[PATCH 3/4] perf inject: Try chroot directory when reading build-id

[Namhyung Kim <namhyung@kernel.org>]

When reading build-id from a DSO, it should consider if it's from a
chroot task.  In that case, the path is different so it needs to
prepend the root directory to access the file correctly.

Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/builtin-inject.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
index fbf43a454cba..3be581abbdb6 100644
--- a/tools/perf/builtin-inject.c
+++ b/tools/perf/builtin-inject.c
@@ -25,6 +25,7 @@
 #include "util/synthetic-events.h"
 #include "util/thread.h"
 #include "util/namespaces.h"
+#include "util/util.h"
 
 #include <linux/err.h>
 #include <subcmd/parse-options.h>
@@ -550,6 +551,15 @@ static int dso__read_build_id(struct dso *dso)
 	nsinfo__mountns_enter(dso->nsinfo, &nsc);
 	if (filename__read_build_id(dso->long_name, &dso->bid) > 0)
 		dso->has_build_id = true;
+	else if (dso->nsinfo) {
+		char *new_name;
+
+		new_name = filename_with_chroot(dso->nsinfo->pid,
+						dso->long_name);
+		if (new_name && filename__read_build_id(new_name, &dso->bid) > 0)
+			dso->has_build_id = true;
+		free(new_name);
+	}
 	nsinfo__mountns_exit(&nsc);
 
 	return dso->has_build_id ? 0 : -1;
-- 
2.35.0.rc2.247.g8bbb082509-goog