TCP 网络程序

和刚才 UDP 类似. 实现一个简单的英译汉的功能。

TCP是面向字节流的可靠传输，如同前文的管道流，只要是流，它的操作就是文件的写出与读入。

TCP socket API 详解

下面介绍程序中用到的 socket API,这些函数都在 sys/socket.h 中。

socket()

bind()

服务器程序所监听的网络地址和端口号通常是固定不变的,客户端程序得知服务器程序的地址和端口号后就可以向服务器发起连接; 服务器需要调用 bind 绑定一个固定的网络地址和端口号;

•bind()成功返回 0,失败返回-1。

• bind()的作用是将参数 sockfd 和 myaddr 绑定在一起, 使 sockfd 这个用于网络通讯的文件描述符监听 myaddr 所描述的地址和端口号;

• 前面讲过,struct sockaddr *是一个通用指针类型,myaddr 参数实际上可以接受多种协议的sockaddr 结构体,而它们的长度各不相同,所以需要第三个参数 addrlen指定结构体的长度;

listen()

accept()

返回一个有实际服务客服端的文件描述符，listenfd为socket()创建返回的负责监听的套接字，它没有实际的服务。

connect()

V123 - Echo Server

共性代码：

Makefile

.PHONY:all
all:tcpserver tcpclienttcpserver:TcpServerMain.ccg++ -o $@ $^ -std=c++14 -lpthread
tcpclient:TcpClientMain.ccg++ -o $@ $^ -std=c++14.PHONY:clean
clean:rm -rf tcpserver tcpclient

LockGuard.hpp(锁的封装)

#pragma once#include <pthread.h>class LockGuard
{
public:LockGuard(pthread_mutex_t *mutex):_mutex(mutex){pthread_mutex_lock(_mutex);}~LockGuard(){pthread_mutex_unlock(_mutex);}
private:pthread_mutex_t *_mutex;
};

Thread.hpp(单线程封装)

#pragma once
#include <iostream>
#include <string>
#include <functional>
#include <pthread.h>namespace ThreadMoudle
{// 线程要执行的方法，后面我们随时调整// typedef void (*func_t)(ThreadData *td); // 函数指针类型// typedef std::function<void()> func_t;using func_t = std::function<void(const std::string&)>;class Thread{public:void Excute(){_isrunning = true;_func(_name);_isrunning = false;}public:Thread(const std::string &name, func_t func):_name(name), _func(func){}static void *ThreadRoutine(void *args) // 新线程都会执行该方法！{Thread *self = static_cast<Thread*>(args); // 获得了当前对象self->Excute();return nullptr;}bool Start(){int n = ::pthread_create(&_tid, nullptr, ThreadRoutine, this);if(n != 0) return false;return true;}std::string Status(){if(_isrunning) return "running";else return "sleep";}void Stop(){if(_isrunning){::pthread_cancel(_tid);_isrunning = false;}}void Join(){::pthread_join(_tid, nullptr);}std::string Name(){return _name;}~Thread(){}private:std::string _name;pthread_t _tid;bool _isrunning;func_t _func; // 线程要执行的回调函数};
} // namespace ThreadModle

