Metadata: add env fields to ease life of viewer

[lttng-tools.git] / src / bin / lttng-sessiond / ust-metadata.c

diff --git a/src/bin/lttng-sessiond/ust-metadata.c b/src/bin/lttng-sessiond/ust-metadata.c
index a657f7c5d3d26b62472e66ecef3f188e987ee121..f05c14c323505e9b35027953491a22e08a39cf88 100644 (file)
--- a/src/bin/lttng-sessiond/ust-metadata.c
+++ b/src/bin/lttng-sessiond/ust-metadata.c
@@ -217,6 +217,41 @@ void sanitize_ctf_identifier(char *out, const char *in)
        }
 }
 
+static
+int print_escaped_ctf_string(struct ust_registry_session *session, const char *string)
+{
+       int ret;
+       size_t i;
+       char cur;
+
+       i = 0;
+       cur = string[i];
+       while (cur != '\0') {
+               switch (cur) {
+               case '\n':
+                       ret = lttng_metadata_printf(session, "%s", "\\n");
+                       break;
+               case '\\':
+               case '"':
+                       ret = lttng_metadata_printf(session, "%c", '\\');
+                       if (ret)
+                               goto error;
+                       /* We still print the current char */
+                       /* Fallthrough */
+               default:
+                       ret = lttng_metadata_printf(session, "%c", cur);
+                       break;
+               }
+
+               if (ret)
+                       goto error;
+
+               cur = string[++i];
+       }
+error:
+       return ret;
+}
+
 /* Called with session registry mutex held. */
 static
 int ust_metadata_enum_statedump(struct ust_registry_session *session,
@@ -869,6 +904,71 @@ int64_t measure_clock_offset(void)
        return offset_best_sample.offset;
 }
 
+static
+int print_metadata_session_information(struct ust_registry_session *registry)
+{
+       int ret;
+       struct ltt_session *session = NULL;
+       char creation_time[ISO8601_LEN];
+
+       rcu_read_lock();
+       session = session_find_by_id(registry->tracing_id);
+       if (!session) {
+               ret = -1;
+               goto error;
+       }
+
+
+       /* Print the trace name */
+       ret = lttng_metadata_printf(registry, " trace_name = \"");
+       if (ret) {
+               goto error;
+       }
+
+       /*
+        * This is necessary since the creation time is present in the session
+        * name when it is generated.
+        */
+       if (session->has_auto_generated_name) {
+               ret = print_escaped_ctf_string(registry, DEFAULT_SESSION_NAME);
+       } else {
+               ret = print_escaped_ctf_string(registry, session->name);
+       }
+       if (ret) {
+               goto error;
+       }
+
+       ret = lttng_metadata_printf(registry, "\";\n");
+       if (ret) {
+               goto error;
+       }
+
+       /* Prepare creation time */
+       ret = time_t_to_ISO8601(creation_time, sizeof(creation_time),
+                       session->creation_time);
+
+       if (ret) {
+               goto error;
+       }
+
+       /* Output the reste of the information */
+       ret = lttng_metadata_printf(registry,
+               "       trace_creation_time = \"%s\";\n"
+               "       hostname = \"%s\";\n",
+               creation_time,
+               session->hostname);
+       if (ret) {
+               goto error;
+       }
+
+error:
+       if (session) {
+               session_put(session);
+       }
+       rcu_read_unlock();
+       return ret;
+}
+
 /*
  * Should be called with session registry mutex held.
  */
@@ -880,7 +980,6 @@ int ust_metadata_session_statedump(struct ust_registry_session *session,
        char uuid_s[UUID_STR_LEN],
                clock_uuid_s[UUID_STR_LEN];
        int ret = 0;
-       char hostname[HOST_NAME_MAX];
 
        assert(session);
 
@@ -930,25 +1029,28 @@ int ust_metadata_session_statedump(struct ust_registry_session *session,
        if (ret)
                goto end;
 
-       /* ignore error, just use empty string if error. */
-       hostname[0] = '\0';
-       ret = gethostname(hostname, sizeof(hostname));
-       if (ret && errno == ENAMETOOLONG)
-               hostname[HOST_NAME_MAX - 1] = '\0';
        ret = lttng_metadata_printf(session,
                "env {\n"
-               "       hostname = \"%s\";\n"
                "       domain = \"ust\";\n"
                "       tracer_name = \"lttng-ust\";\n"
                "       tracer_major = %u;\n"
-               "       tracer_minor = %u;\n",
-               hostname,
+               "       tracer_minor = %u;\n"
+               "       tracer_buffering_scheme = \"%s\";\n"
+               "       tracer_buffering_id = %u;\n"
+               "       isa_length = %u;\n",
                major,
-               minor
+               minor,
+               app ? "pid" : "uid",
+               app ? (int) app->uid : (int) session->tracing_uid,
+               session->bits_per_long
                );
        if (ret)
                goto end;
 
+       ret = print_metadata_session_information(session);
+       if (ret)
+               goto end;
+
        /*
         * If per-application registry, we can output extra information
         * about the application.