[tip: perf/urgent] perf parse-events: Use asprintf() instead of strncpy() to read tracepoint files

[tip-bot2 for Arnaldo Carvalho de Melo]

The following commit has been merged into the perf/urgent branch of tip:

Commit-ID:     7125f204501ed55493593209c6c71ac7c38f6b6c
Gitweb:        https://git.kernel.org/tip/7125f204501ed55493593209c6c71ac7c38f6b6c
Author:        Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate:    Mon, 02 Mar 2020 11:55:47 -03:00
Committer:     Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitterDate: Mon, 02 Mar 2020 11:55:47 -03:00

perf parse-events: Use asprintf() instead of strncpy() to read tracepoint files

Make the code more compact by using asprintf() instead of malloc()+strncpy() which also uses
less memory and avoids these warnings with gcc 10:

    CC       /tmp/build/perf/util/cloexec.o
  In file included from /usr/include/string.h:495,
                   from util/parse-events.h:12,
                   from util/parse-events.c:18:
  In function âstrncpyâ,
      inlined from âtracepoint_id_to_pathâ at util/parse-events.c:271:5:
  /usr/include/bits/string_fortified.h:106:10: error: â__builtin_strncpyâ offset [275, 511] from the object at âsys_direntâ is out of the bounds of referenced subobject âd_nameâ with type âchar[256]â at offset 19 [-Werror=array-bounds]
    106 |   return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest));
        |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  In file included from /usr/include/dirent.h:61,
                   from util/parse-events.c:5:
  util/parse-events.c: In function âtracepoint_id_to_pathâ:
  /usr/include/bits/dirent.h:33:10: note: subobject âd_nameâ declared here
     33 |     char d_name[256];  /* We must not include limits.h! */
        |          ^~~~~~
  In file included from /usr/include/string.h:495,
                   from util/parse-events.h:12,
                   from util/parse-events.c:18:
  In function âstrncpyâ,
      inlined from âtracepoint_id_to_pathâ at util/parse-events.c:273:5:
  /usr/include/bits/string_fortified.h:106:10: error: â__builtin_strncpyâ offset [275, 511] from the object at âevt_direntâ is out of the bounds of referenced subobject âd_nameâ with type âchar[256]â at offset 19 [-Werror=array-bounds]
    106 |   return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest));
        |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  In file included from /usr/include/dirent.h:61,
                   from util/parse-events.c:5:
  util/parse-events.c: In function âtracepoint_id_to_pathâ:
  /usr/include/bits/dirent.h:33:10: note: subobject âd_nameâ declared here
     33 |     char d_name[256];  /* We must not include limits.h! */
        |          ^~~~~~
    CC       /tmp/build/perf/util/call-path.o

Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Link: http://lore.kernel.org/lkml/20200302145535.GA28183@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/parse-events.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index c01ba6f..a149958 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -257,21 +257,15 @@ struct tracepoint_path *tracepoint_id_to_path(u64 config)
 				path = zalloc(sizeof(*path));
 				if (!path)
 					return NULL;
-				path->system = malloc(MAX_EVENT_LENGTH);
-				if (!path->system) {
+				if (asprintf(&path->system, "%.*s", MAX_EVENT_LENGTH, sys_dirent->d_name) < 0) {
 					free(path);
 					return NULL;
 				}
-				path->name = malloc(MAX_EVENT_LENGTH);
-				if (!path->name) {
+				if (asprintf(&path->name, "%.*s", MAX_EVENT_LENGTH, evt_dirent->d_name) < 0) {
 					zfree(&path->system);
 					free(path);
 					return NULL;
 				}
-				strncpy(path->system, sys_dirent->d_name,
-					MAX_EVENT_LENGTH);
-				strncpy(path->name, evt_dirent->d_name,
-					MAX_EVENT_LENGTH);
 				return path;
 			}
 		}