C语言实现多线程版聊天服务

一、概述

　　案例：C+pthread+socket实现多线程聊天服务，要求：服务端可以连接多个客户端，客户端发的消息，服务端再转发给客户端。

　　实现步骤：

　　　　1.创建监听文件描述符socket

　　　　2.绑定端口bind

　　　　3.监听端口listen

　　　　4.接收客户端请求，并在新的线程中执行（pthread+accept）

　　　　5.服务端把收到的数据恢复给客户端

二、示例代码

　　1.封装socket的创建、绑定、监听、接收头文件

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#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <strings.h>
 
void perr_exit(const char *s)
{
    perror(s);
    exit(-1);
}
 
int Accept(int fd, struct sockaddr *sa, socklen_t *salenptr)
{
    int n;
 
again:
    if ((n = accept(fd, sa, salenptr)) < 0) {
        if ((errno == ECONNABORTED) || (errno == EINTR))
            goto again;
        else
            perr_exit("accept error");
    }
    return n;
}
 
int Bind(int fd, const struct sockaddr *sa, socklen_t salen)
{
    int n;
 
    if ((n = bind(fd, sa, salen)) < 0)
        perr_exit("bind error");
 
    return n;
}
 
int Connect(int fd, const struct sockaddr *sa, socklen_t salen)
{
    int n;
 
    if ((n = connect(fd, sa, salen)) < 0)
        perr_exit("connect error");
 
    return n;
}
 
int Listen(int fd, int backlog)
{
    int n;
 
    if ((n = listen(fd, backlog)) < 0)
        perr_exit("listen error");
 
    return n;
}
 
int Socket(int family, int type, int protocol)
{
    int n;
 
    if ((n = socket(family, type, protocol)) < 0)
        perr_exit("socket error");
 
    return n;
}
 
ssize_t Read(int fd, void *ptr, size_t nbytes)
{
    ssize_t n;
 
again:
    if ( (n = read(fd, ptr, nbytes)) == -1) {
        if (errno == EINTR)
            goto again;
        else
            return -1;
    }
    return n;
}
 
ssize_t Write(int fd, const void *ptr, size_t nbytes)
{
    ssize_t n;
 
again:
    if ( (n = write(fd, ptr, nbytes)) == -1) {
        if (errno == EINTR)
            goto again;
        else
            return -1;
    }
    return n;
}
 
int Close(int fd)
{
    int n;
    if ((n = close(fd)) == -1)
        perr_exit("close error");
 
    return n;
}
 
/*参三: 应该读取的字节数*/
ssize_t Readn(int fd, void *vptr, size_t n)
{
    size_t  nleft;              //usigned int 剩余未读取的字节数
    ssize_t nread;              //int 实际读到的字节数
    char   *ptr;
 
    ptr = vptr;
    nleft = n;
 
    while (nleft > 0) {
        if ((nread = read(fd, ptr, nleft)) < 0) {
            if (errno == EINTR)
                nread = 0;
            else
                return -1;
        } else if (nread == 0)
            break;
 
        nleft -= nread;
        ptr += nread;
    }
    return n - nleft;
}
 
ssize_t Writen(int fd, const void *vptr, size_t n)
{
    size_t nleft;
    ssize_t nwritten;
    const char *ptr;
 
    ptr = vptr;
    nleft = n;
    while (nleft > 0) {
        if ( (nwritten = write(fd, ptr, nleft)) <= 0) {
            if (nwritten < 0 && errno == EINTR)
                nwritten = 0;
            else
                return -1;
        }
 
        nleft -= nwritten;
        ptr += nwritten;
    }
    return n;
}
 
static ssize_t my_read(int fd, char *ptr)
{
    static int read_cnt;
    static char *read_ptr;
    static char read_buf[100];
 
    if (read_cnt <= 0) {
again:
        if ( (read_cnt = read(fd, read_buf, sizeof(read_buf))) < 0) {
            if (errno == EINTR)
                goto again;
            return -1;
        } else if (read_cnt == 0)
            return 0;
        read_ptr = read_buf;
    }
    read_cnt--;
    *ptr = *read_ptr++;
 
    return 1;
}
 
ssize_t Readline(int fd, void *vptr, size_t maxlen)
{
    ssize_t n, rc;
    char    c, *ptr;
 
    ptr = vptr;
    for (n = 1; n < maxlen; n++) {
        if ( (rc = my_read(fd, &c)) == 1) {
            *ptr++ = c;
            if (c  == '\n')
                break;
        } else if (rc == 0) {
            *ptr = 0;
            return n - 1;
        } else
            return -1;
    }
    *ptr  = 0;
 
