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: src/sys/kern/kern_context.c,v 1.9 2007/03/05 13:10:57 rwatson Exp $");
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 ret = copyout(&uc, uap->ucp, UC_COPY_SIZE);
75 }
76 return (ret);
77 }
78
79 int
80 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 SIG_CANTMASK(uc.uc_sigmask);
93 PROC_LOCK(td->td_proc);
94 td->td_sigmask = uc.uc_sigmask;
95 PROC_UNLOCK(td->td_proc);
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 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 SIG_CANTMASK(uc.uc_sigmask);
122 PROC_LOCK(td->td_proc);
123 td->td_sigmask = uc.uc_sigmask;
124 PROC_UNLOCK(td->td_proc);
125 }
126 }
127 }
128 }
129 return (ret == 0 ? EJUSTRETURN : ret);
130 }
131
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