debug/strlcat_chk.c

   1 /* Fortified version of strlcat.
   2    Copyright (C) 2023 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <string.h>
  20
  21 /* Check that the user-supplied size does not exceed the
  22    compiler-determined size, and then forward to strlcat.  */
  23 size_t
  24 __strlcat_chk (char *__restrict s1, const char *__restrict s2,
  25                size_t n, size_t s1len)
  26 {
  27   if (__glibc_unlikely (s1len < n))
  28     __chk_fail ();
  29
  30   return __strlcat (s1, s2, n);
  31 }