1/*-
2 * Copyright (c) 2011 David Chisnall
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: stable/11/lib/libc/stdlib/quick_exit.c 325712 2017-11-11 12:16:19Z kib $
27 */
28
29#include <sys/types.h>
30#include <machine/atomic.h>
31#include <stdlib.h>
32#include <pthread.h>
33
34/**
35 * Linked list of quick exit handlers.  This is simpler than the atexit()
36 * version, because it is not required to support C++ destructors or
37 * DSO-specific cleanups.
38 */
39struct quick_exit_handler {
40	struct quick_exit_handler *next;
41	void (*cleanup)(void);
42};
43
44/**
45 * Lock protecting the handlers list.
46 */
47static pthread_mutex_t atexit_mutex = PTHREAD_MUTEX_INITIALIZER;
48/**
49 * Stack of cleanup handlers.  These will be invoked in reverse order when
50 */
51static struct quick_exit_handler *handlers;
52
53int
54at_quick_exit(void (*func)(void))
55{
56	struct quick_exit_handler *h;
57
58	h = malloc(sizeof(*h));
59
60	if (NULL == h)
61		return (1);
62	h->cleanup = func;
63	pthread_mutex_lock(&atexit_mutex);
64	h->next = handlers;
65	__compiler_membar();
66	handlers = h;
67	pthread_mutex_unlock(&atexit_mutex);
68	return (0);
69}
70
71void
72quick_exit(int status)
73{
74	struct quick_exit_handler *h;
75
76	/*
77	 * XXX: The C++ spec requires us to call std::terminate if there is an
78	 * exception here.
79	 */
80	for (h = handlers; NULL != h; h = h->next) {
81		__compiler_membar();
82		h->cleanup();
83	}
84	_Exit(status);
85}
86