perf parse-events: Use get/put_events_file()

Instead of accessing the trace_events_path variable directly, that may
not have been properly initialized wrt detecting where tracefs is
mounted.

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-id7hzn1ydgkxbumeve5wapqz@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

3 files changed, 43 insertions, 22 deletions

diff --git a/tools/perf/tests/parse-events.c b/tools/perf/tests/parse-events.c
index 6829dd416a99..6d57d7082637 100644
--- a/tools/perf/tests/parse-events.c
+++ b/tools/perf/tests/parse-events.c
@@ -1328,7 +1328,7 @@ static int count_tracepoints(void)
         TEST_ASSERT_VAL("Can't open events dir", events_dir);
 
         while ((events_ent = readdir(events_dir))) {
-                char sys_path[PATH_MAX];
+                char *sys_path;
                 struct dirent *sys_ent;
                 DIR *sys_dir;
 
@@ -1339,8 +1339,8 @@ static int count_tracepoints(void)
                     || !strcmp(events_ent->d_name, "header_page"))
                         continue;
 
-                scnprintf(sys_path, PATH_MAX, "%s/%s",
-                          tracing_events_path, events_ent->d_name);
+                sys_path = get_events_file(events_ent->d_name);
+                TEST_ASSERT_VAL("Can't get sys path", sys_path);
 
                 sys_dir = opendir(sys_path);
                 TEST_ASSERT_VAL("Can't open sys dir", sys_dir);
@@ -1356,6 +1356,7 @@ static int count_tracepoints(void)
                 }
 
                 closedir(sys_dir);
+                put_events_file(sys_path);
         }
 
         closedir(events_dir);
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index f9d5bbd63484..24668300b327 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -189,19 +189,19 @@ struct tracepoint_path *tracepoint_id_to_path(u64 config)
         int fd;
         u64 id;
         char evt_path[MAXPATHLEN];
-        char dir_path[MAXPATHLEN];
+        char *dir_path;
 
         sys_dir = opendir(tracing_events_path);
         if (!sys_dir)
                 return NULL;
 
         for_each_subsystem(sys_dir, sys_dirent) {
-
-                snprintf(dir_path, MAXPATHLEN, "%s/%s", tracing_events_path,
-                         sys_dirent->d_name);
+                dir_path = get_events_file(sys_dirent->d_name);
+                if (!dir_path)
+                        continue;
                 evt_dir = opendir(dir_path);
                 if (!evt_dir)
-                        continue;
+                        goto next;
 
                 for_each_event(dir_path, evt_dir, evt_dirent) {
 
@@ -217,6 +217,7 @@ struct tracepoint_path *tracepoint_id_to_path(u64 config)
                         close(fd);
                         id = atoll(id_buf);
                         if (id == config) {
+                                put_events_file(dir_path);
                                 closedir(evt_dir);
                                 closedir(sys_dir);
                                 path = zalloc(sizeof(*path));
@@ -241,6 +242,8 @@ struct tracepoint_path *tracepoint_id_to_path(u64 config)
                         }
                 }
                 closedir(evt_dir);
+next:
+                put_events_file(dir_path);
         }
 
         closedir(sys_dir);
@@ -511,14 +514,19 @@ static int add_tracepoint_multi_event(struct list_head *list, int *idx,
                                       struct parse_events_error *err,
                                       struct list_head *head_config)
 {
-        char evt_path[MAXPATHLEN];
+        char *evt_path;
         struct dirent *evt_ent;
         DIR *evt_dir;
         int ret = 0, found = 0;
 
-        snprintf(evt_path, MAXPATHLEN, "%s/%s", tracing_events_path, sys_name);
+        evt_path = get_events_file(sys_name);
+        if (!evt_path) {
+                tracepoint_error(err, errno, sys_name, evt_name);
+                return -1;
+        }
         evt_dir = opendir(evt_path);
         if (!evt_dir) {
+                put_events_file(evt_path);
                 tracepoint_error(err, errno, sys_name, evt_name);
                 return -1;
         }
@@ -544,6 +552,7 @@ static int add_tracepoint_multi_event(struct list_head *list, int *idx,
                 ret = -1;
         }
 
