1 files changed, 164 insertions, 0 deletions
diff --git a/libs/binder/include/binder/RpcServer.h b/libs/binder/include/binder/RpcServer.h
new file mode 100644
index 0000000000..8f0c6fd5e1
--- /dev/null
+++ b/libs/binder/include/binder/RpcServer.h
@@ -0,0 +1,164 @@
+/*
+ * 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 <android-base/unique_fd.h>
+#include <binder/IBinder.h>
+#include <binder/RpcSession.h>
+#include <utils/Errors.h>
+#include <utils/RefBase.h>
+
+#include <mutex>
+#include <thread>
+
+// WARNING: This is a feature which is still in development, and it is subject
+// to radical change. Any production use of this may subject your code to any
+// number of problems.
+
+namespace android {
+
+class RpcSocketAddress;
+
+/**
+ * This represents a server of an interface, which may be connected to by any
+ * number of clients over sockets.
+ *
+ * Usage:
+ *     auto server = RpcServer::make();
+ *     // only supports one now
+ *     if (!server->setup*Server(...)) {
+ *         :(
+ *     }
+ *     server->join();
+ */
+class RpcServer final : public virtual RefBase {
+public:
+    static sp<RpcServer> make();
+
+    /**
+     * This represents a session for responses, e.g.:
+     *
+     *     process A serves binder a
+     *     process B opens a session to process A
+     *     process B makes binder b and sends it to A
+     *     A uses this 'back session' to send things back to B
+     */
+    [[nodiscard]] bool setupUnixDomainServer(const char* path);
+
+    /**
+     * Creates an RPC server at the current port.
+     */
+    [[nodiscard]] bool setupVsockServer(unsigned int port);
+
+    /**
+     * Creates an RPC server at the current port using IPv4.
+     *
+     * TODO(b/182914638): IPv6 support
+     *
+     * Set |port| to 0 to pick an ephemeral port; see discussion of
+     * /proc/sys/net/ipv4/ip_local_port_range in ip(7). In this case, |assignedPort|
+     * will be set to the picked port number, if it is not null.
+     */
+    [[nodiscard]] bool setupInetServer(unsigned int port, unsigned int* assignedPort);
+
+    /**
+     * If setup*Server has been successful, return true. Otherwise return false.
+     */
+    [[nodiscard]] bool hasServer();
+
+    /**
+     * If hasServer(), return the server FD. Otherwise return invalid FD.
+     */
+    [[nodiscard]] base::unique_fd releaseServer();
+
+    /**
+     * Set up server using an external FD previously set up by releaseServer().
+     * Return false if there's already a server.
+     */
+    bool setupExternalServer(base::unique_fd serverFd);
+
+    void iUnderstandThisCodeIsExperimentalAndIWillNotUseItInProduction();
+
+    /**
+     * This must be called before adding a client session.
+     *
+     * If this is not specified, this will be a single-threaded server.
+     *
+     * TODO(b/185167543): these are currently created per client, but these
+     * should be shared.
+     */
+    void setMaxThreads(size_t threads);
+    size_t getMaxThreads();
+
+    /**
+     * The root object can be retrieved by any client, without any
+     * authentication. TODO(b/183988761)
+     *
+     * Holds a strong reference to the root object.
+     */
+    void setRootObject(const sp<IBinder>& binder);
+    /**
+     * Holds a weak reference to the root object.
+     */
+    void setRootObjectWeak(const wp<IBinder>& binder);
+    sp<IBinder> getRootObject();
+
+    /**
+     * You must have at least one client session before calling this.
+     *
+     * TODO(b/185167543): way to shut down?
+     */
+    void join();
+
+    /**
+     * Accept one connection on this server. You must have at least one client
+     * session before calling this.
+     */
+    [[nodiscard]] bool acceptOne();
+
+    /**
+     * For debugging!
+     */
+    std::vector<sp<RpcSession>> listSessions();
+    size_t numUninitializedSessions();
+
+    ~RpcServer();
+
+    // internal use only
+
+    void onSessionTerminating(const sp<RpcSession>& session);
+
+private:
+    friend sp<RpcServer>;
+    RpcServer();
+
+    void establishConnection(sp<RpcServer>&& session, base::unique_fd clientFd);
+    bool setupSocketServer(const RpcSocketAddress& address);
+
+    bool mAgreedExperimental = false;
+    bool mStarted = false; // TODO(b/185167543): support dynamically added clients
+    size_t mMaxThreads = 1;
+    base::unique_fd mServer; // socket we are accepting sessions on
+
+    std::mutex mLock; // for below
+    std::map<std::thread::id, std::thread> mConnectingThreads;
+    sp<IBinder> mRootObject;
+    wp<IBinder> mRootObjectWeak;
+    std::map<int32_t, sp<RpcSession>> mSessions;
+    int32_t mSessionIdCounter = 0;
+};
+
+} // namespace android