add ADB server/client + tests

4 files changed, 344 insertions, 1 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 982aa49..414a750 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -5,6 +5,7 @@ add_definitions (-DG_LOG_DOMAIN="${CMAKE_PROJECT_NAME}")
 
 # handwritten source code...
 set (SERVICE_LIB_HANDWRITTEN_SOURCES
+     adbd-client.cpp
      exporter.cpp
      rotation-lock.cpp)
 
@@ -19,7 +20,7 @@ link_directories (${SERVICE_DEPS_LIBRARY_DIRS})
 
 set (SERVICE_EXEC_HANDWRITTEN_SOURCES main.cpp)
 add_executable (${SERVICE_EXEC} ${SERVICE_EXEC_HANDWRITTEN_SOURCES})
-target_link_libraries (${SERVICE_EXEC} ${SERVICE_LIB} ${SERVICE_DEPS_LIBRARIES} ${GCOV_LIBS})
+target_link_libraries (${SERVICE_EXEC} ${SERVICE_LIB} ${SERVICE_DEPS_LIBRARIES} Threads::Threads ${GCOV_LIBS})
 install (TARGETS ${SERVICE_EXEC} RUNTIME DESTINATION ${CMAKE_INSTALL_FULL_PKGLIBEXECDIR})
 
 # add warnings/coverage info on handwritten files
diff --git a/src/adbd-client.cpp b/src/adbd-client.cpp
new file mode 100644
index 0000000..38f202f
--- /dev/null
+++ b/src/adbd-client.cpp
@@ -0,0 +1,258 @@
+/*
+ * Copyright 2016 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 3, as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranties of
+ * MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors:
+ *   Charles Kerr <charles.kerr@canonical.com>
+ */
+
+#include <src/adbd-client.h>
+
+#include <gio/gio.h>
+#include <gio/gunixsocketaddress.h>
+
+#include <chrono>
+#include <condition_variable>
+#include <mutex>
+#include <thread>
+
+class GAdbdClient::Impl
+{
+public:
+
+    explicit Impl(const std::string& socket_path):
+        m_socket_path{socket_path},
+        m_cancellable{g_cancellable_new()},
+        m_worker_thread{&Impl::worker_func, this}
+    {
+    }
+
+    ~Impl()
+    {
+        // tell the worker thread to stop whatever it's doing and exit.
+        g_cancellable_cancel(m_cancellable);
+        m_sleep_cv.notify_one();
+        m_worker_thread.join();
+        g_clear_object(&m_cancellable);
+    }
+
+    core::Signal<const PKRequest&>& on_pk_request()
+    {
+        return m_on_pk_request;
+    }
+
+private:
+
+    // struct to carry request info from the worker thread to the GMainContext thread
+    struct PKIdleData
+    {
+        Impl* self = nullptr;
+        GCancellable* cancellable = nullptr;
+        const std::string public_key;
+
+        PKIdleData(Impl* self_, GCancellable* cancellable_, std::string public_key_):
+            self(self_),
+            cancellable(G_CANCELLABLE(g_object_ref(cancellable_))),
+            public_key(public_key_) {}
+
+        ~PKIdleData() {g_clear_object(&cancellable);}
+        
+    };
+
+    void pass_public_key_to_main_thread(const std::string& public_key)
+    {
+        g_idle_add_full(G_PRIORITY_DEFAULT_IDLE,
+                        on_public_key_request_static,
+                        new PKIdleData{this, m_cancellable, public_key},
+                        [](gpointer id){delete static_cast<PKIdleData*>(id);});
+    }
+
+    static gboolean on_public_key_request_static (gpointer gdata) // runs in main thread
+    {
+        /* NB: It's possible (though unlikely) that data.self was destroyed
+           while this callback was pending, so we must check is-cancelled FIRST */
+        auto data = static_cast<PKIdleData*>(gdata);
+        if (!g_cancellable_is_cancelled(data->cancellable))
+        {
+            // notify our listeners of the request
+            auto self = data->self;
+            struct PKRequest req;
+            req.public_key = data->public_key;
+            req.respond = [self](PKResponse response){self->on_public_key_response(response);};
+            self->m_on_pk_request(req);
+        }
+
+        return G_SOURCE_REMOVE;
+    }
+
+    void on_public_key_response(PKResponse response)
+    {
+        // set m_pkresponse and wake up the waiting worker thread
+        std::unique_lock<std::mutex> lk(m_pkresponse_mutex);
+        m_pkresponse = response;
