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/sysent.h> 39 #include <sys/systm.h> 40 #include <sys/sysproto.h> 41 #include <sys/signalvar.h> 42 #include <sys/ucontext.h> 43 44 /* 45 * The first two fields of a ucontext_t are the signal mask and the machine 46 * context. The next field is uc_link; we want to avoid destroying the link 47 * when copying out contexts. 48 */ 49 #define UC_COPY_SIZE offsetof(ucontext_t, uc_link) 50 51 #ifndef _SYS_SYSPROTO_H_ 52 struct getcontext_args { 53 struct __ucontext *ucp; 54 } 55 struct setcontext_args { 56 const struct __ucontext_t *ucp; 57 } 58 struct swapcontext_args { 59 struct __ucontext *oucp; 60 const struct __ucontext_t *ucp; 61 } 62 #endif 63 64 int 65 sys_getcontext(struct thread *td, struct getcontext_args *uap) 66 { 67 ucontext_t uc; 68 int ret; 69 70 if (uap->ucp == NULL) 71 ret = EINVAL; 72 else { 73 bzero(&uc, sizeof(ucontext_t)); 74 get_mcontext(td, &uc.uc_mcontext, GET_MC_CLEAR_RET); 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 int 84 sys_setcontext(struct thread *td, struct setcontext_args *uap) 85 { 86 ucontext_t uc; 87 int ret; 88 89 if (uap->ucp == NULL) 90 ret = EINVAL; 91 else { 92 ret = copyin(uap->ucp, &uc, UC_COPY_SIZE); 93 if (ret == 0) { 94 ret = set_mcontext(td, &uc.uc_mcontext); 95 if (ret == 0) { 96 kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask, 97 NULL, 0); 98 } 99 } 100 } 101 return (ret == 0 ? EJUSTRETURN : ret); 102 } 103 104 int 105 sys_swapcontext(struct thread *td, struct swapcontext_args *uap) 106 { 107 ucontext_t uc; 108 int ret; 109 110 if (uap->oucp == NULL || uap->ucp == NULL) 111 ret = EINVAL; 112 else { 113 bzero(&uc, sizeof(ucontext_t)); 114 get_mcontext(td, &uc.uc_mcontext, GET_MC_CLEAR_RET); 115 PROC_LOCK(td->td_proc); 116 uc.uc_sigmask = td->td_sigmask; 117 PROC_UNLOCK(td->td_proc); 118 ret = copyout(&uc, uap->oucp, UC_COPY_SIZE); 119 if (ret == 0) { 120 ret = copyin(uap->ucp, &uc, UC_COPY_SIZE); 121 if (ret == 0) { 122 ret = set_mcontext(td, &uc.uc_mcontext); 123 if (ret == 0) { 124 kern_sigprocmask(td, SIG_SETMASK, 125 &uc.uc_sigmask, NULL, 0); 126 } 127 } 128 } 129 } 130 return (ret == 0 ? EJUSTRETURN : ret); 131 } 132