ThreadPool.hpp

#pragma once#include <iostream>
#include <unistd.h>
#include <string>
#include <vector>
#include <queue>
#include <functional>
#include "Thread.hpp"
#include "Log.hpp"
#include "LockGuard.hpp"using namespace ThreadMoudle;
using namespace log_ns;static const int gdefaultnum = 10;void test()
{while (true){std::cout << "hello world" << std::endl;sleep(1);}
}template <typename T>
class ThreadPool
{
private:void LockQueue(){pthread_mutex_lock(&_mutex);}void UnlockQueue(){pthread_mutex_unlock(&_mutex);}void Wakeup(){pthread_cond_signal(&_cond);}void WakeupAll(){pthread_cond_broadcast(&_cond);}void Sleep(){pthread_cond_wait(&_cond, &_mutex);}bool IsEmpty(){return _task_queue.empty();}void HandlerTask(const std::string &name) // this{while (true){// 取任务LockQueue();while (IsEmpty() && _isrunning){_sleep_thread_num++;LOG(INFO, "%s thread sleep begin!\n", name.c_str());Sleep();LOG(INFO, "%s thread wakeup!\n", name.c_str());_sleep_thread_num--;}// 判定一种情况if (IsEmpty() && !_isrunning){UnlockQueue();LOG(INFO, "%s thread quit\n", name.c_str());break;}// 有任务T t = _task_queue.front();_task_queue.pop();UnlockQueue();// 处理任务t(); // 处理任务，此处不用/不能在临界区中处理// std::cout << name << ": " << t.result() << std::endl;// LOG(DEBUG, "hander task done, task is : %s\n", t.result().c_str());}}void Init(){func_t func = std::bind(&ThreadPool::HandlerTask, this, std::placeholders::_1);for (int i = 0; i < _thread_num; i++){std::string threadname = "thread-" + std::to_string(i + 1);_threads.emplace_back(threadname, func);LOG(DEBUG, "construct thread %s done, init success\n", threadname.c_str());}}void Start(){_isrunning = true;for (auto &thread : _threads){LOG(DEBUG, "start thread %s done.\n", thread.Name().c_str());thread.Start();}}ThreadPool(int thread_num = gdefaultnum): _thread_num(thread_num), _isrunning(false), _sleep_thread_num(0){pthread_mutex_init(&_mutex, nullptr);pthread_cond_init(&_cond, nullptr);}ThreadPool(const ThreadPool<T> &) = delete;void operator=(const ThreadPool<T> &) = delete;public:void Stop(){LockQueue();_isrunning = false;WakeupAll();UnlockQueue();LOG(INFO, "Thread Pool Stop Success!\n");}// 如果是多线程获取单例呢？static ThreadPool<T> *GetInstance(){if (_tp == nullptr){LockGuard lockguard(&_sig_mutex);if (_tp == nullptr){LOG(INFO, "create threadpool\n");// thread-1 thread-2 thread-3...._tp = new ThreadPool<T>();_tp->Init();_tp->Start();}else{LOG(INFO, "get threadpool\n");}}return _tp;}void Equeue(const T &in){LockQueue();if (_isrunning){_task_queue.push(in);if (_sleep_thread_num > 0)Wakeup();}UnlockQueue();}~ThreadPool(){pthread_mutex_destroy(&_mutex);pthread_cond_destroy(&_cond);}private:int _thread_num;std::vector<Thread> _threads;std::queue<T> _task_queue;bool _isrunning;int _sleep_thread_num;pthread_mutex_t _mutex;pthread_cond_t _cond;// 单例模式// volatile static ThreadPool<T> *_tp;static ThreadPool<T> *_tp;static pthread_mutex_t _sig_mutex;
};template <typename T>
ThreadPool<T> *ThreadPool<T>::_tp = nullptr;
template <typename T>
pthread_mutex_t ThreadPool<T>::_sig_mutex = PTHREAD_MUTEX_INITIALIZER;

Log.hpp(日志)

