1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2002 Daniel M. Eischen <deischen@freebsd.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <sys/param.h> 33 #include <sys/kernel.h> 34 #include <sys/lock.h> 35 #include <sys/mutex.h> 36 #include <sys/proc.h> 37 #include <sys/syscallsubr.h> 38 #include <sys/systm.h> 39 #include <sys/sysproto.h> 40 #include <sys/signalvar.h> 41 #include <sys/ucontext.h> 42 43 /* 44 * The first two fields of a ucontext_t are the signal mask and the machine 45 * context. The next field is uc_link; we want to avoid destroying the link 46 * when copying out contexts. 47 */ 48 #define UC_COPY_SIZE offsetof(ucontext_t, uc_link) 49 50 #ifndef _SYS_SYSPROTO_H_ 51 struct getcontext_args { 52 struct __ucontext *ucp; 53 } 54 struct setcontext_args { 55 const struct __ucontext_t *ucp; 56 } 57 struct swapcontext_args { 58 struct __ucontext *oucp; 59 const struct __ucontext_t *ucp; 60 } 61 #endif 62 63 int 64 sys_getcontext(struct thread *td, struct getcontext_args *uap) 65 { 66 ucontext_t uc; 67 int ret; 68 69 if (uap->ucp == NULL) 70 ret = EINVAL; 71 else { 72 bzero(&uc, sizeof(ucontext_t)); 73 get_mcontext(td, &uc.uc_mcontext, GET_MC_CLEAR_RET); 74 PROC_LOCK(td->td_proc); 75 uc.uc_sigmask = td->td_sigmask; 76 PROC_UNLOCK(td->td_proc); 77 ret = copyout(&uc, uap->ucp, UC_COPY_SIZE); 78 } 79 return (ret); 80 } 81 82 int 83 sys_setcontext(struct thread *td, struct setcontext_args *uap) 84 { 85 ucontext_t uc; 86 int ret; 87 88 if (uap->ucp == NULL) 89 ret = EINVAL; 90 else { 91 ret = copyin(uap->ucp, &uc, UC_COPY_SIZE); 92 if (ret == 0) { 93 ret = set_mcontext(td, &uc.uc_mcontext); 94 if (ret == 0) { 95 kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask, 96 NULL, 0); 97 } 98 } 99 } 100 return (ret == 0 ? EJUSTRETURN : ret); 101 } 102 103 int 104 sys_swapcontext(struct thread *td, struct swapcontext_args *uap) 105 { 106 ucontext_t uc; 107 int ret; 108 109 if (uap->oucp == NULL || uap->ucp == NULL) 110 ret = EINVAL; 111 else { 112 bzero(&uc, sizeof(ucontext_t)); 113 get_mcontext(td, &uc.uc_mcontext, GET_MC_CLEAR_RET); 114 PROC_LOCK(td->td_proc); 115 uc.uc_sigmask = td->td_sigmask; 116 PROC_UNLOCK(td->td_proc); 117 ret = copyout(&uc, uap->oucp, UC_COPY_SIZE); 118 if (ret == 0) { 119 ret = copyin(uap->ucp, &uc, UC_COPY_SIZE); 120 if (ret == 0) { 121 ret = set_mcontext(td, &uc.uc_mcontext); 122 if (ret == 0) { 123 kern_sigprocmask(td, SIG_SETMASK, 124 &uc.uc_sigmask, NULL, 0); 125 } 126 } 127 } 128 } 129 return (ret == 0 ? EJUSTRETURN : ret); 130 } 131