第6章 I/O多路复用

#include <sys/select.h>
#include<sys/time.h>
 int select(int nfds, fd_set *readfds, fd_set *writefds,
                  fd_set *exceptfds, struct timeval *timeout);

struct timeval{
long tv_sec;
long tv_usec;
};

void FD_ZERO(fd_set*fdset);
void FD_SET(int fd,fd_set*fdset);
void FD_CLR(int fd,fd_set *fdset);
int  FD_ISSET(int fd,fd_set *fdset);

#include "unp.h"
void
str_cli(FILE *fp, int sockfd)
{
	int			maxfdp1, stdineof;
	fd_set		rset;
	char		buf[MAXLINE];
	int		n;
	stdineof = 0;
	FD_ZERO(&rset);
	for ( ; ; ) {
		if (stdineof == 0)
		FD_SET(fileno(fp), &rset);
		FD_SET(sockfd, &rset);
		maxfdp1 = max(fileno(fp), sockfd) + 1;
		Select(maxfdp1, &rset, NULL, NULL, NULL);
		if (FD_ISSET(sockfd, &rset)) {	/* socket is readable */
			if ( (n = Read(sockfd, buf, MAXLINE)) == 0) {
			   if (stdineof == 1)
					return;		/* normal termination */
				else
					err_quit("str_cli: server terminated prematurely");
			}
			Write(fileno(stdout), buf, n);
		}
   if (FD_ISSET(fileno(fp), &rset)) { 
	if ( (n = Read(fileno(fp), buf, MAXLINE)) == 0) {
				stdineof = 1;
				Shutdown(sockfd, SHUT_WR);	
				FD_CLR(fileno(fp), &rset);
				continue;
		}
	    Writen(sockfd, buf, n);
		}
	}
}
int main(int argc,char *argv[])
{
	if(argc<3)
		err_quit("please input IP Address : Port");
	
	int connfd=Socket(AF_INET,SOCK_STREAM,0);
	struct sockaddr_in servaddr;
	servaddr.sin_family=AF_INET;
	servaddr.sin_port=htons(atoi(argv[2]));
	Inet_pton(AF_INET,argv[1],&servaddr.sin_addr);
	Connect(connfd,(SA*)&servaddr,sizeof(servaddr));
  str_cli(stdin,connfd);
	return 0;
}

#include "unp.h"
static int  create_sock(char *ip)
{
	int listenfd;
	listenfd=Socket(AF_INET,SOCK_STREAM,0);
	struct sockaddr_in servaddr;
	servaddr.sin_family=AF_INET;
	servaddr.sin_port=htons(atoi(ip));
	Inet_pton(AF_INET,"0.0.0.0",&servaddr.sin_addr);
	Bind(listenfd,(SA*)&servaddr,sizeof(servaddr));
	Listen(listenfd,20);
	return listenfd;
}
static void deal_cli(int listenfd)
{
	int connfd,i;
	fd_set allset,rset;//allset保存的整个描述符集。但并不会直接select.每次select都会使得清0.很不方便。于是当要select的时候把它付给rset
	FD_ZERO(&allset);
	FD_ZERO(&rset);
	char buf[1024];//从客户端读取的缓冲区
	int ret=0;
	int maxfd=listenfd;//select第一个参数
	int allfd[MAXLINE];//连接数组
	for(i=0;i<MAXLINE;++i){
		allfd[i]=-1;
	}
	int nready; //select I/O已经就绪
	int max=0;//表示已完成连接数组中最大的队列
	FD_SET(listenfd,&allset);//将监听连接加入allset集合中
	for(;;){
		rset=allset;//更新
		nready=Select(maxfd+1,&rset,NULL,NULL,NULL);
		if(FD_ISSET(listenfd,&rset)){
			connfd=Accept(listenfd,NULL,NULL); //从已连接套接字拿取一个出来
			for(i=0;i<MAXLINE;++i){  //遍历整个已连接数组。找到alifd[i]等于-1(表示该位可用）
		  	if(allfd[i]<0){ 
				 	allfd[i]=connfd;
					break;
				}
			}
			FD_SET(connfd,&allset);
			if(maxfd<connfd) //每次都需要比较maxfd跟新来的描述符值大小
				 maxfd=connfd;
			if(max<i)//还要更新最后可连接数组最后的那个已连接索引
				max=i;
			if(--nready<=0) //如果该连接已经处理完成。那就
				continue;		
		}
		for(i=0;i<max+1;++i){ //遍历以此处理所有已完成连接
			if(allfd[i]!=-1)//跳过
		if(FD_ISSET(allfd[i],&rset)){ 
       ret=read(allfd[i],buf,1024);
		if(ret==0){
				close(allfd[i]);
				FD_CLR(allfd[i],&allset);
				allfd[i]=-1;		
		}else if(ret<0)	
		{
			perror("error");
		}else
			Writen(allfd[i],buf,ret);
	    }
		if(--nready<=0) //如果处理最后一个连接。继续返回到select中去
				continue;		
	  }
    } 	
  }
}

