1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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 #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/syscallsubr.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 sys_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 bzero(&uc, sizeof(ucontext_t)); 71 get_mcontext(td, &uc.uc_mcontext, GET_MC_CLEAR_RET); 72 PROC_LOCK(td->td_proc); 73 uc.uc_sigmask = td->td_sigmask; 74 PROC_UNLOCK(td->td_proc); 75 ret = copyout(&uc, uap->ucp, UC_COPY_SIZE); 76 } 77 return (ret); 78 } 79 80 int 81 sys_setcontext(struct thread *td, struct setcontext_args *uap) 82 { 83 ucontext_t uc; 84 int ret; 85 86 if (uap->ucp == NULL) 87 ret = EINVAL; 88 else { 89 ret = copyin(uap->ucp, &uc, UC_COPY_SIZE); 90 if (ret == 0) { 91 ret = set_mcontext(td, &uc.uc_mcontext); 92 if (ret == 0) { 93 kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask, 94 NULL, 0); 95 } 96 } 97 } 98 return (ret == 0 ? EJUSTRETURN : ret); 99 } 100 101 int 102 sys_swapcontext(struct thread *td, struct swapcontext_args *uap) 103 { 104 ucontext_t uc; 105 int ret; 106 107 if (uap->oucp == NULL || uap->ucp == NULL) 108 ret = EINVAL; 109 else { 110 bzero(&uc, sizeof(ucontext_t)); 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 kern_sigprocmask(td, SIG_SETMASK, 122 &uc.uc_sigmask, NULL, 0); 123 } 124 } 125 } 126 } 127 return (ret == 0 ? EJUSTRETURN : ret); 128 } 129