epoll处理多连接

#include <stdio.h>#include <stdlib.h>#include <string.h>#include <sys/types.h>#include <sys/socket.h>#include <netdb.h>#include <unistd.h>#include <fcntl.h>#include <sys/epoll.h>#include <errno.h>#include <libgen.h>#define MAXEVENTS 1024#define BUF_SIZE 100//set this descriptor non blockingstatic int set_non_block(int sfd){    int flags, s;    flags = fcntl(sfd, F_GETFL, 0);     if (flags == -1) {        perror ("fcntl");        return -1;     }       flags |= O_NONBLOCK;    s = fcntl(sfd, F_SETFL, flags);    if (s == -1) {        perror ("fcntl");        return -1;     }       return 0;}//static int create_and_bind (char *port){    struct addrinfo hints;    struct addrinfo *result, *rp;    int s, sfd;    memset (&hints, 0, sizeof (struct addrinfo));    hints.ai_family = AF_UNSPEC;     //IPv4 IPv6通用    hints.ai_socktype = SOCK_STREAM; /* We want a TCP socket */    hints.ai_flags = AI_PASSIVE;     //监听套接字；    //根据暗示得到所有可用的addrinfo    s = getaddrinfo (NULL, port, &hints, &result);    if (s != 0){        fprintf (stderr, "getaddrinfo: %s\n", gai_strerror (s));        return -1;    }    //use the first addr to create socket    for (rp = result; rp != NULL; rp = rp->ai_next) {        sfd = socket (rp->ai_family, rp->ai_socktype, rp->ai_protocol);        if (sfd == -1)            continue;        s = bind (sfd, rp->ai_addr, rp->ai_addrlen);        if (s == 0) {            //bind success            break;        }        close (sfd);//if bind failed we close this socket    }  if (rp == NULL) {        fprintf (stderr, "Could not bind\n");        return -1;  }  freeaddrinfo (result);  return sfd;}// add EPOLLIN event of fd to the epollfd, and epoll uses EPOLLLT in defaultvoid addfd(int epollfd, int fd, int enable_et){    struct epoll_event event;    event.data.fd = fd;    event.events = EPOLLIN;    if(enable_et)        event.events |= EPOLLET;    epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &event);    set_non_block(fd);}//the level-trigger logicvoid lt(struct epoll_event *events, int number, int epollfd, int listenfd){    char buf[BUF_SIZE];    int i;    for(i = 0; i < number; i++){        int sockfd = events[i].data.fd;        //new client connection        if(sockfd == listenfd){            struct sockaddr_in client_addr;            socklen_t client_addrlen = sizeof(client_addr);            int connfd = accept(listenfd, (struct sockaddr *)&client_addr, &client_addrlen);            if(connfd < 0){                perror("accept failed..");                exit(-1);            }            //register this event            addfd(epollfd, connfd, 0);        }else if(events[i].events & EPOLLIN){            //if there exists data unreaded , this code will invoke            memset(buf, 0, sizeof(buf));  printf("sockefd %d read event trigger once\n", sockfd);            int ret = recv(sockfd, buf, BUF_SIZE, 0);            if(ret <= 0){                printf("some read error or client closed.\n");                close(sockfd); // will unregister                continue;            }            printf("get %d bytes from client: %s\n", ret, buf);        }else{            // what we are not interested            printf("something else happened\n");        }    }}//the edge-trigger logicvoid et(struct epoll_event *events, int number, int epollfd, int listenfd){    char buf[BUF_SIZE];    int i;    for(i = 0; i < number; i++){        int sockfd = events[i].data.fd;        //new client connection        if(sockfd == listenfd){            struct sockaddr_in client_addr;            socklen_t client_addrlen = sizeof(client_addr);            int connfd = accept(listenfd, (struct sockaddr *)&client_addr, &client_addrlen);            if(connfd < 0){                perror("accept failed..");                exit(-1);            }            //register this event and set edge trigger mode            addfd(epollfd, connfd, 1);        }else if(events[i].events & EPOLLIN){            //in this mode , we should read all the data out once            printf("sockefd %d read event trigger once\n", sockfd);            while(1){                memset(buf, 0, sizeof(buf));                int ret = recv(sockfd, buf, BUF_SIZE, 0);                if(ret < 0){                    //for the nonblocking IO,the following errors indicate the read complete                    if(errno == EAGAIN || errno == EWOULDBLOCK){                        printf("read later\n");                        break;                    }                    printf("some other error\n");                    close(sockfd); // will unregister                    break;                }else if(ret == 0){                    printf("client closed.\n");                    close(sockfd);                    break;                }else{                    printf("get %d bytes from client: %s\n", ret, buf);                }            }        }else{            // what we are not interested            printf("something else happened\n");        }    }}int main (int argc, char *argv[]){    int sfd, s;    int efd;    struct epoll_event event;    struct epoll_event events[MAXEVENTS];    if (argc < 2){        fprintf (stderr, "Usage: %s [port]\n", basename(argv[0]));        exit (EXIT_FAILURE);    }    sfd = create_and_bind (argv[1]);    if (sfd == -1)        abort ();    //listen for connection coming    s = listen (sfd, SOMAXCONN);    if (s == -1) {        perror ("listen");        abort ();    }    //create a epoll object    efd = epoll_create1 (0);    if (efd == -1) {        perror ("epoll_create");        abort ();    }    //add the listen socket to the event poll    addfd(efd, sfd, 1);    while(1){        int ret = epoll_wait(efd, events, MAXEVENTS, -1);        if(ret < 0){            printf("epoll wait failture..\n");            break;        }        //et(events, ret, efd, sfd);        lt(events, ret, efd, sfd);    }    close (sfd);    return EXIT_SUCCESS;}调用的时候 root@root# ./epolltest 5000