| 1 |
/* |
| 2 |
* sigsegv.cpp - SIGSEGV signals support |
| 3 |
* |
| 4 |
* Derived from Bruno Haible's work on his SIGSEGV library for clisp |
| 5 |
* <http://clisp.sourceforge.net/> |
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* |
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* Basilisk II (C) 1997-2002 Christian Bauer |
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* |
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* This program is free software; you can redistribute it and/or modify |
| 10 |
* it under the terms of the GNU General Public License as published by |
| 11 |
* the Free Software Foundation; either version 2 of the License, or |
| 12 |
* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 |
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 17 |
* GNU General Public License for more details. |
| 18 |
* |
| 19 |
* You should have received a copy of the GNU General Public License |
| 20 |
* along with this program; if not, write to the Free Software |
| 21 |
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 22 |
*/ |
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|
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#ifdef HAVE_UNISTD_H |
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#include <unistd.h> |
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#endif |
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|
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#ifdef HAVE_CONFIG_H |
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#include "config.h" |
| 30 |
#endif |
| 31 |
|
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#include <signal.h> |
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#include "sigsegv.h" |
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|
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// Return value type of a signal handler (standard type if not defined) |
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#ifndef RETSIGTYPE |
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#define RETSIGTYPE void |
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#endif |
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|
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// Type of the system signal handler |
| 41 |
typedef RETSIGTYPE (*signal_handler)(int); |
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|
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// Is the fault to be ignored? |
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static bool sigsegv_ignore_fault = false; |
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|
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// User's SIGSEGV handler |
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static sigsegv_fault_handler_t sigsegv_fault_handler = 0; |
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|
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// Function called to dump state if we can't handle the fault |
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static sigsegv_state_dumper_t sigsegv_state_dumper = 0; |
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|
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// Actual SIGSEGV handler installer |
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static bool sigsegv_do_install_handler(int sig); |
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|
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|
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/* |
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* OS-dependant SIGSEGV signals support section |
| 58 |
*/ |
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|
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#if HAVE_SIGINFO_T |
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// Generic extended signal handler |
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#if defined(__NetBSD__) || defined(__FreeBSD__) |
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#define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGBUS) |
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#else |
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#define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV) |
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#endif |
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#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, siginfo_t *sip, void *scp |
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#define SIGSEGV_FAULT_ADDRESS sip->si_addr |
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#if defined(__linux__) |
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#if (defined(i386) || defined(__i386__)) |
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#include <sys/ucontext.h> |
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#define SIGSEGV_FAULT_INSTRUCTION (((ucontext_t *)scp)->uc_mcontext.gregs[14]) /* should use REG_EIP instead */ |
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#define SIGSEGV_REGISTER_FILE (unsigned long *)(((ucontext_t *)scp)->uc_mcontext.gregs) |
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#define SIGSEGV_SKIP_INSTRUCTION ix86_skip_instruction |
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#endif |
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#if (defined(ia64) || defined(__ia64__)) |
