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/param.h> 30 #include <sys/kernel.h> 31 #include <sys/lock.h> 32 #include <sys/mutex.h> 33 #include <sys/proc.h> 34 #include <sys/syscallsubr.h> 35 #include <sys/systm.h> 36 #include <sys/sysproto.h> 37 #include <sys/signalvar.h> 38 #include <sys/ucontext.h> 39 40 /* 41 * The first two fields of a ucontext_t are the signal mask and the machine 42 * context. The next field is uc_link; we want to avoid destroying the link 43 * when copying out contexts. 44 */ 45 #define UC_COPY_SIZE offsetof(ucontext_t, uc_link) 46 47 #ifndef _SYS_SYSPROTO_H_ 48 struct getcontext_args { 49 struct __ucontext *ucp; 50 } 51 struct setcontext_args { 52 const struct __ucontext_t *ucp; 53 } 54 struct swapcontext_args { 55 struct __ucontext *oucp; 56 const struct __ucontext_t *ucp; 57 } 58 #endif 59 60 int 61 sys_getcontext(struct thread *td, struct getcontext_args *uap) 62 { 63 ucontext_t uc; 64 int ret; 65 66 if (uap->ucp == NULL) 67 ret = EINVAL; 68 else { 69 bzero(&uc, sizeof(ucontext_t)); 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 sys_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 sys_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 bzero(&uc, sizeof(ucontext_t)); 110 get_mcontext(td, &uc.uc_mcontext, GET_MC_CLEAR_RET); 111 PROC_LOCK(td->td_proc); 112 uc.uc_sigmask = td->td_sigmask; 113 PROC_UNLOCK(td->td_proc); 114 ret = copyout(&uc, uap->oucp, UC_COPY_SIZE); 115 if (ret == 0) { 116 ret = copyin(uap->ucp, &uc, UC_COPY_SIZE); 117 if (ret == 0) { 118 ret = set_mcontext(td, &uc.uc_mcontext); 119 if (ret == 0) { 120 kern_sigprocmask(td, SIG_SETMASK, 121 &uc.uc_sigmask, NULL, 0); 122 } 123 } 124 } 125 } 126 return (ret == 0 ? EJUSTRETURN : ret); 127 } 128