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/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 kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask, 93 NULL, 0); 94 } 95 } 96 } 97 return (ret == 0 ? EJUSTRETURN : ret); 98 } 99 100 int 101 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 get_mcontext(td, &uc.uc_mcontext, GET_MC_CLEAR_RET); 110 PROC_LOCK(td->td_proc); 111 uc.uc_sigmask = td->td_sigmask; 112 PROC_UNLOCK(td->td_proc); 113 ret = copyout(&uc, uap->oucp, UC_COPY_SIZE); 114 if (ret == 0) { 115 ret = copyin(uap->ucp, &uc, UC_COPY_SIZE); 116 if (ret == 0) { 117 ret = set_mcontext(td, &uc.uc_mcontext); 118 if (ret == 0) { 119 kern_sigprocmask(td, SIG_SETMASK, 120 &uc.uc_sigmask, NULL, 0); 121 } 122 } 123 } 124 } 125 return (ret == 0 ? EJUSTRETURN : ret); 126 } 127