Crash at purple_dnsquery_destroy()

[Jacky Lam]

Dear all,

Currently, I experience crash at dnsquery.c:purple_dnsquery_destroy()
when my WiFi AP suddenly off while I am online with libpurple.

After tracing, I find the data struct PurpleDnsQueryData is freeing
twice. The reason is when purple_dnsquery_failed() is called,
purple_dnsquery_destroy() will try to free the PurpleDnsQueryData's
resolver and itself. But purple_dnsquery_resolver_destroy()'s kill()
will trigger the glib's input hook and finally called host_resolved()
and eventually call purple_dnsquery_failed() again!!

My solution is simple. Just reverse the older to free the object will be ok.

Origin code:

if (resolver->dns_pid > 0)
kill(resolver->dns_pid, SIGKILL);

if (resolver->inpa != 0)
purple_input_remove(resolver->inpa);


Fixed code:

if (resolver->inpa != 0)
{
purple_input_remove(resolver->inpa);
resolver->inpa=0;
}

if (resolver->dns_pid > 0)
kill(resolver->dns_pid, SIGKILL);

I don't know if it applies to all platform nor it has better way to do
that, but hope it is useful to others having this problem.

Thanks.

BR,
Jacky