6f2e733bab
OpenSSL has traditionally done reference counting with |int|s and the |CRYPTO_add| function. Unless a special callback is installed (rare), this is implemented by doing the reference count operations under a lock. This change adds infrastructure for handling reference counts and uses atomic operations when C11 support is available. Change-Id: Ia023ce432319efd00f77a7340da27d16ee4b63c3 Reviewed-on: https://boringssl-review.googlesource.com/4771 Reviewed-by: Adam Langley <agl@google.com>
54 lines
1.6 KiB
C
54 lines
1.6 KiB
C
/* Copyright (c) 2015, Google Inc.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
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#include "internal.h"
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#include <stdlib.h>
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#include <openssl/type_check.h>
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#if !defined(OPENSSL_C11_ATOMIC)
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OPENSSL_COMPILE_ASSERT((CRYPTO_refcount_t)-1 == CRYPTO_REFCOUNT_MAX,
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CRYPTO_REFCOUNT_MAX_is_incorrect);
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static struct CRYPTO_STATIC_MUTEX g_refcount_lock = CRYPTO_STATIC_MUTEX_INIT;
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void CRYPTO_refcount_inc(CRYPTO_refcount_t *count) {
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CRYPTO_STATIC_MUTEX_lock_write(&g_refcount_lock);
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if (*count < CRYPTO_REFCOUNT_MAX) {
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(*count)++;
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}
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CRYPTO_STATIC_MUTEX_unlock(&g_refcount_lock);
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}
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int CRYPTO_refcount_dec_and_test_zero(CRYPTO_refcount_t *count) {
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int ret;
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CRYPTO_STATIC_MUTEX_lock_write(&g_refcount_lock);
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if (*count == 0) {
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abort();
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}
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if (*count < CRYPTO_REFCOUNT_MAX) {
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(*count)--;
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}
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ret = (*count == 0);
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CRYPTO_STATIC_MUTEX_unlock(&g_refcount_lock);
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return ret;
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}
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#endif /* OPENSSL_C11_ATOMIC */
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