Linux socket通讯实验出现段错误 (核心已转储)

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服务端代码

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <netdb.h>
#define SERVPORT 3333
#define BACKLOG 10
#define MAXDATASIZE 100000
int main()
{
	int sockfd,client_fd;
	struct sockaddr_in my_addr;//
	struct sockaddr_in remote_addr;
	int sin_size;
	int recvbytes;
	int i;
	int answer;
	char *delim=",";
	char *p;
	char *str[3];
	char buf[MAXDATASIZE];
	if((sockfd=socket(AF_INET,SOCK_STREAM,0))==-1)
	{
		perror("error in create socket");
		exit(1);
	}
	int ret,on;
	on=1;
	ret=setsockopt(sockfd,SOL_SOCKET,SO_REUSEADDR,&on,sizeof(on));
	my_addr.sin_family=AF_INET;
	my_addr.sin_port=htons(SERVPORT);
	my_addr.sin_addr.s_addr=INADDR_ANY;
	bzero(&(my_addr.sin_zero),8);
	if(bind(sockfd,(struct sockaddr *)&my_addr,sizeof(struct sockaddr))==-1)
	{
		perror("error in bind");
		exit(1);
	}
	if(listen(sockfd,BACKLOG)==-1)
	{
		perror("error in listen");
		exit(1);
	}
	while(1)
	{
		sin_size=sizeof(struct sockaddr_in);
		if((client_fd=accept(sockfd,(struct sockaddr*)&remote_addr,&sin_size))==-1)
		{
			perror("error in accept");
			continue;
		}
		printf("A connection from:%s\n",inet_ntoa(remote_addr.sin_addr));
		if(!fork())
		{
			
			if(send(client_fd,"Server can calculate.Please enter :\n",40,0)==-1)
			{
				perror("error in send");
				exit(1);
			}
			
			if((recvbytes=recv(client_fd,buf,MAXDATASIZE,0))==-1)
			{
				perror("error in recive");
				exit(1);
			}
			
			buf[recvbytes]='\0';
			str[0]=strtok(buf,delim);
			for(i=1;i<3;i++)
				str[i]=strtok(NULL,delim);
			
			if(strcmp("+",str[0])==0)
			{
				answer=atoi(str[1])+atoi(str[2]);
				
				if(send(client_fd,&answer,sizeof(answer),0)==-1)
				{
					perror("error in send");
				}
				
			}
			else if(strcmp("-",str[0])==0)
			{
				answer=atoi(str[1])-atoi(str[2]);
				if(send(client_fd,&answer,sizeof(answer),0)==-1)
				{
					perror("error in send");
				}
			}
			else if(strcmp("*",str[0])==0)
			{
				answer=atoi(str[1])*atoi(str[2]);
				if(send(client_fd,&answer,sizeof(answer),0)==-1)
				{
					perror("error in send");
				}
			}
			else if(strcmp("/",str[0])==0)
			{
				answer=atoi(str[1])/atoi(str[2]);
				if(send(client_fd,&answer,sizeof(answer),0)==-1)
				{
					perror("error in send");
				}
			}
		}
		
		close(client_fd);
		
	}
}

客户端代码

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#define SERVPORT 3333
#define MAXDATASIZE 100000
int main(int argc,char *argv[])
{
	int sockfd,recvbytes;//声明客户端套接字标识，接收消息标识
	char buf[MAXDATASIZE];//建立消息缓冲区
	struct hostent *host;
	struct sockaddr_in serv_addr;//声明一个套接字
	while(1){
		if(argc<2)
		{
			fprintf(stderr,"Please enter the ip address:\n");
			exit(1);
		}

		if((host=gethostbyname(argv[1]))==NULL)//由主机名称取得网络数据
		{
			herror("error in gethostbyname");//打印网络错误原因信息字符串
			exit(1);
		}
		//代码1-------start---------创建客户端socket，将返回值赋值给sockfd，并判断是否创建成功
		if((sockfd=socket(AF_INET,SOCK_STREAM,0))==-1)
		{
			perror("error in create socket");
			exit(1);
		}
		//代码1--------end------------
		//初始化客户端套接字结构体中的变量
		serv_addr.sin_family=AF_INET;
		serv_addr.sin_port=htons(SERVPORT);
		serv_addr.sin_addr=*((struct in_addr *)host->h_addr);
		bzero(&(serv_addr.sin_zero),8);
		//代码2-------start---------客户端向服务端发起一次连接,并判断是否连接成功
		if(connect(sockfd,(struct sockaddr *)&serv_addr,sizeof(struct sockaddr))==-1)
		{
			perror("error in connect");
			exit(1);
		}
		//代码2--------end------------
		//代码3-------start---------从服务器端接收连接消息，将结果存于接收消息标识recvbytes，并是否接收成功
		if((recvbytes=recv(sockfd,buf,MAXDATASIZE,0))==-1)
		{
			perror("error in recive");
			exit(1);
		}
		//代码3--------end------------
		//字符转换
		buf[recvbytes]='\0';
		printf("Recive:%s",buf);
		scanf("%s",buf);
		buf[strlen(buf)]='\0';
		//代码4-------start---------客户端发送计算类型和参数，并判断是否发送成功
		if(send(sockfd,buf,MAXDATASIZE,0)==-1)
		{
			perror("error in send");
			exit(1);
		}
		//代码4--------end------------
		//接收计算结果
		int result=0;
		if((recvbytes=recv(sockfd,&result,sizeof(result),0))==-1)
		{
			perror("error in recive");
			exit(1);
		}
		if(buf[0]=='q') break;
		printf("The answer is :%d\n",result);
		close(sockfd);//关闭客户端套接字
	}
}

运行服务端以及客户端之后直接报错段错误 (核心已转储)


gdb调试
Program terminated with signal SIGSEGV, Segmentation fault.
#0 0x00007ff1ac93fcc0 in _IO_vfprintf_internal (
s=0x7ff1accb6620 <_IO_2_1_stdout_>, format=<optimized out>,
ap=ap@entry=0x7ffcee98fa08) at vfprintf.c:1632
1632 vfprintf.c: 没有那个文件或目录.