1 /*-
2 * Copyright (c) 2002 Daniel M. Eischen <deischen@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/kernel.h>
32 #include <sys/lock.h>
33 #include <sys/mutex.h>
34 #include <sys/proc.h>
35 #include <sys/syscallsubr.h>
36 #include <sys/sysent.h>
37 #include <sys/systm.h>
38 #include <sys/sysproto.h>
39 #include <sys/signalvar.h>
40 #include <sys/ucontext.h>
41
42 /*
43 * The first two fields of a ucontext_t are the signal mask and the machine
44 * context. The next field is uc_link; we want to avoid destroying the link
45 * when copying out contexts.
46 */
47 #define UC_COPY_SIZE offsetof(ucontext_t, uc_link)
48
49 #ifndef _SYS_SYSPROTO_H_
50 struct getcontext_args {
51 struct __ucontext *ucp;
52 }
53 struct setcontext_args {
54 const struct __ucontext_t *ucp;
55 }
56 struct swapcontext_args {
57 struct __ucontext *oucp;
58 const struct __ucontext_t *ucp;
59 }
60 #endif
61
62 int
63 getcontext(struct thread *td, struct getcontext_args *uap)
64 {
65 ucontext_t uc;
66 int ret;
67
68 if (uap->ucp == NULL)
69 ret = EINVAL;
70 else {
71 get_mcontext(td, &uc.uc_mcontext, GET_MC_CLEAR_RET);
72 PROC_LOCK(td->td_proc);
73 uc.uc_sigmask = td->td_sigmask;
74 PROC_UNLOCK(td->td_proc);
75 bzero(uc.__spare__, sizeof(uc.__spare__));
76 ret = copyout(&uc, uap->ucp, UC_COPY_SIZE);
77 }
78 return (ret);
79 }
80
81 int
82 setcontext(struct thread *td, struct setcontext_args *uap)
83 {
84 ucontext_t uc;
85 int ret;
86
87 if (uap->ucp == NULL)
88 ret = EINVAL;
89 else {
90 ret = copyin(uap->ucp, &uc, UC_COPY_SIZE);
91 if (ret == 0) {
92 ret = set_mcontext(td, &uc.uc_mcontext);
93 if (ret == 0) {
94 kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask,
95 NULL, 0);
96 }
97 }
98 }
99 return (ret == 0 ? EJUSTRETURN : ret);
100 }
101
102 int
103 swapcontext(struct thread *td, struct swapcontext_args *uap)
104 {
105 ucontext_t uc;
106 int ret;
107
108 if (uap->oucp == NULL || uap->ucp == NULL)
109 ret = EINVAL;
110 else {
111 get_mcontext(td, &uc.uc_mcontext, GET_MC_CLEAR_RET);
112 bzero(uc.__spare__, sizeof(uc.__spare__));
113 PROC_LOCK(td->td_proc);
114 uc.uc_sigmask = td->td_sigmask;
115 PROC_UNLOCK(td->td_proc);
116 ret = copyout(&uc, uap->oucp, UC_COPY_SIZE);
117 if (ret == 0) {
118 ret = copyin(uap->ucp, &uc, UC_COPY_SIZE);
119 if (ret == 0) {
120 ret = set_mcontext(td, &uc.uc_mcontext);
121 if (ret == 0) {
122 kern_sigprocmask(td, SIG_SETMASK,
123 &uc.uc_sigmask, NULL, 0);
124 }
125 }
126 }
127 }
128 return (ret == 0 ? EJUSTRETURN : ret);
129 }
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