debug/sprintf_chk.c

   1 /* Copyright (C) 1991-2022 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <stdarg.h>
  19 #include <libio/libioP.h>
  20
  21
  22 /* Write formatted output into S, according to the format string FORMAT.  */
  23 int
  24 ___sprintf_chk (char *s, int flag, size_t slen, const char *format, ...)
  25 {
  26   /* For flag > 0 (i.e. __USE_FORTIFY_LEVEL > 1) request that %n
  27      can only come from read-only format strings.  */
  28   unsigned int mode = (flag > 0) ? PRINTF_FORTIFY : 0;
  29   va_list ap;
  30   int ret;
  31
  32   /* Regardless of the value of flag, let __vsprintf_internal know that
  33      this is a call from *printf_chk.  */
  34   mode |= PRINTF_CHK;
  35
  36   if (slen == 0)
  37     __chk_fail ();
  38
  39   va_start (ap, format);
  40   ret = __vsprintf_internal (s, slen, format, ap, mode);
  41   va_end (ap);
  42
  43   return ret;
  44 }
  45 ldbl_strong_alias (___sprintf_chk, __sprintf_chk)