From d0cde45477c69fb7987115e6fc2d34fa9a2b7db2 Mon Sep 17 00:00:00 2001
From: Bogdan Harjoc <bharjoc@bitdefender.com>
Date: Thu, 9 Aug 2018 14:47:17 +0300
Subject: [PATCH] dns-example: free result in getaddrinfo callback

According to evdns.c, the result not freed by libevent after
the callback runs:

evdns_getaddrinfo_gotresolve()
{
    ...
    data->user_cb(0, data->pending_result, data->user_data);
    data->pending_result = NULL;
    ...
}

To reproduce, build with -fsanitize=address, add -g to the getopt
list in dns-example.c like in the current commit and run

  dns-example -g google.com

Closes: #681 # cherry-picked
(cherry picked from commit 855f0804305a545da6880850d16809969ce72edd)
---
 sample/dns-example.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/sample/dns-example.c b/sample/dns-example.c
index 6243458a..21a75de8 100644
--- a/sample/dns-example.c
+++ b/sample/dns-example.c
@@ -78,6 +78,8 @@ gai_callback(int err, struct evutil_addrinfo *ai, void *arg)
 {
 	const char *name = arg;
 	int i;
+	struct evutil_addrinfo *first_ai = ai;
+
 	if (err) {
 		printf("%s: %s\n", name, evutil_gai_strerror(err));
 	}
@@ -99,6 +101,9 @@ gai_callback(int err, struct evutil_addrinfo *ai, void *arg)
 			printf("[%d] %s: %s\n",i,name,buf);
 		}
 	}
+
+	if (first_ai)
+		evutil_freeaddrinfo(first_ai);
 }
 
 static void
@@ -166,7 +171,7 @@ main(int c, char **v) {
 		return 1;
 	}
 
-	while ((opt = getopt(c, v, "xvc:Ts:")) != -1) {
+	while ((opt = getopt(c, v, "xvc:Ts:g")) != -1) {
 		switch (opt) {
 			case 'x': o.reverse = 1; break;
 			case 'v': ++verbose; break;
-- 
2.50.1