From: Azat Khuzhin <a3at.mail@gmail.com>
Date: Fri, 10 May 2013 23:53:11 +0000 (+0400)
Subject: Fix SEGFAULT after evdns_base_resume if no nameservers installed.
X-Git-Tag: release-2.0.22-stable~33^2~1
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=f8d7df859148905195054ed1255f46970039a34f;p=libevent

Fix SEGFAULT after evdns_base_resume if no nameservers installed.

If there is no nameservers installed, using
evdns_base_nameserver_ip_add(), than evdns_base_resume() will SEGFAULT,
because of NULL dereference in evdns_requests_pump_waiting_queue()

Conflicts:
	evdns.c
---

diff --git a/evdns.c b/evdns.c
index e229ab94..085f7146 100644
--- a/evdns.c
+++ b/evdns.c
@@ -727,21 +727,28 @@ request_reissue(struct request *req) {
 
 /* this function looks for space on the inflight queue and promotes */
 /* requests from the waiting queue if it can. */
+/* */
+/* TODO: */
+/* add return code, see at nameserver_pick() and other functions. */
 static void
 evdns_requests_pump_waiting_queue(struct evdns_base *base) {
 	ASSERT_LOCKED(base);
 	while (base->global_requests_inflight < base->global_max_requests_inflight &&
 		   base->global_requests_waiting) {
 		struct request *req;
-		/* move a request from the waiting queue to the inflight queue */
+
 		EVUTIL_ASSERT(base->req_waiting_head);
 		req = base->req_waiting_head;
+
+		req->ns = nameserver_pick(base);
+		if (!req->ns)
+			return;
+
 		evdns_request_remove(req, &base->req_waiting_head);
 
 		base->global_requests_waiting--;
 		base->global_requests_inflight++;
 
-		req->ns = nameserver_pick(base);
 		request_trans_id_set(req, transaction_id_pick(base));
 
 		evdns_request_insert(req, &REQ_HEAD(base, req->trans_id));
@@ -2441,6 +2448,7 @@ evdns_base_resume(struct evdns_base *base)
 	EVDNS_LOCK(base);
 	evdns_requests_pump_waiting_queue(base);
 	EVDNS_UNLOCK(base);
+
 	return 0;
 }