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/* Copyright (c) 2007 Timothy Wall, All Rights Reserved
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
* <p/>
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*/
#ifndef PROTECT_H
#define PROTECT_H
// Native memory access protection
//
// Enable or disable by changing the value of the PROTECT flag.
//
// Example usage:
//
// #define PROTECT _protect
// static int _protect;
// #include "protect.h"
//
// void my_function() {
// int variable_decls;
// PROTECTED_START();
// // do some dangerous stuff here
// PROTECTED_END(fprintf(stderr, "Error!"));
// }
//
// The PROTECT_START() macro must immediately follow any variable declarations
//
// The w32 implementation is based on code by Ranjit Mathew
// http://gcc.gnu.org/ml/java/2003-03/msg00243.html
#ifndef PROTECT
#define PROTECTED_START()
#define PROTECTED_END(ONERR)
#else
#ifdef _WIN32
#ifdef __GNUC__
#include <excpt.h>
#else
// copied from mingw header
typedef EXCEPTION_DISPOSITION (*PEXCEPTION_HANDLER)
(struct _EXCEPTION_RECORD*, void*, struct _CONTEXT*, void*);
typedef struct _EXCEPTION_REGISTRATION {
struct _EXCEPTION_REGISTRATION* prev;
PEXCEPTION_HANDLER handler;
} EXCEPTION_REGISTRATION, *PEXCEPTION_REGISTRATION;
#endif
#include <setjmp.h>
typedef struct _exc_rec {
EXCEPTION_REGISTRATION ex_reg;
jmp_buf buf;
struct _EXCEPTION_RECORD er;
} exc_rec;
static EXCEPTION_DISPOSITION __cdecl
_exc_handler(struct _EXCEPTION_RECORD* exception_record,
void *establisher_frame,
struct _CONTEXT *context_record,
void* dispatcher_context) {
exc_rec* xer = (exc_rec *)establisher_frame;
xer->er = *exception_record;
longjmp(xer->buf, exception_record->ExceptionCode);
// Never reached
return ExceptionContinueExecution;
}
#ifdef _MSC_VER
#define PROTECTED_START() __try {
#define PROTECTED_END(ONERR) } __except((PROTECT)?EXCEPTION_EXECUTE_HANDLER:EXCEPTION_CONTINUE_SEARCH) { ONERR; }
#else
#ifdef _WIN64
#error "GCC does not implement SEh"
#else
#define SEH_TRY(ER) \
__asm__ ("movl %%fs:0, %0" : "=r" ((ER).ex_reg.prev)); \
__asm__ ("movl %0, %%fs:0" : : "r" (&(ER)))
#define SEH_CATCH(ER) \
__asm__ ("movl %0, %%fs:0" : : "r" ((ER).ex_reg.prev))
#endif /* !_WIN64 */
#define PROTECTED_START() \
exc_rec _er; \
int _error = 0; \
if (PROTECT) { \
_er.ex_reg.handler = _exc_handler; \
SEH_TRY(_er); \
if ((_error = setjmp(_er.buf)) != 0) { \
goto _exc_caught; \
} \
}
// The initial conditional is required to ensure GCC doesn't consider
// _exc_caught to be unreachable
#define PROTECTED_END(ONERR) do { \
if (!_error) \
goto _remove_handler; \
_exc_caught: \
ONERR; \
_remove_handler: \
if (PROTECT) { SEH_CATCH(_er); } \
} while(0)
#endif /* !_MSC_VER */
#else // _WIN32
// Most other platforms support signals
// Catch both SIGSEGV and SIGBUS
#include <signal.h>
#include <setjmp.h>
static jmp_buf _context;
static void* _old_segv_handler = NULL;
static void* _old_bus_handler = NULL;
static volatile int _error;
static void _exc_handler(int sig) {
if (sig == SIGSEGV || sig == SIGBUS) {
longjmp(_context, sig);
}
}
#define PROTECTED_START() \
if (PROTECT) { \
_old_segv_handler = signal(SIGSEGV, _exc_handler); \
_old_bus_handler = signal(SIGBUS, _exc_handler); \
if ((_error = setjmp(_context) != 0)) { \
goto _exc_caught; \
} \
}
#define PROTECTED_END(ONERR) do { \
if (!_error) \
goto _remove_handler; \
_exc_caught: \
ONERR; \
_remove_handler: \
if (PROTECT) { \
signal(SIGSEGV, _old_segv_handler); \
signal(SIGBUS, _old_bus_handler); \
} \
} while(0)
#endif
#endif // PROTECT
#endif // PROTECT_H
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