近期有些空闲，正好趁着这段时间做些练手的项目巩固一些Linux下C编程:)

技术

• TCP Socket编程
• SYS V消息队列
• curses lib
• pthread lib

设计

几乎没有设计。。简单的服务端/客户端设计，使用TCP socket传输数据，消息队列做进程间通信。

Server/Client

server端

• 主进程监听，子进程处理每个客户端
• 子进程的子进程收其他进程消息发送给当前客户端

client端

• 两个进程，一个进程获得终端输入，一个进程收socket数据输出
• 派生线程在输出窗口输出服务端信息

结构定义

消息队列结构

    typedef struct mqmesg{
        long mtype;
        long mlen;
        char mdata[MAXLEN];
    }message;

用户登录信息结构

    typedef struct lginfo{
        struct tm       *login_time; // 登录时间结构
        struct sockaddr_in  *cliaddr; // 客户端IPV4结构
        char            login_name[50+1]; // 用户登录名
    }loginfo;

客户端线程参数结构

typedef struct thr_arg{
        WINDOW  *wnd;
        int     socket;
        char    *servip;
}thrarg;

模块

• 通用模块 util.c

  • ssize_t readn(int, void *, size_t); // 循环read函数，确保收取n字节
  • ssize_t writen(int, void *, size_t); // 循环write函数，确保发送n字节
  • int sendMsg(int, void *, int); // 发送socket封装函数
  • int recvMsg(int, void *, int *); // 接收socket封装函数
  • int mqMsgSTInit(message *, char *, long, long); // 消息队列结构赋值函数
  • ssize_t sendMq(int, message *); // 发送消息队列封装函数
  • ssize_t recvMq(int, message *); // 接收消息队列封装函数
  • int tm2DateTimeStr(struct tm *, char *); // linux时间tm结构转YYYY-MM-DD HH:MM:SS字符串
  • int getCurTimeStr(char *); // 获得当前时间串

• 服务端功能模块 servfunc.c

  • int getClientCount(int); // 读取type 1消息代表的客户端数量
  • int putClientCount(int, int); // 向消息队列写入客户端数量
  • int login_serv(int, loginfo *); // 服务端登入处理函数

• 客户端功能模块 clifunc.c
  • int login_cli(int); // 客户端登入处理函数
  • void *thr_fn(thrarg *); // 客户端处理输出线程函数

实现

server 端

#include "chatroom.h"

int main(int argc, char *argv[])
{
    struct sockaddr_in servaddr, cliaddr;
    socklen_t cliaddr_len;
    char buf[MAXLEN+1];
    char buf2[MAXLEN] = {0};
    char addr[INET_ADDRSTRLEN];
    int listenfd,connfd;
    int i,n,len;
    int pid;
    int client_count = 0;
    int fpid = getpid();
    char tt[19+1] = {0};


    listenfd = socket(AF_INET, SOCK_STREAM, 0);
    bzero(&servaddr, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(SERVPORT);

    bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr));

    listen(listenfd, 20);
    printf("Accepting connect...\n");

    int mq_fd = msgget(IPC_PRIVATE, SVMSG_MODE | IPC_CREAT);
    printf("msgid:%d\n",mq_fd);
    putClientCount(mq_fd, client_count);
    message *msg = (message *)malloc(sizeof(message));

    while(1){
        cliaddr_len = sizeof(cliaddr);
        connfd = accept(listenfd, (struct sockaddr *)&cliaddr, &cliaddr_len);
        client_count = getClientCount(mq_fd);   
        client_count++;
        putClientCount(mq_fd, client_count);
        pid = fork();
        if(pid<0) printf("fork err\n");
        else if(pid>0){
            continue;
        }else{
            // child
            printf("this is child process[%d]\n", getpid());
            inet_ntop(AF_INET, &cliaddr.sin_addr, addr, sizeof(addr));
            printf("Recieved connection form [%s] at PORT [%d]\n", addr, ntohs(cliaddr.sin_port));
            client_count = getClientCount(mq_fd);   
            int cliNo = client_count;
            putClientCount(mq_fd, client_count);

            loginfo *cli_log_info = (loginfo *)malloc(sizeof(loginfo));
            cli_log_info->cliaddr = &cliaddr;
            login_serv(connfd, cli_log_info); // client login

            getCurTimeStr(tt);
            sprintf(buf2, "(%s) %s join the chatroom", tt, cli_log_info->login_name);
            client_count = getClientCount(mq_fd);
            for(i=1;i<=client_count;i++){
                if(i==cliNo) continue;
                mqMsgSTInit(msg, buf2, strlen(buf2), 10000+i);
                sendMq(mq_fd, msg);
            }
            putClientCount(mq_fd, client_count);


            char welcome[100] = {0};
            sprintf(welcome, "%s%d%s", "-----welcome to chat room, current user no: ", client_count, "------");
            sendMsg(connfd, welcome, strlen(welcome));

            int pid2 = fork();
            if(pid2<0){ printf("fork err\n"); continue;}
            else if(pid2>0){
                while(1){
                    memset(buf, 0x00, sizeof(buf));
                    if(recvMsg(connfd, buf, &len)<0){
                        printf("The client [%d] closed the connection.\n", getpid());

