1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2004 Marcel Moolenaar, Peter Grehan 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 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #include <sys/param.h> 30 #include <sys/ucontext.h> 31 #include <signal.h> 32 #include <stdlib.h> 33 #include <strings.h> 34 35 typedef void (*handler_t)(uint32_t, uint32_t, uint32_t); 36 37 /* Prototypes */ 38 static void ctx_wrapper(ucontext_t *ucp, handler_t func, uint32_t sig, 39 uint32_t sig_si, uint32_t sig_uc); 40 41 __weak_reference(__signalcontext, signalcontext); 42 43 int 44 __signalcontext(ucontext_t *ucp, int sig, __sighandler_t *func) 45 { 46 siginfo_t *sig_si; 47 ucontext_t *sig_uc; 48 uintptr_t sp; 49 50 /* Bail out if we don't have a valid ucontext pointer. */ 51 if (ucp == NULL) 52 abort(); 53 54 /* 55 * Build a 16-byte-aligned signal frame 56 */ 57 sp = (ucp->uc_mcontext.mc_gpr[1] - sizeof(ucontext_t)) & ~15UL; 58 sig_uc = (ucontext_t *)sp; 59 bcopy(ucp, sig_uc, sizeof(*sig_uc)); 60 sp = (sp - sizeof(siginfo_t)) & ~15UL; 61 sig_si = (siginfo_t *)sp; 62 bzero(sig_si, sizeof(*sig_si)); 63 sig_si->si_signo = sig; 64 65 /* 66 * Subtract 48 bytes from stack to allow for frameptr 67 */ 68 sp -= 6*sizeof(uint64_t); 69 sp &= ~15UL; 70 71 /* 72 * Setup the ucontext of the signal handler. 73 */ 74 bzero(&ucp->uc_mcontext, sizeof(ucp->uc_mcontext)); 75 ucp->uc_link = sig_uc; 76 sigdelset(&ucp->uc_sigmask, sig); 77 78 ucp->uc_mcontext.mc_vers = _MC_VERSION; 79 ucp->uc_mcontext.mc_len = sizeof(struct __mcontext); 80 ucp->uc_mcontext.mc_srr0 = (uint64_t) ctx_wrapper; 81 ucp->uc_mcontext.mc_gpr[1] = (uint64_t) sp; 82 ucp->uc_mcontext.mc_gpr[3] = (uint64_t) func; 83 ucp->uc_mcontext.mc_gpr[4] = (uint64_t) sig; 84 ucp->uc_mcontext.mc_gpr[5] = (uint64_t) sig_si; 85 ucp->uc_mcontext.mc_gpr[6] = (uint64_t) sig_uc; 86 87 return (0); 88 } 89 90 static void 91 ctx_wrapper(ucontext_t *ucp, handler_t func, uint32_t sig, uint32_t sig_si, 92 uint32_t sig_uc) 93 { 94 95 (*func)(sig, sig_si, sig_uc); 96 if (ucp->uc_link == NULL) 97 exit(0); 98 setcontext((const ucontext_t *)ucp->uc_link); 99 /* should never get here */ 100 abort(); 101 /* NOTREACHED */ 102 } 103