53.echo_EPETserv.c

//
// Created by satellite on 2023-06-04.
//
#include <fcntl.h>
#include "errno.h"
#include "stdio.h"
#include "stdlib.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 setnoblock(int fd);
void error_handling(char * message);


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 event;
    struct epoll_event* ep_events;
    int epfd , event_cnt;
    if(argc != 2)
    {
        printf("usage %s : <port>",argv[0]);
        exit(1);
    }

    serv_sock = socket(PF_INET,SOCK_STREAM,0);
    memset(&serv_adr,0,sizeof(serv_adr));
    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);

    setnoblock(serv_sock);
    event.events = EPOLLIN;
    event.data.fd = serv_sock;
    epoll_ctl(epfd,EPOLL_CTL_ADD,serv_sock,&event);

    printf("..........\n");
    while(1)
    {
        event_cnt = epoll_wait(epfd,ep_events,EPOLL_SIZE,-1);
        if(event_cnt == -1)
        {
            puts("epoll wait...");
            break;
        }
        puts("return epoll_wait");
        for(i=0;i<event_cnt;i++)
        {
            if(ep_events[i].data.fd == serv_sock)
            {
                adr_sz = sizeof(clnt_adr);
                clnt_sock = accept(serv_sock,(struct sockaddr*)&clnt_adr,&adr_sz);
                setnoblock(clnt_sock);   //将客户端设为非阻塞模式
                event.events = EPOLLIN | EPOLLET;  //设置注册方式为边缘触发
                event.data.fd = clnt_sock;
                epoll_ctl(epfd,EPOLL_CTL_ADD,clnt_sock,&event);
                printf("connect client : %d \n",clnt_sock);
            }
            else
            {
                while(1)
                {
                    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("closed Client : %d \n",ep_events[i].data.fd);
                        break;
                    }
                    else if(str_len < 0)
                    {
                        if(errno == EAGAIN)  //意味着缓冲区中的全部数据被读完
                            break;
                    }
                    else
                        write(ep_events[i].data.fd,buf,str_len);
                }
            }
        }
    }
    close(serv_sock);
    close(epfd);
    return 0;

}




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

void setnoblock(int fd)
{
    int flag = fcntl(fd,F_GETFL,0);
    fcntl(fd,F_SETFL,O_NONBLOCK);
}