#pragma once#include <iostream>
#include <sys/types.h>
#include <unistd.h>
#include <ctime>
#include <cstdarg>
#include <fstream>
#include <cstring>
#include <pthread.h>
#include "LockGuard.hpp"namespace log_ns
{enum{DEBUG = 1,INFO,WARNING,ERROR,FATAL};std::string LevelToString(int level){switch (level){case DEBUG:return "DEBUG";case INFO:return "INFO";case WARNING:return "WARNING";case ERROR:return "ERROR";case FATAL:return "FATAL";default:return "UNKNOWN";}}std::string GetCurrTime(){time_t now = time(nullptr);struct tm *curr_time = localtime(&now);char buffer[128];snprintf(buffer, sizeof(buffer), "%d-%02d-%02d %02d:%02d:%02d",curr_time->tm_year + 1900,curr_time->tm_mon + 1,curr_time->tm_mday,curr_time->tm_hour,curr_time->tm_min,curr_time->tm_sec);return buffer;}class logmessage{public:std::string _level;pid_t _id;std::string _filename;int _filenumber;std::string _curr_time;std::string _message_info;};#define SCREEN_TYPE 1
#define FILE_TYPE 2const std::string glogfile = "./log.txt";pthread_mutex_t glock = PTHREAD_MUTEX_INITIALIZER;// log.logMessage("", 12, INFO, "this is a %d message ,%f, %s hellwrodl", x, , , );class Log{public:Log(const std::string &logfile = glogfile) : _logfile(logfile), _type(SCREEN_TYPE){}void Enable(int type){_type = type;}void FlushLogToScreen(const logmessage &lg){printf("[%s][%d][%s][%d][%s] %s",lg._level.c_str(),lg._id,lg._filename.c_str(),lg._filenumber,lg._curr_time.c_str(),lg._message_info.c_str());}void FlushLogToFile(const logmessage &lg){std::ofstream out(_logfile, std::ios::app);if (!out.is_open())return;char logtxt[2048];snprintf(logtxt, sizeof(logtxt), "[%s][%d][%s][%d][%s] %s",lg._level.c_str(),lg._id,lg._filename.c_str(),lg._filenumber,lg._curr_time.c_str(),lg._message_info.c_str());out.write(logtxt, strlen(logtxt));out.close();}void FlushLog(const logmessage &lg){// 加过滤逻辑 --- TODOLockGuard lockguard(&glock);switch (_type){case SCREEN_TYPE:FlushLogToScreen(lg);break;case FILE_TYPE:FlushLogToFile(lg);break;}}void logMessage(std::string filename, int filenumber, int level, const char *format, ...){logmessage lg;lg._level = LevelToString(level);lg._id = getpid();lg._filename = filename;lg._filenumber = filenumber;lg._curr_time = GetCurrTime();va_list ap;va_start(ap, format);char log_info[1024];vsnprintf(log_info, sizeof(log_info), format, ap);va_end(ap);lg._message_info = log_info;// 打印出来日志FlushLog(lg);}~Log(){}private:int _type;std::string _logfile;};Log lg;#define LOG(Level, Format, ...)                                        \do                                                                 \{                                                                  \lg.logMessage(__FILE__, __LINE__, Level, Format, ##__VA_ARGS__); \} while (0)
#define EnableScreen()          \do                          \{                           \lg.Enable(SCREEN_TYPE); \} while (0)
#define EnableFILE()          \do                        \{                         \lg.Enable(FILE_TYPE); \} while (0)
};

正文代码：

InetAddr.hpp

#pragma once#include <iostream>
#include <string>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>class InetAddr
{
private:void ToHost(const struct sockaddr_in &addr){_port = ntohs(addr.sin_port);// _ip = inet_ntoa(addr.sin_addr);char ip_buf[32];// inet_p to n// p: process// n: net// inet_pton(int af, const char *src, void *dst);// inet_pton(AF_INET, ip.c_str(), &addr.sin_addr.s_addr);::inet_ntop(AF_INET, &addr.sin_addr, ip_buf, sizeof(ip_buf));_ip = ip_buf;}public:InetAddr(const struct sockaddr_in &addr):_addr(addr){ToHost(addr);}InetAddr(){}bool operator == (const InetAddr &addr){return (this->_ip == addr._ip && this->_port == addr._port);}std::string Ip(){return _ip;}uint16_t Port(){return _port;}struct sockaddr_in Addr(){return _addr;}std::string AddrStr(){return _ip + ":" + std::to_string(_port);}~InetAddr(){}private:std::string _ip;uint16_t _port;struct sockaddr_in _addr;
};

