test14_1.txt

linux under the C programming which complementary with the book of <linux under the C programming

#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <errno.h>
#include <arpa/inet.h>
//#include "safecalls.h"

#define PROTOCOL "tcp"
#define SERVICE 7797
#define WELCOME "You have connected to the counting server. Welcome! \n"

 
int readnlstring(int socket,char *buf,int maxlen);
int read_buffer(int fd,void *buf,int count);
int readdelimstring(int socket,char *buf,int maxlen,char delim);

int main(void){
	int listensock,workersock;
	struct protoent *protocol;
	struct sockaddr_in socketaddr;
	char buffer[1024];
	char size[100];
	int addlen;
	int trueval=1;
    /* 初始化套接字地址结构*/

	bzero((char *)&socketaddr,sizeof(socketaddr));
	socketaddr.sin_family=AF_INET;
	socketaddr.sin_addr.s_addr=INADDR_ANY;
	socketaddr.sin_port=htons(SERVICE);

	protocol=getprotobyname(PROTOCOL);
	if(!protocol){
		HandleError(0, "getprotobyname", "protocol resolution failed");
	}
		/*创建主控和监听套接字*/

	listensock=socket(PF_INET,SOCK_STREAM,protocol->p_proto);
	if(listensock<0){
		HandleError(errno, "socket", "couldn’t create socket");
	}
		/*将套接字绑定到服务器的某个端口*/

	if(bind(listensock,&socketaddr,sizeof(socketaddr))<0){
		HandleError(errno, "bind", "couldn’t bind to port %d", SERVICE);
	}
		/*告诉系统监听连接*/

	setsockopt(listensock,SOL_SOCKET,SO_REUSEADDR,&trueval,sizeof(trueval));
		
	if(listen(listensock,0)<0){
		HandleError(errno, "listen", "couldn’t listen on port %d",SERVICE);
	}

	printf("Listening for a connection…\n");

	workersock=accept(listensock,&socketaddr,&addlen);
	if(workersock<0){
		HandleError(errno, "accept", "couldn’t open worker socket");
	}

	printf("Received connection from a client at");
	printf("%s port %d\n",inet_ntoa(socketaddr.sin_addr),
		ntohs(socketaddr.sin_port));
	write_buffer(workersock,WELCOME,strlen(WELCOME));
	while(readnlstring(workersock,buffer,sizeof(buffer))>=0){
		sprintf(size,"Size:%d\n",strlen(buffer)-1);
		write_buffer(workersock,size,strlen(size));
		if(strncmp(buffer, "exit",4)==0)
			break;
	}

	printf("Shutting down.\n");
	safeclose(workersock);
	safeclose(listensock);
	return 0;
}

int write_buffer(int fd,const void *buf,int count){
	const void *pts=buf;
	int status=0,n;

	if(count<0)
		return(-1);
	while(status!=count){
		n=safewrite(fd,pts+status,count-status);
		if(n<0)
			return(n);
		status+=n;
	}
	return(status);
}

int read_buffer(int fd,void *buf,int count){
	void *pts=buf;
	int status=0,n;

	if(count<0)
		return(-1);
	while(status!=count){
		n=saferead(fd,pts+status,count-status);
		if(n<1)
			return n;
		status+=n;
	}
	return(status);
}

int readnlstring(int socket,char *buf,int maxlen){
	return readdelimstring(socket,buf,maxlen, '\n');
}

int readdelimstring(int socket,char *buf,int maxlen,char delim){
	int status;
	int count=0;

	while(count<maxlen-1){
		if((status=read_buffer(socket,buf+count,1))<1){
			return -1;
		}
		if(buf[count]==delim){
			buf[count]=0;
			return 0;
		}
		count++;
	}
	buf[count]=0;
	return 0;
}