newlib/libc/stdlib/arc4random.h

   1 /*-
   2  * Copyright (c) 2016 embedded brains GmbH
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 /*
  28  * Newlib ports may override the default implementations via the following
  29  * define and macros
  30  *  o _ARC4RANDOM_DATA,
  31  *  o _ARC4RANDOM_GETENTROPY_FAIL(),
  32  *  o _ARC4RANDOM_ALLOCATE(rsp, rspx), and
  33  *  o _ARC4RANDOM_FORKDETECT().
  34  */
  35 #include <machine/_arc4random.h>
  36
  37 #include <sys/lock.h>
  38 #include <signal.h>
  39
  40 #ifndef _ARC4_LOCK_INIT
  41
  42 #define _ARC4_LOCK_INIT __LOCK_INIT(static, __arc4random_mutex);
  43
  44 #define _ARC4_LOCK() __lock_acquire(__arc4random_mutex)
  45
  46 #define _ARC4_UNLOCK() __lock_release(__arc4random_mutex)
  47
  48 #endif /* _ARC4_LOCK_INIT */
  49
  50 #ifndef __SINGLE_THREAD__
  51 _ARC4_LOCK_INIT
  52 #endif
  53
  54 #ifdef _ARC4RANDOM_DATA
  55 _ARC4RANDOM_DATA
  56 #else
  57 static struct {
  58         struct _rs rs;
  59         struct _rsx rsx;
  60 } _arc4random_data;
  61 #endif
  62
  63 static inline void
  64 _getentropy_fail(void)
  65 {
  66 #ifdef _ARC4RANDOM_GETENTROPY_FAIL
  67         _ARC4RANDOM_GETENTROPY_FAIL();
  68 #else
  69         raise(SIGKILL);
  70 #endif
  71 }
  72
  73 static inline int
  74 _rs_allocate(struct _rs **rsp, struct _rsx **rsxp)
  75 {
  76 #ifdef _ARC4RANDOM_ALLOCATE
  77         _ARC4RANDOM_ALLOCATE(rsp, rsxp);
  78 #else
  79         *rsp = &_arc4random_data.rs;
  80         *rsxp = &_arc4random_data.rsx;
  81         return (0);
  82 #endif
  83 }
  84
  85 static inline void
  86 _rs_forkdetect(void)
  87 {
  88 #ifdef _ARC4RANDOM_FORKDETECT
  89         _ARC4RANDOM_FORKDETECT();
  90 #endif
  91 }