TcpServer.hpp

#pragma once
#include <iostream>
#include <cstring>
#include <functional>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/wait.h>
#include <pthread.h>
#include "Log.hpp"
#include "InetAddr.hpp"
#include "ThreadPool.hpp"using namespace log_ns;enum
{SOCKET_ERROR = 1,BIND_ERROR,LISTEN_ERR
};const static int gport = 8888;
const static int gsock = -1;
const static int gblcklog = 8;using task_t = std::function<void()>;class TcpServer
{
public:TcpServer(uint16_t port = gport): _port(port),_listensockfd(gsock),_isrunning(false){}void InitServer(){// 1. 创建socket_listensockfd = ::socket(AF_INET, SOCK_STREAM, 0);if (_listensockfd < 0){LOG(FATAL, "socket create error\n");exit(SOCKET_ERROR);}LOG(INFO, "socket create success, sockfd: %d\n", _listensockfd); // 3struct 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;// 2. bind sockfd 和 Socket addrif (::bind(_listensockfd, (struct sockaddr *)&local, sizeof(local)) < 0){LOG(FATAL, "bind error\n");exit(BIND_ERROR);}LOG(INFO, "bind success\n");// 3. 因为tcp是面向连接的，tcp需要未来不断地能够做到获取连接if (::listen(_listensockfd, gblcklog) < 0){LOG(FATAL, "listen error\n");exit(LISTEN_ERR);}LOG(INFO, "listen success\n");}class ThreadData{public:int _sockfd;TcpServer *_self;InetAddr _addr;public:ThreadData(int sockfd, TcpServer *self, const InetAddr &addr):_sockfd(sockfd), _self(self), _addr(addr){}};void Loop(){// signal(SIGCHLD, SIG_IGN);_isrunning = true;while (_isrunning){struct sockaddr_in client;socklen_t len = sizeof(client);// 4. 获取新连接int sockfd = ::accept(_listensockfd, (struct sockaddr *)&client, &len);if (sockfd < 0){LOG(WARNING, "accept error\n");continue;}InetAddr addr(client);LOG(INFO, "get a new link, client info : %s, sockfd is : %d\n", addr.AddrStr().c_str(), sockfd);// version 0 --- 不靠谱版本// Service(sockfd, addr);// version 1 --- 多进程版本// pid_t id = fork();// if (id == 0)// {//     // child//     ::close(_listensockfd); // 建议！//     if(fork() > 0) exit(0);//     Service(sockfd, addr);//     exit(0);// }// // father// ::close(sockfd);// int n = waitpid(id, nullptr, 0);// if (n > 0)// {//     LOG(INFO, "wait child success.\n");// }// version 2 ---- 多线程版本 --- 不能关闭fd了，也不需要了// pthread_t tid;// ThreadData *td = new ThreadData(sockfd, this, addr);// pthread_create(&tid, nullptr, Execute, td); // 新线程进行分离// version 3 ---- 线程池版本 int sockfd, InetAddr addrtask_t t = std::bind(&TcpServer::Service, this, sockfd, addr);ThreadPool<task_t>::GetInstance()->Equeue(t);}_isrunning = false;}static void *Execute(void *args){pthread_detach(pthread_self());ThreadData *td = static_cast<ThreadData *>(args);td->_self->Service(td->_sockfd, td->_addr);delete td;return nullptr;}void Service(int sockfd, InetAddr addr){// 长服务while (true){char inbuffer[1024]; // 当做字符串ssize_t n = ::read(sockfd, inbuffer, sizeof(inbuffer) - 1);if (n > 0){inbuffer[n] = 0;LOG(INFO, "get message from client %s, message: %s\n", addr.AddrStr().c_str(), inbuffer);std::string echo_string = "[server echo] #";echo_string += inbuffer;write(sockfd, echo_string.c_str(), echo_string.size());}else if (n == 0){LOG(INFO, "client %s quit\n", addr.AddrStr().c_str());break;}else{LOG(ERROR, "read error: %s\n", addr.AddrStr().c_str());break;}}::close(sockfd);}~TcpServer() {}private:uint16_t _port;int _listensockfd;bool _isrunning;
};

