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: releng/8.3/sys/kern/kern_context.c 218836 2011-02-19 07:39:14Z kib $");
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/sysent.h>
36 #include <sys/systm.h>
37 #include <sys/sysproto.h>
38 #include <sys/signalvar.h>
39 #include <sys/ucontext.h>
40
41 /*
42 * The first two fields of a ucontext_t are the signal mask and the machine
43 * context. The next field is uc_link; we want to avoid destroying the link
44 * when copying out contexts.
45 */
46 #define UC_COPY_SIZE offsetof(ucontext_t, uc_link)
47
48 #ifndef _SYS_SYSPROTO_H_
49 struct getcontext_args {
50 struct __ucontext *ucp;
51 }
52 struct setcontext_args {
53 const struct __ucontext_t *ucp;
54 }
55 struct swapcontext_args {
56 struct __ucontext *oucp;
57 const struct __ucontext_t *ucp;
58 }
59 #endif
60
61 int
62 getcontext(struct thread *td, struct getcontext_args *uap)
63 {
64 ucontext_t uc;
65 int ret;
66
67 if (uap->ucp == NULL)
68 ret = EINVAL;
69 else {
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 bzero(uc.__spare__, sizeof(uc.__spare__));
75 ret = copyout(&uc, uap->ucp, UC_COPY_SIZE);
76 }
77 return (ret);
78 }
79
80 int
81 setcontext(struct thread *td, struct setcontext_args *uap)
82 {
83 ucontext_t uc;
84 int ret;
85
86 if (uap->ucp == NULL)
87 ret = EINVAL;
88 else {
89 ret = copyin(uap->ucp, &uc, UC_COPY_SIZE);
90 if (ret == 0) {
91 ret = set_mcontext(td, &uc.uc_mcontext);
92 if (ret == 0) {
93 kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask,
94 NULL, 0);
95 }
96 }
97 }
98 return (ret == 0 ? EJUSTRETURN : ret);
99 }
100
101 int
102 swapcontext(struct thread *td, struct swapcontext_args *uap)
103 {
104 ucontext_t uc;
105 int ret;
106
107 if (uap->oucp == NULL || uap->ucp == NULL)
108 ret = EINVAL;
109 else {
110 get_mcontext(td, &uc.uc_mcontext, GET_MC_CLEAR_RET);
111 bzero(uc.__spare__, sizeof(uc.__spare__));
112 PROC_LOCK(td->td_proc);
113 uc.uc_sigmask = td->td_sigmask;
114 PROC_UNLOCK(td->td_proc);
115 ret = copyout(&uc, uap->oucp, UC_COPY_SIZE);
116 if (ret == 0) {
117 ret = copyin(uap->ucp, &uc, UC_COPY_SIZE);
118 if (ret == 0) {
119 ret = set_mcontext(td, &uc.uc_mcontext);
120 if (ret == 0) {
121 kern_sigprocmask(td, SIG_SETMASK,
122 &uc.uc_sigmask, NULL, 0);
123 }
124 }
125 }
126 }
127 return (ret == 0 ? EJUSTRETURN : ret);
128 }
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