From: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Date: Wed, 13 Jan 2021 15:09:06 +0000 (-0500)
Subject: Fix: backward relayd: path contains a leading "ust" folder
X-Git-Tag: v2.12.4~14
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=52bbdc377b5fdadda1ed83aa95438ec4e63f83a1;p=lttng-tools.git

Fix: backward relayd: path contains a leading "ust" folder

Observed issue
==============

test_output_path_relayd[lttng-tools-2.13-lttng-tools-2.10-uid] from
the lttng-ivc fails on path validation for the resulting trace.

Here lttng-sessiond is 2.13 and lttng-relayd is 2.10

Traces are generated and the following hierarchy is found in the
lttng-relayd trace folder.

 lttng_home
         └── lttng-traces
*            └── ust
                 └── joraj-alpa
                     ├── auto-20210113-165054
                     │   └── ust
                     │       └── uid

Note the extra "ust" (*) in the hierarchy.

The tests expects:
 lttng_home
         └── lttng-traces
                 └── joraj-alpa
                     ├── auto-20210113-165054
                     │   └── ust
                     │       └── uid

Cause
=====

Introduced by: 5da88b0f58d7f838068037ea449ddfb25d3e85ad [1]

relayd_add_stream now suffixes the domain_name to the pathname.
This is only necessary for cases where the corresponding
lttng-relayd version is greater than 2.10. In other cases, modification
of pathname is not necessary.

Solution
========

Perform domain suffixing only for relayd > 2.10.

Known drawbacks
=========

None.

References
==========

[1] https://github.com/lttng/lttng-tools/commit/5da88b0f58d7f838068037ea449ddfb25d3e85ad

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: If43719c0cf8285d3242d846316d7277d4f5519f1
---

diff --git a/src/common/relayd/relayd.c b/src/common/relayd/relayd.c
index dfcb337a0..236f2bc12 100644
--- a/src/common/relayd/relayd.c
+++ b/src/common/relayd/relayd.c
@@ -499,7 +499,6 @@ int relayd_add_stream(struct lttcomm_relayd_sock *rsock, const char *channel_nam
 	int ret;
 	struct lttcomm_relayd_status_stream reply;
 	char pathname[RELAYD_COMM_LTTNG_PATH_MAX];
-	const char *separator;
 
 	/* Code flow error. Safety net. */
 	assert(rsock);
@@ -510,32 +509,36 @@ int relayd_add_stream(struct lttcomm_relayd_sock *rsock, const char *channel_nam
 
 	DBG("Relayd adding stream for channel name %s", channel_name);
 
-	if (_pathname[0] == '\0') {
-		separator = "";
-	} else {
-		separator = "/";
-	}
-	ret = snprintf(pathname, RELAYD_COMM_LTTNG_PATH_MAX, "%s%s%s",
-			domain_name, separator, _pathname);
-	if (ret <= 0 || ret >= RELAYD_COMM_LTTNG_PATH_MAX) {
-		ERR("stream path too long.");
-		ret = -1;
-		goto error;
-	}
-
 	/* Compat with relayd 2.1 */
 	if (rsock->minor == 1) {
 		/* For 2.1 */
-		ret = relayd_add_stream_2_1(rsock, channel_name, pathname);
+		ret = relayd_add_stream_2_1(rsock, channel_name, _pathname);
 	
 	} else if (rsock->minor > 1 && rsock->minor < 11) {
 		/* From 2.2 to 2.10 */
-		ret = relayd_add_stream_2_2(rsock, channel_name, pathname,
+		ret = relayd_add_stream_2_2(rsock, channel_name, _pathname,
 				tracefile_size, tracefile_count);
 	} else {
+		const char *separator;
 		enum lttng_trace_chunk_status chunk_status;
 		uint64_t chunk_id;
 
+		if (_pathname[0] == '\0') {
+			separator = "";
+		} else {
+			separator = "/";
+		}
+
+		ret = snprintf(pathname, RELAYD_COMM_LTTNG_PATH_MAX, "%s%s%s",
+				domain_name, separator, _pathname);
+		if (ret <= 0 || ret >= RELAYD_COMM_LTTNG_PATH_MAX) {
+			ERR("Failed to format stream path: %s",
+					ret <= 0 ? "formatting error" :
+							"path exceeds maximal allowed length");
+			ret = -1;
+			goto error;
+		}
+
 		chunk_status = lttng_trace_chunk_get_id(trace_chunk,
 				&chunk_id);
 		assert(chunk_status == LTTNG_TRACE_CHUNK_STATUS_OK);