v1多进程版本：

子进程文件描述符表是父进程的拷贝，但是父进程和子进程只需要完成各自的任务即可，所以需要断开对方任务的文件描述符。红色虚线为断开的文件描述符。

这样可以避免文件描述符泄露。

上文代码创建了孙子进程，子进程把任务交给孙子进程，让父进程回收了。孙子进程就变成孤儿进程就防止了僵尸进程。

V2多线程版本：

父子线程共用一个文件描述符表。子线程使用完一定要关闭文件描述符。

创建子线程，然后实现分离。这样与父线程无关了。就不需要回收不会导致僵尸线程了。

V3线程池版本：

将任务交给线程池。

TcpServerMain.cc

#include "TcpServer.hpp"#include <memory>// ./tcpserver 8888
int main(int argc, char *argv[])
{if(argc != 2){std::cerr << "Usage: " << argv[0] << " local-port" << std::endl;exit(0);}uint16_t port = std::stoi(argv[1]);std::unique_ptr<TcpServer> tsvr = std::make_unique<TcpServer>(port);tsvr->InitServer();tsvr->Loop();return 0;
}

TcpClientMain.cc

#include <iostream>
#include <cstring>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>// ./tcpclient server-ip server-port
int main(int argc, char *argv[])
{if (argc != 3){std::cerr << "Usage: " << argv[0] << " server-ip server-port" << std::endl;exit(0);}std::string serverip = argv[1];uint16_t serverport = std::stoi(argv[2]);// 1. 创建socketint sockfd = ::socket(AF_INET, SOCK_STREAM, 0);if (sockfd < 0){std::cerr << "create socket error" << std::endl;exit(1);}// 注意：不需要显示的bind，但是一定要有自己的IP和port，所以需要隐式的bind，OS会自动bind sockfd，用自己的IP和随机端口号// 什么时候进行自动bind？If the connection or binding succeedsstruct sockaddr_in server;memset(&server, 0, sizeof(server));server.sin_family = AF_INET;server.sin_port = htons(serverport);::inet_pton(AF_INET, serverip.c_str(), &server.sin_addr);int n = ::connect(sockfd, (struct sockaddr *)&server, sizeof(server));if (n < 0){std::cerr << "connect socket error" << std::endl;exit(2);}while(true){std::string message;std::cout << "Enter #";std::getline(std::cin, message);write(sockfd, message.c_str(), message.size());char echo_buffer[1024];n = read(sockfd, echo_buffer, sizeof(echo_buffer));if(n > 0){echo_buffer[n] = 0;std::cout << echo_buffer << std::endl;}else{break;}}::close(sockfd);return 0;
}

V4-多线程远程命令执行

InetAddr.hpp

#pragma once#include <iostream>
#include <string>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>class InetAddr
{
private:void ToHost(const struct sockaddr_in &addr){_port = ntohs(addr.sin_port);// _ip = inet_ntoa(addr.sin_addr);char ip_buf[32];// inet_p to n// p: process// n: net// inet_pton(int af, const char *src, void *dst);// inet_pton(AF_INET, ip.c_str(), &addr.sin_addr.s_addr);::inet_ntop(AF_INET, &addr.sin_addr, ip_buf, sizeof(ip_buf));_ip = ip_buf;}public:InetAddr(const struct sockaddr_in &addr):_addr(addr){ToHost(addr);}InetAddr(){}bool operator == (const InetAddr &addr){return (this->_ip == addr._ip && this->_port == addr._port);}std::string Ip(){return _ip;}uint16_t Port(){return _port;}struct sockaddr_in Addr(){return _addr;}std::string AddrStr(){return _ip + ":" + std::to_string(_port);}~InetAddr(){}private:std::string _ip;uint16_t _port;struct sockaddr_in _addr;
};

