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.
40 lines
1.4 KiB
C
40 lines
1.4 KiB
C
/* Erasure of sensitive data, generic implementation.
|
|
Copyright (C) 2016-2025 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/>. */
|
|
|
|
/* An assembler implementation of memset_explicit can be created as an
|
|
assembler alias of an optimized memset implementation.
|
|
Architecture-specific implementations also need to define
|
|
__memset_explicit_chk. */
|
|
|
|
#include <string.h>
|
|
|
|
/* glibc-internal users use __memset_explicit_chk, and memset_explicit
|
|
redirects to that. */
|
|
#undef memset_explicit
|
|
|
|
/* Set LEN bytes of S to C. The compiler will not delete a call to
|
|
this function, even if S is dead after the call. */
|
|
void *
|
|
memset_explicit (void *s, int c, size_t len)
|
|
{
|
|
memset (s, c, len);
|
|
/* Compiler barrier. */
|
|
asm volatile ("" ::: "memory");
|
|
return s;
|
|
}
|