mirror of
https://sourceware.org/git/glibc.git
synced 2025-10-27 12:15:39 +03:00
0f201f4a81
Add the C23 memset_explicit function to glibc. Everything here is closely based on the approach taken for explicit_bzero. This includes the bits that relate to internal uses of explicit_bzero within glibc (although we don't currently have any such internal uses of memset_explicit), and also includes the nonnull attribute (when we move to nonnull_if_nonzero for various functions following C2y, this function should be included in that change). The function is declared both for __USE_MISC and for __GLIBC_USE (ISOC23) (so by default not just for compilers defaulting to C23 mode). Tested for x86_64 and x86.
45 lines
1.8 KiB
C
45 lines
1.8 KiB
C
/* Generic implementation of __memset_explicit_chk.
|
|
Copyright (C) 1991-2025 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
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
/* This is the generic definition of __memset_explicit_chk. The
|
|
__memset_explicit_chk symbol is used as the implementation of
|
|
memset_explicit throughout glibc. If this file is overridden by an
|
|
architecture, both __memset_explicit_chk and
|
|
__memset_explicit_chk_internal have to be defined (the latter not as
|
|
an IFUNC). */
|
|
|
|
#include <string.h>
|
|
|
|
void *
|
|
__memset_explicit_chk (void *dst, int c, size_t len, size_t dstlen)
|
|
{
|
|
/* Inline __memset_chk to avoid a PLT reference to __memset_chk. */
|
|
if (__glibc_unlikely (dstlen < len))
|
|
__chk_fail ();
|
|
memset (dst, c, len);
|
|
/* Compiler barrier. */
|
|
asm volatile ("" ::: "memory");
|
|
return dst;
|
|
}
|
|
|
|
/* libc-internal references use the hidden
|
|
__memset_explicit_chk_internal symbol. This is necessary if
|
|
__memset_explicit_chk is implemented as an IFUNC because some
|
|
targets do not support hidden references to IFUNC symbols. */
|
|
strong_alias (__memset_explicit_chk, __memset_explicit_chk_internal)
|