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#define SIGSEGV_FAULT_INSTRUCTION (((struct sigcontext *)scp)->sc_ip & ~0x3ULL) /* slot number is in bits 0 and 1 */ |
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#endif |
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#if (defined(powerpc) || defined(__powerpc__)) |
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#include <sys/ucontext.h> |
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#define SIGSEGV_FAULT_INSTRUCTION (((ucontext_t *)scp)->uc_mcontext.regs->nip) |
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#endif |
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#endif |
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#endif |
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|
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#if HAVE_SIGCONTEXT_SUBTERFUGE |
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// Linux kernels prior to 2.4 ? |
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#if defined(__linux__) |
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#define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV) |
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#if (defined(i386) || defined(__i386__)) |
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#include <asm/sigcontext.h> |
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#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, struct sigcontext scs |
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#define SIGSEGV_FAULT_ADDRESS scs.cr2 |
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#define SIGSEGV_FAULT_INSTRUCTION scs.eip |
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#define SIGSEGV_REGISTER_FILE (unsigned long *)(&scs) |
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#define SIGSEGV_SKIP_INSTRUCTION ix86_skip_instruction |
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#endif |
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#if (defined(sparc) || defined(__sparc__)) |
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#include <asm/sigcontext.h> |
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#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp, char *addr |
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#define SIGSEGV_FAULT_ADDRESS addr |
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#endif |
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#if (defined(powerpc) || defined(__powerpc__)) |
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#include <asm/sigcontext.h> |
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#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, struct sigcontext *scp |
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#define SIGSEGV_FAULT_ADDRESS scp->regs->dar |
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#define SIGSEGV_FAULT_INSTRUCTION scp->regs->nip |
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#endif |
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#if (defined(alpha) || defined(__alpha__)) |
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#include <asm/sigcontext.h> |
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#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp |
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#define SIGSEGV_FAULT_ADDRESS get_fault_address(scp) |
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#define SIGSEGV_FAULT_INSTRUCTION scp->sc_pc |
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|
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// From Boehm's GC 6.0alpha8 |
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static sigsegv_address_t get_fault_address(struct sigcontext *scp) |
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{ |
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unsigned int instruction = *((unsigned int *)(scp->sc_pc)); |
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unsigned long fault_address = scp->sc_regs[(instruction >> 16) & 0x1f]; |
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fault_address += (signed long)(signed short)(instruction & 0xffff); |
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return (sigsegv_address_t)fault_address; |
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} |
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#endif |
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#endif |
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|
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// Irix 5 or 6 on MIPS |
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#if (defined(sgi) || defined(__sgi)) && (defined(SYSTYPE_SVR4) || defined(__SYSTYPE_SVR4)) |
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#include <ucontext.h> |
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#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp |
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#define SIGSEGV_FAULT_ADDRESS scp->sc_badvaddr |
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#define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV) |
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#endif |
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|
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// HP-UX |
