ioserver.c

linux下实现IO通信

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define PORT	1234
#define BACKLOG	5
#define MAXDATASIZE	1000


typedef struct _CLINET
 {
	int 		fd;
	char		*name;
	struct	sockaddr_in	addr;
	char		*data;
}CLIENT;

void savedata(char *recvbuf, int len, char *data)
{
	static int index=0;
        int i;
	for(i=0;i<len-1;i++)
	{
		data[index++] = recvbuf[i];
		
	}
	data[index] = '\0';

//	printf("Message is : %s  from %s \n", data, inet_ntoa(client[i].addr.sin_addr));
//printf("Client (%s) closed connection. User data: %s\n", client[i].name, client[i].data);
}
void process_cli(CLIENT *client, char *recvbuf, int len)
{
		savedata(recvbuf, len, client->data);
		send(client->fd, recvbuf, MAXDATASIZE, 0);
}



int main(void) 
{
	int i, maxi, maxfd, sockfd;
	int nready;
	int n;
	fd_set rset, allset;
	int listenfd, connectfd;
	struct sockaddr_in  server;
	CLIENT  client[FD_SETSIZE];
	char recvbuf[MAXDATASIZE];
	int sin_size;	

	/* Create TCP socket */      
    if((listenfd=socket(AF_INET, SOCK_STREAM, 0))==-1)
	{
		perror("Create socket failed");
		exit(-1);
	}
	/* Bind address */
	int opt = SO_REUSEADDR;
	setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
        bzero(&rset,sizeof(rset));
        bzero(&allset,sizeof(allset));
	bzero(&server, sizeof(server));
	bzero(client, FD_SETSIZE);
	bzero(recvbuf,MAXDATASIZE);
	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) {
		perror("Bind error.");
		exit(-1);
	}

	/* Listen socket listenfd */	
if (listen(listenfd, BACKLOG) == -1) {
		perror("listen error");
		exit(-1);
	}

	sin_size = sizeof(struct sockaddr_in);
	maxfd = listenfd; 
	maxi = -1;

	for (i =0; i< FD_SETSIZE; i++)
		client[i].fd = -1;

	FD_ZERO(&allset);
	FD_SET(listenfd, &allset);

	while (1) 
{
		struct sockaddr_in addr;
		bzero(&addr, sizeof(addr));
		rset = allset;
		nready = select (maxfd+1, &rset, NULL, NULL, NULL);   

		if (FD_ISSET(listenfd, &rset)) 
{
			if ((connectfd = accept(listenfd, (struct sockaddr *)&addr, &sin_size)) == -1)  
{
			perror("accept error");
				continue;
			}	
			for (i = 0; i < FD_SETSIZE; i++) 
				if (client[i].fd < 0) 
{
					client[i].fd = connectfd;  
					client[i].name = (char*)malloc(MAXDATASIZE);
					client[i].addr = addr;
					client[i].data = (char*)malloc(MAXDATASIZE);
					client[i].name[0] = '\0';
					client[i].data[0] = '\0';
					printf("You got a connect from %s. And the port is %d\n", inet_ntoa(client[i].addr.sin_addr), ntohs(client[i].addr.sin_port));  
					break;
				  }
			if (i == FD_SETSIZE)    printf("too many cllients.\n");
			FD_SET(connectfd, &allset);

			if (connectfd > maxfd)   maxfd = connectfd;
			if (i > maxi)   maxi =i;
			if ( -- nready <=0) continue;  /*可以省略？*/
		}  /* if (FD_ISSET (listenfd… */

		for (i = 0; i <= maxi; i++)  
{
			if ((sockfd = client[i].fd) < 0)    continue;
			if (FD_ISSET(sockfd, &rset))
 {
				if (( n = recv(sockfd, recvbuf, MAXDATASIZE, 0)) ==0)  
{
					close(sockfd);
					printf("Client (%s) closed connection. User data: %s\n", client[i].name, client[i].data);
					FD_CLR(sockfd, &allset);
					client[i].fd = -1;
					free(client[i].name);
					free(client[i].data);
				} else 
					process_cli(&client[i], recvbuf, n);
					//printf("Client (%s) closed connection. User data: %s\n", client[i].name, client[i].data);
				if ( --nready <=0 )  break;    /*？？？*/
			}  /* if (FD_ISSET(sockfd, &rset))  */
		} /* for(i = 0; i <= maxi; i++)   */
	}  /* while(1); */
	close(listenfd);
}