分段故障主机获取信息时， [英] Segmentation fault when getting host information

问题描述

它发生在当高并发叫，看来的gethostbyname 没有缓存的结果？

It happens when called at high concurrency,it seems the result of gethostbyname is not cached ?

static int proxy_getaddr(char *HostName)
{
    struct hostent*     Host;
    Host=gethostbyname(HostName);

    if(!Host)
    {
        unsigned long int addr=inet_addr(HostName);
        if(addr!=-1)
            Host=gethostbyaddr((char*)addr,sizeof(addr),AF_INET);
    }
    ...

这里的核心转储：

Here's the core dump:

0x00000034f40e98b1 in gethostbyaddr () from /lib64/libc.so.6
0x000000000040182c in proxy_getaddr (HostName=0x48d75be0 "stackoverflow.com")

我怎样才能解决这个问题？

How can I fix this issue?

推荐答案

您code不正确。你逝去的 inet_addr（），转换为指针，但你真正想要什么的地址的这个结果：

Your code is incorrect. You are passing the result of inet_addr(), cast to a pointer, but what you actually want is the address of this:

Host = gethostbyaddr(&addr, sizeof(addr), AF_INET);

（其它意见，那你应该使用 in_addr_t unsigned long int类型而不是是正确的了，但是这是不可能的，这是专门造成您的问题）。

(The other comments, that you should be using in_addr_t instead of unsigned long int are correct too, but it is unlikely that this specifically is causing your problem).

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