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cancel_outstanding_requests by transaction_id 

to prevent double frees as side effect of getdns_dns_req being canceled by user callbacks.
This commit is contained in:
Willem Toorop 2017-02-19 09:39:10 +01:00
parent c7ae2f5011
commit 8fccd66813
1 changed files with 14 additions and 18 deletions
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32
src/context.c
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@ -2983,38 +2983,34 @@ _getdns_context_request_timed_out(getdns_dns_req *dnsreq)
static void
accumulate_outstanding_transactions(_getdns_rbnode_t *node, void* arg)
{
*(*(getdns_dns_req ***)arg)++ = (getdns_dns_req *)node;
*(*(getdns_transaction_t**)arg)++ = ((getdns_dns_req*)node)->trans_id;
}
static void
cancel_outstanding_requests(getdns_context* context)
{
getdns_dns_req **dnsreqs, **dnsreq_a, **dnsreq_i;
getdns_transaction_t *trans_ids, *tids_a, *tids_i;
if (context->outbound_requests.count == 0)
return;
dnsreq_i = dnsreq_a = dnsreqs = GETDNS_XMALLOC(context->my_mf,
getdns_dns_req *, context->outbound_requests.count);
tids_i = tids_a = trans_ids = GETDNS_XMALLOC(context->my_mf,
getdns_transaction_t, context->outbound_requests.count);
_getdns_traverse_postorder(&context->outbound_requests,
accumulate_outstanding_transactions, &dnsreq_a);
accumulate_outstanding_transactions, &tids_a);
while (dnsreq_i < dnsreq_a) {
getdns_dns_req *dnsreq = *dnsreq_i;
while (tids_i < tids_a) {
if (dnsreq->user_callback) {
dnsreq->context->processing = 1;
dnsreq->user_callback(dnsreq->context,
GETDNS_CALLBACK_CANCEL, NULL,
dnsreq->user_pointer, dnsreq->trans_id);
dnsreq->context->processing = 0;
}
_getdns_context_cancel_request(dnsreq);
dnsreq_i += 1;
/* We have to cancel by transaction_id because we do not know
* what happens when the user_callback is called. It might
* delete getdns_dns_req's that were scheduled to be canceled.
* The extra lookup with transaction_id makes sure we do not
* access freed memory.
*/
(void) getdns_cancel_callback(context, *tids_i++);
}
GETDNS_FREE(context->my_mf, dnsreqs);
GETDNS_FREE(context->my_mf, trans_ids);
}
#ifndef STUB_NATIVE_DNSSEC