+        put_events_file(evt_path);
         closedir(evt_dir);
         return ret;
 }
@@ -2091,7 +2100,7 @@ void print_tracepoint_events(const char *subsys_glob, const char *event_glob,
         DIR *sys_dir, *evt_dir;
         struct dirent *sys_dirent, *evt_dirent;
         char evt_path[MAXPATHLEN];
-        char dir_path[MAXPATHLEN];
+        char *dir_path;
         char **evt_list = NULL;
         unsigned int evt_i = 0, evt_num = 0;
         bool evt_num_known = false;
@@ -2112,11 +2121,12 @@ restart:
                     !strglobmatch(sys_dirent->d_name, subsys_glob))
                         continue;
 
-                snprintf(dir_path, MAXPATHLEN, "%s/%s", tracing_events_path,
-                         sys_dirent->d_name);
+                dir_path = get_events_file(sys_dirent->d_name);
+                if (!dir_path)
+                        continue;
                 evt_dir = opendir(dir_path);
                 if (!evt_dir)
-                        continue;
+                        goto next;
 
                 for_each_event(dir_path, evt_dir, evt_dirent) {
                         if (event_glob != NULL &&
@@ -2132,11 +2142,15 @@ restart:
                                  sys_dirent->d_name, evt_dirent->d_name);
 
                         evt_list[evt_i] = strdup(evt_path);
-                        if (evt_list[evt_i] == NULL)
+                        if (evt_list[evt_i] == NULL) {
+                                put_events_file(dir_path);
                                 goto out_close_evt_dir;
+                        }
                         evt_i++;
                 }
                 closedir(evt_dir);
+next:
+                put_events_file(dir_path);
         }
         closedir(sys_dir);
 
@@ -2184,19 +2198,19 @@ int is_valid_tracepoint(const char *event_string)
         DIR *sys_dir, *evt_dir;
         struct dirent *sys_dirent, *evt_dirent;
         char evt_path[MAXPATHLEN];
-        char dir_path[MAXPATHLEN];
+        char *dir_path;
 
         sys_dir = opendir(tracing_events_path);
         if (!sys_dir)
                 return 0;
 
         for_each_subsystem(sys_dir, sys_dirent) {
-
-                snprintf(dir_path, MAXPATHLEN, "%s/%s", tracing_events_path,
-                         sys_dirent->d_name);
+                dir_path = get_events_file(sys_dirent->d_name);
+                if (!dir_path)
+                        continue;
                 evt_dir = opendir(dir_path);
                 if (!evt_dir)
-                        continue;
+                        goto next;
 
                 for_each_event(dir_path, evt_dir, evt_dirent) {
                         snprintf(evt_path, MAXPATHLEN, "%s:%s",
@@ -2208,6 +2222,8 @@ int is_valid_tracepoint(const char *event_string)
                         }
                 }
                 closedir(evt_dir);
+next:
+                put_events_file(dir_path);
         }
         closedir(sys_dir);
         return 0;
diff --git a/tools/perf/util/trace-event.c b/tools/perf/util/trace-event.c
index 16a776371d03..1aa368603268 100644
--- a/tools/perf/util/trace-event.c
+++ b/tools/perf/util/trace-event.c
@@ -75,6 +75,7 @@ void trace_event__cleanup(struct trace_event *t)
 static struct event_format*
 tp_format(const char *sys, const char *name)
 {
+        char *tp_dir = get_events_file(sys);
         struct pevent *pevent = tevent.pevent;
         struct event_format *event = NULL;
         char path[PATH_MAX];
@@ -82,8 +83,11 @@ tp_format(const char *sys, const char *name)
         char *data;
         int err;
 
-        scnprintf(path, PATH_MAX, "%s/%s/%s/format",
-                  tracing_events_path, sys, name);
+        if (!tp_dir)
+                return ERR_PTR(-errno);
+
+        scnprintf(path, PATH_MAX, "%s/%s/format", tp_dir, name);
+        put_events_file(tp_dir);
 
         err = filename__read_str(path, &data, &size);
         if (err)