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; }
