On Thu, 4 Aug 2005, Harshal Pradhan wrote:

> I really don't know much about the ares API and how ares is used in curl. On
> a random hunch, I tried the following

...

> +#if defined(USE_ARES)
> + ares_cancel(conn->data->state.areschannel);
> +#endif

...

> So, getting to the point .... I have lots of questions: Has anyone
> encountered such a problem earlier? Has there been any work on a similar
> issue in later versions of curl? Is my reasoning above sane? Does the my
> "random hunch" patch above make any sense at all?

Thanks for this.

I believe you are right on track, that there is a pending callback that gets
called after the connectdata struct has been freed and thus it causes havoc.
This is still so in the CVS version.

However, this fix of yours blindly assumes that there is a pending ares
request for this connect data that we should cancel. When the multi interface
is used, the same ares 'channel' is used for name resolves for all easy
handles so this can most probably mistakenly cancel a name resolve request for
another handle if you have a bad day.

I think we need to make sure that we only cancel actual callbacks for this
particular connect struct... But there's no really good API for this in ares
of today! I think we need to figure out and implement one.

I'm open for (other) ideas on how this could be done.

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