1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2022 Jessica Clarke <jrtc27@FreeBSD.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28#define	KILL_TIMEOUT	10
29
30/*
31 * NB: Most of these do not need to be volatile, but a handful are used in
32 * signal handler contexts, so for simplicity we make them all volatile rather
33 * than duplicate the implementation.
34 */
35struct pipe_barrier {
36	volatile int		fds[2];
37};
38
39static __inline int
40pipe_barrier_init(struct pipe_barrier *p)
41{
42	int error, fds[2], i;
43
44	error = pipe(fds);
45	if (error != 0)
46		return (error);
47
48	for (i = 0; i < 2; ++i)
49		p->fds[i] = fds[i];
50
51	return (0);
52}
53
54static __inline void
55pipe_barrier_wait(struct pipe_barrier *p)
56{
57	ssize_t ret;
58	char temp;
59	int fd;
60
61	fd = p->fds[0];
62	p->fds[0] = -1;
63	do {
64		ret = read(fd, &temp, 1);
65	} while (ret == -1 && errno == EINTR);
66	close(fd);
67}
68
69static __inline void
70pipe_barrier_ready(struct pipe_barrier *p)
71{
72	int fd;
73
74	fd = p->fds[1];
75	p->fds[1] = -1;
76	close(fd);
77}
78
79static __inline void
80pipe_barrier_destroy_impl(struct pipe_barrier *p, int i)
81{
82	int fd;
83
84	fd = p->fds[i];
85	if (fd != -1) {
86		p->fds[i] = -1;
87		close(fd);
88	}
89}
90
91static __inline void
92pipe_barrier_destroy_wait(struct pipe_barrier *p)
93{
94	pipe_barrier_destroy_impl(p, 0);
95}
96
97static __inline void
98pipe_barrier_destroy_ready(struct pipe_barrier *p)
99{
100	pipe_barrier_destroy_impl(p, 1);
101}
102
103static __inline void
104pipe_barrier_destroy(struct pipe_barrier *p)
105{
106	pipe_barrier_destroy_wait(p);
107	pipe_barrier_destroy_ready(p);
108}
109
110void	reproduce_signal_death(int sig);
111