9_1.cpp

//
// Created by satellite on 13/07/2023.
//

#include "sys/types.h"
#include "sys/socket.h"
#include "arpa/inet.h"
#include "assert.h"
#include "stdio.h"
#include "unistd.h"
#include "errno.h"
#include "string.h"
#include "fcntl.h"
#include "stdlib.h"

int mian(int argc , char * argv[])
{
    if(argc <= 2)
    {
        printf("usage %s  ip port", basename(argv[0]));
        return 1;
    }
    const char * ip = argv[1];
    int port = atoi(argv[2]);
    int ret = 0;
    struct sockaddr_in address;
    bzero(&address,sizeof (address));
    address.sin_family = AF_INET;
    address.sin_port = htons(port);
    inet_pton(AF_INET,ip,&address.sin_addr);
    int listenfd = socket(AF_INET,SOCK_STREAM,0);
    bind(listenfd,(struct sockaddr*)&address,sizeof(address));
    listen(listenfd,5);
    struct sockaddr_in client_address;
    socklen_t client_addrlength = sizeof(client_address);
    int connfd = accept(listenfd,(struct sockaddr*)&client_address,&client_addrlength);
    if(connfd < 0)
    {
        printf("errno is %d \n",errno);
        close(listenfd);
    }
    char buf[1024];
    fd_set read_fds;
    fd_set exception_fds;
    FD_ZERO(&read_fds);
    FD_ZERO(&exception_fds);
    while(1)
    {
        //每次调用select前都要重新在read_fds和exception_fds中设置文件描述符
        //connfd，因为事件发生之后，文件描述符集合将被内核修改
        memset(buf,'\0',sizeof(buf));
        FD_SET(connfd,&read_fds);
        FD_SET(connfd,&exception_fds);
        ret = select(connfd+1 , &read_fds,NULL,&exception_fds,NULL);
        if(ret < 0)
        {
            printf("selection failure \n");
            break;
        }
        if(FD_ISSET(connfd,&read_fds))
        {
            ret = recv(connfd,buf,sizeof(buf)-1,0);
            if(ret <=0)
            {
                break;
            }
            printf("get %d bytes of normal data : %s \n",ret,buf);
        }
        else if(FD_ISSET(connfd,&exception_fds))
        {
            ret = recv(connfd,buf,sizeof(buf)-1,MSG_OOB);
            if(ret <= 0)
            {
                break;
            }
            printf("get %d bytes of oob data : %s \n",ret , buf);
        }
    }
    close(connfd);
    close(listenfd);

    return 0;
}