signalcontext.c revision 118058
11541Srgrimes/* 21541Srgrimes * Copyright (c) 2003 Marcel Moolenaar 31541Srgrimes * All rights reserved. 41541Srgrimes * 51541Srgrimes * Redistribution and use in source and binary forms, with or without 61541Srgrimes * modification, are permitted provided that the following conditions 71541Srgrimes * are met: 81541Srgrimes * 91541Srgrimes * 1. Redistributions of source code must retain the above copyright 101541Srgrimes * notice, this list of conditions and the following disclaimer. 111541Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 121541Srgrimes * notice, this list of conditions and the following disclaimer in the 131541Srgrimes * documentation and/or other materials provided with the distribution. 141541Srgrimes * 151541Srgrimes * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 161541Srgrimes * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 171541Srgrimes * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 181541Srgrimes * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 191541Srgrimes * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 201541Srgrimes * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 211541Srgrimes * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 221541Srgrimes * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 231541Srgrimes * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 241541Srgrimes * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 251541Srgrimes */ 261541Srgrimes 271541Srgrimes#include <sys/cdefs.h> 281541Srgrimes__FBSDID("$FreeBSD: head/lib/libc/amd64/gen/signalcontext.c 118058 2003-07-26 12:58:28Z davidxu $"); 291541Srgrimes 301541Srgrimes#include <sys/types.h> 311541Srgrimes#include <sys/ucontext.h> 321541Srgrimes#include <signal.h> 331541Srgrimes#include <stdlib.h> 3450477Speter#include <strings.h> 351541Srgrimes 361541Srgrimestypedef void (*handler_t)(uint64_t, uint64_t, uint64_t); 372169Spaul 382169Spaul/* Prototypes */ 392169Spaulstatic void ctx_wrapper(ucontext_t *ucp, handler_t func, uint64_t *args); 401541Srgrimes 411541Srgrimes__weak_reference(__signalcontext, signalcontext); 421541Srgrimes 431541Srgrimesint 441541Srgrimes__signalcontext(ucontext_t *ucp, int sig, __sighandler_t *func) 451541Srgrimes{ 461541Srgrimes uint64_t *args; 471541Srgrimes siginfo_t *sig_si; 481541Srgrimes ucontext_t *sig_uc; 491541Srgrimes uint64_t sp; 501541Srgrimes 511541Srgrimes /* Bail out if we don't have a valid ucontext pointer. */ 521541Srgrimes if (ucp == NULL) 5337620Sbde abort(); 5437620Sbde 5536735Sdfr /* 5637620Sbde * Build a signal frame and copy the arguments of signal handler 5736735Sdfr * 'func' onto the stack. We only need 3 arguments, but we 581541Srgrimes * create room for 4 so that we are 16-byte aligned. 591541Srgrimes */ 601541Srgrimes sp = (ucp->uc_mcontext.mc_rsp - sizeof(ucontext_t)) & ~15UL; 612169Spaul sig_uc = (ucontext_t *)sp; 622169Spaul bcopy(ucp, sig_uc, sizeof(*sig_uc)); 63 sp = (sp - sizeof(siginfo_t)) & ~15UL; 64 sig_si = (siginfo_t *)sp; 65 bzero(sig_si, sizeof(*sig_si)); 66 sig_si->si_signo = sig; 67 sp -= 4 * sizeof(uint64_t); 68 args = (uint64_t *)sp; 69 args[0] = sig; 70 args[1] = (intptr_t)sig_si; 71 args[2] = (intptr_t)sig_uc; 72 args[3] = 0; 73 sp -= 16; 74 75 /* 76 * Setup the ucontext of the signal handler. 77 */ 78 bzero(&ucp->uc_mcontext, sizeof(ucp->uc_mcontext)); 79 ucp->uc_link = sig_uc; 80 sigdelset(&ucp->uc_sigmask, sig); 81 82 ucp->uc_mcontext.mc_len = sizeof(mcontext_t); 83 ucp->uc_mcontext.mc_rdi = (register_t)ucp; 84 ucp->uc_mcontext.mc_rsi = (register_t)func; 85 ucp->uc_mcontext.mc_rdx = (register_t)args; 86 ucp->uc_mcontext.mc_rbp = (register_t)sp; 87 ucp->uc_mcontext.mc_rbx = (register_t)sp; 88 ucp->uc_mcontext.mc_rsp = (register_t)sp; 89 ucp->uc_mcontext.mc_rip = (register_t)ctx_wrapper; 90 return (0); 91} 92 93static void 94ctx_wrapper(ucontext_t *ucp, handler_t func, uint64_t *args) 95{ 96 97 (*func)(args[0], args[1], args[2]); 98 if (ucp->uc_link == NULL) 99 exit(0); 100 setcontext((const ucontext_t *)ucp->uc_link); 101 /* should never get here */ 102 abort(); 103 /* NOTREACHED */ 104} 105