EchoServer: Add a simple echo server

Base/usr/share/man/man1/EchoServer.md

@@ -0,0 +1,23 @@
+## Name
+
+EchoServer - Serenity echo server
+
+## Synopsis
+
+```**sh
+$ EchoServer [options]
+```
+
+## Description
+
+EchoServer is a basic echo server for Serenity. By default, it runs on port 7.
+
+## Options
+
+* `-p`: Choose different port for EchoServer to attach to.
+
+## Examples
+
+```sh
+$ EchoServer -p 1234
+```

Services/CMakeLists.txt

@@ -2,6 +2,7 @@ add_subdirectory(AudioServer)
 add_subdirectory(ChessEngine)
 add_subdirectory(Clipboard)
 add_subdirectory(DHCPClient)
+add_subdirectory(EchoServer)
 add_subdirectory(ImageDecoder)
 add_subdirectory(LaunchServer)
 add_subdirectory(LookupServer)

Services/EchoServer/CMakeLists.txt

@@ -0,0 +1,7 @@
+set(SOURCES
+    Client.cpp
+    main.cpp
+)
+
+serenity_bin(EchoServer)
+target_link_libraries(EchoServer LibCore)

Services/EchoServer/Client.cpp

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "Client.h"
+
+Client::Client(int id, RefPtr<Core::TCPSocket> socket)
+    : m_id(id)
+    , m_socket(move(socket))
+{
+    m_socket->on_ready_to_read = [this] { drain_socket(); };
+}
+
+void Client::drain_socket()
+{
+    NonnullRefPtr<Client> protect(*this);
+    while (m_socket->can_read()) {
+        auto buf = m_socket->read(1024);
+
+        dbg() << "Read " << buf.size() << " bytes: " << buf;
+
+        if (m_socket->eof()) {
+            quit();
+            break;
+        }
+
+        m_socket->write(buf);
+    }
+}
+
+void Client::quit()
+{
+    m_socket->close();
+    if (on_exit)
+        on_exit();
+}

Services/EchoServer/Client.h

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <LibCore/TCPSocket.h>
+
+class Client : public RefCounted<Client> {
+public:
+    static NonnullRefPtr<Client> create(int id, RefPtr<Core::TCPSocket> socket)
+    {
+        return adopt(*new Client(id, move(socket)));
+    }
+
+    Function<void()> on_exit;
+
+protected:
+    Client(int id, RefPtr<Core::TCPSocket> socket);
+
+    void drain_socket();
+    void quit();
+
+private:
+    int m_id { 0 };
+    RefPtr<Core::TCPSocket> m_socket;
+};

Services/EchoServer/main.cpp

@@ -0,0 +1,99 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "Client.h"
+#include <AK/HashMap.h>
+#include <AK/IPv4Address.h>
+#include <LibCore/ArgsParser.h>
+#include <LibCore/EventLoop.h>
+#include <LibCore/TCPServer.h>
+#include <LibCore/TCPSocket.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char** argv)
+{
+    if (pledge("stdio cpath unix fattr inet id accept", nullptr) < 0) {
+        perror("pledge");
+        return 1;
+    }
+
+    if (unveil("/tmp/rpc", "rwc") < 0) {
+        perror("unveil");
+        return 1;
+    }
+
+    if (unveil(nullptr, nullptr) < 0) {
+        perror("unveil");
+        return 1;
+    }
+
+    int port = 7;
+
+    Core::ArgsParser args_parser;
+    args_parser.add_option(port, "Port to listen on", "port", 'p', "port");
+    args_parser.parse(argc, argv);
+
+    if ((u16)port != port) {
+        warnln("Invalid port number: {}", port);
+        exit(1);
+    }
+
+    Core::EventLoop event_loop;
+
+    auto server = Core::TCPServer::construct();
+
+    if (!server->listen({}, port)) {
+        warnln("Listening on 0.0.0.0:{} failed", port);
+        exit(1);
+    }
+
+    HashMap<int, NonnullRefPtr<Client>> clients;
+    int next_id = 0;
+
+    server->on_ready_to_accept = [&next_id, &clients, &server] {
+        int id = next_id++;
+
+        auto client_socket = server->accept();
+        if (!client_socket) {
+            perror("accept");
+            return;
+        }
+
+        outln("Client {} connected", id);
+
+        auto client = Client::create(id, move(client_socket));
+        client->on_exit = [&clients, id] {
+            clients.remove(id);
+            outln("Client {} disconnected", id);
+        };
+        clients.set(id, client);
+    };
+
+    outln("Listening on 0.0.0.0:{}", port);
+
+    return event_loop.exec();
+}