From: Timo Sirainen <tss@iki.fi>
Date: Sat, 23 Nov 2013 16:35:08 +0000 (+0200)
Subject: lib-dns: If existing dns connection dies in write(), retry connect once.
X-Git-Tag: 2.2.9~19
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=30f128cc663b8aeb68bb3bfb9ed49ab2e48029e1;p=thirdparty%2Fdovecot%2Fcore.git

lib-dns: If existing dns connection dies in write(), retry connect once.
---

diff --git a/src/lib-dns/dns-lookup.c b/src/lib-dns/dns-lookup.c
index b8f7380e58..70d2b16324 100644
--- a/src/lib-dns/dns-lookup.c
+++ b/src/lib-dns/dns-lookup.c
@@ -302,6 +302,28 @@ int dns_client_connect(struct dns_client *client, const char **error_r)
 	return 0;
 }
 
+static int
+dns_client_send_request(struct dns_client *client, const char *cmd,
+			const char **error_r)
+{
+	int ret;
+
+	if (client->fd == -1) {
+		if (dns_client_connect(client, error_r) < 0)
+			return -1;
+		ret = -1;
+	} else {
+		/* already connected. if write() fails, retry connecting */
+		ret = 0;
+	}
+
+	if (write_full(client->fd, cmd, strlen(cmd)) < 0) {
+		*error_r = t_strdup_printf("write(%s) failed: %m", client->path);
+		return ret;
+	}
+	return 1;
+}
+
 static int
 dns_client_lookup_common(struct dns_client *client,
 			 const char *cmd, bool ptr_lookup,
@@ -310,20 +332,20 @@ dns_client_lookup_common(struct dns_client *client,
 {
 	struct dns_lookup *lookup;
 	struct dns_lookup_result result;
+	int ret;
 
 	memset(&result, 0, sizeof(result));
 	result.ret = EAI_FAIL;
 
-	if (dns_client_connect(client, &result.error) < 0) {
-		callback(&result, context);
-		return -1;
-	}
-	if (write_full(client->fd, cmd, strlen(cmd)) < 0) {
-		result.error = t_strdup_printf("write(%s) failed: %m",
-					       client->path);
-		dns_client_disconnect(client, result.error);
-		callback(&result, context);
-		return -1;
+	if ((ret = dns_client_send_request(client, cmd, &result.error)) <= 0) {
+		if (ret == 0) {
+			/* retry once */
+			ret = dns_client_send_request(client, cmd, &result.error);
+		}
+		if (ret <= 0) {
+			callback(&result, context);
+			return -1;
+		}
 	}
 
 	lookup = i_new(struct dns_lookup, 1);