1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2011 David Chisnall
5 * Copyright (c) 2023 Klara, Inc.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 #include <sys/types.h>
31
32 #include <stdatomic.h>
33 #include <stdlib.h>
34
35 /**
36 * Linked list of quick exit handlers. These will be invoked in reverse
37 * order of insertion when quick_exit() is called. This is simpler than
38 * the atexit() version, because it is not required to support C++
39 * destructors or DSO-specific cleanups.
40 */
41 struct quick_exit_handler {
42 struct quick_exit_handler *next;
43 void (*cleanup)(void);
44 };
45
46 static _Atomic(struct quick_exit_handler *) handlers;
47
48 int
at_quick_exit(void (* func)(void))49 at_quick_exit(void (*func)(void))
50 {
51 struct quick_exit_handler *h;
52
53 if ((h = calloc(1, sizeof(*h))) == NULL) {
54 return (-1);
55 }
56 h->cleanup = func;
57 while (!atomic_compare_exchange_strong(&handlers, &h->next, h)) {
58 /* nothing */ ;
59 }
60 return (0);
61 }
62
63 void
quick_exit(int status)64 quick_exit(int status)
65 {
66 struct quick_exit_handler *h;
67
68 /*
69 * XXX: The C++ spec requires us to call std::terminate if there is an
70 * exception here.
71 */
72 for (h = atomic_load_explicit(&handlers, memory_order_acquire);
73 h != NULL; h = h->next) {
74 h->cleanup();
75 }
76 _Exit(status);
77 }
78