#include <iostream>

#include <unistd.h>

#include <cstdlib>

#include <arpa/inet.h>

#include <sys/socket.h>

#include <sys/wait.h>

#include <signal.h>

#include <string>

using namespace std;

const int BUFFER_SIZE = ;

void read_child_proc(int sig)

{

    int status = ;

    waitpid(-, &status, WNOHANG);

}

int deal_error(string error_msg)

{

    cout << error_msg << endl;

    return ;

}

int main()

{

    // 创建套接字

    int ser_sock = socket(PF_INET, SOCK_STREAM, );

    if (ser_sock == -) {

        return deal_error("socket() failed");

    }

    // 套接字绑定ip及端口号

    sockaddr_in ser_addr;

    ser_addr.sin_family = AF_INET;

    ser_addr.sin_addr.s_addr = htonl(INADDR_ANY);

    ser_addr.sin_port = htons();

    if (bind(ser_sock, (sockaddr *)&ser_addr, sizeof(ser_addr)) == -) {

        close(ser_sock);

        return deal_error("bind() failed");

    }

    // 开始监听

    if (listen(ser_sock, ) == -) {

        close(ser_sock);

        return deal_error("listen() failed");

    }

    // 注册信号

    signal(SIGCHLD, read_child_proc);   // 子进程执行结束信号注册，防止僵尸进程产生

    signal(SIGINT, exit);               // CTRL+C信号注册，退出程序

    while() {

        sockaddr_in clnt_addr;

        socklen_t addr_length = sizeof(clnt_addr);

        int clnt_sock = accept(ser_sock, (sockaddr *)&clnt_addr, &addr_length);

        if (clnt_sock == -) {

            continue;

        }

        cout << "new client connected: " << clnt_sock << endl;

        pid_t pid = fork();

        if (pid < ) {

            continue;

        } else if (pid == ) {  // 子进程

            close(ser_sock);

            char message[BUFFER_SIZE];

            int str_len = read(clnt_sock, message, BUFFER_SIZE-);

            if (str_len > ) {

                message[str_len] = '\0';

                cout << message << endl;

            }

            close(clnt_sock);

            sleep();

            return ;

        } else {    // 父进程

            close(clnt_sock);

        }

    }

    close(ser_sock);

    return ;

}