explicit_bzero.c

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/*-------------------------------------------------------------------------
 *
 * explicit_bzero.c
 *
 * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *    src/port/explicit_bzero.c
 *
 *-------------------------------------------------------------------------
 */
 
#define __STDC_WANT_LIB_EXT1__ 1    /* needed to access memset_s() */
 
#include "c.h"
 
#if defined(HAVE_MEMSET_EXPLICIT)
 
void
explicit_bzero(void *buf, size_t len)
{
    (void) memset_explicit(buf, 0, len);
}
 
#elif defined(HAVE_EXPLICIT_MEMSET)
 
void
explicit_bzero(void *buf, size_t len)
{
    (void) explicit_memset(buf, 0, len);
}
 
#elif HAVE_DECL_MEMSET_S
 
void
explicit_bzero(void *buf, size_t len)
{
    (void) memset_s(buf, len, 0, len);
}
 
#elif defined(WIN32)
 
void
explicit_bzero(void *buf, size_t len)
{
    (void) SecureZeroMemory(buf, len);
}
 
#else
 
/*
 * Indirect call through a volatile pointer to hopefully avoid dead-store
 * optimisation eliminating the call.  (Idea taken from OpenSSH.)  We can't
 * assume bzero() is present either, so for simplicity we define our own.
 */
 
static void
bzero2(void *buf, size_t len)
{
    memset(buf, 0, len);
}
 
static void (*volatile bzero_p) (void *, size_t) = bzero2;
 
void
explicit_bzero(void *buf, size_t len)
{
    bzero_p(buf, len);
}
 
#endif