Fix: path of snapshots with a relay and default URI

When recording a snapshot to a relay without custom URI (ex:
net://localhost vs net://localhost/custom), the snapshots end up being
stored in ~/lttng-traces/<hostname>/snapshot-XXX instead of being inside
the <session-name> folder like on local snapshots. We would expect the
path to be: ~/lttng-traces/<hostname>/<session-name>/snapshot-XXX

So there is a discrepancy between the local and remote behaviour. This
behaviour has been there since at least v2.6, maybe earlier.

Moreover, there is nothing that informs the user about the default
snapshot name, so it is not possible to know where a snapshot has been
stored.

After parsing the URI provided by the user, we now check if a custom
name was provided or copy the session name there. This is the same
operation performed in _lttng_create_session_ext.

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

diff --git a/src/lib/lttng-ctl/lttng-ctl.c b/src/lib/lttng-ctl/lttng-ctl.c
index a1e10f25e82176393f92206c2779d09355c063e6..3db9b89b440d12796ce7565423cac04d2f7db2ad 100644 (file)
--- a/src/lib/lttng-ctl/lttng-ctl.c
+++ b/src/lib/lttng-ctl/lttng-ctl.c
@@ -2485,9 +2485,22 @@ int lttng_create_session_snapshot(const char *name, const char *snapshot_url)
 
        lsm.u.uri.size = size;
 
+       /*
+        * If the user does not specify a custom subdir, use the session name.
+        */
+       if (size > 0 && uris[0].dtype != LTTNG_DST_PATH && strlen(uris[0].subdir) == 0) {
+               ret = snprintf(uris[0].subdir, sizeof(uris[0].subdir), "%s", name);
+               if (ret < 0) {
+                       PERROR("snprintf uri subdir");
+                       ret = -LTTNG_ERR_FATAL;
+                       goto error;
+               }
+       }
+
        ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(&lsm, uris,
                        sizeof(struct lttng_uri) * size, NULL);
 
+error:
        free(uris);
        return ret;
 }