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
#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; }