int main(int argc,char *argv[])
{
	if(argc<2){
		err_quit("please input ip aiddress\n");
	}
	int listenfd=create_sock(argv[1]);//创建一个套接字
	deal_cli(listenfd);//开始处理细节
	return 0;
}

 #include <poll.h>
int poll(struct pollfd *fds, nfds_t nfds, int timeout);

struct pollfd {
      int   fd;         /* file descriptor */
      short events;     /* requested events */
      short revents;    /* returned events */
    };

/* include fig01 */
#include	"unp.h"
//#include	<limits.h>		/* for OPEN_MAX */
int
main(int argc, char **argv)
{
	int					i, maxi, listenfd, connfd, sockfd;
	int					nready;
	ssize_t				n;
	char				buf[MAXLINE];
	socklen_t			clilen;
	long OPEN_MAX = sysconf(_SC_OPEN_MAX);  
	struct pollfd		client[OPEN_MAX];
	struct sockaddr_in	cliaddr, servaddr;
 
	listenfd = Socket(AF_INET, SOCK_STREAM, 0);
	bzero(&servaddr, sizeof(servaddr));
	servaddr.sin_family      = AF_INET;
	servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
	servaddr.sin_port        = htons(SERV_PORT);
	Bind(listenfd, (SA *) &servaddr, sizeof(servaddr));
	Listen(listenfd, LISTENQ);
	client[0].fd = listenfd;
	client[0].events = POLLRDNORM;
	for (i = 1; i < OPEN_MAX; i++)
		client[i].fd = -1;		/* -1 indicates available entry */
	maxi = 0;					/* max index into client[] array */
/* end fig01 */
/* include fig02 */
	for ( ; ; ) {
		nready = Poll(client, maxi+1, INFTIM);
		if (client[0].revents & POLLRDNORM) {	/* new client connection */
			clilen = sizeof(cliaddr);
			connfd = Accept(listenfd, (SA *) &cliaddr, &clilen);
#ifdef	NOTDEF
			printf("new client: %s\n", Sock_ntop((SA *) &cliaddr, clilen));
#endif
			for (i = 1; i < OPEN_MAX; i++)
				if (client[i].fd < 0) {
					client[i].fd = connfd;	/* save descriptor */
					break;
				}
			if (i == OPEN_MAX)
				err_quit("too many clients");
			client[i].events = POLLRDNORM;
			if (i > maxi)
				maxi = i;				/* max index in client[] array */
			if (--nready <= 0)
				continue;				/* no more readable descriptors */
		}
		for (i = 1; i <= maxi; i++) {	/* check all clients for data */
			if ( (sockfd = client[i].fd) < 0)
				continue;
			if (client[i].revents & (POLLRDNORM | POLLERR)) {
				if ( (n = read(sockfd, buf, MAXLINE)) < 0) {
					if (errno == ECONNRESET) {
							/*4connection reset by client */
#ifdef	NOTDEF
						printf("client[%d] aborted connection\n", i);
#endif
						Close(sockfd);
						client[i].fd = -1;
					} else
						err_sys("read error");
				} else if (n == 0) {
						/*4connection closed by client */
#ifdef	NOTDEF
					printf("client[%d] closed connection\n", i);
#endif
					Close(sockfd);
					client[i].fd = -1;
				} else
					Writen(sockfd, buf, n);
				if (--nready <= 0)
					break;				/* no more readable descriptors */
			}
		}
	}
}
/* end fig02 */