Tcp服务端

TcpServer.hpp

TCP服务端创建流程如下：

创建socket文件套接字对象，面向字节流SOCK_STREAM

bind绑定自己的网络信息，通常端口是固定的，IP地址默认为(0.0.0.0或者NADDR_ANY)

设置socket为监听状态(listen)，一直帮我们获取新连接，接收请求，UDP没有链接，发过来的就是数据，TCP需要listen状态，是因为TCP是面向连接的，这点与UDP不同，TCP还需要进行监听

服务端获取客服端连接请求(accept)

最后进行通信,由于TCP是面向字节流，后续全是文件操作(read/write)

       void initServer()
        {
            // 1. 创建socket文件套接字对象
            _listensock = socket(AF_INET, SOCK_STREAM, 0);
            if (_listensock < 0)
            {
                logMessage(FATAL, "create socket error");
                exit(SOCKET_ERR);
            }
            logMessage(NORMAL, "create socket success: %d", _listensock);

            // 2. bind绑定自己的网络信息
            struct sockaddr_in local;
            memset(&local, 0, sizeof(local));
            local.sin_family = AF_INET;
            local.sin_port = htons(_port);
            local.sin_addr.s_addr = INADDR_ANY;
            if (bind(_listensock, (struct sockaddr *)&local, sizeof(local)) < 0)
            {
                logMessage(FATAL, "bind socket error");
                exit(BIND_ERR);
            }
            logMessage(NORMAL, "bind socket success");

            // 3. 设置socket 为监听状态
            if (listen(_listensock, gbacklog) < 0)
            {
                logMessage(FATAL, "listen socket error");
                exit(LISTEN_ERR);
            }
            logMessage(NORMAL, "listen socket success");
        }

		void start()
        {
            for (;;)
            {
                // 4. server 获取新链接
                // sock, 和client进行通信的fd
                struct sockaddr_in peer;
                socklen_t len = sizeof(peer);
                int sock = accept(_listensock, (struct sockaddr *)&peer, &len);
                if (sock < 0)
                {
                    logMessage(ERROR, "accept error, next");
                    continue;
                }
                logMessage(NORMAL, "accept a new link success, get new sock: %d", sock); 
                cout<<"sock: "<<sock<<endl;
                
                //5.未来通信就用这个sock
                serviceIO(sock);
                close(sock);
            }
        }

void serviceIO(int sock)
{
    char buffer[1024];
    while (true)
    {
        ssize_t n = read(sock, buffer, sizeof(buffer) - 1);
        if (n > 0)
        {
            buffer[n] = 0;
            std::cout << "recv message: " << buffer << std::endl;

            std::string outbuffer = buffer;
            outbuffer += " server[echo]";
            write(sock, outbuffer.c_str(), outbuffer.size()); 
        }
        else if (n == 0)
        {
            logMessage(NORMAL, "client quit, me too!");
            break;
        }
    }
}

logMessage函数：打印出自己模拟相关的日志信息

TcpServer.cc

TcpServer.cc主函数进行相关函数的调用

static void Usage(string proc)
{
    cout << "\nUsage:\n\t" << proc << " local_port\n\n";
}
// tcp服务器，启动上和udp server一模一样
// ./tcpserver local_port
int main(int argc, char *argv[])
{ 
    if (argc != 2)
    {
        Usage(argv[0]);
        exit(USAGE_ERR);
    }
    uint16_t port = atoi(argv[1]);

    unique_ptr<TcpServer> tsvr(new TcpServer(port));
    tsvr->initServer();
    tsvr->start();
    return 0;
}

Tcp客户端

TcpClient.hpp

Tcp客户端创建流程如下：

创建套接字（socket）对象，面向字节流SOCK_STREAM

客户端需要bind，但是客户端的绑定不需要我们自己写，操作系统会去绑定（无需程序员bind）

客户端发起连接请求（connect）

进行通信，客户端输入通信的内容，进行文件操作进行读写通信（read/write）

 void initClient()
    {
        // 1. 创建socket
        _sock = socket(AF_INET, SOCK_STREAM, 0);
        if(_sock < 0)
        {
            std::cerr << "socket create error" << std::endl;
            exit(2);
        }
        // 2. tcp的客户端要bind,不要显示的bind
    }
    void start()
    {
        struct sockaddr_in server;
        memset(&server, 0, sizeof(server));
        server.sin_family = AF_INET;
        server.sin_port = htons(_serverport);
        server.sin_addr.s_addr = inet_addr(_serverip.c_str());

