POLL（C/S模型）实现简单聊天室，通过server广播信息

参考Linux高性能服务器编程一书

之前只学过select现在学了epoll和poll记录一下。
Server

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define  USER_LIMIT 5   //最大用户数量
#define  BUFFER_SIZE 64  //读缓冲区的大小
#define  FD_LIMIT 65535 //文件描述符数量限制

//客户数据 ： socket地址、待写到客户端的数据的位置、从客户端读入的数据
struct client_data
{
    sockaddr_in address;
    char * write_buf;
    char buf[BUFFER_SIZE];
};
int setnoblocking(int fd)
{
    int old_option = fcntl(fd,F_GETFL);
    int new_option = old_option | O_NONBLOCK;
    fcntl(fd,F_SETFL,new_option);
    return old_option;
}

int main()
{
    const char* ip = "192.168.174.129" ;
    int port = 5000 ;

    int ret = 0;
    struct sockaddr_in address;
    bzero(&address,sizeof(address));
    address.sin_family = AF_INET;
    inet_pton(AF_INET,ip,&address.sin_addr);
    address.sin_port = htons(port);

    int listenfd = socket(PF_INET,SOCK_STREAM,0);
    assert(listenfd >=0 );
    ret = bind(listenfd,(struct sockaddr *)&address,sizeof(address));
    assert(ret != -1);
    ret = listen(listenfd,5);
    assert(ret != -1);
    client_data* users = new client_data[FD_LIMIT];
    pollfd fds[USER_LIMIT+1];
    int user_couner = 0;
    for (int i = 1 ; i <= USER_LIMIT; i++ )
    {
        fds[i].fd = -1;
        fds[i].events = 0;
    }
    fds[0].fd = listenfd;
    fds[0].events = POLLIN | POLLERR;
    fds[0].revents = 0;

    while ( 1 )
    {
        ret = poll(fds,user_couner+1,-1);
        if ( ret < 0 )
        {
            printf(" poll failure\n");
            break;
        }
        for (int i = 0; i < user_couner+1; i++ )
        {
            if ( (fds[i].fd == listenfd ) && ( fds[i].revents & POLLIN ) )
            {
                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("error  accept \n" );
                    continue;
                }

                if ( user_couner >= USER_LIMIT )
                {
                    const char * info = "too manny users\n";
                    printf("%s",info);
                    send(connfd,info, strlen(info),0);
                    close(connfd);
                    continue;
                }
                user_couner++;
                users[connfd].address = client_address;
                setnoblocking(connfd);
                fds[user_couner].fd = connfd;
                fds[user_couner].events = POLLIN | POLLRDHUP | POLLERR;
                fds[user_couner].revents = 0;
                printf("comes a new user,now have %d users\n", user_couner);
            }
            else if ( fds[i].revents & POLLRDHUP )
            {
                users[fds[i].fd] = users[fds[user_couner].fd];
                close(fds[i].fd);
                fds[i] = fds[user_couner];
                i--;
                user_couner--;
                printf("a client left\n");
            }else if ( fds[i].revents & POLLIN )
            {
                int connfd = fds[i].fd;
                memset(users[connfd].buf,'\0',BUFFER_SIZE);
                ret = recv(connfd,users[connfd].buf,BUFFER_SIZE-1,0);
                printf("get %d bytes of client data %s from %d \n",ret,users[connfd].buf,connfd);
                if ( ret < 0 )
                {
                    if ( errno != EAGAIN )
                    {
                        close(connfd);
                        users[fds[i].fd] = users[fds[user_couner].fd];
                        fds[i] = fds[user_couner];
                        i--;
                        user_couner--;
                    }
                }else if ( ret == 0 )
                {

                }else
                {
                    for (int j = 1 ; j <= user_couner ; ++j )
                    {
                        if ( fds[j].fd == connfd )
                            continue;
                        fds[j].events |= ~POLLIN;
                        fds[j].events |= POLLOUT;
                        users[fds[j].fd].write_buf = users[connfd].buf;
                    }
                }
            }else if ( fds[i].revents & POLLOUT )
            {
                int connfd = fds[i].fd;
                if ( !users[connfd].write_buf )
                    continue;
                ret = send(connfd,users[connfd].write_buf, strlen(users[connfd].write_buf),0);
                users[connfd].write_buf = NULL;
                fds[i].events |= ~POLLOUT;
                fds[i].events |= POLLIN;
            }
        }
    }
    delete [] users;
    close(listenfd);
    return 0;
}

Client

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define BUFFER_SIZE 64

int main()
{
    const char *ip = "192.168.174.129" ;
    int port = 5000;
    struct sockaddr_in server_address ;
    bzero(&server_address,sizeof(server_address));
    server_address.sin_family = AF_INET;
    inet_pton(AF_INET,ip,&server_address.sin_addr);
    server_address.sin_port = htons(port);

    int sockfd = socket(PF_INET,SOCK_STREAM,0);
    assert(sockfd >= 0);
    if ( connect(sockfd,(struct sockaddr *)&server_address,sizeof(server_address)) < 0 )
    {
        printf("connection failed\n");
        close(sockfd);
        return 1;
    }
    pollfd fds[2] ;
    fds[0].fd = 0 ;
    fds[0].events = POLLIN;
    fds[1].fd = sockfd;
    fds[1].events = POLLIN | POLLRDHUP;
    fds[1].revents = 0;
    char read_buf[BUFFER_SIZE];
    int pipefd[2];
    int ret = pipe(pipefd);
    assert(ret != -1);
    while ( 1 )
    {
        ret = poll(fds,2,-1);
        if ( ret < 0 )
        {
            printf("poll failure\n");
            break;
        }
        if ( fds[1].revents & POLLRDHUP )
        {
            printf(" server close!\n");
            break;
        }else if ( fds[1].revents & POLLIN)
        {
            memset(read_buf,'\0',BUFFER_SIZE);
            int Ret = recv(fds[1].fd,read_buf,BUFFER_SIZE-1,0);
            printf("rev : %s\n", read_buf);

        }
        if ( fds[0].revents & POLLIN )
        {
            ret = splice(0,NULL,pipefd[1],NULL,32768,SPLICE_F_MORE|SPLICE_F_MOVE);
            ret = splice(pipefd[0],NULL,sockfd,NULL,32768,SPLICE_F_MORE|SPLICE_F_MOVE);
        }
    }
    close(sockfd);
    return 0;
}