57 lines
1.6 KiB
C
57 lines
1.6 KiB
C
// Copyright (c) 2015, Google Inc.
|
|
// SPDX-License-Identifier: ISC
|
|
|
|
#include "internal.h"
|
|
|
|
|
|
#if defined(OPENSSL_C11_ATOMIC)
|
|
|
|
#include <assert.h>
|
|
#include <stdalign.h>
|
|
#include <stdatomic.h>
|
|
#include <stdlib.h>
|
|
|
|
#include <openssl/type_check.h>
|
|
|
|
|
|
// See comment above the typedef of CRYPTO_refcount_t about these tests.
|
|
OPENSSL_STATIC_ASSERT(alignof(CRYPTO_refcount_t) == alignof(_Atomic CRYPTO_refcount_t),
|
|
_Atomic_alters_the_needed_alignment_of_a_reference_count)
|
|
OPENSSL_STATIC_ASSERT(sizeof(CRYPTO_refcount_t) == sizeof(_Atomic CRYPTO_refcount_t),
|
|
_Atomic_alters_the_size_of_a_reference_count)
|
|
|
|
OPENSSL_STATIC_ASSERT((CRYPTO_refcount_t)-1 == CRYPTO_REFCOUNT_MAX,
|
|
CRYPTO_REFCOUNT_MAX_is_incorrect)
|
|
|
|
void CRYPTO_refcount_inc(CRYPTO_refcount_t *in_count) {
|
|
_Atomic CRYPTO_refcount_t *count = (_Atomic CRYPTO_refcount_t *) in_count;
|
|
uint32_t expected = atomic_load(count);
|
|
|
|
while (expected != CRYPTO_REFCOUNT_MAX) {
|
|
uint32_t new_value = expected + 1;
|
|
if (atomic_compare_exchange_weak(count, &expected, new_value)) {
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
int CRYPTO_refcount_dec_and_test_zero(CRYPTO_refcount_t *in_count) {
|
|
_Atomic CRYPTO_refcount_t *count = (_Atomic CRYPTO_refcount_t *)in_count;
|
|
uint32_t expected = atomic_load(count);
|
|
|
|
for (;;) {
|
|
if (expected == 0) {
|
|
abort();
|
|
} else if (expected == CRYPTO_REFCOUNT_MAX) {
|
|
return 0;
|
|
} else {
|
|
const uint32_t new_value = expected - 1;
|
|
if (atomic_compare_exchange_weak(count, &expected, new_value)) {
|
|
return new_value == 0;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
#endif // OPENSSL_C11_ATOMIC
|