171 lines
3.3 KiB
C
171 lines
3.3 KiB
C
/***
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*heapwalk.c - walk the heap
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*
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* Copyright (c) 1989-1991, Microsoft Corporation. All rights reserved.
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*
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*Purpose:
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* Defines the _heapwalk() function
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*
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*Revision History:
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* 07-05-89 JCR Module created.
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* 11-13-89 GJF Added MTHREAD support, also fixed copyright.
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* 11-14-89 JCR Fixed bug -- returned address was off by HDRSIZE
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* 12-18-89 GJF Removed DEBUG286 stuff, also some tuning, cleaned up
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* format a bit, changed header file name to heap.h, added
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* explicit _cdecl to function definition
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* 12-20-89 GJF Removed references to plastdesc
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* 03-11-90 GJF Replaced _cdecl with _CALLTYPE1, added #include
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* <cruntime.h> and removed #include <register.h>.
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* 09-28-90 GJF New-style function declarator.
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*
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*******************************************************************************/
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#include <cruntime.h>
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#include <heap.h>
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#include <malloc.h>
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#include <os2dll.h>
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#include <stddef.h>
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/***
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*int _heapwalk() - Walk the heap
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*
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*Purpose:
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* Walk the heap returning information on one entry at a time.
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*
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*Entry:
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* struct _heapinfo {
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* int * _pentry; heap entry pointer
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* size_t size; size of heap entry
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* int _useflag; free/inuse flag
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* } *entry;
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*
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*Exit:
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* Returns one of the following values:
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*
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* _HEAPOK - completed okay
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* _HEAPEMPTY - heap not initialized
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* _HEAPBADPTR - _pentry pointer is bogus
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* _HEAPBADBEGIN - can't find initial header info
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* _HEAPBADNODE - malformed node somewhere
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* _HEAPEND - end of heap successfully reached
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*
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*Uses:
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*
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*Exceptions:
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*
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*******************************************************************************/
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int _CALLTYPE1 _heapwalk (
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struct _heapinfo *_entry
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)
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{
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REG1 _PBLKDESC pdesc;
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_PBLKDESC polddesc;
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int retval = _HEAPOK;
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/*
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* Lock the heap
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*/
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_mlock(_HEAP_LOCK);
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/*
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* Quick header check
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*/
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if ( (_heap_desc.pfirstdesc == NULL) ||
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(_heap_desc.proverdesc == NULL) ||
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(_heap_desc.sentinel.pnextdesc != NULL) ) {
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retval = _HEAPBADBEGIN;
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goto done;
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}
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/*
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* Check for an empty heap
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*/
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if ( _heap_desc.pfirstdesc == &_heap_desc.sentinel ) {
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retval = _HEAPEMPTY;
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goto done;
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}
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/*
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* If _pentry is NULL, return info about the first entry.
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* Else, get info about the next entry in the heap.
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*/
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if ( _entry->_pentry == NULL ) {
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pdesc = _heap_desc.pfirstdesc;
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}
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else {
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/*
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* Find the entry we gave to the user last time around
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*/
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if ( _heap_findaddr( (void *)((char *)(_entry->_pentry) -
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_HDRSIZE), &polddesc) != _HEAPFIND_EXACT ) {
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retval = _HEAPBADPTR;
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goto done;
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}
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pdesc = polddesc->pnextdesc;
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} /* else */
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/*
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* pdesc = entry to return info about
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*/
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/*
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* Skip over dummy entries
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*/
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while ( _IS_DUMMY(pdesc) )
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pdesc = pdesc->pnextdesc;
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/*
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* See if we're at the end of the heap
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*/
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if ( pdesc == &_heap_desc.sentinel ) {
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retval = _HEAPEND;
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goto done;
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}
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/*
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* Check back pointer (note that pdesc cannot point to a dummy
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* descriptor since we have skipped over them)
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*/
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if (!_CHECK_PDESC(pdesc)) {
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retval = _HEAPBADPTR;
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goto done;
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}
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/*
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* Return info on the next block
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*/
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_entry->_pentry = ( (void *)((char *)_ADDRESS(pdesc) + _HDRSIZE) );
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_entry->_size = _BLKSIZE(pdesc);
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_entry->_useflag = ( _IS_INUSE(pdesc) ? _USEDENTRY : _FREEENTRY );
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/*
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* Common return
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*/
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done:
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/*
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* Release the heap lock
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*/
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_munlock(_HEAP_LOCK);
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return(retval);
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}
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