一步一步创建聊天程序2-利用epoll来创建简单的聊天室

如图，这个是看视频时，最后的作业，除了客户端未使用select实现外，其它的要求都有简单实现。

服务端代码如下：

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <errno.h>
#include <sys/epoll.h>
#include <netinet/in.h>
#include <unistd.h>
#include<netinet/tcp.h>

#define MAX_LISTEN 10
#define EPOLL_SIZE 100

struct message
{
    int target_id;
    char buf[];
};

struct user_password
{
    char username[];
    char password[];
};

//设置保活参数 keepalive_time保活时间，keepalive_intvl保活间隔，keepalive_probes保活探测数。
int set_keepalive(int sockfd,int keepalive_time, int keepalive_intvl, int keepalive_probes)
{
    int optval;
    socklen_t optlen= sizeof(optval);

    optval=;
    if(-==setsockopt(sockfd,SOL_SOCKET, SO_KEEPALIVE, &optval, optlen))
    {
        perror("setsockopt failture.\n");
        return -;
    }

    optval=keepalive_probes;
    if(-==setsockopt(sockfd,SOL_TCP,TCP_KEEPCNT, &optval,optlen))
    {
        perror("setsockopt failture.\n");
        return -;
    }

    optval=keepalive_intvl;
    if(-==setsockopt(sockfd,SOL_TCP,TCP_KEEPINTVL, &optval,optlen))
    {
        perror("setsockopt failture.\n");
        return -;
    }

    optval=keepalive_time;
    if(-==setsockopt(sockfd,SOL_TCP,TCP_KEEPIDLE, &optval, optlen))
    {
        perror("setsockopt failture\n");
        return -;
    }
    return ;
}

void set_user_password(struct user_password users[])
{
    int fd=fopen("./password.txt","r");
    if(fd==NULL)
    {
        perror("open password failed\n");
        return;
    }

    char buf[];
    int count=;
    int i=;
    while(feof(fd)==)
    {
        fscanf(fd,"%s",buf);
        if(count%==)
        {
            strcpy(users[i].username,buf);
            count++;
        }
        else
        {
            strcpy(users[i++].password,buf);
            count++;
        }
    }

    fclose(fd);
}

int main(int argc,char * argv[])
{

    //读取设定的用户名和密码
    struct user_password users[];
    set_user_password(users);
    for(int i=;i<;i++)
    {
        printf("user: %s,\t password: %s\n",users[i].username,users[i].password);
    }

    struct sockaddr_in server_ip,customer_ip;
    int err,sd;

    sd=socket(AF_INET,SOCK_STREAM,);
    if(sd==-)
    {
        perror("socket failed\n");
        close(sd);
        return -;
    }

    server_ip.sin_family=AF_INET;
    server_ip.sin_port=htons();
    server_ip.sin_addr.s_addr=htonl(INADDR_ANY);
    memset(server_ip.sin_zero,,);

    err=bind(sd,(struct sockaddr *)(&server_ip),sizeof(struct sockaddr));
    if(err==-)
    {
        perror("bind failed\n");
        close(sd);
        return -;
    }

    err=listen(sd,MAX_LISTEN);
    if(err==-)
    {
        perror("listen failed\n");
        close(sd);
        return -;
    }

    int epfd=epoll_create(EPOLL_SIZE);
    if(epfd<)
    {
        perror("epoll create failed\n");
        return -;
    }
    printf("epoll created, epollfd=%d\n",epfd);

    struct  epoll_event events[EPOLL_SIZE];
    struct  epoll_event  event;
    event.data.fd=sd;
    event.events=EPOLLIN;
    err=epoll_ctl(epfd,EPOLL_CTL_ADD,sd,&event);
    if(err==-)
    {
        perror("epoll add failed\n");
        return -;
    }

    while()
    {
        int epoll_events_count=epoll_wait(epfd,events,EPOLL_SIZE,-);
        if(epoll_events_count<)
        {
            perror("epoll wait failed\n");
            break;
        }

        printf("epoll_events_count= %d\n",epoll_events_count);

        for(int i=;i<epoll_events_count;i++)
        {
            int sockfd=events[i].data.fd;
            if(sockfd==sd)
            {
                int length=sizeof(struct sockaddr);
                int client_fd=accept(sockfd,(struct sockaddr *)(&customer_ip),&length);

                //用户名和密码检验
                int flag=;
                char buf[]="please input username and password ";
                struct user_password login_user;

                send(client_fd,buf,,);
                recv(client_fd,&login_user,sizeof(struct user_password),);
                memset(buf,,);
                for(int i=;i<;i++)
                {
                    if((strcmp(users[i].username,login_user.username)==)&&(strcmp(users[i].password,login_user.password)==))
                    {
                        flag=;
                        break;
                    }
                }

                if(flag)
                {
                    err=set_keepalive(sockfd,,,);
                    if(err!=)
                    {
                        perror("set keep alive failed.\n");
                        continue;
                    }

                    printf("USER %d online\n",client_fd);
                    event.data.fd=client_fd;
                    event.events=EPOLLIN;
                    err=epoll_ctl(epfd,EPOLL_CTL_ADD,client_fd,&event);
                    if(err==-)
                    {
                        perror("epoll add failed\n");
                        return -;
                    }
                }
                else
                {
                    memset(buf,,);
                    strcpy(buf,"login failed\n");
                    send(client_fd,buf,,);
                }

