getifaddrs导致Segmentation fault

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想获取所有网卡的IP地址，但是遇到比如pppd拨号时候，网卡会是pp0，就会出现类似内存操作错误Segmentation fault，搜索谷歌，发现原因可能是At the moment it finds PPP interfaces, but does not return the destination address.就是说，如果找到的是PPP设备，返回的地址就可能为空，这样继续打印对应的IP地址就会出错。

kill掉pppd进程以后，再运行获取IP地址，就正常了，貌似是个bug，但是如何解决呢？

基本代码如下：

#include <stdlib.h>#include <string.h>#include <stdio.h>#include <arpa/inet.h>#include <sys/socket.h>#include <netdb.h>#include <ifaddrs.h>#include <stdio.h>#include <stdlib.h>#include <unistd.h>#include <linux/if_link.h>#define INET_ADDRSTRLEN 16#define INET6_ADDRSTRLEN 46int main(void){struct ifaddrs * ifAddrStruct=NULL;struct ifaddrs * ifa=NULL;int ret=0;ret=getifaddrs(&ifAddrStruct);printf("End getifaddrs %d\n",ret);printf("Following IP addresses are available:\n\n");for (ifa = ifAddrStruct; ifa != NULL; ifa = ifa->ifa_next){printf("Entry for ifa=%08x\n",ifa);if (ifa ->ifa_addr->sa_family==AF_INET){ // check it is IP4printf("ACTG: ipv4\n");void * tmpAddrPtr=NULL;// is a valid IP4 AddresstmpAddrPtr=&((struct sockaddr_in *)ifa->ifa_addr)->sin_addr;char addressBuffer[INET_ADDRSTRLEN];inet_ntop(AF_INET, tmpAddrPtr, addressBuffer, INET_ADDRSTRLEN);printf(" IPv4: interface: %s\t IP Address %s\n", ifa->ifa_name, addressBuffer);}else if (ifa->ifa_addr->sa_family==AF_INET6){ // check it is IP6printf("ACTG: ipv6\n");// is a valid IP6 Addresschar addressBuffer[INET6_ADDRSTRLEN];inet_ntop(AF_INET6, (void*)&((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr, addressBuffer, INET6_ADDRSTRLEN);printf(" IPv6: interface: %s\t IP Address %s\n", ifa->ifa_name, addressBuffer);}printf("Leave for ifa=%08x\n",ifa);}if (ifAddrStruct!=NULL) freeifaddrs(ifAddrStruct);return 0;}

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