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/* |
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* sigsegv.cpp - SIGSEGV signals support |
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* |
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* Derived from Bruno Haible's work on his SIGSEGV library for clisp |
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* <http://clisp.sourceforge.net/> |
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* |
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* Basilisk II (C) 1997-2001 Christian Bauer |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; either version 2 of the License, or |
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* (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 |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program; if not, write to the Free Software |
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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*/ |
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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" |
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#endif |
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|
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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 |
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typedef RETSIGTYPE (*signal_handler)(int); |
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|
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// User's SIGSEGV handler |
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static sigsegv_handler_t sigsegv_user_handler = 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 |
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*/ |
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|
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#if HAVE_SIGINFO_T |
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// Generic extended signal handler |
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#define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV) |
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#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, siginfo_t *sip, void * |
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#define SIGSEGV_FAULT_ADDRESS sip->si_addr |
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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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#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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#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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#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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// OSF/1 on Alpha |
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#if defined(__osf__) |
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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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#endif |
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|
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// Fallbacks |
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#ifndef SIGSEGV_FAULT_INSTRUCTION |
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#define SIGSEGV_FAULT_INSTRUCTION SIGSEGV_INVALID_PC |
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#endif |
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|
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// SIGSEGV recovery supported ? |
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#if defined(SIGSEGV_ALL_SIGNALS) && defined(SIGSEGV_FAULT_HANDLER_ARGLIST) && defined(SIGSEGV_FAULT_ADDRESS) |
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#define HAVE_SIGSEGV_RECOVERY |
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#endif |
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|
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|
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/* |
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* SIGSEGV global handler |
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*/ |
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|
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#ifdef HAVE_SIGSEGV_RECOVERY |
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static void sigsegv_handler(SIGSEGV_FAULT_HANDLER_ARGLIST) |
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{ |
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// Call user's handler and reinstall the global handler, if required |
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if (sigsegv_user_handler((sigsegv_address_t)SIGSEGV_FAULT_ADDRESS, (sigsegv_address_t)SIGSEGV_FAULT_INSTRUCTION)) { |
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#if (defined(HAVE_SIGACTION) ? defined(SIGACTION_NEED_REINSTALL) : defined(SIGNAL_NEED_REINSTALL)) |
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sigsegv_do_install_handler(sig); |
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#endif |
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} |
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else { |
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// FAIL: reinstall default handler for "safe" crash |
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#define FAULT_HANDLER(sig) signal(sig, SIG_DFL); |
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SIGSEGV_ALL_SIGNALS |
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#undef FAULT_HANDLER |
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} |
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} |
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#endif |
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|
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|
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/* |
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* SIGSEGV handler initialization |
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*/ |
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|
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#if defined(HAVE_SIGINFO_T) |
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static bool sigsegv_do_install_handler(int sig) |
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{ |
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// Setup SIGSEGV handler to process writes to frame buffer |
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#ifdef HAVE_SIGACTION |
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struct sigaction vosf_sa; |
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sigemptyset(&vosf_sa.sa_mask); |
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vosf_sa.sa_sigaction = sigsegv_handler; |
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vosf_sa.sa_flags = SA_SIGINFO; |
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return (sigaction(sig, &vosf_sa, 0) == 0); |
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#else |
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return (signal(sig, (signal_handler)sigsegv_handler) != SIG_ERR); |
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#endif |
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} |
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#endif |
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|
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#if defined(HAVE_SIGCONTEXT_SUBTERFUGE) |
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static bool sigsegv_do_install_handler(int sig) |
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{ |
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// Setup SIGSEGV handler to process writes to frame buffer |
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#ifdef HAVE_SIGACTION |
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struct sigaction vosf_sa; |
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sigemptyset(&vosf_sa.sa_mask); |
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vosf_sa.sa_handler = (signal_handler)sigsegv_handler; |
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#if !EMULATED_68K && defined(__NetBSD__) |
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sigaddset(&vosf_sa.sa_mask, SIGALRM); |
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vosf_sa.sa_flags = SA_ONSTACK; |
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#else |
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vosf_sa.sa_flags = 0; |
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#endif |
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return (sigaction(sig, &vosf_sa, 0) == 0); |
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#else |
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return (signal(sig, (signal_handler)sigsegv_handler) != SIG_ERR); |
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#endif |
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} |
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#endif |
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|
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bool sigsegv_install_handler(sigsegv_handler_t handler) |
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{ |
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#ifdef HAVE_SIGSEGV_RECOVERY |
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sigsegv_user_handler = handler; |
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bool success = true; |
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#define FAULT_HANDLER(sig) success = success && sigsegv_do_install_handler(sig); |
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SIGSEGV_ALL_SIGNALS |
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#undef FAULT_HANDLER |
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return success; |
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#else |
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// FAIL: no siginfo_t nor sigcontext subterfuge is available |
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return false; |
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#endif |
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} |
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|
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|
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/* |
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* SIGSEGV handler deinitialization |
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*/ |
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|
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void sigsegv_deinstall_handler(void) |
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{ |
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#ifdef HAVE_SIGSEGV_RECOVERY |
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sigsegv_user_handler = 0; |
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#define FAULT_HANDLER(sig) signal(sig, SIG_DFL); |
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SIGSEGV_ALL_SIGNALS |
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#undef FAULT_HANDLER |
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#endif |
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} |
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|
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/* |
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* Test program used for configure/test |
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*/ |
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|
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#ifdef CONFIGURE_TEST |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <unistd.h> |
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#include <fcntl.h> |
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#include <sys/mman.h> |
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|
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static int page_size; |
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static volatile char * page = 0; |
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static volatile int handler_called = 0; |
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|
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static bool sigsegv_test_handler(sigsegv_address_t fault_address, sigsegv_address_t instruction_address) |
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{ |
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handler_called++; |
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if ((fault_address - 123) != page) |
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exit(1); |
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if (mprotect((char *)((unsigned long)fault_address & -page_size), page_size, PROT_READ | PROT_WRITE) != 0) |
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exit(1); |
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return true; |
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} |
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|
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int main(void) |
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{ |
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int zero_fd = open("/dev/zero", O_RDWR); |
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if (zero_fd < 0) |
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return 1; |
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|
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page_size = getpagesize(); |
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page = (char *)mmap(0, page_size, PROT_READ, MAP_PRIVATE, zero_fd, 0); |
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if (page == MAP_FAILED) |
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return 1; |
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|
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if (!sigsegv_install_handler(sigsegv_test_handler)) |
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return 1; |
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|
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page[123] = 45; |
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page[123] = 45; |
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|
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if (handler_called != 1) |
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return 1; |
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|
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return 0; |
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} |
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#endif |