        if(connect(_sock, (struct sockaddr*)&server, sizeof(server)) != 0)
        {
            std::cerr << "socket connect error" << std::endl;
        }
        else
        {
            std::string msg;
            while(true)
            {
                std::cout << "Enter# ";
                std::getline(std::cin, msg);
                write(_sock, msg.c_str(), msg.size());

                char buffer[NUM];
                int n = read(_sock, buffer, sizeof(buffer)-1);
                if(n > 0)
                {
                    buffer[n] = 0;
                    std::cout << "Server回显# " << buffer << std::endl;
                }
                else
                {
                    break;
                }
            }
        }
    }

TcpClient.cc

TcpClinet.cc主函数进行相关函数的调用

static void Usage(string proc)
{
    cout << "\nUsage:\n\t" << proc << " serverip serverport\n\n";
}
// ./tcpclient serverip serverport
int main(int argc, char *argv[])
{
    if (argc != 3)
    {
        Usage(argv[0]);
        exit(1);
    }
    string serverip = argv[1];
    uint16_t serverport = atoi(argv[2]);

    unique_ptr<TcpClient> tcli(new TcpClient(serverip, serverport));
    tcli->initClient();
    tcli->start();
    return 0;
}

如上就是TCP套接字创建的整体流程

上述TCP服务端TcpServer.hpp整体代码如下👇

#pragma once
#include <iostream>
#include <string>
#include <cstring>
#include <cstdlib>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/wait.h>
#include <signal.h>
#include <pthread.h>
#include "log.hpp"
namespace server
{
    enum
    {
        USAGE_ERR = 1,
        SOCKET_ERR,
        BIND_ERR,
        LISTEN_ERR
    };
    static const uint16_t gport = 8080;
    static const int gbacklog = 5;
    class TcpServer;

    class ThreadData
    {
    };

    class TcpServer
    {
    public:
        TcpServer(const uint16_t &port = gport) : _listensock(-1), _port(port)
        {
        }

        void initServer()
        {
            // 1. 创建socket文件套接字对象
            _listensock = socket(AF_INET, SOCK_STREAM, 0);
            if (_listensock < 0)
            {
                logMessage(FATAL, "create socket error");
                exit(SOCKET_ERR);
            }
            logMessage(NORMAL, "create socket success: %d", _listensock);

            // 2. bind绑定自己的网络信息
            struct sockaddr_in local;
            memset(&local, 0, sizeof(local));
            local.sin_family = AF_INET;
            local.sin_port = htons(_port);
            local.sin_addr.s_addr = INADDR_ANY;
            if (bind(_listensock, (struct sockaddr *)&local, sizeof(local)) < 0)
            {
                logMessage(FATAL, "bind socket error");
                exit(BIND_ERR);
            }
            logMessage(NORMAL, "bind socket success");

            // 3. 设置socket 为监听状态
            if (listen(_listensock, gbacklog) < 0)
            {
                logMessage(FATAL, "listen socket error");
                exit(LISTEN_ERR);
            }
            logMessage(NORMAL, "listen socket success");
        }

        void start()
        {
            for (;;)
            {
                // 4. server 获取新链接
                // sock, 和client进行通信的fd
                struct sockaddr_in peer;
                socklen_t len = sizeof(peer);
                int sock = accept(_listensock, (struct sockaddr *)&peer, &len);
                if (sock < 0)
                {
                    logMessage(ERROR, "accept error, next");
                    continue;
                }
                logMessage(NORMAL, "accept a new link success, get new sock: %d", sock);
                cout << "sock: " << sock << endl;
                serviceIO(sock);
                close(sock);
            }
        }

        void serviceIO(int sock)
        {
            char buffer[1024];
            while (true)
            {
                ssize_t n = read(sock, buffer, sizeof(buffer) - 1);
                if (n > 0)
                {
                    buffer[n] = 0;
                    std::cout << "recv message: " << buffer << std::endl;

                    std::string outbuffer = buffer;
                    outbuffer += " server[echo]";
                    write(sock, outbuffer.c_str(), outbuffer.size());
                }
                else if (n == 0)
                {
                    logMessage(NORMAL, "client quit, me too!");
                    break;
                }
            }
        }

