Leaked source code of windows server 2003
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 

215 lines
5.6 KiB

//+-------------------------------------------------------------------------
//
// Copyright (C) 1992, Microsoft Corporation.
//
// File: SysMem.CXX
//
// Contents: System Memory Management routines
//
// Functions: MemAlloc, MemFree, MemAllocLinked
//
// History: 10-Feb-92 AlexT Created
// 07-May-92 MikeSe Converted to using Win32 Heap functions.
// 14-Jul-92 randyd Added MemSwitchRoot, see memmgmt.doc.
// 5-Oct-93 isaache Slight reorganization, conversion to 'new'
// 13-Jul-94 doncl stole from ole32, put in ADs proj, deleted
// MemSwitchRoot, switched to naked
// Win32 CRITICAL_SECTION usage
//
// Notes: For additional information, see win4adm\standrds\memmgmt.doc.
//
// This memory management package is multithread capable - the
// only place it makes a difference is in MemAllocLinked and
// MemSwitchRoot, where we use a critical section t
// protect adding link blocks to the list. We rely on the fact
// that LocalAlloc is multi-thread safe.
//
//--------------------------------------------------------------------------
#include "dswarn.h"
#include <ADs.hxx>
#if 0
#include <excpt.h>
#include <except.hxx>
#include <dllsem.hxx>
#endif
CRITICAL_SECTION g_csMem;
// Memory block prefix (for signature and link)
typedef struct _smheader
{
unsigned long ulSignature;
struct _smheader *psmNext;
} SMHEADER, *PSMHEADER;
// Memory block signatures (for strict checks)
const ULONG ROOT_BLOCK = 0x726f6f74; // 'root'
const ULONG LINKED_BLOCK = 0x6c696e6b; // 'link'
static BOOL
VerifySignature(PSMHEADER psm, ULONG ulSig )
{
BOOL fReturn;
__try
{
fReturn = (ulSig == psm->ulSignature );
}
__except ( EXCEPTION_EXECUTE_HANDLER )
{
fReturn = FALSE;
}
return fReturn;
}
// This module acts as the declarer of debug support symbols for COMMNOT
DECLARE_INFOLEVEL(Cn);
//+-------------------------------------------------------------------------
//
// Function: MemAlloc
//
// Synopsis: allocates memory block
//
// Arguments: [ulSize] -- size of block in bytes
// [ppv] -- output pointer
//
// Returns: status code
//
// Algorithm: call new, adding space for header
//
// History: 10-Feb-92 AlexT Created
//
//--------------------------------------------------------------------------
HRESULT
MemAlloc ( unsigned long ulSize, void ** ppv )
{
PSMHEADER psm;
*ppv = NULL;
psm = (PSMHEADER) LocalAlloc(LMEM_FIXED, ulSize + sizeof(SMHEADER));
if ( psm != NULL )
{
psm->ulSignature = ROOT_BLOCK;
psm->psmNext = NULL;
*ppv = psm + 1;
return S_OK;
}
return E_OUTOFMEMORY;
}
//+-------------------------------------------------------------------------
//
// Function: MemFree
//
// Synopsis: release system memory block
//
// Arguments: [pvBlockToFree] -- memory block to release
//
// Algorithm: Walk list of linked blocks, deleting each one
//
// History: 10-Feb-92 AlexT Created
//
//--------------------------------------------------------------------------
HRESULT
MemFree( void *pvBlockToFree )
{
PSMHEADER psm = ((PSMHEADER) pvBlockToFree) - 1;
if( pvBlockToFree == NULL || psm == NULL )
return S_OK;
if( !VerifySignature( psm, ROOT_BLOCK ) )
{
Win4Assert( !"MemFree -- not a root block!\n" );
return MEM_E_INVALID_ROOT;
}
do {
PSMHEADER psmNext = psm->psmNext;
psm->ulSignature = 0;
LocalFree(psm);
psm = psmNext;
if( psm && !VerifySignature( psm, LINKED_BLOCK ) )
{
Win4Assert( !"MemFree -- invalid linked block!\n" );
return MEM_E_INVALID_LINK;
}
} while( psm != NULL );
return S_OK;
}
//+-------------------------------------------------------------------------
//
// Function: MemAllocLinked
//
// Synopsis: allocates linked memory block
//
//
// Arguments: [pvRootBlock] -- root memory block
// [ulSize] -- size of new memory block
// [ppv] -- output pointer
//
// Returns: status code
//
//
// History: 10-Feb-92 AlexT Created
//
// Notes: pvRootBlock can specify either a root block, or another
// linked block.
//
//--------------------------------------------------------------------------
HRESULT
MemAllocLinked ( void *pvRootBlock, unsigned long ulSize, void ** ppv )
{
PSMHEADER psm = NULL;
PSMHEADER psmRoot = ((PSMHEADER) pvRootBlock) - 1;
*ppv = NULL;
if ( pvRootBlock == NULL || psmRoot == NULL )
{
Win4Assert( !"MemAllocLinked - null root block\n" );
return MEM_E_INVALID_ROOT;
}
if ( !VerifySignature(psmRoot, ROOT_BLOCK)
&& !VerifySignature(psmRoot,LINKED_BLOCK) )
{
Win4Assert( !"MemAllocLinked - invalid root block\n" );
return MEM_E_INVALID_ROOT;
}
psm = (PSMHEADER) LocalAlloc(LMEM_FIXED, ulSize + sizeof(SMHEADER));
if ( psm == NULL )
return E_OUTOFMEMORY;
psm->ulSignature = LINKED_BLOCK;
EnterCriticalSection(&g_csMem);
psm->psmNext = psmRoot->psmNext;
psmRoot->psmNext = psm;
LeaveCriticalSection(&g_csMem);
// move psm past header
*ppv = psm+1;
return S_OK;
}