debug/wcpcpy_chk.c

   1 /* Copyright (C) 1996-2021 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1996.
   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 <wchar.h>
  20
  21 #define __need_ptrdiff_t
  22 #include <stddef.h>
  23
  24
  25 /* Copy SRC to DEST, returning the address of the terminating L'\0' in
  26    DEST.  Check for overflows.  */
  27 wchar_t *
  28 __wcpcpy_chk (wchar_t *dest, const wchar_t *src, size_t destlen)
  29 {
  30   wchar_t *wcp = (wchar_t *) dest - 1;
  31   wint_t c;
  32   const ptrdiff_t off = src - dest + 1;
  33
  34   do
  35     {
  36       if (__glibc_unlikely (destlen-- == 0))
  37         __chk_fail ();
  38       c = wcp[off];
  39       *++wcp = c;
  40     }
  41   while (c != L'\0');
  42
  43   return wcp;
  44 }