                        getCurTimeStr(tt);
                        sprintf(buf2, "(%s) %s quit the chatroom", tt, cli_log_info->login_name);
                        client_count = getClientCount(mq_fd);
                        for(i=1;i<=client_count;i++){
                            if(i==cliNo) continue;
                            mqMsgSTInit(msg, buf2, strlen(buf2), 10000+i);
                            sendMq(mq_fd, msg);
                        }
                        putClientCount(mq_fd, client_count);

                        kill(pid2, SIGKILL);
                        break;
                    }
                    printf("CLIENT[%s]:PID[%d]:LOGIN_NAME[%s]:LEN[%d]:MSG[%s]\n", addr, getpid(), cli_log_info->login_name, len, buf);
                    
                    getCurTimeStr(tt);
                    
                    sprintf(buf2, "(%s) %s: %s", tt, cli_log_info->login_name, buf);
                //  strcat(buf, "[B]");
    //              printf("DEBUG: [%d], buf[%s]\n", strlen(buf), buf);
                    client_count = getClientCount(mq_fd);
                    for(i=1;i<=client_count;i++){
                        //if(i==cliNo) continue;
                        mqMsgSTInit(msg, buf2, strlen(buf2), 10000+i);
                        sendMq(mq_fd, msg);
                    }
                    putClientCount(mq_fd, client_count);
                }
            }else{
                while(1){
                    mqMsgSTInit(msg, NULL, 0, 10000+cliNo);
                    if(recvMq(mq_fd, msg)<=0) continue;
                    else{
                        sendMsg(connfd, msg->mdata, msg->mlen);
                    }
                }
            }
            client_count = getClientCount(mq_fd);
            client_count--;
            putClientCount(mq_fd, client_count);
            close(connfd);
            break;
        }
    }
    close(listenfd);
    free(msg);
    if(getpid() == fpid){
        msgctl(mq_fd, IPC_RMID, NULL);
    }

    return 0;
}

client 端

#include "chatroom.h"

int nrows, ncols;
pthread_t ntid;


int main(int argc, char *argv[])
{
    struct sockaddr_in servaddr;
    char buf[MAXLEN], buf2[MAXLEN];
    int sockfd;
    int n,len,flag;
    int pid;
    char servip[15+1];
    int ret;

    if(argc == 2)
    {
        strcpy(servip, argv[1]);
    }else{
        printf("USAGE: client [serverip]\n");
        exit(0);
    }

    WINDOW *wnd = initscr();
    getmaxyx(wnd, nrows, ncols);

    WINDOW *logwin = newwin(0,0,0,0);

    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    bzero(&servaddr, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    inet_pton(AF_INET, (const char *)servip, &servaddr.sin_addr);
    servaddr.sin_port = htons(SERVPORT);

    
    ret = connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr));
    if(!ret){
        wprintw(logwin,"Connect succeed!\n");
        wrefresh(logwin);
    }else{
        wprintw(logwin,"Cant connect to the server:%s\n", servip);
        wrefresh(logwin);
        exit(1);
    }
    // login
    login_cli_cgi(sockfd, logwin);

    werase(logwin);
    delwin(logwin);

    WINDOW *winin, *winout;
    winin = newwin(0, 0, nrows-1, 0);
    winout = newwin(nrows-2, 0, 0, 0);
    scrollok(winout, 1);

    thrarg ta = {winout, sockfd, servip};

    ret = pthread_create(&ntid, NULL, (void *)thr_fn, &ta);
    if(ret != 0){
        wprintw(winout, "cant create thread\n");
        exit(ret);
    }

    wprintw(winin, "> ");
    wrefresh(winin);
    while(!wgetnstr(winin, buf, MAXLEN)){
        sendMsg(sockfd, buf, strlen(buf));
        wclrtoeol(winin);
        wprintw(winin, "> ");
        wrefresh(winin);
    }
    
    close(sockfd);

    delwin(winin);
    delwin(winout);

    endwin();
    return 0;
}

其他

• 目前已知的几个缺陷：
  • 客户端终端输入输出在一起，有时候输入时会有输出冒出来
  • Ctrl-C kill掉服务端后，建立的消息队列没有删除