        ~TcpServer()
        {
        }

    private:
        int _listensock;
        uint16_t _port;
    };
}

TCP客户端处理

• 多进程版本处理

上面的是单进程版本，要想实现多进程，我们只需要改造TcpServer.hpp即可：

namespace server
{
    enum
    {
        USAGE_ERR = 1,
        SOCKET_ERR,
        BIND_ERR,
        LISTEN_ERR
    };
    static const uint16_t gport = 8080;
    static const int gbacklog = 5;
    class TcpServer
    {
    public:
        TcpServer(const uint16_t &port = gport) : _listensock(-1), _port(port)
        {
        }

        void initServer()
        {
            // 1. 创建socket文件套接字对象
            _listensock = socket(AF_INET, SOCK_STREAM, 0);
            if (_listensock < 0)
            {
                logMessage(FATAL, "create socket error");
                exit(SOCKET_ERR);
            }
            logMessage(NORMAL, "create socket success: %d", _listensock);

            // 2. bind绑定自己的网络信息
            struct sockaddr_in local;
            memset(&local, 0, sizeof(local));
            local.sin_family = AF_INET;
            local.sin_port = htons(_port);
            local.sin_addr.s_addr = INADDR_ANY;
            if (bind(_listensock, (struct sockaddr *)&local, sizeof(local)) < 0)
            {
                logMessage(FATAL, "bind socket error");
                exit(BIND_ERR);
            }
            logMessage(NORMAL, "bind socket success");

            // 3. 设置socket 为监听状态
            if (listen(_listensock, gbacklog) < 0)
            {
                logMessage(FATAL, "listen socket error");
                exit(LISTEN_ERR);
            }
            logMessage(NORMAL, "listen socket success");
        }

        void start()
        {
            for (;;)
            {
                // 4. server 获取新链接
                // sock, 和client进行通信的fd
                struct sockaddr_in peer;
                socklen_t len = sizeof(peer);
                int sock = accept(_listensock, (struct sockaddr *)&peer, &len);
                if (sock < 0)
                {
                    logMessage(ERROR, "accept error, next");
                    continue;
                }
                logMessage(NORMAL, "accept a new link success, get new sock: %d", sock);
                cout << "sock: " << sock << endl;

                pid_t id = fork();
                if (id == 0) // child
                {
                    close(_listensock);
                    if(fork()>0) exit(0);
                    serviceIO(sock);
                    close(sock);
                    exit(0);
                }
                close(sock);

                //father
                pid_t ret = waitpid(id, nullptr, 0);
                if(ret>0)
                {
                    std::cout << "waitsuccess: " << ret << std::endl;
                }
            }
        }

        void serviceIO(int sock)
        {
            char buffer[1024];
            while (true)
            {
                ssize_t n = read(sock, buffer, sizeof(buffer) - 1);
                if (n > 0)
                {
                    buffer[n] = 0;
                    std::cout << "recv message: " << buffer << std::endl;

                    std::string outbuffer = buffer;
                    outbuffer += " server[echo]";
                    write(sock, outbuffer.c_str(), outbuffer.size());
                }
                else if (n == 0)
                {
                    logMessage(NORMAL, "client quit, me too!");
                    break;
                }
            }
        }

        ~TcpServer()
        {
        }

    private:
        int _listensock;
        uint16_t _port;
    };
}

进程创建的理解：

利用fork创建子进程，id==0时是子进程，此时关闭子进程的监听sock，即close(_listensock)（注意：虽然后续代码会让子进程退出，最好还是close一下）;对于if(fork()>0)此时由子进程去创建进程，创建出来的进程，我们为了方便描述，称为孙子进程，如果fork()>0,说明是父进程，也就是此时我们的子进程，让子进程退出，父进程在外部就不用阻塞等待子进程退出了，而我们的孙子进程成为孤儿进程，会被1号进程领养，无需关心。
孙子进程close(sock)，关闭s使用完sock文件描述符,防止泄漏（后续代码是退出，最好还是close一下）。父进程close(sock),关闭通信的sock,父进程与顺子进程都有，父进程关闭，文件描述符引用计数–，直到孙子进程退出，fd才减为0.关闭。父进程提前关闭并不会影响孙子进程。父进程如果不关会造成文件描述符泄漏，最后等待采用阻塞等待