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#if (defined(hpux) || defined(__hpux__)) |
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#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp |
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#define SIGSEGV_FAULT_ADDRESS scp->sc_sl.sl_ss.ss_narrow.ss_cr21 |
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#define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV) FAULT_HANDLER(SIGBUS) |
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#endif |
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|
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// OSF/1 on Alpha |
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#if defined(__osf__) |
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#include <ucontext.h> |
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#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp |
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#define SIGSEGV_FAULT_ADDRESS scp->sc_traparg_a0 |
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#define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV) |
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#endif |
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|
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// AIX |
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#if defined(_AIX) |
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#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp |
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#define SIGSEGV_FAULT_ADDRESS scp->sc_jmpbuf.jmp_context.o_vaddr |
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#define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV) |
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#endif |
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|
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// NetBSD or FreeBSD |
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#if defined(__NetBSD__) || defined(__FreeBSD__) |
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#if (defined(m68k) || defined(__m68k__)) |
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#include <m68k/frame.h> |
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#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp |
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#define SIGSEGV_FAULT_ADDRESS ({ \ |
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struct sigstate { \ |
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int ss_flags; \ |
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struct frame ss_frame; \ |
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}; \ |
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struct sigstate *state = (struct sigstate *)scp->sc_ap; \ |
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char *fault_addr; \ |
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switch (state->ss_frame.f_format) { \ |
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case 7: /* 68040 access error */ \ |
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/* "code" is sometimes unreliable (i.e. contains NULL or a bogus address), reason unknown */ \ |
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fault_addr = state->ss_frame.f_fmt7.f_fa; \ |
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break; \ |
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default: \ |
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fault_addr = (char *)code; \ |
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break; \ |
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} \ |
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fault_addr; \ |
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}) |
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#define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV) |
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#else |
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#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, void *scp, char *addr |
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#define SIGSEGV_FAULT_ADDRESS addr |
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#define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGBUS) |
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#endif |
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#endif |
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|
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// MacOS X |
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#if defined(__APPLE__) && defined(__MACH__) |
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#if (defined(ppc) || defined(__ppc__)) |
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#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp |
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#define SIGSEGV_FAULT_ADDRESS get_fault_address(scp) |
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#define SIGSEGV_FAULT_INSTRUCTION scp->sc_ir |
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#define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGBUS) |
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|
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// From Boehm's GC 6.0alpha8 |
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#define EXTRACT_OP1(iw) (((iw) & 0xFC000000) >> 26) |
