crypto/libressl/crypto/compat/arc4random_win.h

   1 /*      $OpenBSD: arc4random_win.h,v 1.4 2014/07/20 20:51:13 bcook Exp $        */
   2
   3 /*
   4  * Copyright (c) 1996, David Mazieres <dm@uun.org>
   5  * Copyright (c) 2008, Damien Miller <djm@openbsd.org>
   6  * Copyright (c) 2013, Markus Friedl <markus@openbsd.org>
   7  * Copyright (c) 2014, Theo de Raadt <deraadt@openbsd.org>
   8  *
   9  * Permission to use, copy, modify, and distribute this software for any
  10  * purpose with or without fee is hereby granted, provided that the above
  11  * copyright notice and this permission notice appear in all copies.
  12  *
  13  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  14  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  15  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  16  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  17  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  18  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  19  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  20  */
  21
  22 /*
  23  * Stub functions for portability.
  24  */
  25
  26 #include <windows.h>
  27
  28 static volatile HANDLE arc4random_mtx = NULL;
  29
  30 /*
  31  * Initialize the mutex on the first lock attempt. On collision, each thread
  32  * will attempt to allocate a mutex and compare-and-swap it into place as the
  33  * global mutex. On failure to swap in the global mutex, the mutex is closed.
  34  */
  35 #define _ARC4_LOCK() { \
  36         if (!arc4random_mtx) { \
  37                 HANDLE p = CreateMutex(NULL, FALSE, NULL); \
  38                 if (InterlockedCompareExchangePointer((void **)&arc4random_mtx, (void *)p, NULL)) \
  39                         CloseHandle(p); \
  40         } \
  41         WaitForSingleObject(arc4random_mtx, INFINITE); \
  42 } \
  43
  44 #define _ARC4_UNLOCK() ReleaseMutex(arc4random_mtx)
  45
  46 static inline void
  47 _getentropy_fail(void)
  48 {
  49         TerminateProcess(GetCurrentProcess(), 0);
  50 }
  51
  52 static inline int
  53 _rs_allocate(struct _rs **rsp, struct _rsx **rsxp)
  54 {
  55         *rsp = VirtualAlloc(NULL, sizeof(**rsp),
  56             MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
  57         if (*rsp == NULL)
  58                 return (-1);
  59
  60         *rsxp = VirtualAlloc(NULL, sizeof(**rsxp),
  61             MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
  62         if (*rsxp == NULL) {
  63                 VirtualFree(*rsp, 0, MEM_RELEASE);
  64                 *rsp = NULL;
  65                 return (-1);
  66         }
  67         return (0);
  68 }
  69
  70 static inline void
  71 _rs_forkhandler(void)
  72 {
  73 }
  74
  75 static inline void
  76 _rs_forkdetect(void)
  77 {
  78 }