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
38 extern void _ctx_start(ucontext_t *, int argc, ...);
39
40 int
__signalcontext(ucontext_t * ucp,int sig,__sighandler_t * func)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