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73 lines
2.3 KiB
C
73 lines
2.3 KiB
C
/* Copyright (C) 2002-2018 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include "pthreadP.h"
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#include <assert.h>
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#include <atomic.h>
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static int
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claim_key (pthread_key_t *key, void (*destr) (void *), size_t cnt)
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{
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uintptr_t seq = __pthread_keys[cnt].seq;
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if (KEY_UNUSED (seq) && KEY_USABLE (seq)
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/* We found an unused slot. Try to allocate it. */
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&& ! atomic_compare_and_exchange_bool_acq (&__pthread_keys[cnt].seq,
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seq + 1, seq))
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{
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/* Remember the destructor. */
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__pthread_keys[cnt].destr = destr;
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/* Return the key to the caller. */
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*key = cnt;
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return 0;
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}
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return -1;
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}
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int
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__pthread_key_create (pthread_key_t *key, void (*destr) (void *))
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{
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/* Find a slot in __pthread_keys which is unused. */
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for (size_t cnt = PTHREAD_SIGNAL_SAFE_KEYS_MAX; cnt < PTHREAD_KEYS_MAX; ++cnt)
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{
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if (claim_key (key, destr, cnt) == 0)
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return 0;
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}
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return EAGAIN;
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}
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int __google_pthread_signal_safe_key_create (
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pthread_key_t *key, void (*destr) (void *))
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{
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/* Our implementation makes signal safe keys easy: they just have to
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reside in the first (inline) block. */
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assert (PTHREAD_SIGNAL_SAFE_KEYS_MAX <= PTHREAD_KEY_1STLEVEL_SIZE);
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/* Find a slot in __pthread_keys which is unused. */
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for (size_t cnt = 0; cnt < PTHREAD_SIGNAL_SAFE_KEYS_MAX; ++cnt)
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{
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if (claim_key (key, destr, cnt) == 0)
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return 0;
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}
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return EAGAIN;
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}
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weak_alias (__pthread_key_create, pthread_key_create)
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hidden_def (__pthread_key_create)
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