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https://github.com/jart/cosmopolitan.git
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76957983cf
- Ensure SIGTHR isn't blocked in newly created threads - Use TIB rather than thread_local for thread atexits - Make POSIX thread keys atomic within thread - Don't bother logging prctl() to --strace - Log thread destructor names to --strace
61 lines
3.5 KiB
C
61 lines
3.5 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et 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/errno.h"
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#include "libc/intrin/atomic.h"
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#include "libc/thread/posixthread.internal.h"
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#include "libc/thread/thread.h"
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/**
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* Allocates TLS slot.
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*
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* This function creates a thread-local storage registration, that will
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* apply to all threads. The new identifier is written to `key`, and it
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* can be passed to the pthread_setspecific() and pthread_getspecific()
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* functions to set and get its associated value. Each thread will have
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* its key value initialized to zero upon creation. It is also possible
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* to use pthread_key_delete() to unregister a key.
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*
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* If `dtor` is non-null, then it'll be called upon pthread_exit() when
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* the key's value is nonzero. The key's value is set to zero before it
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* is called. The ordering of multiple destructor calls is unspecified.
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* The same key can be destroyed `PTHREAD_DESTRUCTOR_ITERATIONS` times,
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* in cases where it gets set again by a destructor.
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*
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* @param key is set to the allocated key on success
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* @param dtor specifies an optional destructor callback
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* @return 0 on success, or errno on error
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* @raise EAGAIN if `PTHREAD_KEYS_MAX` keys exist
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*/
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int pthread_key_create(pthread_key_t *key, pthread_key_dtor dtor) {
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int i;
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pthread_key_dtor expect;
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if (!dtor)
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dtor = (pthread_key_dtor)-1;
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for (i = 0; i < PTHREAD_KEYS_MAX; ++i) {
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if (!(expect = atomic_load_explicit(&_pthread_key_dtor[i],
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memory_order_relaxed)) &&
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atomic_compare_exchange_strong_explicit(&_pthread_key_dtor[i], &expect,
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dtor, memory_order_release,
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memory_order_relaxed)) {
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*key = i;
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return 0;
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}
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}
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return EAGAIN;
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}
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