52.echo_EPLTserv.c

//
// Created by satellite on 2023-06-03.
//

//条件触发

#include "stdlib.h"
#include "stdio.h"
#include "string.h"
#include "unistd.h"
#include "arpa/inet.h"
#include "sys/socket.h"
#include "sys/epoll.h"

#define BUF_SIZE 4
#define EPOLL_SIZE 50

void error_handling(char *message) {
    fputs(message, stderr);
    fputc('\n', stderr);
    exit(1);
}

int main(int argc , char * argv[])
{
    int serv_sock , clnt_sock;
    struct sockaddr_in serv_adr , clnt_adr;
    socklen_t adr_sz;
    int str_len , i;
    char buf[BUF_SIZE];

    struct epoll_event *ep_events;
    struct epoll_event event;

    int epfd , event_cnt;

    if(argc != 2)
    {
        printf("Usage : %s <port> \n",argv[0]);
        exit(1);
    }
    serv_sock = socket(PF_INET,SOCK_STREAM,0);
    memset(&serv_adr,0,sizeof(serv_sock));
    serv_adr.sin_family = AF_INET;
    serv_adr.sin_addr.s_addr = htonl(INADDR_ANY);
    serv_adr.sin_port = htons(atoi(argv[1]));

    if( bind(serv_sock,(struct sockaddr*)&serv_adr,sizeof serv_adr) == -1)
        error_handling("bind() error");
    if( listen(serv_sock,5) == -1)
        error_handling("listen() error");

    epfd = epoll_create(EPOLL_SIZE);
    ep_events = malloc(sizeof(struct epoll_event) * EPOLL_SIZE);
    event.events = EPOLLIN;
    event.data.fd = serv_sock;
    epoll_ctl(epfd,EPOLL_CTL_ADD,serv_sock,&event);

    while(1)
    {
        event_cnt = epoll_wait(epfd,ep_events,EPOLL_SIZE,-1);
        if(event_cnt == -1)
        {
            puts("epoll_wait() error");
            exit(1);
        }
        puts("return epoll_wait");
        for (i = 0; i < event_cnt; ++i)
        {
            if(ep_events[i].data.fd == serv_sock)  //若服务端socket存在待读数据
            {
                adr_sz = sizeof clnt_adr;
                clnt_sock = accept(serv_sock,(struct sockaddr*)&clnt_adr,&adr_sz);
                event.events = EPOLLIN;
                //event.events = EPOLLIN | EPOLLET;  //改为边缘触发
                event.data.fd = clnt_sock;
                epoll_ctl(epfd,EPOLL_CTL_ADD,clnt_sock,&event);
                printf("connected client : %d \n",clnt_sock);
            }
            else    //客户端socket存在待读数据
            {
                //printf("read.....\n");
                str_len = read(ep_events[i].data.fd,buf,BUF_SIZE);
                if(str_len == 0)
                {
                    epoll_ctl(epfd,EPOLL_CTL_DEL,clnt_sock,NULL);
                    close(ep_events[i].data.fd);
                    printf("close client : %d \n",clnt_sock);
                }
                else
                {
                    write(ep_events[i].data.fd,buf, str_len);
                }
            }
        }
    }
    close(serv_sock);
    close(epfd);
    return 0;

}