1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2002 Daniel M. Eischen <deischen@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/kernel.h>
31 #include <sys/lock.h>
32 #include <sys/mutex.h>
33 #include <sys/proc.h>
34 #include <sys/syscallsubr.h>
35 #include <sys/systm.h>
36 #include <sys/sysproto.h>
37 #include <sys/signalvar.h>
38 #include <sys/ucontext.h>
39
40 /*
41 * The first two fields of a ucontext_t are the signal mask and the machine
42 * context. The next field is uc_link; we want to avoid destroying the link
43 * when copying out contexts.
44 */
45 #define UC_COPY_SIZE offsetof(ucontext_t, uc_link)
46
47 #ifndef _SYS_SYSPROTO_H_
48 struct getcontext_args {
49 struct __ucontext *ucp;
50 }
51 struct setcontext_args {
52 const struct __ucontext_t *ucp;
53 }
54 struct swapcontext_args {
55 struct __ucontext *oucp;
56 const struct __ucontext_t *ucp;
57 }
58 #endif
59
60 int
sys_getcontext(struct thread * td,struct getcontext_args * uap)61 sys_getcontext(struct thread *td, struct getcontext_args *uap)
62 {
63 ucontext_t uc;
64 int ret;
65
66 if (uap->ucp == NULL)
67 ret = EINVAL;
68 else {
69 bzero(&uc, sizeof(ucontext_t));
70 get_mcontext(td, &uc.uc_mcontext, GET_MC_CLEAR_RET);
71 PROC_LOCK(td->td_proc);
72 uc.uc_sigmask = td->td_sigmask;
73 PROC_UNLOCK(td->td_proc);
74 ret = copyout(&uc, uap->ucp, UC_COPY_SIZE);
75 }
76 return (ret);
77 }
78
79 int
sys_setcontext(struct thread * td,struct setcontext_args * uap)80 sys_setcontext(struct thread *td, struct setcontext_args *uap)
81 {
82 ucontext_t uc;
83 int ret;
84
85 if (uap->ucp == NULL)
86 ret = EINVAL;
87 else {
88 ret = copyin(uap->ucp, &uc, UC_COPY_SIZE);
89 if (ret == 0) {
90 ret = set_mcontext(td, &uc.uc_mcontext);
91 if (ret == 0) {
92 kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask,
93 NULL, 0);
94 }
95 }
96 }
97 return (ret == 0 ? EJUSTRETURN : ret);
98 }
99
100 int
sys_swapcontext(struct thread * td,struct swapcontext_args * uap)101 sys_swapcontext(struct thread *td, struct swapcontext_args *uap)
102 {
103 ucontext_t uc;
104 int ret;
105
106 if (uap->oucp == NULL || uap->ucp == NULL)
107 ret = EINVAL;
108 else {
109 bzero(&uc, sizeof(ucontext_t));
110 get_mcontext(td, &uc.uc_mcontext, GET_MC_CLEAR_RET);
111 PROC_LOCK(td->td_proc);
112 uc.uc_sigmask = td->td_sigmask;
113 PROC_UNLOCK(td->td_proc);
114 ret = copyout(&uc, uap->oucp, UC_COPY_SIZE);
115 if (ret == 0) {
116 ret = copyin(uap->ucp, &uc, UC_COPY_SIZE);
117 if (ret == 0) {
118 ret = set_mcontext(td, &uc.uc_mcontext);
119 if (ret == 0) {
120 kern_sigprocmask(td, SIG_SETMASK,
121 &uc.uc_sigmask, NULL, 0);
122 }
123 }
124 }
125 }
126 return (ret == 0 ? EJUSTRETURN : ret);
127 }
128