X-Git-Url: http://git.efficios.com/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Flib%2Flttng-ctl%2Fchannel.c;h=5487d051b5013fd60b080491ce865966bc6ffeab;hp=5214fe73a41eeae6d96985e16fece47d45f1d7f8;hb=f83bcd90ceb5ce659ffe9d7747d6f3366a09748a;hpb=03732c3281c0cfbfd5f1a6b7723c577cab43bab3

diff --git a/src/lib/lttng-ctl/channel.c b/src/lib/lttng-ctl/channel.c
index 5214fe73a..5487d051b 100644
--- a/src/lib/lttng-ctl/channel.c
+++ b/src/lib/lttng-ctl/channel.c
@@ -211,6 +211,7 @@ lttng_notification_channel_get_next_notification(
 	struct lttng_notification *notification = NULL;
 	enum lttng_notification_channel_status status =
 			LTTNG_NOTIFICATION_CHANNEL_STATUS_OK;
+	fd_set read_fds;
 
 	if (!channel || !_notification) {
 		status = LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID;
@@ -239,6 +240,28 @@ lttng_notification_channel_get_next_notification(
 		goto end_unlock;
 	}
 
+	/*
+	 * Block on select() instead of the message reception itself as the
+	 * recvmsg() wrappers always restard on EINTR. We choose to wait
+	 * using select() in order to:
+	 *   1) Return if a signal occurs,
+	 *   2) Not deal with partially received messages.
+	 *
+	 * The drawback to this approach is that we assume that messages
+	 * are complete/well formed. If a message is shorter than its
+	 * announced length, receive_message() will block on recvmsg()
+	 * and never return (even if a signal is received).
+	 */
+	FD_ZERO(&read_fds);
+	FD_SET(channel->socket, &read_fds);
+	ret = select(channel->socket + 1, &read_fds, NULL, NULL, NULL);
+	if (ret == -1) {
+		status = errno == EINTR ?
+			LTTNG_NOTIFICATION_CHANNEL_STATUS_INTERRUPTED :
+			LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR;
+		goto end_unlock;
+	}
+
 	ret = receive_message(channel);
 	if (ret) {
 		status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR;