glibc/debug/stpncpy_chk.c

/* Copyright (C) 1993-2017 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

/* This is almost copied from strncpy.c, written by Torbjorn Granlund.  */

#include <string.h>


/* Copy no more than N characters of SRC to DEST, returning the address of
   the terminating '\0' in DEST, if any, or else DEST + N.  */
char *
__stpncpy_chk (char *dest, const char *src, size_t n, size_t destlen)
{
  if (__builtin_expect (destlen < n, 0))
    __chk_fail ();

  return __stpncpy (dest, src, n);
}