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#define EXTRACT_OP2(iw) (((iw) & 0x000007FE) >> 1) |
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#define EXTRACT_REGA(iw) (((iw) & 0x001F0000) >> 16) |
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#define EXTRACT_REGB(iw) (((iw) & 0x03E00000) >> 21) |
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#define EXTRACT_REGC(iw) (((iw) & 0x0000F800) >> 11) |
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#define EXTRACT_DISP(iw) ((short *) &(iw))[1] |
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|
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static sigsegv_address_t get_fault_address(struct sigcontext *scp) |
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{ |
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unsigned int instr = *((unsigned int *) scp->sc_ir); |
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unsigned int * regs = &((unsigned int *) scp->sc_regs)[2]; |
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int disp = 0, tmp; |
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unsigned int baseA = 0, baseB = 0; |
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unsigned int addr, alignmask = 0xFFFFFFFF; |
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|
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switch(EXTRACT_OP1(instr)) { |
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case 38: /* stb */ |
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case 39: /* stbu */ |
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case 54: /* stfd */ |
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case 55: /* stfdu */ |
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case 52: /* stfs */ |
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case 53: /* stfsu */ |
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case 44: /* sth */ |
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case 45: /* sthu */ |
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case 47: /* stmw */ |
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case 36: /* stw */ |
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case 37: /* stwu */ |
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tmp = EXTRACT_REGA(instr); |
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if(tmp > 0) |
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baseA = regs[tmp]; |
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disp = EXTRACT_DISP(instr); |
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break; |
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case 31: |
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switch(EXTRACT_OP2(instr)) { |
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case 86: /* dcbf */ |
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case 54: /* dcbst */ |
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case 1014: /* dcbz */ |
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case 247: /* stbux */ |
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case 215: /* stbx */ |
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case 759: /* stfdux */ |
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case 727: /* stfdx */ |
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case 983: /* stfiwx */ |
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case 695: /* stfsux */ |
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case 663: /* stfsx */ |
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case 918: /* sthbrx */ |
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case 439: /* sthux */ |
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case 407: /* sthx */ |
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case 661: /* stswx */ |
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case 662: /* stwbrx */ |
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case 150: /* stwcx. */ |
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case 183: /* stwux */ |
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case 151: /* stwx */ |
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case 135: /* stvebx */ |
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case 167: /* stvehx */ |
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case 199: /* stvewx */ |
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case 231: /* stvx */ |
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case 487: /* stvxl */ |
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tmp = EXTRACT_REGA(instr); |
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if(tmp > 0) |
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baseA = regs[tmp]; |
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baseB = regs[EXTRACT_REGC(instr)]; |
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/* determine Altivec alignment mask */ |
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switch(EXTRACT_OP2(instr)) { |
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case 167: /* stvehx */ |
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alignmask = 0xFFFFFFFE; |
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break; |
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case 199: /* stvewx */ |
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alignmask = 0xFFFFFFFC; |
