include/internal/refcount.h

   1 /*
   2  * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9 #ifndef HEADER_INTERNAL_REFCOUNT_H
  10 # define HEADER_INTERNAL_REFCOUNT_H
  11
  12 /* Used to checking reference counts, most while doing perl5 stuff :-) */
  13 # if defined(OPENSSL_NO_STDIO)
  14 #  if defined(REF_PRINT)
  15 #   error "REF_PRINT requires stdio"
  16 #  endif
  17 # endif
  18
  19 # if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L \
  20      && !defined(__STDC_NO_ATOMICS__)
  21 # include <stdatomic.h>
  22 # define HAVE_C11_ATOMICS
  23 # endif
  24
  25 # if defined(HAVE_C11_ATOMICS) && defined(ATOMIC_INT_LOCK_FREE) \
  26      && ATOMIC_INT_LOCK_FREE > 0
  27
  28 # define HAVE_ATOMICS 1
  29
  30 typedef _Atomic int CRYPTO_REF_COUNT;
  31
  32 static ossl_inline int CRYPTO_UP_REF(_Atomic int *val, int *ret, void *lock)
  33 {
  34     *ret = atomic_fetch_add_explicit(val, 1, memory_order_relaxed) + 1;
  35     return 1;
  36 }
  37
  38 static ossl_inline int CRYPTO_DOWN_REF(_Atomic int *val, int *ret, void *lock)
  39 {
  40     *ret = atomic_fetch_sub_explicit(val, 1, memory_order_release) - 1;
  41     if (*ret == 0)
  42         atomic_thread_fence(memory_order_acquire);
  43     return 1;
  44 }
  45
  46 # elif defined(__GNUC__) && defined(__ATOMIC_RELAXED) && __GCC_ATOMIC_INT_LOCK_FREE > 0
  47
  48 # define HAVE_ATOMICS 1
  49
  50 typedef int CRYPTO_REF_COUNT;
  51
  52 static ossl_inline int CRYPTO_UP_REF(int *val, int *ret, void *lock)
  53 {
  54     *ret = __atomic_fetch_add(val, 1, __ATOMIC_RELAXED) + 1;
  55     return 1;
  56 }
  57
  58 static ossl_inline int CRYPTO_DOWN_REF(int *val, int *ret, void *lock)
  59 {
  60     *ret = __atomic_fetch_sub(val, 1, __ATOMIC_RELEASE) - 1;
  61     if (*ret == 0)
  62         __atomic_thread_fence(__ATOMIC_ACQUIRE);
  63     return 1;
  64 }
  65
  66 # else
  67
  68 typedef int CRYPTO_REF_COUNT;
  69
  70 # define CRYPTO_UP_REF(val, ret, lock) CRYPTO_atomic_add(val, 1, ret, lock)
  71 # define CRYPTO_DOWN_REF(val, ret, lock) CRYPTO_atomic_add(val, -1, ret, lock)
  72
  73 # endif
  74
  75 # if !defined(NDEBUG) && !defined(OPENSSL_NO_STDIO)
  76 #  define REF_ASSERT_ISNT(test) \
  77     (void)((test) ? (OPENSSL_die("refcount error", __FILE__, __LINE__), 1) : 0)
  78 # else
  79 #  define REF_ASSERT_ISNT(i)
  80 # endif
  81
  82 # ifdef REF_PRINT
  83 #  define REF_PRINT_COUNT(a, b) \
  84         fprintf(stderr, "%p:%4d:%s\n", b, b->references, a)
  85 # else
  86 #  define REF_PRINT_COUNT(a, b)
  87 # endif
  88
  89 #endif