mirror of
https://github.com/jart/cosmopolitan.git
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63 lines
3 KiB
C
63 lines
3 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2022 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above 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 │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/calls/calls.h"
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#include "libc/errno.h"
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#include "libc/intrin/atomic.h"
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#include "libc/intrin/likely.h"
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#include "libc/intrin/weaken.h"
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#include "libc/thread/thread.h"
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#include "libc/thread/tls.h"
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#include "third_party/nsync/mu.h"
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/**
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* Releases mutex.
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*
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* @return 0 on success or error number on failure
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* @raises EPERM if in error check mode and not owned by caller
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*/
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int pthread_mutex_unlock(pthread_mutex_t *mutex) {
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int c, t;
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if (LIKELY(__tls_enabled && //
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mutex->_type == PTHREAD_MUTEX_NORMAL && //
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mutex->_pshared == PTHREAD_PROCESS_PRIVATE && //
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weaken(nsync_mu_unlock))) {
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weaken(nsync_mu_unlock)((nsync_mu *)mutex);
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return 0;
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}
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t = gettid();
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if (mutex->_type == PTHREAD_MUTEX_ERRORCHECK) {
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c = atomic_load_explicit(&mutex->_lock, memory_order_relaxed);
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if ((c & 0x000fffff) != t) {
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return EPERM;
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}
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}
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c = atomic_fetch_sub(&mutex->_lock, 0x00100000);
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if ((c & 0x0ff00000) == 0x00100000) {
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atomic_store_explicit(&mutex->_lock, 0, memory_order_release);
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if ((c & 0xf0000000) == 0x20000000) {
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// _futex_wake(&mutex->_lock, 1, mutex->_pshared);
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pthread_yield();
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}
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}
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return 0;
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}
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