From: David Goulet <dgoulet@efficios.com>
Date: Tue, 11 Sep 2012 19:28:59 +0000 (-0400)
Subject: Fix: consumer recv command error path
X-Git-Url: http://git.efficios.com/?p=lttng-tools.git;a=commitdiff_plain;h=4cbc1a04e8ac3c1dd4f9a4dc44b56ee8430189f0

Fix: consumer recv command error path

See bug #332.

The debug output now prints this and does not infinite loop:

DEBUG1: Communication interrupted on command socket [in
lttng_consumer_thread_receive_fds() at consumer.c:1784]
DEBUG1: consumer_thread_receive_fds exiting [in
lttng_consumer_thread_receive_fds() at consumer.c:1794]

Fixes #332

Signed-off-by: David Goulet <dgoulet@efficios.com>
---

diff --git a/src/common/consumer.c b/src/common/consumer.c
index 008bf8e54..1c9190036 100644
--- a/src/common/consumer.c
+++ b/src/common/consumer.c
@@ -1776,8 +1776,12 @@ void *lttng_consumer_thread_receive_fds(void *data)
 			DBG("Received STOP command");
 			goto end;
 		}
-		if (ret < 0) {
-			ERR("Communication interrupted on command socket");
+		if (ret <= 0) {
+			/*
+			 * This could simply be a session daemon quitting. Don't output
+			 * ERR() here.
+			 */
+			DBG("Communication interrupted on command socket");
 			goto end;
 		}
 		if (consumer_quit) {
diff --git a/src/common/kernel-consumer/kernel-consumer.c b/src/common/kernel-consumer/kernel-consumer.c
index 86e405158..47463c650 100644
--- a/src/common/kernel-consumer/kernel-consumer.c
+++ b/src/common/kernel-consumer/kernel-consumer.c
@@ -257,7 +257,12 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 	} while (ret < 0 && errno == EINTR);
 end_nosignal:
 	rcu_read_unlock();
-	return 0;
+
+	/*
+	 * Return 1 to indicate success since the 0 value can be a socket
+	 * shutdown during the recv() or send() call.
+	 */
+	return 1;
 }
 
 /*
diff --git a/src/common/ust-consumer/ust-consumer.c b/src/common/ust-consumer/ust-consumer.c
index 855d07141..2b8098835 100644
--- a/src/common/ust-consumer/ust-consumer.c
+++ b/src/common/ust-consumer/ust-consumer.c
@@ -92,6 +92,11 @@ int lttng_ustconsumer_get_produced_snapshot(
 	return ret;
 }
 
+/*
+ * Receive command from session daemon and process it.
+ *
+ * Return 1 on success else a negative value or 0.
+ */
 int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 		int sock, struct pollfd *consumer_sockpoll)
 {
@@ -305,9 +310,13 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 		ret = write(ctx->consumer_poll_pipe[1], "", 1);
 	} while (ret < 0 && errno == EINTR);
 end_nosignal:
-	/* XXX: At some point we might want to return something else than zero */
 	rcu_read_unlock();
-	return 0;
+
+	/*
+	 * Return 1 to indicate success since the 0 value can be a socket
+	 * shutdown during the recv() or send() call.
+	 */
+	return 1;
 }
 
 int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)