1 /* 2 * Copyright (c) 2004 Marcel Moolenaar, Peter Grehan 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 * 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <sys/param.h> 31 #include <sys/ucontext.h> 32 #include <signal.h> 33 #include <stdlib.h> 34 #include <strings.h> 35 36 typedef void (*handler_t)(uint32_t, uint32_t, uint32_t); 37 38 /* Prototypes */ 39 static void ctx_wrapper(ucontext_t *ucp, handler_t func, uint32_t sig, 40 uint32_t sig_si, uint32_t sig_uc); 41 42 __weak_reference(__signalcontext, signalcontext); 43 44 int 45 __signalcontext(ucontext_t *ucp, int sig, __sighandler_t *func) 46 { 47 siginfo_t *sig_si; 48 ucontext_t *sig_uc; 49 uintptr_t sp; 50 51 /* Bail out if we don't have a valid ucontext pointer. */ 52 if (ucp == NULL) 53 abort(); 54 55 /* 56 * Build a 16-byte-aligned signal frame 57 */ 58 sp = (ucp->uc_mcontext.mc_gpr[1] - sizeof(ucontext_t)) & ~15UL; 59 sig_uc = (ucontext_t *)sp; 60 bcopy(ucp, sig_uc, sizeof(*sig_uc)); 61 sp = (sp - sizeof(siginfo_t)) & ~15UL; 62 sig_si = (siginfo_t *)sp; 63 bzero(sig_si, sizeof(*sig_si)); 64 sig_si->si_signo = sig; 65 66 /* 67 * Subtract 48 bytes from stack to allow for frameptr 68 */ 69 sp -= 6*sizeof(uint64_t); 70 sp &= ~15UL; 71 72 /* 73 * Setup the ucontext of the signal handler. 74 */ 75 bzero(&ucp->uc_mcontext, sizeof(ucp->uc_mcontext)); 76 ucp->uc_link = sig_uc; 77 sigdelset(&ucp->uc_sigmask, sig); 78 79 ucp->uc_mcontext.mc_vers = _MC_VERSION; 80 ucp->uc_mcontext.mc_len = sizeof(struct __mcontext); 81 ucp->uc_mcontext.mc_srr0 = (uint64_t) ctx_wrapper; 82 ucp->uc_mcontext.mc_gpr[1] = (uint64_t) sp; 83 ucp->uc_mcontext.mc_gpr[3] = (uint64_t) func; 84 ucp->uc_mcontext.mc_gpr[4] = (uint64_t) sig; 85 ucp->uc_mcontext.mc_gpr[5] = (uint64_t) sig_si; 86 ucp->uc_mcontext.mc_gpr[6] = (uint64_t) sig_uc; 87 88 return (0); 89 } 90 91 static void 92 ctx_wrapper(ucontext_t *ucp, handler_t func, uint32_t sig, uint32_t sig_si, 93 uint32_t sig_uc) 94 { 95 96 (*func)(sig, sig_si, sig_uc); 97 if (ucp->uc_link == NULL) 98 exit(0); 99 setcontext((const ucontext_t *)ucp->uc_link); 100 /* should never get here */ 101 abort(); 102 /* NOTREACHED */ 103 } 104