1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2002 Jonathan Mini <mini@freebsd.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/param.h>
30#include <sys/ucontext.h>
31#include <machine/psl.h>
32#include <machine/sigframe.h>
33#include <signal.h>
34#include <strings.h>
35
36__weak_reference(__signalcontext, signalcontext);
37
38extern void _ctx_start(ucontext_t *, int argc, ...);
39
40int
41__signalcontext(ucontext_t *ucp, int sig, __sighandler_t *func)
42{
43	register_t *p;
44	struct sigframe *sfp;
45
46	/*-
47	 * Set up stack.
48	 * (n = sizeof(int))
49	 * 2n+sizeof(struct sigframe)	ucp
50	 * 2n				struct sigframe
51	 * 1n				&func
52	 * 0n				&_ctx_start
53	 */
54	p = (register_t *)(void *)(intptr_t)ucp->uc_mcontext.mc_esp;
55	*--p = (register_t)(intptr_t)ucp;
56	p = (register_t *)((u_register_t)p & ~0xF);  /* Align to 16 bytes. */
57	p = (register_t *)((u_register_t)p - sizeof(struct sigframe));
58	sfp = (struct sigframe *)p;
59	bzero(sfp, sizeof(struct sigframe));
60	sfp->sf_signum = sig;
61	sfp->sf_siginfo = (register_t)(intptr_t)&sfp->sf_si;
62	sfp->sf_ucontext = (register_t)(intptr_t)&sfp->sf_uc;
63	sfp->sf_ahu.sf_action = (__siginfohandler_t *)func;
64	bcopy(ucp, &sfp->sf_uc, sizeof(ucontext_t));
65	sfp->sf_si.si_signo = sig;
66	*--p = (register_t)(intptr_t)func;
67
68	/*
69	 * Set up ucontext_t.
70	 */
71	ucp->uc_mcontext.mc_esi = ucp->uc_mcontext.mc_esp - sizeof(int);
72	ucp->uc_mcontext.mc_esp = (register_t)(intptr_t)p;
73	ucp->uc_mcontext.mc_eip = (register_t)(intptr_t)_ctx_start;
74	ucp->uc_mcontext.mc_eflags &= ~PSL_T;
75	ucp->uc_link = &sfp->sf_uc;
76	sigdelset(&ucp->uc_sigmask, sig);
77	return (0);
78}
79