            }
            else
            {
                struct message recv_message;
                int bytes=recv(sockfd,&recv_message,sizeof(struct message),);
                if(bytes<)
                {
                    perror("recv failed\n");
                    return -;
                }
                else if(bytes==)
                {
                    err=epoll_ctl(epfd,EPOLL_CTL_DEL,sockfd,events);
                    if(err==-)
                    {
                        perror("epoll del failed\n");
                        return -;
                    }
                    printf("USER %d offline\n",sockfd);
                    close(sockfd);
                }
                else
                {
                    printf("recv message from cliend %d, buf: %s\n",sockfd,recv_message.buf);
                    if(recv_message.target_id!=-)//请求向客户端发送信息
                    {
                        err=send(recv_message.target_id,recv_message.buf,,);
                        if(err==-)
                        {
                            perror("send failed\n");
                        }
                    }
                    else if(strcmp(recv_message.buf,"quit")==)//用户输入quit，客户端推出。
                    {
                        printf("USER %d offline\n",sockfd);
                        send(sockfd,recv_message.buf,,);
                        close(sockfd);
                    }
                    else
                    {
                        char cmd[];
                        strcat(cmd,recv_message.buf);
                        strcat(cmd," >> test.txt");

                        int fd=fopen("./test.txt","w");
                        if(fd==NULL)
                        {
                            perror("clear file failed\n");
                            continue;
                        }
                        close(fd);

                        printf("exec cmd: %s\n",cmd);

                        system(cmd);
                        memset(cmd,,);

                        //将结果回送客户端
                        fd=fopen("./test.txt","r");
                        if(fd==NULL)
                        {
                            perror("open file failed\n");
                            continue;
                        }
                        char buf[];
                        while(feof(fd)==)
                        {
                            int fread_ret=fread(buf,sizeof(char),sizeof(buf),fd);
                            send(sockfd,buf,,);
                            memset(buf,,);
                        }
                        fclose(fd);
                    }
                }
            }
        }
    }
    return ;
}

客户端代码还是之前的版本，没有使用select实现：

#include <stdio.h>
#include <pthread.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>

struct message
{
    int target_id;
    char buf[];
};

struct user_password
{
    char username[];
    char password[];
};

int sd;
struct message send_message;

void * read_message(void * argv)
{
    while()
    {
        //读服务器发来的消息
        char revBuf[];
        read(sd,revBuf,);
        printf("recevice from server: %s",revBuf);
    }
}

void * write_message(void * argv)
{
    while()
    {
        printf("input message: \n");
        memset(send_message.buf,,);
        send_message.target_id=-;
        scanf("%d %s",&send_message.target_id,send_message.buf);

        write(sd,&send_message,sizeof(send_message));
        sleep();
    }
}

int main()
{
    struct sockaddr_in server_ip,customer_ip;
    int err;

    sd=socket(AF_INET,SOCK_STREAM,);
    if(sd==-)
    {
        printf("socket failed\n");
        close(sd);
        return -;
    }

    //server_ip初始化
    server_ip.sin_family=AF_INET;
    server_ip.sin_port=htons();
    server_ip.sin_addr.s_addr=htonl(INADDR_ANY);
    //err=inet_aton("115.157.201.179",&server_ip.sin_addr.s_addr);
    memset(server_ip.sin_zero,,);

    err=connect(sd,(struct sockaddr *)(&server_ip),sizeof(server_ip));
    if(err==-)
    {
        printf("connect failed\n");
        close(sd);
        return -;
    }

    pid_t pid=fork();
    if(pid==)
    {
        while()
        {
            //读服务器发来的消息
            //printf("read message: \n");
            char revBuf[];
            recv(sd,revBuf,,);
            //read(sd,revBuf,100);
            if(strcmp(revBuf,"quit")==)
            {
                return ;
            }
            printf("recevice from server: %s\n",revBuf);
        }
    }
    int flag=;
    while()
    {
        printf("input message: \n");
        if(flag++==)
        {
            struct user_password login_user;
            scanf("%s %s",login_user.username,login_user.password);
            err=send(sd,&login_user,sizeof(struct user_password),);
            if(err==-)
            {
                printf("send failed\n");
            }
            continue;
        }
        memset(send_message.buf,,);
        send_message.target_id=-;
        scanf("%d %s",&send_message.target_id,send_message.buf);

        //if(send_message.target_id!=-1&&(strcmp(send_message.buf,"")!=0))
        //{
            //err=send(sd,send_message.buf,100,0);
            err=send(sd,&send_message,sizeof(send_message),);
            if(err==-)
            {
                printf("send failed\n");
            }
            //write(sd,&send_message,sizeof(send_message));

        //}
        if(strcmp(send_message.buf,"quit")==)
        {
            printf("USER offline\n");
            close(sd);
            return ;
        }
        send_message.target_id=-;
        memset(send_message.buf,,sizeof(send_message.buf));
        sleep();
    }

    close(sd);
    return ;
}