1/*-
2 * Copyright (c) 2002 Jonathan Mini <mini@freebsd.org>
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
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD$");
29
30#include <sys/param.h>
31#include <sys/ucontext.h>
32#include <machine/psl.h>
33#include <machine/sigframe.h>
34#include <signal.h>
35#include <strings.h>
36
37__weak_reference(__signalcontext, signalcontext);
38
39extern void _ctx_start(ucontext_t *, int argc, ...);
40
41int
42__signalcontext(ucontext_t *ucp, int sig, __sighandler_t *func)
43{
44	register_t *p;
45	struct sigframe *sfp;
46
47	/*-
48	 * Set up stack.
49	 * (n = sizeof(int))
50	 * 2n+sizeof(struct sigframe)	ucp
51	 * 2n				struct sigframe
52	 * 1n				&func
53	 * 0n				&_ctx_start
54	 */
55	p = (register_t *)(void *)(intptr_t)ucp->uc_mcontext.mc_esp;
56	*--p = (register_t)(intptr_t)ucp;
57	p = (register_t *)((u_register_t)p & ~0xF);  /* Align to 16 bytes. */
58	p = (register_t *)((u_register_t)p - sizeof(struct sigframe));
59	sfp = (struct sigframe *)p;
60	bzero(sfp, sizeof(struct sigframe));
61	sfp->sf_signum = sig;
62	sfp->sf_siginfo = (register_t)(intptr_t)&sfp->sf_si;
63	sfp->sf_ucontext = (register_t)(intptr_t)&sfp->sf_uc;
64	sfp->sf_ahu.sf_action = (__siginfohandler_t *)func;
65	bcopy(ucp, &sfp->sf_uc, sizeof(ucontext_t));
66	sfp->sf_si.si_signo = sig;
67	*--p = (register_t)(intptr_t)func;
68
69	/*
70	 * Set up ucontext_t.
71	 */
72	ucp->uc_mcontext.mc_esi = ucp->uc_mcontext.mc_esp - sizeof(int);
73	ucp->uc_mcontext.mc_esp = (register_t)(intptr_t)p;
74	ucp->uc_mcontext.mc_eip = (register_t)(intptr_t)_ctx_start;
75	ucp->uc_mcontext.mc_eflags &= ~PSL_T;
76	ucp->uc_link = &sfp->sf_uc;
77	sigdelset(&ucp->uc_sigmask, sig);
78	return (0);
79}
80