network_programming/echo_EPETserv.c at master · weeweetan/network_programming · GitHub

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//
// Created by Administrator on 2019/1/29.
//
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/epoll.h>
#include <fcntl.h>
#include <errno.h>

#define BUF_SIZE 4
#define EPOLL_SIZE 50

void setnonblockingmode(int fd);
void error_handling(char *message);

int main(int argc, char *argv[])
{
    int serv_sock, clnt_sock;
    struct sockaddr_in serv_addr, clnt_addr;
    struct epoll_event *ep_events;
    struct epoll_event event;

    socklen_t adr_sz;

    int epfd, str_len, event_cnt, i;
    char buf[BUF_SIZE];
    if (argc != 2){
        printf("Usage: %s <PORT>\n", argv[0]);
        exit(1);
    }

    serv_sock=socket(PF_INET, SOCK_STREAM, 0);
    memset(&serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    serv_addr.sin_port = htons(atoi(argv[1]));

    if (bind(serv_sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) == -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("event_wait() error");
            break;
        }

        puts("return epoll_wait");
        for (i = 0; i < event_cnt; ++i)
        {
            if (ep_events[i].data.fd == serv_sock)
            {
                adr_sz = sizeof(clnt_addr);
                clnt_sock = accept(serv_sock, (struct sockaddr*)&clnt_addr, &adr_sz);
                setnonblockingmode(clnt_sock);
                event.events = EPOLLIN|EPOLLET;
                event.data.fd = clnt_sock;
                epoll_ctl(epfd, EPOLL_CTL_ADD, clnt_sock, &event);
                printf("connected client: %d\n", clnt_sock);
            }
            else
            {
                while (1) {
                    str_len = read(ep_events->data.fd, buf, BUF_SIZE);
                    if (str_len == 0)
                    {
                        epoll_ctl(epfd, EPOLL_CTL_DEL, ep_events[i].data.fd, NULL);
                        close(ep_events[i].data.fd);
                        printf("closed client: %d", ep_events[i].data.fd);
                        break;
                    }
                    else if (str_len < 0)
                    {
                        if (errno == EAGAIN)
                        {
                            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 setnonblockingmode(int fd)
{
    int flag = fcntl(fd, F_GETFL, 0);
    fcntl(fd, F_SETFL, flag|O_NONBLOCK);
}