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 /* 28 * $FreeBSD$ 29 */ 30 31 #include <sys/param.h> 32 #include <sys/kernel.h> 33 #include <sys/lock.h> 34 #include <sys/mutex.h> 35 #include <sys/proc.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 44 * the machine context. The next field is uc_link; we want to 45 * avoid destroying the link 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 /* 63 * MPSAFE 64 */ 65 int 66 getcontext(struct thread *td, struct getcontext_args *uap) 67 { 68 ucontext_t uc; 69 int ret; 70 71 if (uap->ucp == NULL) 72 ret = EINVAL; 73 else { 74 get_mcontext(td, &uc.uc_mcontext, 1); 75 PROC_LOCK(td->td_proc); 76 uc.uc_sigmask = td->td_sigmask; 77 PROC_UNLOCK(td->td_proc); 78 ret = copyout(&uc, uap->ucp, UC_COPY_SIZE); 79 } 80 return (ret); 81 } 82 83 /* 84 * MPSAFE 85 */ 86 int 87 setcontext(struct thread *td, struct setcontext_args *uap) 88 { 89 ucontext_t uc; 90 int ret; 91 92 if (uap->ucp == NULL) 93 ret = EINVAL; 94 else { 95 ret = copyin(uap->ucp, &uc, UC_COPY_SIZE); 96 if (ret == 0) { 97 ret = set_mcontext(td, &uc.uc_mcontext); 98 if (ret == 0) { 99 SIG_CANTMASK(uc.uc_sigmask); 100 PROC_LOCK(td->td_proc); 101 td->td_sigmask = uc.uc_sigmask; 102 PROC_UNLOCK(td->td_proc); 103 } 104 } 105 } 106 return (ret == 0 ? EJUSTRETURN : ret); 107 } 108 109 int 110 swapcontext(struct thread *td, struct swapcontext_args *uap) 111 { 112 ucontext_t uc; 113 int ret; 114 115 if (uap->oucp == NULL || uap->ucp == NULL) 116 ret = EINVAL; 117 else { 118 get_mcontext(td, &uc.uc_mcontext, 1); 119 PROC_LOCK(td->td_proc); 120 uc.uc_sigmask = td->td_sigmask; 121 PROC_UNLOCK(td->td_proc); 122 ret = copyout(&uc, uap->oucp, UC_COPY_SIZE); 123 if (ret == 0) { 124 ret = copyin(uap->ucp, &uc, UC_COPY_SIZE); 125 if (ret == 0) { 126 ret = set_mcontext(td, &uc.uc_mcontext); 127 if (ret == 0) { 128 SIG_CANTMASK(uc.uc_sigmask); 129 PROC_LOCK(td->td_proc); 130 td->td_sigmask = uc.uc_sigmask; 131 PROC_UNLOCK(td->td_proc); 132 } 133 } 134 } 135 } 136 return (ret == 0 ? EJUSTRETURN : ret); 137 } 138