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break; |
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case 231: /* stvx */ |
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alignmask = 0xFFFFFFF0; |
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break; |
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case 487: /* stvxl */ |
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alignmask = 0xFFFFFFF0; |
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break; |
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} |
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break; |
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case 725: /* stswi */ |
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tmp = EXTRACT_REGA(instr); |
| 275 |
if(tmp > 0) |
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baseA = regs[tmp]; |
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break; |
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default: /* ignore instruction */ |
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return 0; |
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break; |
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} |
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break; |
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default: /* ignore instruction */ |
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return 0; |
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break; |
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} |
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|
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addr = (baseA + baseB) + disp; |
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addr &= alignmask; |
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return (sigsegv_address_t)addr; |
| 291 |
} |
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#endif |
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#endif |
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#endif |
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|
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#ifdef HAVE_SIGSEGV_SKIP_INSTRUCTION |
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// Decode and skip X86 instruction |
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#if (defined(i386) || defined(__i386__)) |
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#if defined(__linux__) |
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enum { |
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X86_REG_EIP = 14, |
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X86_REG_EAX = 11, |
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X86_REG_ECX = 10, |
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X86_REG_EDX = 9, |
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X86_REG_EBX = 8, |
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X86_REG_ESP = 7, |
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X86_REG_EBP = 6, |
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X86_REG_ESI = 5, |
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X86_REG_EDI = 4 |
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}; |
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#endif |
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// FIXME: this is partly redundant with the instruction decoding phase |
| 313 |
// to discover transfer type and register number |
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static inline int ix86_step_over_modrm(unsigned char * p) |
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{ |
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int mod = (p[0] >> 6) & 3; |
| 317 |
int rm = p[0] & 7; |
| 318 |
int offset = 0; |
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|
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// ModR/M Byte |
| 321 |
switch (mod) { |
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case 0: // [reg] |
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if (rm == 5) return 4; // disp32 |
| 324 |
break; |
| 325 |
case 1: // disp8[reg] |
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offset = 1; |
| 327 |
break; |
| 328 |
case 2: // disp32[reg] |
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offset = 4; |
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break; |
| 331 |
case 3: // register |
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return 0; |
| 333 |
} |
| 334 |
|
| 335 |
// SIB Byte |
| 336 |
if (rm == 4) { |
| 337 |
if (mod == 0 && (p[1] & 7) == 5) |
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offset = 5; // disp32[index] |
| 339 |
else |
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offset++; |
| 341 |
} |
| 342 |
|
| 343 |
return offset; |
| 344 |
} |
| 345 |
|
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static bool ix86_skip_instruction(sigsegv_address_t fault_instruction, unsigned long * regs) |
| 347 |
{ |
| 348 |
unsigned char * eip = (unsigned char *)fault_instruction; |
| 349 |
|
| 350 |
if (eip == 0) |
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return false; |
| 352 |
|
| 353 |
// Transfer type |
| 354 |
enum { |
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TYPE_UNKNOWN, |
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TYPE_LOAD, |
| 357 |