    return n;
}
 
int tcp4bind(short port,const char *IP)
{
    struct sockaddr_in serv_addr;
    int lfd = Socket(AF_INET,SOCK_STREAM,0);
    bzero(&serv_addr,sizeof(serv_addr));
    if(IP == NULL){
        //如果这样使用 0.0.0.0,任意ip将可以连接
        serv_addr.sin_addr.s_addr = INADDR_ANY;
    }else{
        if(inet_pton(AF_INET,IP,&serv_addr.sin_addr.s_addr) <= 0){
            perror(IP);//转换失败
            exit(1);
        }
    }
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port   = htons(port);
    Bind(lfd,(struct sockaddr *)&serv_addr,sizeof(serv_addr));
    return lfd;
}

　　2.连天服务端实现代码

//多线程版本的服务器（优化）
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <ctype.h>
#include <pthread.h>
#include "wrap.h"
typedef struct info{
        int cfd;//若为-1表示可用，大于0表示已被占用
        int idx;
        pthread_t thread;
        struct sockaddr_in client;
}INFO;

INFO thInfo[1024];

//线程执行函数
void * thread_work(void *arg){
        INFO *p = (INFO*)arg;
        printf("idx==[%d]\n",p->idx);

        char sIP[16];
        memset(sIP,0x00,sizeof(sIP));

        int n;
        int cfd = p->cfd;
        struct sockaddr_in  client;
        memcpy(&client,&(p->client),sizeof(client));
        char buf[1024];
        while(1){
                memset(buf,0x00,sizeof(buf));
                //读数据
                n = Read(cfd,buf,sizeof(buf));
                if(n<0){
                        printf("read error or client closed,n==[%d]\n",n);
                        Close(cfd);
                        p->cfd = -1;//设置-1表示该位置可用
                        pthread_exit(NULL);
                }
                for(int i=0;i<n;i++){
                        buf[i] = toupper(buf[i]);
                }
                //发送数据
                Write(cfd,buf,n);

        }
}


void init_thInfo(){
        int i=0;
        for(i=0;i<1024;i++){
                thInfo[i].cfd = -1;
        }
}

/**
 * 查找空闲位置
 * */
int findIndex(){
        int i;
        for(i=0;i<1024;i++){
                if(thInfo[i].cfd ==-1){
                        break;
                }
        }
        if(i==1024){
                return -1;
        }
        return i;
}
int main(){
        //创建socket
        int lfd = Socket(AF_INET,SOCK_STREAM,0);
        //设置是端口复用
        int opt = 1;
        setsockopt(lfd,SOL_SOCKET,SO_REUSEADDR,&opt,sizeof(int));

        //绑定ip及端口
        struct sockaddr_in serv;
        bzero(&serv,sizeof(serv));
        serv.sin_family = AF_INET;
        serv.sin_port = htons(8888);
        serv.sin_addr.s_addr = htonl(INADDR_ANY);
        Bind(lfd,(struct sockaddr *)&serv,sizeof(serv));
        //监听
        Listen(lfd,128);

        //初始化
        init_thInfo();

        int cfd;//通讯文件描述符
        int ret;
        int idx;
        socklen_t len;
        pthread_t thread;
        struct sockaddr_in client;
        while(1){
                len = sizeof(client);
                //获得一个新的链接
                cfd = Accept(lfd,(struct sockaddr *)&client,&len);
                //创建一个子线程，让子线程处理链接----接收数据和发送数据
                //找数组中空闲位置
                idx = findIndex();
                if(idx==-1){
                        Close(cfd);
                        continue;
                }
                //对空闲位置的元素的成员赋值
                thInfo[idx].cfd = cfd;
                thInfo[idx].idx = idx;
                memcpy(&thInfo[idx].client,&client,sizeof(client));
                //创建子线程，该子线程完成对数据的收发
                ret = pthread_create(&thInfo[idx].thread,NULL,thread_work,&thInfo[idx]);
                if(ret!=0){
                        printf("create thread error:[%s]\n",strerror(ret));
                        exit(-1);
                }
                //设置子线程分离属性
                pthread_detach(thInfo[idx].thread);
        }
        Close(lfd);
        return 0;
}

posted on 2021-12-13 13:35 飘杨...... 阅读(419) 评论(0) 编辑收藏举报

C语言实现多线程版聊天服务

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