Re: [PATCH] Workaround for ai_canonname sometimes coming back as null

From: Augie Fackler <durin42@gmail.com>
Date: Apr 29, 2009, 21:56 UTC
Message-ID: <6B7EA51D-8412-4E6A-BA7B-156FD5B755E8@gmail.com>
In-Reply-To: <81b0412b0904291455n47f83e9ftcbdec0ff1c0ea03@mail.gmail.com>

On Apr 29, 2009, at 4:55 PM, Alex Riesen wrote:

Show 25 quoted lines

> 2009/4/29 Augie Fackler <durin42@gmail.com>:
>> @@ -459,7 +459,10 @@ static void parse_extra_args(char *extra_args,  
>> int
>> buflen)
>>                                inet_ntop(AF_INET, &sin_addr- 
>> >sin_addr,
>>                                          addrbuf, sizeof(addrbuf));
>>                                free(canon_hostname);
>> -                               canon_hostname = xstrdup(ai- 
>> >ai_canonname);
>> +                               if (ai->ai_canonname)
>> +                                       canon_hostname =
>> xstrdup(ai->ai_canonname);
>> +                               else
>> +                                       canon_hostname = "unknown";
>
> This last line will crash some lines down, when canon_hostname is  
> free'd:
>
> 		inet_ntop(hent->h_addrtype, &sa.sin_addr,
> 			  addrbuf, sizeof(addrbuf));
>
> 		free(canon_hostname); /* CRASH */
> 		canon_hostname = xstrdup(hent->h_name);
> 		free(ip_address);

Odd, because I'm running with that exact code and not seeing the problem. Should I resubmit an updated patch that xstrdup's unknown into canon_hostname?