perf tools: Use readdir() instead of deprecated readdir_r() again

commit 22a9f41b555673e7499b97acf3ffb07bf0af31ad upstream.

The readdir() function is thread safe as long as just one thread uses a
DIR, which is the case when parsing tracepoint event definitions, to
avoid breaking the build with glibc-2.23.90 (upcoming 2.24), use it
instead of readdir_r().

See: http://man7.org/linux/man-pages/man3/readdir.3.html

"However, in modern implementations (including the glibc implementation),
concurrent calls to readdir() that specify different directory streams
are thread-safe.  In cases where multiple threads must read from the
same directory stream, using readdir() with external synchronization is
still preferable to the use of the deprecated readdir_r(3) function."

Noticed while building on a Fedora Rawhide docker container.

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: http://lkml.kernel.org/n/tip-wddn49r6bz6wq4ee3dxbl7lo@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index a35db828bd0d32d09068fed2e1c451e28db90dbf..38304b7e4f810d261a0286f097760f26ea573b83 100644 (file)
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -138,11 +138,11 @@ struct event_symbol event_symbols_sw[PERF_COUNT_SW_MAX] = {
 #define PERF_EVENT_TYPE(config)                __PERF_EVENT_FIELD(config, TYPE)
 #define PERF_EVENT_ID(config)          __PERF_EVENT_FIELD(config, EVENT)
 
-#define for_each_subsystem(sys_dir, sys_dirent, sys_next)             \
-       while (!readdir_r(sys_dir, &sys_dirent, &sys_next) && sys_next)        \
-       if (sys_dirent.d_type == DT_DIR &&                                     \
-          (strcmp(sys_dirent.d_name, ".")) &&                                 \
-          (strcmp(sys_dirent.d_name, "..")))
+#define for_each_subsystem(sys_dir, sys_dirent)                        \
+       while ((sys_dirent = readdir(sys_dir)) != NULL)         \
+               if (sys_dirent->d_type == DT_DIR &&             \
+                   (strcmp(sys_dirent->d_name, ".")) &&        \
+                   (strcmp(sys_dirent->d_name, "..")))
 
 static int tp_event_has_id(struct dirent *sys_dir, struct dirent *evt_dir)
 {
@@ -159,12 +159,12 @@ static int tp_event_has_id(struct dirent *sys_dir, struct dirent *evt_dir)
        return 0;
 }
 
-#define for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next)             \
-       while (!readdir_r(evt_dir, &evt_dirent, &evt_next) && evt_next)        \
-       if (evt_dirent.d_type == DT_DIR &&                                     \
-          (strcmp(evt_dirent.d_name, ".")) &&                                 \
-          (strcmp(evt_dirent.d_name, "..")) &&                                \
-          (!tp_event_has_id(&sys_dirent, &evt_dirent)))
+#define for_each_event(sys_dirent, evt_dir, evt_dirent)                \
+       while ((evt_dirent = readdir(evt_dir)) != NULL)         \
+               if (evt_dirent->d_type == DT_DIR &&             \
+                   (strcmp(evt_dirent->d_name, ".")) &&        \
+                   (strcmp(evt_dirent->d_name, "..")) &&       \
+                   (!tp_event_has_id(sys_dirent, evt_dirent)))
 
 #define MAX_EVENT_LENGTH 512
 
@@ -173,7 +173,7 @@ struct tracepoint_path *tracepoint_id_to_path(u64 config)
 {
        struct tracepoint_path *path = NULL;
        DIR *sys_dir, *evt_dir;
-       struct dirent *sys_next, *evt_next, sys_dirent, evt_dirent;
+       struct dirent *sys_dirent, *evt_dirent;
        char id_buf[24];
        int fd;
        u64 id;
@@ -184,18 +184,18 @@ struct tracepoint_path *tracepoint_id_to_path(u64 config)
        if (!sys_dir)
                return NULL;
 
-       for_each_subsystem(sys_dir, sys_dirent, sys_next) {
+       for_each_subsystem(sys_dir, sys_dirent) {
 
                snprintf(dir_path, MAXPATHLEN, "%s/%s", tracing_events_path,
-                        sys_dirent.d_name);
+                        sys_dirent->d_name);
                evt_dir = opendir(dir_path);
                if (!evt_dir)
                        continue;
 
