I don't know whether it helps. Before we have a case that
gethhostbyname is blocking so long(usually more than 2 minutes...) when
the it doesn't get any response from DNS server. We can't find any way
to stop gethostbyname from waiting until we find there is s variable
(struct _res_state _res) defined in resolv.h. It allows us to set the
internal retry time and timeout limit inside gethostbyname.

        Hope this help(or related... :)

Jacky

¦b ¶g¤@, 2002-06-10 14:26, Daniel Stenberg ¼g¹D¡G
> Hey skilled people!
>
> We've been through this before, I know. I thought we solved the problems long
> ago, but no. We have a problem with curl not timing out properly on name
> lookups. The SIGALRM is not properly stopping the operation.
>
> I tried it just now on both Linux i686 and on Solaris 2.7, and neither of
> them did return after the given timeout time when the name didn't resolve
> quickly enough:
>
> $ curl -m5 [host]
>
> The host in my test is always taking a long time and never succeeds to
> resolve. It just don't return failure after 5 seconds. It takes a lot longer.
>
> So, how is this *supposed* to work?
>
> On line lib/url.c:2206 the section that sets up the signal handler starts.
> It sets the signal without SA_RESTART to prevent system calls from getting
> restarted when the signal handler function returns.
>
> On line lib/url.c:2231 alarm() is called.
>
> On line lib/url.c:2253 we call Curl_resolv() that very quickly calls the
> DNS resolve function and there it sits...
>
> [if I add some silly output in the signal handler, I can see it get written
> and then continue waiting...]
>
> ... until it times out and then returns a failure code all the way back to
> the libcurl user.
>
> What do I need to do to make the alarm() abort the name lookup?
>
> --
> Daniel Stenberg -- curl groks URLs -- http://curl.haxx.se/
>
>
> _______________________________________________________________
>
> Don't miss the 2002 Sprint PCS Application Developer's Conference
> August 25-28 in Las Vegas - http://devcon.sprintpcs.com/adp/index.cfm?source=osdntextlink
>

_______________________________________________________________

Don't miss the 2002 Sprint PCS Application Developer's Conference
August 25-28 in Las Vegas - http://devcon.sprintpcs.com/adp/index.cfm?source
Received on 2002-06-10