Question

段错误 linux 请看一下怎么改

//client

#include"apue.h"
#include<netdb.h>
#include<errno.h>
#include<sys/socket.h>

#define MAXADDRLEN 256
#define BUFLEN 128

extern int connect_retry(int , const struct sockaddr * , socklen_t);

#define MAXSLEEP 128

int connect_retry(int sockfd,const struct sockaddr *addr,socklen_t alen)
{
int nsec;

for(nsec=1;nsec<=MAXSLEEP;nsec<<=1)
{
if (connect(sockfd,addr,alen)==0) return(0);
else if (nsec<=MAXSLEEP/2) sleep(nsec);
}
return(-1)

}

void print_uptime(int sockfd)
{
int n;
char buf[BUFLEN];

while((n=recv(sockfd,buf,BUFLEN,0))>0) write(STDOUT_FILENO,buf,n);

if (n<0) printf("recv error");

}

int main(int argc ,char *argv[])
{
struct addrinfo *ailist ,*aip;
struct addrinfo hint;
int sockfd,err;
if (argc !=2) printf("usage:ruptime hostname");
hint.ai_flags =0;
hint.ai_family=0;
hint.ai_socktype=SOCK_STREAM;
hint.ai_protocol=0;
hint.ai_addrlen=0;
hint.ai_canonname =NULL;
hint.ai_addr=NULL;
hint.ai_next=NULL;
if ((err=getaddrinfo(argv[1],"ruptime",&hint,&ailist))!=0)
printf("getaddrinfo error:%s",gai_strerror(err));
for(aip = ailist;aip!=NULL;aip=aip->ai_next)
{
if ((sockfd=socket(aip->ai_family,SOCK_STREAM,0))<0)
err=errno;
if (connect_retry(sockfd,aip->ai_addr,aip->ai_addrlen)<0)
{
err=errno;
}
else
{
print_uptime(sockfd);
exit(0);
}
}
fprintf(stderr,"can't connect to %s:%s\n",argv[1],strerror(err));
exit(1);
}

我用了gdb结果是这样：
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y

Starting program: /home/nannanwu/network/remote-uptime/a.out

Program received signal SIGSEGV, Segmentation fault.
0x08048b58 in main (argc=1, argv=0xbf91f234) at uptime.c:60
60 if ((sockfd=socket(aip->ai_family,SOCK_STREAM,0))<0)
(gdb) q

请高手指教，我该怎么改

Answer 1

if ((err=getaddrinfo(argv[1],"ruptime",&hint,&ailist))!=0)
printf("getaddrinfo error:%s",gai_strerror(err));

这里如果错误应该调用exit();不能继续往下执行

Answer 2

应该是connect调用出错了吧
connect函数原型：
int connect( SOCKET s, const struct sockaddr * name,int len);
第二个参数是对象的地址，第三个参数是sockaddr的大小