-               for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next) {
+               for_each_event(sys_dirent, evt_dir, evt_dirent) {
 
                        snprintf(evt_path, MAXPATHLEN, "%s/%s/id", dir_path,
-                                evt_dirent.d_name);
+                                evt_dirent->d_name);
                        fd = open(evt_path, O_RDONLY);
                        if (fd < 0)
                                continue;
@@ -220,9 +220,9 @@ struct tracepoint_path *tracepoint_id_to_path(u64 config)
                                        free(path);
                                        return NULL;
                                }
-                               strncpy(path->system, sys_dirent.d_name,
+                               strncpy(path->system, sys_dirent->d_name,
                                        MAX_EVENT_LENGTH);
-                               strncpy(path->name, evt_dirent.d_name,
+                               strncpy(path->name, evt_dirent->d_name,
                                        MAX_EVENT_LENGTH);
                                return path;
                        }
@@ -1629,7 +1629,7 @@ void print_tracepoint_events(const char *subsys_glob, const char *event_glob,
                             bool name_only)
 {
        DIR *sys_dir, *evt_dir;
-       struct dirent *sys_next, *evt_next, sys_dirent, evt_dirent;
+       struct dirent *sys_dirent, *evt_dirent;
        char evt_path[MAXPATHLEN];
        char dir_path[MAXPATHLEN];
        char **evt_list = NULL;
@@ -1647,20 +1647,20 @@ restart:
                        goto out_close_sys_dir;
        }
 
-       for_each_subsystem(sys_dir, sys_dirent, sys_next) {
+       for_each_subsystem(sys_dir, sys_dirent) {
                if (subsys_glob != NULL &&
-                   !strglobmatch(sys_dirent.d_name, subsys_glob))
+                   !strglobmatch(sys_dirent->d_name, subsys_glob))
                        continue;
 
                snprintf(dir_path, MAXPATHLEN, "%s/%s", tracing_events_path,
-                        sys_dirent.d_name);
+                        sys_dirent->d_name);
                evt_dir = opendir(dir_path);
                if (!evt_dir)
                        continue;
 
-               for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next) {
+               for_each_event(sys_dirent, evt_dir, evt_dirent) {
                        if (event_glob != NULL &&
-                           !strglobmatch(evt_dirent.d_name, event_glob))
+                           !strglobmatch(evt_dirent->d_name, event_glob))
                                continue;
 
                        if (!evt_num_known) {
@@ -1669,7 +1669,7 @@ restart:
                        }
 
                        snprintf(evt_path, MAXPATHLEN, "%s:%s",
-                                sys_dirent.d_name, evt_dirent.d_name);
+                                sys_dirent->d_name, evt_dirent->d_name);
 
                        evt_list[evt_i] = strdup(evt_path);
                        if (evt_list[evt_i] == NULL)
@@ -1722,7 +1722,7 @@ out_close_sys_dir:
 int is_valid_tracepoint(const char *event_string)
 {
        DIR *sys_dir, *evt_dir;
-       struct dirent *sys_next, *evt_next, sys_dirent, evt_dirent;
+       struct dirent *sys_dirent, *evt_dirent;
        char evt_path[MAXPATHLEN];
        char dir_path[MAXPATHLEN];
 
@@ -1730,17 +1730,17 @@ int is_valid_tracepoint(const char *event_string)
        if (!sys_dir)
                return 0;
 
-       for_each_subsystem(sys_dir, sys_dirent, sys_next) {
+       for_each_subsystem(sys_dir, sys_dirent) {
 
                snprintf(dir_path, MAXPATHLEN, "%s/%s", tracing_events_path,
-                        sys_dirent.d_name);
+                        sys_dirent->d_name);
                evt_dir = opendir(dir_path);
                if (!evt_dir)
                        continue;
 
-               for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next) {
+               for_each_event(sys_dirent, evt_dir, evt_dirent) {
                        snprintf(evt_path, MAXPATHLEN, "%s:%s",
-                                sys_dirent.d_name, evt_dirent.d_name);
+                                sys_dirent->d_name, evt_dirent->d_name);
                        if (!strcmp(evt_path, event_string)) {
                                closedir(evt_dir);
                                closedir(sys_dir);