From: Julien Desfossez <jdesfossez@efficios.com>
Date: Thu, 30 Jan 2014 20:44:20 +0000 (-0500)
Subject: Fix: force the client to create a viewer session before attaching
X-Git-Tag: v2.4.0-rc5~43
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=04420afbdb0a5be910a4bf11cc81430b645f05ca;p=lttng-tools.git

Fix: force the client to create a viewer session before attaching

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
---

diff --git a/src/bin/lttng-relayd/connection.h b/src/bin/lttng-relayd/connection.h
index 6fb8913bf..931169ec0 100644
--- a/src/bin/lttng-relayd/connection.h
+++ b/src/bin/lttng-relayd/connection.h
@@ -44,6 +44,7 @@ enum connection_type {
 struct relay_connection {
 	struct lttcomm_sock *sock;
 	struct relay_session *session;
+	struct relay_viewer_session *viewer_session;
 	struct cds_wfq_node qnode;
 	struct lttng_ht_node_ulong sock_n;
 	struct rcu_head rcu_node;
diff --git a/src/bin/lttng-relayd/live.c b/src/bin/lttng-relayd/live.c
index b3b7ee427..b2e8e7c8b 100644
--- a/src/bin/lttng-relayd/live.c
+++ b/src/bin/lttng-relayd/live.c
@@ -926,6 +926,12 @@ int viewer_attach_session(struct relay_connection *conn)
 
 	health_code_update();
 
+	if (!conn->viewer_session) {
+		DBG("Client trying to attach before creating a live viewer session");
+		response.status = htobe32(LTTNG_VIEWER_ATTACH_NO_SESSION);
+		goto send_reply;
+	}
+
 	rcu_read_lock();
 	session = session_find_by_id(conn->sessions_ht,
 			be64toh(request.session_id));
@@ -1491,6 +1497,42 @@ end:
 	return ret;
 }
 
+/*
+ * Create a viewer session.
+ *
+ * Return 0 on success or else a negative value.
+ */
+static
+int viewer_create_session(struct relay_connection *conn)
+{
+	int ret;
+	struct lttng_viewer_create_session_response resp;
+
+	DBG("Viewer create session received");
+
+	resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_OK);
+	conn->viewer_session = zmalloc(sizeof(conn->viewer_session));
+	if (!conn->viewer_session) {
+		ERR("Allocation viewer session");
+		resp.status = htobe32(LTTNG_VIEWER_CREATE_SESSION_ERR);
+		goto send_reply;
+	}
+	CDS_INIT_LIST_HEAD(&conn->viewer_session->sessions_head);
+
+send_reply:
+	health_code_update();
+	ret = send_response(conn->sock, &resp, sizeof(resp));
+	if (ret < 0) {
+		goto end;
+	}
+	health_code_update();
+	ret = 0;
+
+end:
+	return ret;
+}
+
+
 /*
  * live_relay_unknown_command: send -1 if received unknown command
  */
@@ -1550,6 +1592,9 @@ int process_control(struct lttng_viewer_cmd *recv_hdr,
 	case LTTNG_VIEWER_GET_NEW_STREAMS:
 		ret = viewer_get_new_streams(conn);
 		break;
+	case LTTNG_VIEWER_CREATE_SESSION:
+		ret = viewer_create_session(conn);
+		break;
 	default:
 		ERR("Received unknown viewer command (%u)", be32toh(recv_hdr->cmd));
 		live_relay_unknown_command(conn);
diff --git a/src/bin/lttng-relayd/lttng-viewer-abi.h b/src/bin/lttng-relayd/lttng-viewer-abi.h
index 3a91da8a6..aa073c4e0 100644
--- a/src/bin/lttng-relayd/lttng-viewer-abi.h
+++ b/src/bin/lttng-relayd/lttng-viewer-abi.h
@@ -47,6 +47,7 @@ enum lttng_viewer_command {
 	LTTNG_VIEWER_GET_PACKET		= 5,
 	LTTNG_VIEWER_GET_METADATA	= 6,
 	LTTNG_VIEWER_GET_NEW_STREAMS	= 7,
+	LTTNG_VIEWER_CREATE_SESSION	= 8,
 };
 
 enum lttng_viewer_attach_return_code {
@@ -55,6 +56,7 @@ enum lttng_viewer_attach_return_code {
 	LTTNG_VIEWER_ATTACH_UNK		= 3, /* The session ID is unknown. */
 	LTTNG_VIEWER_ATTACH_NOT_LIVE	= 4, /* The session is not live. */
 	LTTNG_VIEWER_ATTACH_SEEK_ERR	= 5, /* Seek error. */
+	LTTNG_VIEWER_ATTACH_NO_SESSION	= 6, /* No viewer session created. */
 };
 
 enum lttng_viewer_next_index_return_code {
@@ -97,6 +99,11 @@ enum lttng_viewer_new_streams_return_code {
 	LTTNG_VIEWER_NEW_STREAMS_ERR          = 3, /* Error. */
 };
 
+enum lttng_viewer_create_session_return_code {
+	LTTNG_VIEWER_CREATE_SESSION_OK		= 1,
+	LTTNG_VIEWER_CREATE_SESSION_ERR		= 2,
+};
+
 struct lttng_viewer_session {
 	uint64_t id;
 	uint32_t live_timer;
@@ -219,4 +226,9 @@ struct lttng_viewer_new_streams_response {
 	char stream_list[];
 } __attribute__((__packed__));
 
+struct lttng_viewer_create_session_response {
+	/* enum lttng_viewer_create_session_return_code */
+	uint32_t status;
+} __attribute__((__packed__));
+
 #endif /* LTTNG_VIEWER_H */
diff --git a/src/bin/lttng-relayd/session.h b/src/bin/lttng-relayd/session.h
index 4953cdcd3..cb125be18 100644
--- a/src/bin/lttng-relayd/session.h
+++ b/src/bin/lttng-relayd/session.h
@@ -22,6 +22,7 @@
 #include <limits.h>
 #include <inttypes.h>
 #include <pthread.h>
+#include <urcu/list.h>
 
 #include <common/hashtable/hashtable.h>
 
@@ -71,6 +72,15 @@ struct relay_session {
 	 * process of sending those streams.
 	 */
 	pthread_mutex_t viewer_ready_lock;
+
+	/*
+	 * Member of the session list in struct relay_viewer_session.
+	 */
+	struct cds_list_head viewer_session_list;
+};
+
+struct relay_viewer_session {
+	struct cds_list_head sessions_head;
 };
 
 static inline void session_viewer_attach(struct relay_session *session)