ef2gamesource/Executable/win32/win_bounds.cpp

//-----------------------------------------------------------------------------
//
//  $Logfile:: /Code/executable/win32/win_bounds.cpp                          $
// $Revision:: 4                                                              $
//     $Date:: 9/29/02 10:46a                                                 $
//
// Copyright (C) 1999 by Ritual Entertainment, Inc.
// All rights reserved.
//
// This source is may not be distributed and/or modified without
// expressly written permission by Ritual Entertainment, Inc.
//
//
// DESCRIPTION:
// Bounds checks all new's and delete's
// 

extern "C"
{
	void *b_malloc ( unsigned int size );
	void  b_free ( void * );
}

//////////////////////////
// Bounds checking
//
//   #define DISABLE_BOUNDS to disable checking a compiler 
//   warning will happen if checking is enabled
//
//   #define BOUNDS_ENDOFPAGE to check for overflowed, don't
//   define it to check for underflows
//
//   functions:
//     void *b_malloc ( unsigned ); 
//       Does a bounds-malloc, or just a normal one if checking's
//       disabled
//     void  b_free ( void * );
//       Frees a bounds pointer, or just a normal free if no
//       checking
//
//     void *operator new ( size_t ), operator new[] ( size )
//       For C++ new's and new []'s, bounds checked
//     void operator delete ( void * ), operator delete[] ( void * )
//       For C++ delete's and delete []'s, bounds checked
//////////////////////////
#define DISABLE_BOUNDS

#if defined(GAME_DLL) || defined(CGAME_DLL)
#define DISABLE_BOUNDS
#endif

//#define BOUNDS_ENDOFPAGE

/////////////////////////
// If bounds are disabled
/////////////////////////

#ifdef DISABLE_BOUNDS

#include <malloc.h>

void *b_malloc ( unsigned int size )
{
	return malloc ( size );
}

void b_free ( void *what )
{
	free ( what );
}

///////////////////////////
// If bounds are enabled
///////////////////////////
#else

#pragma message ("win_bounds.cpp: Warning - Bounds checking is enabled\n" )

#include <stdio.h>
#include <windows.h>

typedef struct 
{
	unsigned int header;
	int size;
	void *returned;
} bounds_type_t;

#define PAGE_SIZE ( 4096 )

#define NORMAL_HEADER 0xdeadbeef
#define ARRAY_HEADER 0xdeadbabe

static unsigned int bounds_numpages ( unsigned int size ) 
{
	unsigned int ret;
	
	ret = size / PAGE_SIZE + 3;
	if ( size % PAGE_SIZE )
		ret++;
	
	return ret;
}

void *bounds_malloc ( unsigned int size, unsigned head = NORMAL_HEADER ) 
{
	bounds_type_t *where;
	unsigned int num_pages;
	void *mainaddress;

	num_pages = bounds_numpages ( size );

	mainaddress = VirtualAlloc ( NULL, num_pages * PAGE_SIZE, MEM_RESERVE, PAGE_NOACCESS );
	VirtualAlloc ( mainaddress, PAGE_SIZE, MEM_COMMIT, PAGE_READWRITE );
	VirtualAlloc ( (char *) mainaddress + PAGE_SIZE * 2, ( num_pages - 3 ) * PAGE_SIZE, MEM_COMMIT, PAGE_READWRITE );
	where = (bounds_type_t *) mainaddress;

	where->header = head;
	where->size = size;
#ifdef BOUNDS_ENDOFPAGE
	where->returned = (char *) mainaddress + ( num_pages - 1 ) * PAGE_SIZE - size;
#else
	where->returned = (char *) mainaddress + PAGE_SIZE * 2;
#endif
   memset ( where->returned, 0xdc, size );
   
   return where->returned;
}

void bounds_free ( void *address, unsigned head = NORMAL_HEADER ) 
{
	bounds_type_t *where;
	unsigned int num_pages;
	void *mainaddress;

	mainaddress = (char *) address - PAGE_SIZE * 2;
#ifdef BOUNDS_ENDOFPAGE
	mainaddress = (char *) mainaddress - ( (unsigned int) mainaddress % 4096 );
#endif

	where = (bounds_type_t *) mainaddress;

	if ( where->header != head || where->returned != address ) 
	{
		__asm int 3 // Breakpoint
	}
	num_pages = bounds_numpages ( where->size );

	// All pages must be in the same state to be MEM_RELEASED
	VirtualFree ( mainaddress, PAGE_SIZE, MEM_DECOMMIT );
	VirtualFree ( (char *) mainaddress + PAGE_SIZE * 2, (num_pages - 3 ) * PAGE_SIZE, MEM_DECOMMIT );
	VirtualFree ( mainaddress, 0, MEM_RELEASE );
}

void *b_malloc ( unsigned int size )
{
	return bounds_malloc ( size );   
}

void b_free ( void *what )
{
	bounds_free ( what );
}

void *operator new[] ( size_t size )
{
	return bounds_malloc ( size, ARRAY_HEADER );
}

void *operator new ( size_t size )
{
	return bounds_malloc ( size );
}

void operator delete [] ( void *what )
{
	if ( what )
		bounds_free ( what, ARRAY_HEADER );
}

void operator delete ( void *what )
{
	if ( what )
		bounds_free ( what );
}

#endif /* !DISABLE_BOUNDS */