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1dc3abb052
Compiler memory barriers do not prevent the CPU from executing the code out of order. Switch to C11 atomics. This also lets us get rid of the mutex; instead, loop until the compare_exchange succeeds. While here, change the return value of at_quick_exit() on failure to the more traditional -1, matching atexit(). Sponsored by: Klara, Inc. Reviewed by: Olivier Certner, kevans, kib Differential Revision: https://reviews.freebsd.org/D41936
78 lines
2.4 KiB
C
78 lines
2.4 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2011 David Chisnall
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* Copyright (c) 2023 Klara, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/types.h>
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#include <stdatomic.h>
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#include <stdlib.h>
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/**
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* Linked list of quick exit handlers. These will be invoked in reverse
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* order of insertion when quick_exit() is called. This is simpler than
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* the atexit() version, because it is not required to support C++
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* destructors or DSO-specific cleanups.
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*/
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struct quick_exit_handler {
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struct quick_exit_handler *next;
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void (*cleanup)(void);
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};
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static _Atomic(struct quick_exit_handler *) handlers;
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int
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at_quick_exit(void (*func)(void))
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{
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struct quick_exit_handler *h;
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if ((h = calloc(1, sizeof(*h))) == NULL) {
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return (-1);
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}
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h->cleanup = func;
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while (!atomic_compare_exchange_strong(&handlers, &h->next, h)) {
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/* nothing */ ;
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}
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return (0);
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}
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void
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quick_exit(int status)
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{
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struct quick_exit_handler *h;
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/*
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* XXX: The C++ spec requires us to call std::terminate if there is an
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* exception here.
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*/
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for (h = atomic_load_explicit(&handlers, memory_order_acquire);
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h != NULL; h = h->next) {
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h->cleanup();
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}
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_Exit(status);
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}
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