• 多线程版本处理

对于一个进程中的所有线程，它们共享相同的文件描述符表，所以对于一个线程所对应的fd在使用完毕之后我们需要对其进行close关闭：

namespace server
{
    enum
    {
        USAGE_ERR = 1,
        SOCKET_ERR,
        BIND_ERR,
        LISTEN_ERR
    };
    static const uint16_t gport = 8080;
    static const int gbacklog = 5;
    class TcpServer;

    class ThreadData
    {
    public:
        ThreadData(TcpServer *self, int sock) : _self(self), _sock(sock)
        {
        }

    public:
        TcpServer *_self;
        int _sock;
    };

    class TcpServer
    {
    public:
        TcpServer(const uint16_t &port = gport) : _listensock(-1), _port(port)
        {
        }

        void initServer()
        {
            // 1. 创建socket文件套接字对象
            _listensock = socket(AF_INET, SOCK_STREAM, 0);
            if (_listensock < 0)
            {
                logMessage(FATAL, "create socket error");
                exit(SOCKET_ERR);
            }
            logMessage(NORMAL, "create socket success: %d", _listensock);

            // 2. bind绑定自己的网络信息
            struct sockaddr_in local;
            memset(&local, 0, sizeof(local));
            local.sin_family = AF_INET;
            local.sin_port = htons(_port);
            local.sin_addr.s_addr = INADDR_ANY;
            if (bind(_listensock, (struct sockaddr *)&local, sizeof(local)) < 0)
            {
                logMessage(FATAL, "bind socket error");
                exit(BIND_ERR);
            }
            logMessage(NORMAL, "bind socket success");

            // 3. 设置socket 为监听状态
            if (listen(_listensock, gbacklog) < 0) // 第二个参数backlog后面在填这个坑
            {
                logMessage(FATAL, "listen socket error");
                exit(LISTEN_ERR);
            }
            logMessage(NORMAL, "listen socket success");
        }

        void start()
        {
            for (;;)
            {
                // 4. server 获取新链接
                // sock, 和client进行通信的fd
                struct sockaddr_in peer;
                socklen_t len = sizeof(peer);
                int sock = accept(_listensock, (struct sockaddr *)&peer, &len);
                if (sock < 0)
                {
                    logMessage(ERROR, "accept error, next");
                    continue;
                }
                logMessage(NORMAL, "accept a new link success, get new sock: %d", sock);
                cout << "sock: " << sock << endl;

                pthread_t tid;
                ThreadData *td = new ThreadData(this, sock);
                pthread_create(&tid, nullptr, threadRoutine, td);
                pthread_join(tid, nullptr);
            }
        }
        static void *threadRoutine(void *args)
        {
            pthread_detach(pthread_self());
            ThreadData *td = static_cast<ThreadData *>(args);
            td->_self->serviceIO(td->_sock);
            close(td->_sock);
            delete td;
            return nullptr;
        }

        void serviceIO(int sock)
        {
            char buffer[1024];
            while (true)
            {
                ssize_t n = read(sock, buffer, sizeof(buffer) - 1);
                if (n > 0)
                {
                    buffer[n] = 0;
                    std::cout << "recv message: " << buffer << std::endl;

                    std::string outbuffer = buffer;
                    outbuffer += " server[echo]";
                    write(sock, outbuffer.c_str(), outbuffer.size());
                }
                else if (n == 0)
                {
                    logMessage(NORMAL, "client quit, me too!");
                    break;
                }
            }
        }

        ~TcpServer()
        {
        }

    private:
        int _listensock;
        uint16_t _port;
    };
}

• 线程池版本处理

Tcpserver.hpp

#include "log.hpp"
#include "Task.hpp"
#include "ThreadPool.hpp"
namespace server
{
    static const uint16_t gport = 8080;
    static const int gbacklog = 5;
    enum
    {
        USAGE_ERR = 1,
        SOCKET_ERR,
        BIND_ERR,
        LISTEN_ERR
    };

    class TcpServer;
    class ThreadData
    {
    public:
        ThreadData(TcpServer *self, int sock)
            : _self(self), _sock(sock)
        {
        }

    public:
        TcpServer *_self;
        int _sock;
    };

    class TcpServer
    {
    public:
        TcpServer(const uint16_t port = gport)
            : _port(port), _listensock(-1)
        {
        }

        void initServer()
        {
            // 1.创建socket文件套接字对象
            _listensock = socket(AF_INET, SOCK_STREAM, 0);
            if (_listensock < 0)
            {
                logMessage(FATAL, "create socket error");
                exit(SOCKET_ERR);
            }
            logMessage(NORMAL, "create socket success : %d",_listensock);

