From b0c30a3f7deb558d71a5a43a2528b817d6f815d9 Mon Sep 17 00:00:00 2001
From: Con Kolivas <kernel@kolivas.org>
Date: Fri, 20 Nov 2015 10:09:19 +1100
Subject: [PATCH] Disconnect clients whose sends block for more than 60 seconds

---
 src/connector.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/connector.c b/src/connector.c
index a7b776ab..981e8173 100644
--- a/src/connector.c
+++ b/src/connector.c
@@ -57,6 +57,9 @@ struct client_instance {
 	/* Are we currently sending a blocked message from this client */
 	sender_send_t *sending;
 	bool passthrough;
+
+	/* Time this client started blocking, 0 when not blocked */
+	time_t blocked_time;
 };
 
 struct sender_send {
@@ -556,6 +559,7 @@ out:
 static bool send_sender_send(ckpool_t *ckp, cdata_t *cdata, sender_send_t *sender_send)
 {
 	client_instance_t *client = sender_send->client;
+	time_t now_t;
 
 	if (unlikely(client->invalid))
 		goto out_true;
@@ -563,14 +567,26 @@ static bool send_sender_send(ckpool_t *ckp, cdata_t *cdata, sender_send_t *sende
 	/* Make sure we only send one message at a time to each client */
 	if (unlikely(client->sending && client->sending != sender_send))
 		return false;
+
 	client->sending = sender_send;
+	now_t = time(NULL);
 
 	while (sender_send->len) {
 		int ret = write(client->fd, sender_send->buf + sender_send->ofs, sender_send->len);
 
 		if (unlikely(ret < 1)) {
-			if (errno == EAGAIN || errno == EWOULDBLOCK || !ret)
+			/* Invalidate clients that block for more than 60 seconds */
+			if (unlikely(client->blocked_time && now_t - client->blocked_time >= 60)) {
+				LOGNOTICE("Client id %"PRId64" fd %d blocked for >60 seconds, disconnecting",
+					  client->id, client->fd);
+				invalidate_client(ckp, cdata, client);
+				goto out_true;
+			}
+			if (errno == EAGAIN || errno == EWOULDBLOCK || !ret) {
+				if (!client->blocked_time)
+					client->blocked_time = now_t;
 				return false;
+			}
 			LOGINFO("Client id %"PRId64" fd %d disconnected with write errno %d:%s",
 				client->id, client->fd, errno, strerror(errno));
 			invalidate_client(ckp, cdata, client);
@@ -578,6 +594,7 @@ static bool send_sender_send(ckpool_t *ckp, cdata_t *cdata, sender_send_t *sende
 		}
 		sender_send->ofs += ret;
 		sender_send->len -= ret;
+		client->blocked_time = 0;
 	}
 out_true:
 	client->sending = NULL;