linux下一个单进程并发服务器的实例 使用select

linux下一个单进程并发服务器的实例 使用select

/*单进程并发服务器实例。该程序采用单进程并发服务器算法实现的。*/

#include <stdio.h>

#include <string.h>

#include <unistd.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <sys/time.h>

#include <stdlib.h>

#define PORT 1234 //服务器端口

#define BACKLOG 5 //listen队列中等待的连接数

#define MAXDATASIZE 1024 //缓冲区大小

typedef struct _CLIENT{ //客户端结构体

int fd; //客户端socket描述符

char* name;

struct sockaddr_in addr; //客户端地址信息结构体

char* data;

} CLIENT;

void process_cli(CLIENT *client, char* recvbuf, int len); //客户请求处理函数

void savedata(char* recvbuf, int len, char* data);

main()

{

int i, maxi, maxfd,sockfd;

int nready;

ssize_t n;

fd_set rset, allset; //select所需的文件描述符集合

int listenfd, connectfd; //socket文件描述符

struct sockaddr_in server; //服务器地址信息结构体

CLIENT client[FD_SETSIZE]; //FD_SETSIZE为select函数支持的最大描述符个数

char recvbuf[MAXDATASIZE]; //缓冲区

int sin_size; //地址信息结构体大小

if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) { //调用socket创建用于监听客户端的socket

perror("Creating socket failed.");

exit(1);

}

int opt = SO_REUSEADDR;

setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)); //设置socket属性

bzero(&server,sizeof(server));

server.sin_family=AF_INET;

server.sin_port=htons(PORT);

server.sin_addr.s_addr = htonl (INADDR_ANY);

if (bind(listenfd, (struct sockaddr *)&server, sizeof(struct sockaddr)) == -1) { //调用bind绑定地址

perror("Bind error.");

exit(1);

}

if(listen(listenfd,BACKLOG) == -1){ //调用listen开始监听

perror("listen() error\n");

exit(1);

}

sin_size=sizeof(struct sockaddr_in);

//初始化select

maxfd = listenfd;

maxi = -1;

for (i = 0; i < FD_SETSIZE; i++) {

client[i].fd = -1;

}

FD_ZERO(&allset); //清空

FD_SET(listenfd, &allset); //将监听socket加入select检测的描述符集合

while(1)

{

struct sockaddr_in addr;

rset = allset;

nready = select(maxfd+1, &rset, NULL, NULL, NULL); //调用select

printf("select saw rset actions and the readfset num is %d. \n",nready );

if (FD_ISSET(listenfd, &rset)) { //检测是否有新客户端请求

printf("accept a connection.\n");

//调用accept，返回服务器与客户端连接的socket描述符

if ((connectfd = accept(listenfd,(struct sockaddr *)&addr,(socklen_t *)&sin_size))==-1) {

perror("accept() error\n");

continue;

}

//将新客户端的加入数组

for (i = 0; i < FD_SETSIZE; i++){

if (client[i].fd < 0) {

client[i].fd = connectfd; //保存客户端描述符

client[i].name = new char[MAXDATASIZE];

client[i].addr = addr;

client[i].data = new char[MAXDATASIZE];

client[i].name[0] = '\0';

client[i].data[0] = '\0';

printf("You got a connection from %s. ",inet_ntoa(client[i].addr.sin_addr) );

break;

}

}

printf("add new connect fd.\n");

if (i == FD_SETSIZE)

printf("too many clients\n");

FD_SET(connectfd, &allset); //将新socket连接放入select监听集合

if (connectfd > maxfd)

maxfd = connectfd; //确认maxfd是最大描述符

if (i > maxi) //数组最大元素值

maxi = i;

if (--nready <= 0)

continue; //如果没有新客户端连接，继续循环

}

for (i = 0; i <= maxi; i++) {

if ( (sockfd = client[i].fd) < 0) //如果客户端描述符小于0，则没有客户端连接，检测下一个

continue;

if (FD_ISSET(sockfd, &rset)) { //检测此客户端socket是否有数据

printf("recv occured for connect fd[%d].\n",i);

if ( (n = recv(sockfd, recvbuf, MAXDATASIZE,0)) == 0) { //从客户端socket读数据，等于0表示网络中断

close(sockfd); //关闭socket连接

printf("Client( %s ) closed connection. User's data: %s\n",client[i].name,client[i].data);

FD_CLR(sockfd, &allset); //从监听集合中删除此socket连接

client[i].fd = -1; //数组元素设初始值，表示没客户端连接

delete client[i].name;

delete client[i].data;

} else

process_cli(&client[i], recvbuf, n); //接收到客户数据，开始处理

if (--nready <= 0)

break; //如果没有新客户端有数据，跳出for循环回到while循环

}

}

}

close(listenfd); //关闭服务器监听socket

}

void process_cli(CLIENT *client, char* recvbuf, int len)

{

char sendbuf[MAXDATASIZE];

recvbuf[len-1] = '\0';

if (strlen(client->name) == 0) {

memcpy(client->name,recvbuf, len);

printf("Client's name is %s.\n",client->name);

return;

}

printf("Received client( %s ) message: %s\n",client->name, recvbuf);

savedata(recvbuf,len, client->data);

for (int i1 = 0; i1 < len - 1; i1++) {

sendbuf[i1] = recvbuf[len - i1 -2];

}

sendbuf[len - 1] = '\0';

send(client->fd,sendbuf,strlen(sendbuf),0);

}

void savedata(char* recvbuf, int len, char* data)

{

int start = strlen(data);

for (int i = 0; i < len; i++) {

data[start + i] = recvbuf[i];

}

}