glibc/debug/strcpy_chk.c

68 lines
1.7 KiB
C

/* Copyright (C) 1991, 1997, 2000, 2003, 2004 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/>. */
#include <stddef.h>
#include <string.h>
#include <memcopy.h>
#undef strcpy
/* Copy SRC to DEST with checking of destination buffer overflow. */
char *
__strcpy_chk (dest, src, destlen)
char *dest;
const char *src;
size_t destlen;
{
reg_char c;
char *s = (char *) src;
const ptrdiff_t off = dest - s;
while (__builtin_expect (destlen >= 4, 0))
{
c = s[0];
s[off] = c;
if (c == '\0')
return dest;
c = s[1];
s[off + 1] = c;
if (c == '\0')
return dest;
c = s[2];
s[off + 2] = c;
if (c == '\0')
return dest;
c = s[3];
s[off + 3] = c;
if (c == '\0')
return dest;
destlen -= 4;
s += 4;
}
do
{
if (__builtin_expect (destlen-- == 0, 0))
__chk_fail ();
c = *s;
*(s++ + off) = c;
}
while (c != '\0');
return dest;
}