            // 2.绑定自己的网络信息
            struct sockaddr_in local;
            memset(&local, 0, sizeof local);
            local.sin_family = AF_INET;
            local.sin_port = htons(_port);
            local.sin_addr.s_addr = INADDR_ANY;
            if (bind(_listensock, (struct sockaddr *)&local, sizeof local) < 0)
            {
                logMessage(FATAL, "bind socket error");
                exit(BIND_ERR);
            }
            logMessage(NORMAL, "bind socket success");

            // 3.设置socket为监听状态，面向链接
            if (listen(_listensock, gbacklog) < 0)
            {
                logMessage(FATAL, "listen socket error");
                exit(LISTEN_ERR);
            }
            logMessage(NORMAL, "liseten socket success");
        }

        void start()
        {
            // 线程池的初始化
            ThreadPool<Task>::getInstance()->run();
            logMessage(NORMAL,"Thread init success");
            // signal(SIGCHLD,SIG_IGN);
            for (;;)
            {
                // server获取新链接
                struct sockaddr_in peer;
                socklen_t len = sizeof(peer);
                // sock:和client进程通信的fd
                int sock = accept(_listensock, (struct sockaddr *)&peer, &len);
                if (sock < 0)
                {
                    logMessage(FATAL, "accept error,next");
                    continue;
                }
                logMessage(NORMAL, "accept a new link success,get new sock:%d",sock);
                std::cout << "sock: " << sock << std::endl;
       
                //线程池
                ThreadPool<Task>::getInstance()->Push(Task(sock,serverIO));
            }
        }
        ~TcpServer()
        {
        }

    private:
        int _listensock; 
        uint16_t _port;
    };
}

Task.hpp

#pragma once
#include <iostream>
#include <functional>

void serverIO(int sock)
{
    char buffer[1024];
    while (true)
    {
        ssize_t n = read(sock, buffer, sizeof(buffer) - 1);
        if (n > 0)
        {
            buffer[n] = 0;
            std::cout << "Server message: " << buffer << std::endl;

            std::string outbuffer = buffer;
            outbuffer += "server[echo]";
            write(sock, outbuffer.c_str(), outbuffer.size());
        }
        else if (n == 0)
        {
            logMessage(NORMAL, "client quit,mee too");
            break;
        }
    }
}
class Task
{
    using func_t = std::function<void(int)>;

public:
    Task() {}

    Task(int sock,func_t func)
        : _sock(sock), _callback(func)
    {
    }

    void operator()()
    {
        _callback(_sock);
    }
private:
    int _sock;
    func_t _callback;
};

Threadpool.hpp

#pragma once
#include "Thread.hpp"
#include "LockGuard.hpp"
#include "log.hpp"
#include <vector>
#include <queue>
#include <pthread.h>
#include <mutex>
#include <unistd.h>
#include <mutex>
using namespace ThreadNs;

const int gnum = 10;

template <class T>
class ThreadPool;

template <class T>
class ThreadData
{
public:
    ThreadPool<T> *threadpool;
    std::string name;

public:
    ThreadData(ThreadPool<T> *tp, const std::string &n) : threadpool(tp), name(n)
    {
    }
};
template <class T>
class ThreadPool
{
private:
    static void *handlerTask(void *args)
    {
        ThreadData<T> *td = (ThreadData<T> *)args;
        while (true)
        {
            T t;
            {
                LockGuard lockguard(td->threadpool->mutex());

                while (td->threadpool->isQueueEmpty())
                {
                    td->threadpool->threadWait();
                }
                t = td->threadpool->pop(); // pop的本质是将任务从公共队列中拿到当前线程独立的栈中
            }
            t();
        }
        delete td;
        return nullptr;
    }

    ThreadPool(const int &num = gnum) : _num(num)
    {
        pthread_mutex_init(&_mutex, nullptr);
        pthread_cond_init(&_cond, nullptr);
        for (int i = 0; i < _num; i++)
        {
            _threads.push_back(new Thread());
        }
    }

    void operator=(const ThreadPool &) = delete;
    ThreadPool(const ThreadPool &) = delete;

public:
    void lockQueue() { pthread_mutex_lock(&_mutex); }
    void unlockQueue() { pthread_mutex_unlock(&_mutex); }
    bool isQueueEmpty() { return _task_queue.empty(); }
    void threadWait() { pthread_cond_wait(&_cond, &_mutex); }
    T pop()
    {
        T t = _task_queue.front();
        _task_queue.pop();
        return t;
    }

