X-Git-Url: http://git.efficios.com/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Flib%2Flttng-ctl%2Fchannel.c;h=5271aa13fbd76218fca47b8984c6a055fc84b35f;hp=16474464d880a9ffaa6c0fbad6c068dbeb781407;hb=a57a7f22e21b8b5dbb32e6b0096c81e869543aa2;hpb=1d757b1cd3b4669b52e2d9ceafb03eafd42490ff

diff --git a/src/lib/lttng-ctl/channel.c b/src/lib/lttng-ctl/channel.c
index 16474464d..5271aa13f 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;
@@ -266,10 +289,8 @@ lttng_notification_channel_get_next_notification(
 
 end_unlock:
 	pthread_mutex_unlock(&channel->lock);
+	*_notification = notification;
 end:
-	if (_notification) {
-		*_notification = notification;
-	}
 	return status;
 }
 
@@ -430,14 +451,14 @@ lttng_notification_channel_has_pending_notification(
 	case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION:
 		ret = enqueue_notification_from_current_message(channel);
 		if (ret) {
-			goto end;
+			goto end_unlock;
 		}
 		*_notification_pending = true;
 		break;
 	case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION_DROPPED:
 		ret = enqueue_dropped_notification(channel);
 		if (ret) {
-			goto end;
+			goto end_unlock;
 		}
 		*_notification_pending = true;
 		break;
@@ -575,14 +596,16 @@ enum lttng_notification_channel_status send_condition_command(
 		const struct lttng_condition *condition)
 {
 	int socket;
-	ssize_t command_size, ret;
+	ssize_t ret;
 	enum lttng_notification_channel_status status =
 			LTTNG_NOTIFICATION_CHANNEL_STATUS_OK;
-	char *command_buffer = NULL;
-	struct lttng_notification_channel_message cmd_message = {
-		.type = type,
+	struct lttng_dynamic_buffer buffer;
+	struct lttng_notification_channel_message cmd_header = {
+		.type = (int8_t) type,
 	};
 
+	lttng_dynamic_buffer_init(&buffer);
+
 	if (!channel) {
 		status = LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID;
 		goto end;
@@ -598,28 +621,24 @@ enum lttng_notification_channel_status send_condition_command(
 		goto end_unlock;
 	}
 
-	ret = lttng_condition_serialize(condition, NULL);
-	if (ret < 0) {
-		status = LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID;
-		goto end_unlock;
-	}
-	assert(ret < UINT32_MAX);
-	cmd_message.size = (uint32_t) ret;
-	command_size = ret + sizeof(
-			struct lttng_notification_channel_message);
-	command_buffer = zmalloc(command_size);
-	if (!command_buffer) {
+	ret = lttng_dynamic_buffer_append(&buffer, &cmd_header,
+			sizeof(cmd_header));
+	if (ret) {
+		status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR;
 		goto end_unlock;
 	}
 
-	memcpy(command_buffer, &cmd_message, sizeof(cmd_message));
-	ret = lttng_condition_serialize(condition,
-			command_buffer + sizeof(cmd_message));
-	if (ret < 0) {
+	ret = lttng_condition_serialize(condition, &buffer);
+	if (ret) {
+		status = LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID;
 		goto end_unlock;
 	}
 
-	ret = lttcomm_send_unix_sock(socket, command_buffer, command_size);
+	/* Update payload length. */
+	((struct lttng_notification_channel_message *) buffer.data)->size =
+			(uint32_t) (buffer.size - sizeof(cmd_header));
+
+	ret = lttcomm_send_unix_sock(socket, buffer.data, buffer.size);
 	if (ret < 0) {
 		status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR;
 		goto end_unlock;
@@ -633,7 +652,7 @@ enum lttng_notification_channel_status send_condition_command(
 end_unlock:
 	pthread_mutex_unlock(&channel->lock);
 end:
-	free(command_buffer);
+	lttng_dynamic_buffer_reset(&buffer);
 	return status;
 }