+        m_pkresponse_ready = true;
+        m_pkresponse_cv.notify_one();
+    }
+
+    /***
+    ****
+    ***/
+
+    void worker_func() // runs in worker thread
+    {
+        const auto socket_path {m_socket_path};
+
+        while (!g_cancellable_is_cancelled(m_cancellable))
+        {
+            g_debug("%s creating a client socket", G_STRLOC);
+            auto socket = create_client_socket(socket_path);
+            bool got_valid_req = false;
+
+            g_debug("%s calling read_request", G_STRLOC);
+            std::string reqstr;
+            if (socket != nullptr)
+                reqstr = read_request(socket);
+            if (!reqstr.empty())
+                g_debug("%s got request [%s]", G_STRLOC, reqstr.c_str());
+
+            if (reqstr.substr(0,2) == "PK") {
+                PKResponse response = PKResponse::DENY;
+                const auto public_key = reqstr.substr(2);
+                g_debug("%s got pk [%s]", G_STRLOC, public_key.c_str());
+                if (!public_key.empty()) {
+                    got_valid_req = true;
+                    std::unique_lock<std::mutex> lk(m_pkresponse_mutex);
+                    m_pkresponse_ready = false;
+                    pass_public_key_to_main_thread(public_key);
+                    m_pkresponse_cv.wait(lk, [this](){
+                        return m_pkresponse_ready || g_cancellable_is_cancelled(m_cancellable);
+                    });
+                    response = m_pkresponse;
+                    g_debug("%s got response '%d'", G_STRLOC, int(response));
+                }
+                if (!g_cancellable_is_cancelled(m_cancellable))
+                    send_pk_response(socket, response);
+            } else if (!reqstr.empty()) {
+                g_warning("Invalid ADB request: [%s]", reqstr.c_str());
+            }
+
+            g_clear_object(&socket);
+
+            // If nothing interesting's happening, sleep a bit.
+            // (Interval copied from UsbDebuggingManager.java)
+            static constexpr auto sleep_interval {std::chrono::seconds(1)};
+            if (!got_valid_req && !g_cancellable_is_cancelled(m_cancellable)) {
+                std::unique_lock<std::mutex> lk(m_sleep_mutex);
+                m_sleep_cv.wait_for(lk, sleep_interval);
+            }
+        }
+    }
+
+    // connect to a local domain socket
+    GSocket* create_client_socket(const std::string& socket_path)
+    {
+        GError* error {};
+        auto socket = g_socket_new(G_SOCKET_FAMILY_UNIX,
+                                   G_SOCKET_TYPE_STREAM,
+                                   G_SOCKET_PROTOCOL_DEFAULT,
+                                   &error);
+        if (error != nullptr) {
+            g_warning("Error creating adbd client socket: %s", error->message);
+            g_clear_error(&error);
+            g_clear_object(&socket);
+            return nullptr;
+        }
+
+        auto address = g_unix_socket_address_new(socket_path.c_str());
+        const auto connected = g_socket_connect(socket, address, m_cancellable, nullptr);
+        g_clear_object(&address);
+        if (!connected) {
+            g_clear_object(&socket);
+            return nullptr;
+        }
+
+        return socket;
+    }
+
+    std::string read_request(GSocket* socket)
+    {
+        char buf[4096] = {};
+        g_debug("%s calling g_socket_receive()", G_STRLOC);
+        const auto n_bytes = g_socket_receive (socket, buf, sizeof(buf), m_cancellable, nullptr);
+        std::string ret;
+        if (n_bytes > 0)
+            ret.append(buf, std::string::size_type(n_bytes));
+        g_debug("%s g_socket_receive got %d bytes: [%s]", G_STRLOC, int(n_bytes), ret.c_str());
+        return ret;
+    }
+
+    void send_pk_response(GSocket* socket, PKResponse response)
+    {
+        std::string response_str;
+        switch(response) {
+            case PKResponse::ALLOW: response_str = "OK"; break;
+            case PKResponse::DENY:  response_str = "NO"; break;
+        }
+        g_debug("%s sending reply: [%s]", G_STRLOC, response_str.c_str());
+
+        GError* error {};
+        g_socket_send(socket,
+                      response_str.c_str(),
+                      response_str.size(),
+                      m_cancellable,
+                      &error);
+        if (error != nullptr) {
+            if (!g_error_matches(error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
+                g_warning("GAdbdServer: Error accepting socket connection: %s", error->message);
+            g_clear_error(&error);
+        }
+    }
+
+    const std::string m_socket_path;
+    GCancellable* m_cancellable = nullptr;
+    std::thread m_worker_thread;
+    core::Signal<const PKRequest&> m_on_pk_request;
+
+    std::mutex m_sleep_mutex;
+    std::condition_variable m_sleep_cv;
+
+    std::mutex m_pkresponse_mutex;
+    std::condition_variable m_pkresponse_cv;
+    bool m_pkresponse_ready = false;
+    PKResponse m_pkresponse = PKResponse::DENY;
+};
+
+/***
+****
+***/
+
+AdbdClient::~AdbdClient()
+{
+}
+
+GAdbdClient::GAdbdClient(const std::string& socket_path):
+    impl{new Impl{socket_path}}
+{
+}
+
+GAdbdClient::~GAdbdClient()
+{
+}
+
+core::Signal<const AdbdClient::PKRequest&>&
+GAdbdClient::on_pk_request()
+{
+    return impl->on_pk_request();
+}
+
diff --git a/src/adbd-client.h b/src/adbd-client.h
new file mode 100644
index 0000000..aef7674
--- /dev/null
+++ b/src/adbd-client.h
@@ -0,0 +1,73 @@
+/*
+ * Copyright 2016 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 3, as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranties of
+ * MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors:
+ *   Charles Kerr <charles.kerr@canonical.com>
+ */
+
+#pragma once
+
+#include <functional>
+#include <memory>
+#include <string>
+
+#include <core/signal.h>
+
+/**
+ * Receives public key requests from ADBD and sends a response back.
+ *
+ * AdbClient only provides a receive/respond mechanism. The decision
+ * of what response gets sent is delegated out to a listener via
+ * the on_pk_request signal.
+ *
+ * The decider should connect to on_pk_request, listen for PKRequests,
+ * and call the request's `respond' method with the desired response.
+ */
+class AdbdClient
+{
+public:
+    virtual ~AdbdClient();
+
+    enum class PKResponse { DENY, ALLOW };
+
+    struct PKRequest {
+        std::string public_key;
+        std::function<void(PKResponse)> respond;
+    };
+
+    virtual core::Signal<const PKRequest&>& on_pk_request() =0;
+
+protected:
+    AdbdClient() =default;
+};
+
+/**
+ * An AdbdClient designed to work with GLib's event loop.
+ *
+ * The on_pk_request() signal will be called in global GMainContext's thread;
+ * ie, just like a function passed to g_idle_add() or g_timeout_add().
+ */
+class GAdbdClient: public AdbdClient
+{
+public:
+    explicit GAdbdClient(const std::string& socket_path);
+    ~GAdbdClient();
+    core::Signal<const PKRequest&>& on_pk_request() override;
+
+private:
+    class Impl;
+    std::unique_ptr<Impl> impl;
+};
+
diff --git a/src/main.cpp b/src/main.cpp
index 86bdeb3..0c56bd6 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -17,6 +17,7 @@
  *   Charles Kerr <charles.kerr@canonical.com>
  */
 
+#include <src/adbd-client.h>
 #include <src/exporter.h>
 #include <src/rotation-lock.h>
 
@@ -54,6 +55,16 @@ main(int /*argc*/, char** /*argv*/)
       exporters.push_back(exporter);
     }
 
+    // We need the ADBD handler running,
+    // even though it doesn't have an indicator component yet
+    static constexpr char const * ADB_SOCKET_PATH {"/dev/socket/adb"};
+    GAdbdClient adbd_client{ADB_SOCKET_PATH};
+    adbd_client.on_pk_request().connect([](const AdbdClient::PKRequest& req){
+        g_debug("%s got pk_request [%s]", G_STRLOC, req.public_key.c_str());
+        // FIXME: actually decide what response to send back
+        req.respond(AdbdClient::PKResponse::ALLOW);
+    });
+
     g_main_loop_run(loop);
 
     // cleanup