kern_context.c revision 209613
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: head/sys/kern/kern_context.c 209613 2010-06-30 18:03:42Z jhb $"); 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 63getcontext(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 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 80int 81setcontext(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 101int 102swapcontext(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 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