TYPE_STORE |
| 358 |
} transfer_type = TYPE_UNKNOWN; |
| 359 |
|
| 360 |
// Transfer size |
| 361 |
enum { |
| 362 |
SIZE_BYTE, |
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SIZE_WORD, |
| 364 |
SIZE_LONG |
| 365 |
} transfer_size = SIZE_LONG; |
| 366 |
|
| 367 |
int reg = -1; |
| 368 |
int len = 0; |
| 369 |
|
| 370 |
// Operand size prefix |
| 371 |
if (*eip == 0x66) { |
| 372 |
eip++; |
| 373 |
len++; |
| 374 |
transfer_size = SIZE_WORD; |
| 375 |
} |
| 376 |
|
| 377 |
// Decode instruction |
| 378 |
switch (eip[0]) { |
| 379 |
case 0x8a: // MOV r8, r/m8 |
| 380 |
transfer_size = SIZE_BYTE; |
| 381 |
case 0x8b: // MOV r32, r/m32 (or 16-bit operation) |
| 382 |
switch (eip[1] & 0xc0) { |
| 383 |
case 0x80: |
| 384 |
reg = (eip[1] >> 3) & 7; |
| 385 |
transfer_type = TYPE_LOAD; |
| 386 |
break; |
| 387 |
case 0x40: |
| 388 |
reg = (eip[1] >> 3) & 7; |
| 389 |
transfer_type = TYPE_LOAD; |
| 390 |
break; |
| 391 |
case 0x00: |
| 392 |
reg = (eip[1] >> 3) & 7; |
| 393 |
transfer_type = TYPE_LOAD; |
| 394 |
break; |
| 395 |
} |
| 396 |
len += 2 + ix86_step_over_modrm(eip + 1); |
| 397 |
break; |
| 398 |
case 0x88: // MOV r/m8, r8 |
| 399 |
transfer_size = SIZE_BYTE; |
| 400 |
case 0x89: // MOV r/m32, r32 (or 16-bit operation) |
| 401 |
switch (eip[1] & 0xc0) { |
| 402 |
case 0x80: |
| 403 |
reg = (eip[1] >> 3) & 7; |
| 404 |
transfer_type = TYPE_STORE; |
| 405 |
break; |
| 406 |
case 0x40: |
| 407 |
reg = (eip[1] >> 3) & 7; |
| 408 |
transfer_type = TYPE_STORE; |
| 409 |
break; |
| 410 |
case 0x00: |
| 411 |
reg = (eip[1] >> 3) & 7; |
| 412 |
transfer_type = TYPE_STORE; |
| 413 |
break; |
| 414 |
} |
| 415 |
len += 2 + ix86_step_over_modrm(eip + 1); |
| 416 |
break; |
| 417 |
} |
| 418 |
|
| 419 |
if (transfer_type == TYPE_UNKNOWN) { |
| 420 |
// Unknown machine code, let it crash. Then patch the decoder |
| 421 |
return false; |
| 422 |
} |
| 423 |
|
| 424 |
if (transfer_type == TYPE_LOAD && reg != -1) { |
| 425 |
static const int x86_reg_map[8] = { |
| 426 |
X86_REG_EAX, X86_REG_ECX, X86_REG_EDX, X86_REG_EBX, |
| 427 |
X86_REG_ESP, X86_REG_EBP, X86_REG_ESI, X86_REG_EDI |
| 428 |
}; |
| 429 |
|
| 430 |
if (reg < 0 || reg >= 8) |
| 431 |
return false; |
| 432 |
|
| 433 |
int rloc = x86_reg_map[reg]; |
| 434 |
switch (transfer_size) { |
| 435 |
case SIZE_BYTE: |
| 436 |
regs[rloc] = (regs[rloc] & ~0xff); |
| 437 |
break; |
| 438 |
case SIZE_WORD: |
| 439 |
regs[rloc] = (regs[rloc] & ~0xffff); |
| 440 |
break; |
| 441 |
case SIZE_LONG: |
| 442 |
regs[rloc] = 0; |
| 443 |
break; |
| 444 |
} |
| 445 |
} |
| 446 |
|
| 447 |
#if DEBUG |
| 448 |
printf("%08x: %s %s access", regs[X86_REG_EIP], |
| 449 |
transfer_size == SIZE_BYTE ? "byte" : transfer_size == SIZE_WORD ? "word" : "long", |
| 450 |
transfer_type == TYPE_LOAD ? "read" : "write"); |
| 451 |
|
| 452 |
if (reg != -1) { |
| 453 |
static const char * x86_reg_str_map[8] = { |
| 454 |
"eax", "ecx", "edx", "ebx", |
| 455 |
"esp", "ebp", "esi", "edi" |
| 456 |
}; |
| 457 |
printf(" %s register %%%s", transfer_type == TYPE_LOAD ? "to" : "from", x86_reg_str_map[reg]); |
| 458 |
} |
| 459 |
printf(", %d bytes instruction\n", len); |
| 460 |
#endif |
| 461 |
|
| 462 |
regs[X86_REG_EIP] += len; |
| 463 |
return true; |
| 464 |
} |
| 465 |
#endif |
| 466 |
#endif |
| 467 |
|
| 468 |
// Fallbacks |
| 469 |
#ifndef SIGSEGV_FAULT_INSTRUCTION |
| 470 |
#define SIGSEGV_FAULT_INSTRUCTION SIGSEGV_INVALID_PC |
| 471 |
#endif |
| 472 |
|
| 473 |
// SIGSEGV recovery supported ? |
| 474 |
#if defined(SIGSEGV_ALL_SIGNALS) && defined(SIGSEGV_FAULT_HANDLER_ARGLIST) && defined(SIGSEGV_FAULT_ADDRESS) |
| 475 |
#define HAVE_SIGSEGV_RECOVERY |
| 476 |
#endif |
| 477 |
|
| 478 |
|
| 479 |
/* |
| 480 |
* SIGSEGV global handler |
| 481 |
*/ |
| 482 |
|
| 483 |
#ifdef HAVE_SIGSEGV_RECOVERY |
| 484 |
static void sigsegv_handler(SIGSEGV_FAULT_HANDLER_ARGLIST) |
| 485 |
{ |
| 486 |
sigsegv_address_t fault_address = (sigsegv_address_t)SIGSEGV_FAULT_ADDRESS; |
| 487 |
sigsegv_address_t fault_instruction = (sigsegv_address_t)SIGSEGV_FAULT_INSTRUCTION; |
| 488 |
bool fault_recovered = false; |
| 489 |
|
| 490 |
// Call user's handler and reinstall the global handler, if required |
| 491 |
if (sigsegv_fault_handler(fault_address, fault_instruction)) { |
| 492 |
#if (defined(HAVE_SIGACTION) ? defined(SIGACTION_NEED_REINSTALL) : defined(SIGNAL_NEED_REINSTALL)) |
| 493 |
sigsegv_do_install_handler(sig); |
| 494 |
#endif |
| 495 |
fault_recovered = true; |
| 496 |
} |
| 497 |
#if HAVE_SIGSEGV_SKIP_INSTRUCTION |
| 498 |
else if (sigsegv_ignore_fault) { |
| 499 |
// Call the instruction skipper with the register file available |
| 500 |
if (SIGSEGV_SKIP_INSTRUCTION(fault_instruction, SIGSEGV_REGISTER_FILE)) |
| 501 |
fault_recovered = true; |
| 502 |
} |
| 503 |
#endif |
| 504 |
|
| 505 |
if (!fault_recovered) { |
| 506 |
// FAIL: reinstall default handler for "safe" crash |
| 507 |
#define FAULT_HANDLER(sig) signal(sig, SIG_DFL); |
| 508 |
SIGSEGV_ALL_SIGNALS |
| 509 |
#undef FAULT_HANDLER |
| 510 |
|
| 511 |
// We can't do anything with the fault_address, dump state? |
| 512 |
if (sigsegv_state_dumper != 0) |
| 513 |
sigsegv_state_dumper(fault_address, fault_instruction); |
| 514 |
} |
| 515 |
} |
| 516 |
#endif |
| 517 |
|
| 518 |
|
| 519 |
/* |
| 520 |
* SIGSEGV handler initialization |
| 521 |
*/ |
| 522 |
|
| 523 |
#if defined(HAVE_SIGINFO_T) |
| 524 |
