tools lib api fs tracing_path: Introduce get/put_events_file() helpers

To make reading events files a tad more compact than with
get_tracing_files("events/foo").

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-do6xgtwpmfl8zjs1euxsd2du@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/lib/api/fs/tracing_path.c

@@ -86,6 +86,21 @@ void put_tracing_file(char *file)
 	free(file);
 }
 
+char *get_events_file(const char *name)
+{
+	char *file;
+
+	if (asprintf(&file, "%s/events/%s", tracing_path_mount(), name) < 0)
+		return NULL;
+
+	return file;
+}
+
+void put_events_file(char *file)
+{
+	free(file);
+}
+
 int tracing_path__strerror_open_tp(int err, char *buf, size_t size,
 				   const char *sys, const char *name)
 {

tools/lib/api/fs/tracing_path.h

@@ -12,5 +12,10 @@ const char *tracing_path_mount(void);
 char *get_tracing_file(const char *name);
 void put_tracing_file(char *file);
 
+char *get_events_file(const char *name);
+void put_events_file(char *file);
+
+#define zput_events_file(ptr) ({ free(*ptr); *ptr = NULL; })
+
 int tracing_path__strerror_open_tp(int err, char *buf, size_t size, const char *sys, const char *name);
 #endif /* __API_FS_TRACING_PATH_H */

tools/perf/util/trace-event-info.c

@@ -103,11 +103,10 @@ out:
 
 static int record_header_files(void)
 {
-	char *path;
+	char *path = get_events_file("header_page");
 	struct stat st;
 	int err = -EIO;
 
-	path = get_tracing_file("events/header_page");
 	if (!path) {
 		pr_debug("can't get tracing/events/header_page");
 		return -ENOMEM;
@@ -128,9 +127,9 @@ static int record_header_files(void)
 		goto out;
 	}
 
-	put_tracing_file(path);
+	put_events_file(path);
 
-	path = get_tracing_file("events/header_event");
+	path = get_events_file("header_event");
 	if (!path) {
 		pr_debug("can't get tracing/events/header_event");
 		err = -ENOMEM;
@@ -154,7 +153,7 @@ static int record_header_files(void)
 
 	err = 0;
 out:
-	put_tracing_file(path);
+	put_events_file(path);
 	return err;
 }
 
@@ -243,7 +242,7 @@ static int record_ftrace_files(struct tracepoint_path *tps)
 	char *path;
 	int ret;
 
-	path = get_tracing_file("events/ftrace");
+	path = get_events_file("ftrace");
 	if (!path) {
 		pr_debug("can't get tracing/events/ftrace");
 		return -ENOMEM;