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: stable/11/sys/kern/kern_context.c 338983 2018-09-27 18:42:40Z gordon $"); 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/syscallsubr.h> 36#include <sys/sysent.h> 37#include <sys/systm.h> 38#include <sys/sysproto.h> 39#include <sys/signalvar.h> 40#include <sys/ucontext.h> 41 42/* 43 * The first two fields of a ucontext_t are the signal mask and the machine 44 * context. The next field is uc_link; we want to avoid destroying the link 45 * when copying out contexts. 46 */ 47#define UC_COPY_SIZE offsetof(ucontext_t, uc_link) 48 49#ifndef _SYS_SYSPROTO_H_ 50struct getcontext_args { 51 struct __ucontext *ucp; 52} 53struct setcontext_args { 54 const struct __ucontext_t *ucp; 55} 56struct swapcontext_args { 57 struct __ucontext *oucp; 58 const struct __ucontext_t *ucp; 59} 60#endif 61 62int 63sys_getcontext(struct thread *td, struct getcontext_args *uap) 64{ 65 ucontext_t uc; 66 int ret; 67 68 if (uap->ucp == NULL) 69 ret = EINVAL; 70 else { 71 bzero(&uc, sizeof(ucontext_t)); 72 get_mcontext(td, &uc.uc_mcontext, GET_MC_CLEAR_RET); 73 PROC_LOCK(td->td_proc); 74 uc.uc_sigmask = td->td_sigmask; 75 PROC_UNLOCK(td->td_proc); 76 bzero(uc.__spare__, sizeof(uc.__spare__)); 77 ret = copyout(&uc, uap->ucp, UC_COPY_SIZE); 78 } 79 return (ret); 80} 81 82int 83sys_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 103int 104sys_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 bzero(uc.__spare__, sizeof(uc.__spare__)); 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