perf thread_map: Correctly size buffer used with dirent->dt_name

The size of dirent->dt_name is NAME_MAX + 1, but the size for the 'path'
buffer is hard coded at 256, which may truncate it because we also
prepend "/proc/", so that all that into account and thank gcc 7 for this
warning:

  /git/linux/tools/perf/util/thread_map.c: In function 'thread_map__new_by_uid':
  /git/linux/tools/perf/util/thread_map.c:119:39: error: '%s' directive output may be truncated writing up to 255 bytes into a region of size 250 [-Werror=format-truncation=]
     snprintf(path, sizeof(path), "/proc/%s", dirent->d_name);
                                         ^~
  In file included from /usr/include/stdio.h:939:0,
                   from /git/linux/tools/perf/util/thread_map.c:5:
  /usr/include/bits/stdio2.h:64:10: note: '__builtin___snprintf_chk' output between 7 and 262 bytes into a destination of size 256
     return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
          __bos (__s), __fmt, __va_arg_pack ());
          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Cc: Adrian Hunter <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

0 files changed, 0 insertions, 0 deletions