src/port/explicit_bzero.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * explicit_bzero.c
   4  *
   5  * Portions Copyright (c) 1996-2021, 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
  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
  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
  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
  50 explicit_bzero(void *buf, size_t len)
  51 {
  52         bzero_p(buf, len);
  53 }
  54
  55 #endif