1/* Erasure of sensitive data, generic implementation.
2 Copyright (C) 2016-2020 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19/* An assembler implementation of explicit_bzero can be created as an
20 assembler alias of an optimized bzero implementation.
21 Architecture-specific implementations also need to define
22 __explicit_bzero_chk. */
23
24#include <string.h>
25
26/* glibc-internal users use __explicit_bzero_chk, and explicit_bzero
27 redirects to that. */
28#undef explicit_bzero
29
30/* Set LEN bytes of S to 0. The compiler will not delete a call to
31 this function, even if S is dead after the call. */
32void
33explicit_bzero (void *s, size_t len)
34{
35 memset (s, '\0', len);
36 /* Compiler barrier. */
37 asm volatile ("" ::: "memory");
38}
39