static bool sigsegv_do_install_handler(int sig) |
| 525 |
{ |
| 526 |
// Setup SIGSEGV handler to process writes to frame buffer |
| 527 |
#ifdef HAVE_SIGACTION |
| 528 |
struct sigaction vosf_sa; |
| 529 |
sigemptyset(&vosf_sa.sa_mask); |
| 530 |
vosf_sa.sa_sigaction = sigsegv_handler; |
| 531 |
vosf_sa.sa_flags = SA_SIGINFO; |
| 532 |
return (sigaction(sig, &vosf_sa, 0) == 0); |
| 533 |
#else |
| 534 |
return (signal(sig, (signal_handler)sigsegv_handler) != SIG_ERR); |
| 535 |
#endif |
| 536 |
} |
| 537 |
#endif |
| 538 |
|
| 539 |
#if defined(HAVE_SIGCONTEXT_SUBTERFUGE) |
| 540 |
static bool sigsegv_do_install_handler(int sig) |
| 541 |
{ |
| 542 |
// Setup SIGSEGV handler to process writes to frame buffer |
| 543 |
#ifdef HAVE_SIGACTION |
| 544 |
struct sigaction vosf_sa; |
| 545 |
sigemptyset(&vosf_sa.sa_mask); |
| 546 |
vosf_sa.sa_handler = (signal_handler)sigsegv_handler; |
| 547 |
#if !EMULATED_68K && defined(__NetBSD__) |
| 548 |
sigaddset(&vosf_sa.sa_mask, SIGALRM); |
| 549 |
vosf_sa.sa_flags = SA_ONSTACK; |
| 550 |
#else |
| 551 |
vosf_sa.sa_flags = 0; |
| 552 |
#endif |
| 553 |
return (sigaction(sig, &vosf_sa, 0) == 0); |
| 554 |
#else |
| 555 |
return (signal(sig, (signal_handler)sigsegv_handler) != SIG_ERR); |
| 556 |
#endif |
| 557 |
} |
| 558 |
#endif |
| 559 |
|
| 560 |
bool sigsegv_install_handler(sigsegv_fault_handler_t handler) |
| 561 |
{ |
| 562 |
#ifdef HAVE_SIGSEGV_RECOVERY |
| 563 |
sigsegv_fault_handler = handler; |
| 564 |
bool success = true; |
| 565 |
#define FAULT_HANDLER(sig) success = success && sigsegv_do_install_handler(sig); |
| 566 |
SIGSEGV_ALL_SIGNALS |
| 567 |
#undef FAULT_HANDLER |
| 568 |
return success; |
| 569 |
#else |
| 570 |
// FAIL: no siginfo_t nor sigcontext subterfuge is available |
| 571 |
return false; |
| 572 |
#endif |
| 573 |
} |
| 574 |
|
| 575 |
|
| 576 |
/* |
| 577 |
* SIGSEGV handler deinitialization |
| 578 |
*/ |
| 579 |
|
| 580 |
void sigsegv_deinstall_handler(void) |
| 581 |
{ |
| 582 |
#ifdef HAVE_SIGSEGV_RECOVERY |
| 583 |
sigsegv_fault_handler = 0; |
| 584 |
#define FAULT_HANDLER(sig) signal(sig, SIG_DFL); |
| 585 |
SIGSEGV_ALL_SIGNALS |
| 586 |
#undef FAULT_HANDLER |
| 587 |
#endif |
| 588 |
} |
| 589 |
|
| 590 |
|
| 591 |
/* |
| 592 |
* SIGSEGV ignore state modifier |
| 593 |
*/ |
| 594 |
|
| 595 |
void sigsegv_set_ignore_state(bool ignore_fault) |
| 596 |
{ |
| 597 |
sigsegv_ignore_fault = ignore_fault; |
| 598 |
} |
| 599 |
|
| 600 |
|
| 601 |
/* |
| 602 |
* Set callback function when we cannot handle the fault |
| 603 |
*/ |
| 604 |
|
| 605 |
void sigsegv_set_dump_state(sigsegv_state_dumper_t handler) |
| 606 |
{ |
| 607 |
sigsegv_state_dumper = handler; |
| 608 |
} |
| 609 |
|
| 610 |
|
| 611 |
/* |
| 612 |
* Test program used for configure/test |
| 613 |
*/ |
| 614 |
|
| 615 |
#ifdef CONFIGURE_TEST_SIGSEGV_RECOVERY |
| 616 |
#include <stdio.h> |
| 617 |
#include <stdlib.h> |
| 618 |
#include <fcntl.h> |
| 619 |
#include <sys/mman.h> |
| 620 |
#include "vm_alloc.h" |
| 621 |
|
| 622 |
static int page_size; |
| 623 |
static volatile char * page = 0; |
| 624 |
static volatile int handler_called = 0; |
| 625 |
|
| 626 |
static bool sigsegv_test_handler(sigsegv_address_t fault_address, sigsegv_address_t instruction_address) |
| 627 |
{ |
| 628 |
handler_called++; |
| 629 |
if ((fault_address - 123) != page) |
| 630 |
exit(1); |
| 631 |
if (vm_protect((char *)((unsigned long)fault_address & -page_size), page_size, VM_PAGE_READ | VM_PAGE_WRITE) != 0) |
| 632 |
exit(1); |
| 633 |
return true; |
| 634 |
} |
| 635 |
|
| 636 |
#ifdef HAVE_SIGSEGV_SKIP_INSTRUCTION |
| 637 |
static bool sigsegv_insn_handler(sigsegv_address_t fault_address, sigsegv_address_t instruction_address) |
| 638 |
{ |
| 639 |
return false; |
| 640 |
} |
| 641 |
#endif |
| 642 |
|
| 643 |
int main(void) |
| 644 |
{ |
| 645 |
if (vm_init() < 0) |
| 646 |
return 1; |
| 647 |
|
| 648 |
page_size = getpagesize(); |
| 649 |
if ((page = (char *)vm_acquire(page_size)) == VM_MAP_FAILED) |
| 650 |
return 1; |
| 651 |
|
| 652 |
if (vm_protect((char *)page, page_size, VM_PAGE_READ) < 0) |
| 653 |
return 1; |
| 654 |
|
| 655 |
if (!sigsegv_install_handler(sigsegv_test_handler)) |
| 656 |
return 1; |
| 657 |
|
| 658 |
page[123] = 45; |
| 659 |
page[123] = 45; |
| 660 |
|
| 661 |
if (handler_called != 1) |
| 662 |
return 1; |
| 663 |
|
| 664 |
#ifdef HAVE_SIGSEGV_SKIP_INSTRUCTION |
| 665 |
if (!sigsegv_install_handler(sigsegv_insn_handler)) |
| 666 |
return 1; |
| 667 |
|
| 668 |
if (vm_protect((char *)page, page_size, VM_PAGE_WRITE) < 0) |
| 669 |
return 1; |
| 670 |
|
| 671 |
for (int i = 0; i < page_size; i++) |
| 672 |
page[i] = (i + 1) % page_size; |
| 673 |
|
| 674 |
if (vm_protect((char *)page, page_size, VM_PAGE_NOACCESS) < 0) |
| 675 |
return 1; |
| 676 |
|
| 677 |
sigsegv_set_ignore_state(true); |
| 678 |
|
| 679 |
#define TEST_SKIP_INSTRUCTION(TYPE) do { \ |
| 680 |
const unsigned int TAG = 0x12345678; \ |
| 681 |
TYPE data = *((TYPE *)(page + sizeof(TYPE))); \ |
| 682 |
volatile unsigned int effect = data + TAG; \ |
| 683 |
if (effect != TAG) \ |
| 684 |
return 1; \ |
| 685 |
} while (0) |
| 686 |
|
| 687 |
TEST_SKIP_INSTRUCTION(unsigned char); |
| 688 |
TEST_SKIP_INSTRUCTION(unsigned short); |
| 689 |
TEST_SKIP_INSTRUCTION(unsigned int); |
| 690 |
#endif |
| 691 |
|
| 692 |
vm_exit(); |
| 693 |
return 0; |
| 694 |
} |
| 695 |
#endif |
