debug/wcpcpy_chk.c

   1 /* Copyright (C) 1996-2022 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 <wchar.h>
  19
  20 #define __need_ptrdiff_t
  21 #include <stddef.h>
  22
  23
  24 /* Copy SRC to DEST, returning the address of the terminating L'\0' in
  25    DEST.  Check for overflows.  */
  26 wchar_t *
  27 __wcpcpy_chk (wchar_t *dest, const wchar_t *src, size_t destlen)
  28 {
  29   wchar_t *wcp = (wchar_t *) dest - 1;
  30   wint_t c;
  31   const ptrdiff_t off = src - dest + 1;
  32
  33   do
  34     {
  35       if (__glibc_unlikely (destlen-- == 0))
  36         __chk_fail ();
  37       c = wcp[off];
  38       *++wcp = c;
  39     }
  40   while (c != L'\0');
  41
  42   return wcp;
  43 }