1 /*-------------------------------------------------------------------------
2 *
3 * explicit_bzero.c
4 *
5 * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
6 * Portions Copyright (c) 1994, Regents of the University of California
7 *
8 *
9 * IDENTIFICATION
10 * src/port/explicit_bzero.c
11 *
12 *-------------------------------------------------------------------------
13 */
14
15 #include "c.h"
16
17 #if defined(HAVE_MEMSET_S)
18
19 void
explicit_bzero(void * buf,size_t len)20 explicit_bzero(void *buf, size_t len)
21 {
22 (void) memset_s(buf, len, 0, len);
23 }
24
25 #elif defined(WIN32)
26
27 void
explicit_bzero(void * buf,size_t len)28 explicit_bzero(void *buf, size_t len)
29 {
30 (void) SecureZeroMemory(buf, len);
31 }
32
33 #else
34
35 /*
36 * Indirect call through a volatile pointer to hopefully avoid dead-store
37 * optimisation eliminating the call. (Idea taken from OpenSSH.) We can't
38 * assume bzero() is present either, so for simplicity we define our own.
39 */
40
41 static void
bzero2(void * buf,size_t len)42 bzero2(void *buf, size_t len)
43 {
44 memset(buf, 0, len);
45 }
46
47 static void (*volatile bzero_p) (void *, size_t) = bzero2;
48
49 void
explicit_bzero(void * buf,size_t len)50 explicit_bzero(void *buf, size_t len)
51 {
52 bzero_p(buf, len);
53 }
54
55 #endif
56