    pthread_mutex_t *mutex()
    {
        return &_mutex;
    }

public:
    void run()
    {
        for (const auto &t : _threads)
        {
            ThreadData<T> *td = new ThreadData<T>(this, t->threadname());
            t->start(handlerTask, td);
            //std::cout << t->threadname() << "start..." << std::endl;
            logMessage(DEBUG,"%s start ...",t->threadname().c_str());
        }
    }
    void Push(const T &in)
    {
        LockGuard lockguard(&_mutex);
        _task_queue.push(in);
        pthread_cond_signal(&_cond);
    }
    ~ThreadPool()
    {
        pthread_mutex_destroy(&_mutex);
        pthread_cond_destroy(&_cond);
        for (const auto &t : _threads)
            delete t;
    }
    static ThreadPool<T> *getInstance()
    {
        if (nullptr == tp)
        {

            _singlock.lock();
            if (nullptr == tp)
            {
                tp = new ThreadPool<T>();
            }
            _singlock.unlock();
            return tp;
        }
    }
private:
    int _num;
    std::vector<Thread *> _threads;
    std::queue<T> _task_queue;
    pthread_mutex_t _mutex;
    pthread_cond_t _cond;

    static ThreadPool<T> *tp;
    static std::mutex _singlock;
};
template <class T>
ThreadPool<T> *ThreadPool<T>::tp = nullptr;
template <class T>
std::mutex ThreadPool<T>::_singlock;

守护进程

守护进程：服务器要做到一点：服务器启动之后，不在受到用户的登录退出影响，服务器可以自定义运行，不受用户登录注销影响的进程是守护进程

&：让一个命令在后台运行

jobs命令用于显示当前shell会话中的活动作业（jobs），包括前台作业和后台作业。

任务由进程组完成

从哪里看出是同一个会话：SID

现在，把作业放在前台。fg 2:既我们把上面的2号作业放在前台

ctrl+z:

一个任务在前台如果暂停了会立马放在后台：

此时我们的2号任务是stopped状态的，我们让它启动起来：bg 2:

fg:放前台然后ctrl+z停止，bg:启动，作业是可以互相前后端转化的：

把任务提到前台后，命令行解释器就不会做响应了：这是因为当前整个会话中只能有一个前台任务，退出时任务都会被清掉，这样的任务是可能受到用户登录和注销的影响的！

要想不受影响，我们要独立出来，自成会话，自成进程组，和终端设备无关。这就是守护进程，可以一直运行，除非未来不让它运行了。

守护进程化

系统提供了接口。守护进程的原理以及代码：

daemon.hpp: setsid：形成一个新的进程组，创建一个新的会话，不能随便掉，调用这个函数的进程不能是组长

#pragma once
#include <unistd.h>
#include <signal.h>
#include <cstdlib>
#include <cassert>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#define DEV "/dev/null"//数据黑洞，写入的数据会被吃掉，读取数据什么都读不到

void daemonSelf(const char *currPath = nullptr)
{
    // 1. 让调用进程忽略掉异常的信号
    signal(SIGPIPE, SIG_IGN);

    // 2. 如何让自己不是组长，setsid
    if (fork() > 0)
        exit(0);
    // 子进程 -- 守护进程，精灵进程，本质就是孤儿进程的一种！
    pid_t n = setsid();
    assert(n != -1);

    // 3. 守护进程是脱离终端的，关闭或者重定向以前进程默认打开的文件
    int fd = open(DEV, O_RDWR);
    if(fd >= 0)
    {
        dup2(fd, 0);
        dup2(fd, 1);
        dup2(fd, 2);

        close(fd);
    }
    else
    {
        close(0);
        close(1);
        close(2);
    }

    // 4. 可选：进程执行路径发生更改

    if(currPath) chdir(currPath);

直接在TcpServer.cc文件中进行调用即可：

#include "tcpServer.hpp"
#include "memory"
#include "daemon.hpp"
using namespace Server;
static void Usage(std::string proc)
{
    std::cout<<"Usage:\n\t"<<proc<<"serverPort\n\n";
}

int main(int argc,char* argv[])
{
    if(argc!=2)//判断外部传入的参数是否为2
    {
        Usage(argv[0]);
        exit(USAGE_ERR);
    }
    uint16_t port=std::stoi(argv[1]);
    std::unique_ptr<TcpServer> tsvr(new TcpServer(port));
    tsvr->InitServer();
    daemonSele();//守护进程化，让这个独立的孤儿进程去启动服务器
    tsvr->Start();
    return 0;
}