From 5b92fc082c835bebfa94f790e428b8c039afc457 Mon Sep 17 00:00:00 2001
From: Ian Rogers <irogers@google.com>
Date: Tue, 10 Feb 2026 17:52:40 -0800
Subject: [PATCH] perf json: Pipe mode --to-ctf support

In pipe mode the environment may not be fully initialized so be robust
to fields being NULL.

Add default handling of attr events, use the feature events to populate
the ctf writer environment.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Derek Foreman <derek.foreman@collabora.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/data-convert-bt.c | 54 +++++++++++++++++++++++++++++--
 1 file changed, 52 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/data-convert-bt.c b/tools/perf/util/data-convert-bt.c
index a22e9049ff30..ba1c8e48d495 100644
--- a/tools/perf/util/data-convert-bt.c
+++ b/tools/perf/util/data-convert-bt.c
@@ -35,6 +35,7 @@
 #include "clockid.h"
 #include "util/sample.h"
 #include "util/time-utils.h"
+#include "header.h"
 
 #ifdef HAVE_LIBTRACEEVENT
 #include <event-parse.h>
@@ -1338,7 +1339,8 @@ static void cleanup_events(struct perf_session *session)
 		struct evsel_priv *priv;
 
 		priv = evsel->priv;
-		bt_ctf_event_class_put(priv->event_class);
+		if (priv)
+			bt_ctf_event_class_put(priv->event_class);
 		zfree(&evsel->priv);
 	}
 
@@ -1387,7 +1389,7 @@ static int ctf_writer__setup_env(struct ctf_writer *cw,
 
 #define ADD(__n, __v)							\
 do {									\
-	if (bt_ctf_writer_add_environment_field(writer, __n, __v))	\
+	if (__v && bt_ctf_writer_add_environment_field(writer, __n, __v))	\
 		return -1;						\
 } while (0)
 
@@ -1403,6 +1405,52 @@ do {									\
 	return 0;
 }
 
+static int process_feature_event(const struct perf_tool *tool,
+				 struct perf_session *session,
+				 union perf_event *event)
+{
+	struct convert *c = container_of(tool, struct convert, tool);
+	struct ctf_writer *cw = &c->writer;
+	struct perf_record_header_feature *fe = &event->feat;
+
+	if (event->feat.feat_id < HEADER_LAST_FEATURE) {
+		int ret = perf_event__process_feature(session, event);
+
+		if (ret)
+			return ret;
+	}
+
+	switch (fe->feat_id) {
+	case HEADER_HOSTNAME:
+		if (session->header.env.hostname) {
+			return bt_ctf_writer_add_environment_field(cw->writer, "host",
+								   session->header.env.hostname);
+		}
+		break;
+	case HEADER_OSRELEASE:
+		if (session->header.env.os_release) {
+			return bt_ctf_writer_add_environment_field(cw->writer, "release",
+								   session->header.env.os_release);
+		}
+		break;
+	case HEADER_VERSION:
+		if (session->header.env.version) {
+			return bt_ctf_writer_add_environment_field(cw->writer, "version",
+								   session->header.env.version);
+		}
+		break;
+	case HEADER_ARCH:
+		if (session->header.env.arch) {
+			return bt_ctf_writer_add_environment_field(cw->writer, "machine",
+								   session->header.env.arch);
+		}
+		break;
+	default:
+		break;
+	}
+	return 0;
+}
+
 static int ctf_writer__setup_clock(struct ctf_writer *cw,
 				   struct perf_session *session,
 				   bool tod)
@@ -1635,6 +1683,8 @@ int bt_convert__perf2ctf(const char *input, const char *path,
 	c.tool.tracing_data    = perf_event__process_tracing_data;
 	c.tool.build_id        = perf_event__process_build_id;
 	c.tool.namespaces      = perf_event__process_namespaces;
+	c.tool.attr            = perf_event__process_attr;
+	c.tool.feature         = process_feature_event;
 	c.tool.ordering_requires_timestamps = true;
 
 	if (opts->all) {