1/*-
2 * Copyright (c) 2004 Olivier Houchard
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/signal.h>
32#include <sys/ucontext.h>
33
34#include <machine/frame.h>
35#include <machine/sigframe.h>
36
37#include <errno.h>
38#include <stdarg.h>
39#include <stdlib.h>
40#include <unistd.h>
41#include <strings.h>
42#include <signal.h>
43
44__weak_reference(__signalcontext, signalcontext);
45
46extern void _ctx_start(void);
47
48int
49__signalcontext(ucontext_t *ucp, int sig, __sighandler_t *func)
50{
51	struct sigframe *sfp;
52	__greg_t *gr = ucp->uc_mcontext.__gregs;
53	unsigned int *sp;
54
55	sp = (unsigned int *)gr[_REG_SP];
56
57	sfp = (struct sigframe *)sp - 1;
58
59	bzero(sfp, sizeof(*sfp));
60	bcopy(ucp, &sfp->sf_uc, sizeof(*ucp));
61	sfp->sf_si.si_signo = sig;
62
63	gr[_REG_SP] = (__greg_t)sfp;
64	/* Wipe out frame pointer. */
65	gr[_REG_FP] = 0;
66	/* Arrange for return via the trampoline code. */
67	gr[_REG_PC] = (__greg_t)_ctx_start;
68	gr[_REG_R4] = (__greg_t)func;
69	gr[_REG_R5] = (__greg_t)ucp;
70	gr[_REG_R0] = (__greg_t)sig;
71	gr[_REG_R1] = (__greg_t)&sfp->sf_si;
72	gr[_REG_R2] = (__greg_t)&sfp->sf_uc;
73
74	ucp->uc_link = &sfp->sf_uc;
75	sigdelset(&ucp->uc_sigmask, sig);
76
77	return (0);
78}
79