TcpServer.hpp

#pragma once
#include <iostream>
#include <cstring>
#include <functional>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/wait.h>
#include <pthread.h>
#include "Log.hpp"
#include "InetAddr.hpp"using namespace log_ns;enum
{SOCKET_ERROR = 1,BIND_ERROR,LISTEN_ERR
};const static int gport = 8888;
const static int gsock = -1;
const static int gblcklog = 8;using command_service_t = std::function<void(int sockfd, InetAddr addr)>;class TcpServer
{
public:TcpServer(command_service_t service, uint16_t port = gport): _port(port),_listensockfd(gsock),_isrunning(false),_service(service){}void InitServer(){// 1. 创建socket_listensockfd = ::socket(AF_INET, SOCK_STREAM, 0);if (_listensockfd < 0){LOG(FATAL, "socket create error\n");exit(SOCKET_ERROR);}LOG(INFO, "socket create success, sockfd: %d\n", _listensockfd); // 3struct 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;// 2. bind sockfd 和 Socket addrif (::bind(_listensockfd, (struct sockaddr *)&local, sizeof(local)) < 0){LOG(FATAL, "bind error\n");exit(BIND_ERROR);}LOG(INFO, "bind success\n");// 3. 因为tcp是面向连接的，tcp需要未来不断地能够做到获取连接if (::listen(_listensockfd, gblcklog) < 0){LOG(FATAL, "listen error\n");exit(LISTEN_ERR);}LOG(INFO, "listen success\n");}class ThreadData{public:int _sockfd;TcpServer *_self;InetAddr _addr;public:ThreadData(int sockfd, TcpServer *self, const InetAddr &addr):_sockfd(sockfd), _self(self), _addr(addr){}};void Loop(){// signal(SIGCHLD, SIG_IGN);_isrunning = true;while (_isrunning){struct sockaddr_in client;socklen_t len = sizeof(client);// 4. 获取新连接int sockfd = ::accept(_listensockfd, (struct sockaddr *)&client, &len);if (sockfd < 0){LOG(WARNING, "accept error\n");continue;}InetAddr addr(client);LOG(INFO, "get a new link, client info : %s, sockfd is : %d\n", addr.AddrStr().c_str(), sockfd);// version 2 ---- 多线程版本 --- 不能关闭fd了，也不需要了pthread_t tid;ThreadData *td = new ThreadData(sockfd, this, addr);pthread_create(&tid, nullptr, Execute, td); // 新线程进行分离}_isrunning = false;}static void *Execute(void *args){pthread_detach(pthread_self());ThreadData *td = static_cast<ThreadData *>(args);td->_self->_service(td->_sockfd, td->_addr);::close(td->_sockfd);delete td;return nullptr;}// void Service(int sockfd, InetAddr addr)// {//     // 长服务//     while (true)//     {//         char inbuffer[1024]; // 当做字符串//         ssize_t n = ::read(sockfd, inbuffer, sizeof(inbuffer) - 1);//         if (n > 0)//         {//             inbuffer[n] = 0;//             LOG(INFO, "get message from client %s, message: %s\n", addr.AddrStr().c_str(), inbuffer);//             std::string echo_string = "[server echo] #";//             echo_string += inbuffer;//             write(sockfd, echo_string.c_str(), echo_string.size());//         }//         else if (n == 0)//         {//             LOG(INFO, "client %s quit\n", addr.AddrStr().c_str());//             break;//         }//         else//         {//             LOG(ERROR, "read error: %s\n", addr.AddrStr().c_str());//             break;//         }//     }// }~TcpServer() {}private:uint16_t _port;int _listensockfd;bool _isrunning;command_service_t _service;
};

