secure/snprintf_chk.c

   1 /*
   2  * Copyright (c) 2007 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #include <stdlib.h>
  25 #include <stdio.h>
  26 #include <stdarg.h>
  27 #include <limits.h>
  28
  29 extern void __chk_fail (void) __attribute__((__noreturn__));
  30 extern int __snprintf_chk (char * __restrict, size_t, int, size_t,
  31                            const char * __restrict, ...)
  32   __DARWIN_LDBL_COMPAT (__snprintf_chk);
  33
  34 int
  35 __snprintf_chk (char *s, size_t maxlen, int flags, size_t len,
  36                 const char *format, ...)
  37 {
  38   va_list arg;
  39   int done;
  40
  41   if (__builtin_expect (maxlen > len, 0))
  42     __chk_fail ();
  43
  44   va_start (arg, format);
  45
  46   done = vsnprintf (s, maxlen, format, arg);
  47
  48   va_end (arg);
  49
  50   return done;
  51 }