perf data: Add has_kcore_dir()

Add a helper function has_kcore_dir(), so that perf inject can determine if
it needs to keep the kcore_dir.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20220520132404.25853-5-adrian.hunter@intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/data.c

@@ -479,6 +479,20 @@ int perf_data__make_kcore_dir(struct perf_data *data, char *buf, size_t buf_sz)
 	return mkdir(buf, S_IRWXU);
 }
 
+bool has_kcore_dir(const char *path)
+{
+	char *kcore_dir;
+	int ret;
+
+	if (asprintf(&kcore_dir, "%s/kcore_dir", path) < 0)
+		return false;
+
+	ret = access(kcore_dir, F_OK);
+
+	free(kcore_dir);
+	return !ret;
+}
+
 char *perf_data__kallsyms_name(struct perf_data *data)
 {
 	char *kallsyms_name;

tools/perf/util/data.h

@@ -99,6 +99,7 @@ void perf_data__close_dir(struct perf_data *data);
 int perf_data__update_dir(struct perf_data *data);
 unsigned long perf_data__size(struct perf_data *data);
 int perf_data__make_kcore_dir(struct perf_data *data, char *buf, size_t buf_sz);
+bool has_kcore_dir(const char *path);
 char *perf_data__kallsyms_name(struct perf_data *data);
 bool is_perf_data(const char *path);
 #endif /* __PERF_DATA_H */