tomoyo: add format attributes to functions

Format attributes on functions taking format string can help compilers
detect argument type or count mismatches.

Please the compiler when building with W=1:

    security/tomoyo/audit.c: In function ‘tomoyo_init_log’:
    security/tomoyo/audit.c:290:9: error: function ‘tomoyo_init_log’ might be a candidate for ‘gnu_printf’ format attribute [-Werror=suggest-attribute=format]
      290 |         vsnprintf(buf + pos, len - pos, fmt, args);
          |         ^~~~~~~~~
    security/tomoyo/audit.c: In function ‘tomoyo_write_log2’:
    security/tomoyo/audit.c:376:9: error: function ‘tomoyo_write_log2’ might be a candidate for ‘gnu_printf’ format attribute [-Werror=suggest-attribute=format]
      376 |         buf = tomoyo_init_log(r, len, fmt, args);
          |         ^~~
    security/tomoyo/common.c: In function ‘tomoyo_addprintf’:
    security/tomoyo/common.c:193:9: error: function ‘tomoyo_addprintf’ might be a candidate for ‘gnu_printf’ format attribute [-Werror=suggest-attribute=format]
      193 |         vsnprintf(buffer + pos, len - pos - 1, fmt, args);
          |         ^~~~~~~~~
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

security/tomoyo/common.c

@@ -184,6 +184,7 @@ static bool tomoyo_manage_by_non_root;
  *
  * Returns nothing.
  */
+__printf(3, 4)
 static void tomoyo_addprintf(char *buffer, int len, const char *fmt, ...)
 {
 	va_list args;

security/tomoyo/common.h

@@ -954,7 +954,7 @@ bool tomoyo_str_starts(char **src, const char *find);
 char *tomoyo_encode(const char *str);
 char *tomoyo_encode2(const char *str, int str_len);
 char *tomoyo_init_log(struct tomoyo_request_info *r, int len, const char *fmt,
-		      va_list args);
+		      va_list args) __printf(3, 0);
 char *tomoyo_read_token(struct tomoyo_acl_param *param);
 char *tomoyo_realpath_from_path(const struct path *path);
 char *tomoyo_realpath_nofollow(const char *pathname);
@@ -1067,7 +1067,7 @@ void tomoyo_warn_oom(const char *function);
 void tomoyo_write_log(struct tomoyo_request_info *r, const char *fmt, ...)
 	__printf(2, 3);
 void tomoyo_write_log2(struct tomoyo_request_info *r, int len, const char *fmt,
-		       va_list args);
+		       va_list args) __printf(3, 0);
 
 /********** External variable definitions. **********/