kolibrios/programs/develop/open watcom/trunk/clib/heap/nheapchk.c
Sergey Semyonov (Serge) 836c97f0ac Clib string & memory functions
git-svn-id: svn://kolibrios.org@553 a494cfbc-eb01-0410-851d-a64ba20cac60
2007-06-26 00:54:22 +00:00

163 lines
5.0 KiB
C

/****************************************************************************
*
* Open Watcom Project
*
* Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
*
* ========================================================================
*
* This file contains Original Code and/or Modifications of Original
* Code as defined in and that are subject to the Sybase Open Watcom
* Public License version 1.0 (the 'License'). You may not use this file
* except in compliance with the License. BY USING THIS FILE YOU AGREE TO
* ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is
* provided with the Original Code and Modifications, and is also
* available at www.sybase.com/developer/opensource.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND SYBASE AND ALL CONTRIBUTORS HEREBY DISCLAIM
* ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR
* NON-INFRINGEMENT. Please see the License for the specific language
* governing rights and limitations under the License.
*
* ========================================================================
*
* Description: Implementation of near _heapchk() and _nheapchk().
*
****************************************************************************/
//#include "dll.h" // needs to be first
#include "variety.h"
#include <stddef.h>
#include <malloc.h>
#include "heap.h"
#include "heapacc.h"
frlptr __nheapchk_current;
static int checkFreeList( size_t *free_size )
{
frlptr p;
frlptr end;
size_t new_size;
size_t free_list_size = 0;
mheapptr mhp;
for( mhp = __nheapbeg; mhp != NULL; mhp = mhp ->next ) {
/* check that the free list is a doubly linked ring */
__nheapchk_current = p = mhp->freehead.next;
/* make sure we start off on the right track */
if( (p->prev == NULL) ||
(p->prev < &(mhp->freehead)) ||
(((PTR)p->prev) > (((PTR)mhp)+mhp->len)) ) {
return( _HEAPBADNODE );
}
if( p->prev->next != p ) {
return( _HEAPBADNODE );
}
end = p;
do {
/* loop invariant: p->prev->next == p */
/* are we still in a ring if we move to p->next? */
/* nb. this check is sufficient to ensure that we will
never cycle */
if( (p->next == NULL) ||
(p->next < &(mhp->freehead)) ||
(((PTR)p->next) > (((PTR)mhp)+mhp->len)) ) {
return( _HEAPBADNODE );
}
if( p->next->prev != p ) {
return( _HEAPBADNODE );
}
/* is entry allocated? */
if( p->len & 1 ) {
return( _HEAPBADNODE );
}
new_size = free_list_size + p->len;
if( new_size < free_list_size ) {
/* this is a case where we do not know where memory
is corrupted */
return( _HEAPBADNODE );
}
free_list_size = new_size;
__nheapchk_current = p = p->next;
} while( p != end );
}
*free_size = free_list_size;
return( _HEAPOK );
}
static int checkFree( frlptr p )
{
frlptr next;
frlptr prev;
frlptr next_next;
frlptr prev_prev;
__nheapchk_current = p;
if( p->len & 1 ) {
return( _HEAPBADNODE );
}
next = p->next;
prev = p->prev;
if( next->prev != p || prev->next != p ) {
return( _HEAPBADNODE );
}
next_next = next->next;
prev_prev = prev->prev;
if( next_next->prev != next || prev_prev->next != prev ) {
return( _HEAPBADNODE );
}
if( next_next->prev != next || prev_prev->next != prev ) {
return( _HEAPBADNODE );
}
return( _HEAPOK );
}
#if defined(__SMALL_DATA__)
_WCRTLINK int _heapchk( void )
{
return( _nheapchk() );
}
#endif
_WCRTLINK int _nheapchk( void )
{
struct _heapinfo hi;
int heap_status;
size_t free_size;
_AccessNHeap();
heap_status = checkFreeList( &free_size );
if( heap_status != _HEAPOK ) {
_ReleaseNHeap();
return( heap_status );
}
hi._pentry = NULL;
for(;;) {
heap_status = __NHeapWalk( &hi, __nheapbeg );
if( heap_status != _HEAPOK )
break;
if( hi._useflag == _FREEENTRY ) {
heap_status = checkFree( (frlptr) hi._pentry );
if( heap_status != _HEAPOK )
break;
free_size -= hi._size;
}
}
if( free_size != 0 ) {
heap_status = _HEAPBADNODE;
} else if( heap_status == _HEAPBADPTR ) {
heap_status = _HEAPBADNODE;
} else {
if( heap_status == _HEAPEND ) {
heap_status = _HEAPOK;
}
}
_ReleaseNHeap();
return( heap_status );
}