+
+    bool StopSnapuserd();
+
+    // Initializing a snapuserd handler is a three-step process:
+    //
+    //  1. Client invokes InitDmUserCow. This creates the snapuserd handler and validates the
+    //     COW. The number of sectors required for the dm-user target is returned.
+    //  2. Client creates the device-mapper device with the dm-user target.
+    //  3. Client calls AttachControlDevice.
+    //
+    // The misc_name must be the "misc_name" given to dm-user in step 2.
+    //
+    uint64_t InitDmUserCow(const std::string& misc_name, const std::string& cow_device,
+                           const std::string& backing_device);
+    bool AttachDmUser(const std::string& misc_name);
+
+    // Wait for snapuserd to disassociate with a dm-user control device. This
+    // must ONLY be called if the control device has already been deleted.
+    bool WaitForDeviceDelete(const std::string& control_device);
+
+    void CloseConnection() { sockfd_ = {}; }
+
+    // Detach snapuserd. This shuts down the listener socket, and will cause
+    // snapuserd to gracefully exit once all handler threads have terminated.
+    // This should only be used on first-stage instances of snapuserd.
+    bool DetachSnapuserd();
+};
+
+}  // namespace snapshot
+}  // namespace android