Command.hpp

#pragma once#include <iostream>
#include <string>
#include <cstring>
#include <cstdio>
#include <set>
#include "Log.hpp"
#include "InetAddr.hpp"class Command
{
public:Command(){// 白名单_safe_command.insert("ls");_safe_command.insert("touch"); // touch filename_safe_command.insert("pwd");_safe_command.insert("whoami");_safe_command.insert("which"); // which pwd}~Command() {}// ls;rm -rf /bool SafeCheck(const std::string &cmdstr){for(auto &cmd : _safe_command){if(strncmp(cmd.c_str(), cmdstr.c_str(), cmd.size()) == 0){return true;}}return false;}std::string Excute(const std::string &cmdstr){if(!SafeCheck(cmdstr)){return "unsafe";}std::string result;FILE *fp = popen(cmdstr.c_str(), "r");if(fp){char line[1024];while(fgets(line, sizeof(line), fp)){result += line;}return result.empty() ? "success" : result;}return "execute error";}void HandlerCommand(int sockfd, InetAddr addr){// 我们把他当做一个长服务while (true){char commandbuf[1024]; // 当做字符串, ls -a -l -> os --> ls -ssize_t n = ::recv(sockfd, commandbuf, sizeof(commandbuf) - 1, 0); // TODOif (n > 0){commandbuf[n] = 0;LOG(INFO, "get command from client %s, command: %s\n", addr.AddrStr().c_str(), commandbuf);std::string result = Excute(commandbuf);::send(sockfd, result.c_str(), result.size(), 0);}else if (n == 0){LOG(INFO, "client %s quit\n", addr.AddrStr().c_str());break;}else{LOG(ERROR, "read error: %s\n", addr.AddrStr().c_str());break;}}}
private:std::set<std::string> _safe_command;
};

FILE* popen(const char* command,const char* type);

创建一个子进程和管道，让子进程执行命令，结果写入管道。主进程去读取管道内容返还给文件指针。

TcpServerMain.cc

#include "TcpServer.hpp"
#include "Command.hpp"#include <memory>// ./tcpserver 8888
int main(int argc, char *argv[])
{if (argc != 2){std::cerr << "Usage: " << argv[0] << " local-port" << std::endl;exit(0);}uint16_t port = std::stoi(argv[1]);Command cmdservice;std::unique_ptr<TcpServer> tsvr = std::make_unique<TcpServer>(std::bind(&Command::HandlerCommand,&cmdservice, std::placeholders::_1,std::placeholders::_2),port);tsvr->InitServer();tsvr->Loop();return 0;
}

TcpClientMain.cc

#include <iostream>
#include <cstring>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>// ./tcpclient server-ip server-port
int main(int argc, char *argv[])
{if (argc != 3){std::cerr << "Usage: " << argv[0] << " server-ip server-port" << std::endl;exit(0);}std::string serverip = argv[1];uint16_t serverport = std::stoi(argv[2]);// 1. 创建socketint sockfd = ::socket(AF_INET, SOCK_STREAM, 0);if (sockfd < 0){std::cerr << "create socket error" << std::endl;exit(1);}// 注意：不需要显示的bind，但是一定要有自己的IP和port，所以需要隐式的bind，OS会自动bind sockfd，用自己的IP和随机端口号// 什么时候进行自动bind？If the connection or binding succeedsstruct sockaddr_in server;memset(&server, 0, sizeof(server));server.sin_family = AF_INET;server.sin_port = htons(serverport);::inet_pton(AF_INET, serverip.c_str(), &server.sin_addr);int n = ::connect(sockfd, (struct sockaddr *)&server, sizeof(server));if (n < 0){std::cerr << "connect socket error" << std::endl;exit(2);}while(true){std::string message;std::cout << "Enter #";std::getline(std::cin, message);write(sockfd, message.c_str(), message.size());char echo_buffer[1024];n = read(sockfd, echo_buffer, sizeof(echo_buffer));if(n > 0){echo_buffer[n] = 0;std::cout << echo_buffer << std::endl;}else{break;}}::close(sockfd);return 0;
}