perf parse-events: Fix unchecked usage of strncpy()

Commit-ID:  d18302245c157e0cd87efe20b3ce530265907ca5
Gitweb:     https://git.kernel.org/tip/d18302245c157e0cd87efe20b3ce530265907ca5
Author:     Arnaldo Carvalho de Melo <[email protected]>
AuthorDate: Thu, 6 Dec 2018 13:52:13 -0300
Committer:  Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Thu, 6 Dec 2018 16:42:53 -0300

perf parse-events: Fix unchecked usage of strncpy()

The strncpy() function may leave the destination string buffer unterminated, better use strlcpy() that we have a __weak fallback implementation for systems without it.

This fixes this warning on an Alpine Linux Edge system with gcc 8.2:

util/parse-events.c: In function 'print_symbol_events':
util/parse-events.c:2465:4: error: 'strncpy' specified bound 100 equals destination size [-Werror=stringop-truncation]

      strncpy(name, syms->symbol, MAX_NAME_LEN);
      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  In function 'print_symbol_events.constprop',
      inlined from 'print_events' at util/parse-events.c:2508:2:
  util/parse-events.c:2465:4: error: 'strncpy' specified bound 100 equals destination size [-Werror=stringop-truncation]
      strncpy(name, syms->symbol, MAX_NAME_LEN);
      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  In function 'print_symbol_events.constprop',
      inlined from 'print_events' at util/parse-events.c:2511:2:
  util/parse-events.c:2465:4: error: 'strncpy' specified bound 100 equals destination size [-Werror=stringop-truncation]
      strncpy(name, syms->symbol, MAX_NAME_LEN);
      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

cc1: all warnings being treated as errors

---
 tools/perf/util/parse-events.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 59be3466d64d..920e1e6551dd 100644
@@ -2462,7 +2462,7 @@ restart:
 		if (!name_only && strlen(syms->alias))
 			snprintf(name, MAX_NAME_LEN, "%s OR %s", syms->symbol, syms->alias);
 		else
-			strncpy(name, syms->symbol, MAX_NAME_LEN);
+			strlcpy(name, syms->symbol, MAX_NAME_LEN);
 
 		evt_list[evt_i] = strdup(name);
 		if (evt_list[evt_i] == NULL)