1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2002 Jonathan Mini <mini@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/ucontext.h> 34 #include <machine/psl.h> 35 #include <machine/sigframe.h> 36 #include <signal.h> 37 #include <strings.h> 38 39 __weak_reference(__signalcontext, signalcontext); 40 41 extern void _ctx_start(ucontext_t *, int argc, ...); 42 43 int 44 __signalcontext(ucontext_t *ucp, int sig, __sighandler_t *func) 45 { 46 register_t *p; 47 struct sigframe *sfp; 48 49 /*- 50 * Set up stack. 51 * (n = sizeof(int)) 52 * 2n+sizeof(struct sigframe) ucp 53 * 2n struct sigframe 54 * 1n &func 55 * 0n &_ctx_start 56 */ 57 p = (register_t *)(void *)(intptr_t)ucp->uc_mcontext.mc_esp; 58 *--p = (register_t)(intptr_t)ucp; 59 p = (register_t *)((u_register_t)p & ~0xF); /* Align to 16 bytes. */ 60 p = (register_t *)((u_register_t)p - sizeof(struct sigframe)); 61 sfp = (struct sigframe *)p; 62 bzero(sfp, sizeof(struct sigframe)); 63 sfp->sf_signum = sig; 64 sfp->sf_siginfo = (register_t)(intptr_t)&sfp->sf_si; 65 sfp->sf_ucontext = (register_t)(intptr_t)&sfp->sf_uc; 66 sfp->sf_ahu.sf_action = (__siginfohandler_t *)func; 67 bcopy(ucp, &sfp->sf_uc, sizeof(ucontext_t)); 68 sfp->sf_si.si_signo = sig; 69 *--p = (register_t)(intptr_t)func; 70 71 /* 72 * Set up ucontext_t. 73 */ 74 ucp->uc_mcontext.mc_esi = ucp->uc_mcontext.mc_esp - sizeof(int); 75 ucp->uc_mcontext.mc_esp = (register_t)(intptr_t)p; 76 ucp->uc_mcontext.mc_eip = (register_t)(intptr_t)_ctx_start; 77 ucp->uc_mcontext.mc_eflags &= ~PSL_T; 78 ucp->uc_link = &sfp->sf_uc; 79 sigdelset(&ucp->uc_sigmask, sig); 80 return (0); 81 } 82