1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2004 Marcel Moolenaar, Peter Grehan
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 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include <sys/param.h>
30 #include <sys/ucontext.h>
31 #include <signal.h>
32 #include <stdlib.h>
33 #include <strings.h>
34
35 typedef void (*handler_t)(uint32_t, uint32_t, uint32_t);
36
37 /* Prototypes */
38 static void ctx_wrapper(ucontext_t *ucp, handler_t func, uint32_t sig,
39 uint32_t sig_si, uint32_t sig_uc);
40
41 __weak_reference(__signalcontext, signalcontext);
42
43 int
__signalcontext(ucontext_t * ucp,int sig,__sighandler_t * func)44 __signalcontext(ucontext_t *ucp, int sig, __sighandler_t *func)
45 {
46 siginfo_t *sig_si;
47 ucontext_t *sig_uc;
48 uint32_t sp;
49
50 /* Bail out if we don't have a valid ucontext pointer. */
51 if (ucp == NULL)
52 abort();
53
54 /*
55 * Build a 16-byte-aligned signal frame
56 */
57 sp = (ucp->uc_mcontext.mc_gpr[1] - sizeof(ucontext_t)) & ~15UL;
58 sig_uc = (ucontext_t *)sp;
59 bcopy(ucp, sig_uc, sizeof(*sig_uc));
60 sp = (sp - sizeof(siginfo_t)) & ~15UL;
61 sig_si = (siginfo_t *)sp;
62 bzero(sig_si, sizeof(*sig_si));
63 sig_si->si_signo = sig;
64
65 /*
66 * Subtract 8 bytes from stack to allow for frameptr
67 */
68 sp -= 2*sizeof(uint32_t);
69 sp &= ~15UL;
70
71 /*
72 * Setup the ucontext of the signal handler.
73 */
74 bzero(&ucp->uc_mcontext, sizeof(ucp->uc_mcontext));
75 ucp->uc_link = sig_uc;
76 sigdelset(&ucp->uc_sigmask, sig);
77
78 ucp->uc_mcontext.mc_vers = _MC_VERSION;
79 ucp->uc_mcontext.mc_len = sizeof(struct __mcontext);
80 ucp->uc_mcontext.mc_srr0 = (uint32_t) ctx_wrapper;
81 ucp->uc_mcontext.mc_gpr[1] = (uint32_t) sp;
82 ucp->uc_mcontext.mc_gpr[3] = (uint32_t) func;
83 ucp->uc_mcontext.mc_gpr[4] = (uint32_t) sig;
84 ucp->uc_mcontext.mc_gpr[5] = (uint32_t) sig_si;
85 ucp->uc_mcontext.mc_gpr[6] = (uint32_t) sig_uc;
86
87 return (0);
88 }
89
90 static void
ctx_wrapper(ucontext_t * ucp,handler_t func,uint32_t sig,uint32_t sig_si,uint32_t sig_uc)91 ctx_wrapper(ucontext_t *ucp, handler_t func, uint32_t sig, uint32_t sig_si,
92 uint32_t sig_uc)
93 {
94
95 (*func)(sig, sig_si, sig_uc);
96 if (ucp->uc_link == NULL)
97 exit(0);
98 setcontext((const ucontext_t *)ucp->uc_link);
99 /* should never get here */
100 abort();
101 /* NOTREACHED */
102 }
103