#include <stdio.h>
#include <signal.h>
#if !defined(__GNUC__)
#	include <windows.h>
#endif /* !__GNUC__ */


#if defined(__GNUC__)
#	define START_STACK		(0xC000000)
#else
#	if defined(__HP_NC4200)
#	define START_STACK		(0x0013FFFF)
#	else
#	define START_STACK		(0x0012FFFF)
#	endif
#endif /* __GNUC__ */

#define DEFAULT_MEMSIZE		(1024)


unsigned long	end_stack;

void signal_handler( int signo )
{
	fprintf( stderr, "Guessing end stack: 0x%08x\n", end_stack );
	fflush(NULL);
	exit(0);
}

#if !defined(__GNUC__)
LONG WINAPI unhandled_exception_handler( struct _EXCEPTION_POINTERS *ExceptionInfo )
{
	fprintf( stderr, "Guessing end stack: 0x%08x\n", end_stack );
	fflush(NULL);
	exit(0);
}
#endif /* !__GNUC__ */

void attach_signal( void )
{

#if !defined(__GNUC__)
	signal( SIGTERM, signal_handler );
	signal( SIGSEGV, signal_handler );
	signal( SIGINT, signal_handler );
	SetUnhandledExceptionFilter( unhandled_exception_handler );
#else
	struct sigaction   action;

	stack_t         sigstk;

	if ( (sigstk.ss_sp = (char *) malloc(SIGSTKSZ*2)) == NULL) {
		fprintf(stderr, "can't alloc alt stack\n");
		return;
	}
	sigstk.ss_size = SIGSTKSZ*2;
	sigstk.ss_flags = 0;
	if (sigaltstack(&sigstk, (stack_t *) 0) < 0) {
		perror("sigaltstack");
		return;
	}

	action.sa_handler = &signal_handler;
	action.sa_flags = SA_RESETHAND | SA_ONSTACK;

	sigaction(SIGKILL, &action, NULL);
	sigaction(SIGHUP, &action, NULL);
	sigaction(SIGINT, &action, NULL);
	sigaction(SIGQUIT, &action, NULL);
	sigaction(SIGILL, &action, NULL);
	sigaction(SIGABRT, &action, NULL);
	sigaction(SIGFPE, &action, NULL);
	sigaction(SIGSEGV, &action, NULL); 
	sigaction(SIGTERM, &action, NULL);
	sigaction(SIGBUS, &action, NULL);
	sigaction(SIGUSR1, &action, NULL);
#endif /* !__GNUC__ */
}

void check_stack( void )
{
	void *p;
	int	array[DEFAULT_MEMSIZE];


	end_stack = (unsigned long)&p;

	check_stack();
}

void check_heap( void )
{
	void	*p;
	void	*backup;	
	int		i = 0;


	do {
		backup = p;
		p = (char *)malloc(DEFAULT_MEMSIZE);
	} while ( (unsigned int)p < START_STACK );
	fprintf( stderr, "Guessing after heap: 0x%08x\n", backup );

	do {
		p = (char *)malloc(DEFAULT_MEMSIZE*100);
		if ( p == NULL )
			break;
		backup = p;
		if ( i < 5 ) {
			fprintf( stderr, "Guessing %02d's heap: 0x%08x\n", i, backup );
			++i;
		}
	} while (1);
	fprintf( stderr, "...\n");

	fprintf( stderr, "Guessing end heap: 0x%08x\n", backup );
}

int main(int argc, char *argv[])
{
	void	*p;
	void	*backup;	


	fprintf( stderr, "Guessing start stack: 0x%08x\n", &p );
	fprintf( stderr, "Guessing next stack: 0x%08x\n", &backup );

	p = (char *)malloc(0);
	fprintf( stderr, "Guessing start heap: 0x%08x\n", p );

	printf( " input 1(stack) or 2(heap): ");
	switch( getchar() ) {
		case '1' :
			attach_signal();
			check_stack();
			break;

		case '2' :
			check_heap();

			break;

		default  : fprintf( stderr, "unknown input.\n" );
	}


	return 0;
}