1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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 #include <sys/param.h> 31 #include <sys/ucontext.h> 32 #include <machine/psl.h> 33 #include <machine/sigframe.h> 34 #include <signal.h> 35 #include <strings.h> 36 37 __weak_reference(__signalcontext, signalcontext); 38 39 extern void _ctx_start(ucontext_t *, int argc, ...); 40 41 int 42 __signalcontext(ucontext_t *ucp, int sig, __sighandler_t *func) 43 { 44 register_t *p; 45 struct sigframe *sfp; 46 47 /*- 48 * Set up stack. 49 * (n = sizeof(int)) 50 * 2n+sizeof(struct sigframe) ucp 51 * 2n struct sigframe 52 * 1n &func 53 * 0n &_ctx_start 54 */ 55 p = (register_t *)(void *)(intptr_t)ucp->uc_mcontext.mc_esp; 56 *--p = (register_t)(intptr_t)ucp; 57 p = (register_t *)((u_register_t)p & ~0xF); /* Align to 16 bytes. */ 58 p = (register_t *)((u_register_t)p - sizeof(struct sigframe)); 59 sfp = (struct sigframe *)p; 60 bzero(sfp, sizeof(struct sigframe)); 61 sfp->sf_signum = sig; 62 sfp->sf_siginfo = (register_t)(intptr_t)&sfp->sf_si; 63 sfp->sf_ucontext = (register_t)(intptr_t)&sfp->sf_uc; 64 sfp->sf_ahu.sf_action = (__siginfohandler_t *)func; 65 bcopy(ucp, &sfp->sf_uc, sizeof(ucontext_t)); 66 sfp->sf_si.si_signo = sig; 67 *--p = (register_t)(intptr_t)func; 68 69 /* 70 * Set up ucontext_t. 71 */ 72 ucp->uc_mcontext.mc_esi = ucp->uc_mcontext.mc_esp - sizeof(int); 73 ucp->uc_mcontext.mc_esp = (register_t)(intptr_t)p; 74 ucp->uc_mcontext.mc_eip = (register_t)(intptr_t)_ctx_start; 75 ucp->uc_mcontext.mc_eflags &= ~PSL_T; 76 ucp->uc_link = &sfp->sf_uc; 77 sigdelset(&ucp->uc_sigmask, sig); 78 return (0); 79 } 80