1f4e427204234da139fd0585def4b4e22502e33f0Adam Langley/* Copyright (c) 2015, Google Inc. 2f4e427204234da139fd0585def4b4e22502e33f0Adam Langley * 3f4e427204234da139fd0585def4b4e22502e33f0Adam Langley * Permission to use, copy, modify, and/or distribute this software for any 4f4e427204234da139fd0585def4b4e22502e33f0Adam Langley * purpose with or without fee is hereby granted, provided that the above 5f4e427204234da139fd0585def4b4e22502e33f0Adam Langley * copyright notice and this permission notice appear in all copies. 6f4e427204234da139fd0585def4b4e22502e33f0Adam Langley * 7f4e427204234da139fd0585def4b4e22502e33f0Adam Langley * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 8f4e427204234da139fd0585def4b4e22502e33f0Adam Langley * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 9f4e427204234da139fd0585def4b4e22502e33f0Adam Langley * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 10f4e427204234da139fd0585def4b4e22502e33f0Adam Langley * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 11f4e427204234da139fd0585def4b4e22502e33f0Adam Langley * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION 12f4e427204234da139fd0585def4b4e22502e33f0Adam Langley * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN 13f4e427204234da139fd0585def4b4e22502e33f0Adam Langley * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ 14f4e427204234da139fd0585def4b4e22502e33f0Adam Langley 15f4e427204234da139fd0585def4b4e22502e33f0Adam Langley#include "internal.h" 16f4e427204234da139fd0585def4b4e22502e33f0Adam Langley 17f4e427204234da139fd0585def4b4e22502e33f0Adam Langley 18f4e427204234da139fd0585def4b4e22502e33f0Adam Langley#if defined(OPENSSL_C11_ATOMIC) 19f4e427204234da139fd0585def4b4e22502e33f0Adam Langley 20f4e427204234da139fd0585def4b4e22502e33f0Adam Langley#include <assert.h> 21f4e427204234da139fd0585def4b4e22502e33f0Adam Langley#include <stdalign.h> 22f4e427204234da139fd0585def4b4e22502e33f0Adam Langley#include <stdatomic.h> 23f4e427204234da139fd0585def4b4e22502e33f0Adam Langley#include <stdlib.h> 24f4e427204234da139fd0585def4b4e22502e33f0Adam Langley 25f4e427204234da139fd0585def4b4e22502e33f0Adam Langley#include <openssl/type_check.h> 26f4e427204234da139fd0585def4b4e22502e33f0Adam Langley 27f4e427204234da139fd0585def4b4e22502e33f0Adam Langley 28f4e427204234da139fd0585def4b4e22502e33f0Adam Langley/* See comment above the typedef of CRYPTO_refcount_t about these tests. */ 29f4e427204234da139fd0585def4b4e22502e33f0Adam Langleystatic_assert(alignof(CRYPTO_refcount_t) == alignof(_Atomic CRYPTO_refcount_t), 30f4e427204234da139fd0585def4b4e22502e33f0Adam Langley "_Atomic alters the needed alignment of a reference count"); 31f4e427204234da139fd0585def4b4e22502e33f0Adam Langleystatic_assert(sizeof(CRYPTO_refcount_t) == sizeof(_Atomic CRYPTO_refcount_t), 32f4e427204234da139fd0585def4b4e22502e33f0Adam Langley "_Atomic alters the size of a reference count"); 33f4e427204234da139fd0585def4b4e22502e33f0Adam Langley 34f4e427204234da139fd0585def4b4e22502e33f0Adam Langleystatic_assert((CRYPTO_refcount_t)-1 == CRYPTO_REFCOUNT_MAX, 35f4e427204234da139fd0585def4b4e22502e33f0Adam Langley "CRYPTO_REFCOUNT_MAX is incorrect"); 36f4e427204234da139fd0585def4b4e22502e33f0Adam Langley 37f4e427204234da139fd0585def4b4e22502e33f0Adam Langleyvoid CRYPTO_refcount_inc(CRYPTO_refcount_t *in_count) { 38f4e427204234da139fd0585def4b4e22502e33f0Adam Langley _Atomic CRYPTO_refcount_t *count = (_Atomic CRYPTO_refcount_t *) in_count; 39f4e427204234da139fd0585def4b4e22502e33f0Adam Langley uint32_t expected = atomic_load(count); 40f4e427204234da139fd0585def4b4e22502e33f0Adam Langley 41f4e427204234da139fd0585def4b4e22502e33f0Adam Langley while (expected != CRYPTO_REFCOUNT_MAX) { 42f4e427204234da139fd0585def4b4e22502e33f0Adam Langley uint32_t new_value = expected + 1; 43f4e427204234da139fd0585def4b4e22502e33f0Adam Langley if (atomic_compare_exchange_weak(count, &expected, new_value)) { 44f4e427204234da139fd0585def4b4e22502e33f0Adam Langley break; 45f4e427204234da139fd0585def4b4e22502e33f0Adam Langley } 46f4e427204234da139fd0585def4b4e22502e33f0Adam Langley } 47f4e427204234da139fd0585def4b4e22502e33f0Adam Langley} 48f4e427204234da139fd0585def4b4e22502e33f0Adam Langley 49f4e427204234da139fd0585def4b4e22502e33f0Adam Langleyint CRYPTO_refcount_dec_and_test_zero(CRYPTO_refcount_t *in_count) { 50f4e427204234da139fd0585def4b4e22502e33f0Adam Langley _Atomic CRYPTO_refcount_t *count = (_Atomic CRYPTO_refcount_t *)in_count; 51f4e427204234da139fd0585def4b4e22502e33f0Adam Langley uint32_t expected = atomic_load(count); 52f4e427204234da139fd0585def4b4e22502e33f0Adam Langley 53f4e427204234da139fd0585def4b4e22502e33f0Adam Langley for (;;) { 54f4e427204234da139fd0585def4b4e22502e33f0Adam Langley if (expected == 0) { 55f4e427204234da139fd0585def4b4e22502e33f0Adam Langley abort(); 56f4e427204234da139fd0585def4b4e22502e33f0Adam Langley } else if (expected == CRYPTO_REFCOUNT_MAX) { 57f4e427204234da139fd0585def4b4e22502e33f0Adam Langley return 0; 58f4e427204234da139fd0585def4b4e22502e33f0Adam Langley } else { 59f4e427204234da139fd0585def4b4e22502e33f0Adam Langley const uint32_t new_value = expected - 1; 60f4e427204234da139fd0585def4b4e22502e33f0Adam Langley if (atomic_compare_exchange_weak(count, &expected, new_value)) { 61f4e427204234da139fd0585def4b4e22502e33f0Adam Langley return new_value == 0; 62f4e427204234da139fd0585def4b4e22502e33f0Adam Langley } 63f4e427204234da139fd0585def4b4e22502e33f0Adam Langley } 64f4e427204234da139fd0585def4b4e22502e33f0Adam Langley } 65f4e427204234da139fd0585def4b4e22502e33f0Adam Langley} 66f4e427204234da139fd0585def4b4e22502e33f0Adam Langley 67f4e427204234da139fd0585def4b4e22502e33f0Adam Langley#endif /* OPENSSL_C11_ATOMIC */ 68