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//+---------------------------------------------------------------------------
//
// Microsoft Windows
// Copyright (C) Microsoft Corporation, 1996 - 2002.
//
// File : SMem.hxx
//
// Contents : Shared memory (named + file based)
//
// Classes : CNamedSharedMem
//
// History: 22-Mar-94 t-joshh Created
//
//----------------------------------------------------------------------------
#pragma once
#include <secutil.hxx>
//+---------------------------------------------------------------------------
//
// Class: CNamedSharedMem
//
// Purpose: Named shared memory
//
// History: 22-Mar-94 t-joshh Created
//
//----------------------------------------------------------------------------
class CNamedSharedMem{public:
inline CNamedSharedMem( WCHAR const * pwszName, ULONG cb, SECURITY_DESCRIPTOR * psd = 0, BOOL fWrite = TRUE );
CNamedSharedMem() : _hMap( 0 ), _pb( 0 ) { }
enum eNameType { AppendPid };
CNamedSharedMem( WCHAR const * pwszName, eNameType eNT, ULONG cb ) : _hMap( 0 ), _pb( 0 ) { Win4Assert( eNT == CNamedSharedMem::AppendPid );
unsigned ccName = wcslen( pwszName ); WCHAR wcsNewName[MAX_PATH];
RtlCopyMemory( wcsNewName, pwszName, ccName * sizeof(WCHAR) ); _itow( GetCurrentProcessId(), wcsNewName + ccName, 16 );
Init( wcsNewName, cb, 0 ); }
~CNamedSharedMem() { if ( 0 != _pb ) UnmapViewOfFile( _pb );
if ( 0 != _hMap ) CloseHandle( _hMap ); }
BYTE * GetPointer() { return _pb; }
BYTE * Get() { return _pb; }
BOOL Ok() { return ( 0 != _pb ); }
inline void Init( WCHAR const * pwszName, ULONG cb, SECURITY_DESCRIPTOR * psd = 0, BOOL fWrite = TRUE );
void CreateForWriteFromRegKey( WCHAR const * pwszName, ULONG cb, WCHAR const * pwcRegKey ) { Win4Assert( 0 == _hMap ); Win4Assert( 0 == _pb ); Win4Assert( 0 != pwcRegKey );
_hMap = CreateFileMapping( INVALID_HANDLE_VALUE, // Map to page file
0, // Security attributes
PAGE_READWRITE, // Page-level protection
0, // Size high
cb, // size low
pwszName ); // Name
if ( 0 == _hMap ) THROW( CException() );
DWORD dwErr = CopyNamedDacls( pwszName, pwcRegKey );
if ( NO_ERROR != dwErr ) THROW( CException( HRESULT_FROM_WIN32( dwErr ) ) ); _pb = (BYTE *) MapViewOfFile( _hMap, // Handle to map
FILE_MAP_WRITE, // Access
0, // Offset (high)
0, // Offset (low)
0 ); // Map all
if ( 0 == _pb ) { DWORD dwErr = GetLastError(); CloseHandle( _hMap ); _hMap = 0; THROW( CException( HRESULT_FROM_WIN32( dwErr ) ) ); } }
void CreateForWriteFromSA( WCHAR const * pwszName, ULONG cb, SECURITY_ATTRIBUTES & sa ) { Win4Assert( 0 == _hMap ); Win4Assert( 0 == _pb );
_hMap = CreateFileMapping( INVALID_HANDLE_VALUE, // Map to page file
&sa, // Security attributes
PAGE_READWRITE, // Page-level protection
0, // Size high
cb, // size low
pwszName ); // Name
if ( 0 == _hMap ) THROW( CException() );
_pb = (BYTE *) MapViewOfFile( _hMap, // Handle to map
FILE_MAP_WRITE, // Access
0, // Offset (high)
0, // Offset (low)
0 ); // Map all
if ( 0 == _pb ) { DWORD dwErr = GetLastError(); CloseHandle( _hMap ); _hMap = 0; THROW( CException( HRESULT_FROM_WIN32( dwErr ) ) ); } }
BOOL OpenForRead( WCHAR const * pwszName ) { Win4Assert( 0 == _hMap ); Win4Assert( 0 == _pb );
//
// Note: you have to ask for PAGE_READWRITE even though we only want
// PAGE_READ, otherwise you get ERROR_ACCESS_DENIED. I don't know
// why, but since only a limited # of contexts have write access,
// it should be OK.
//
_hMap = OpenFileMapping( PAGE_READWRITE, // Access
FALSE, // Inherit
pwszName ); // Name
if ( 0 == _hMap ) { if ( ERROR_FILE_NOT_FOUND == GetLastError() ) return FALSE; THROW( CException() ); } _pb = (BYTE *) MapViewOfFile( _hMap, FILE_MAP_READ, // Access
0, // Offset (high)
0, // Offset (low)
0 ); // Map all
if ( 0 == _pb ) { DWORD dwErr = GetLastError(); CloseHandle( _hMap ); _hMap = 0; THROW( CException( HRESULT_FROM_WIN32( dwErr ) ) ); }
return TRUE; }
private:
HANDLE _hMap; BYTE * _pb;};
//+---------------------------------------------------------------------------
//
// Member: CNamedSharedMem::CNamedSharedMem, public
//
// Synopsis: Create/Open named shared memory
//
// Arguments: [pwszName] -- Name of shared memory region
// [cb] -- Size of shared memory region
// [psd] -- Security
// [fWrite] -- TRUE if write-access is required
//
// History: 06-Oct-1999 KyleP Heavily modified
//
//----------------------------------------------------------------------------
inline CNamedSharedMem::CNamedSharedMem( WCHAR const * pwszName, ULONG cb, SECURITY_DESCRIPTOR * psd, BOOL fWrite ) : _hMap( 0 ), _pb( 0 ){ //
// Create null security descriptor, if needed
//
struct { SECURITY_DESCRIPTOR _sdMaxAccess; BYTE _sdExtra[SECURITY_DESCRIPTOR_MIN_LENGTH]; } sd;
if ( 0 == psd ) {
if ( !InitializeSecurityDescriptor( &sd, SECURITY_DESCRIPTOR_REVISION ) ) { THROW( CException() ); }
if ( !SetSecurityDescriptorDacl( &sd._sdMaxAccess,// Security descriptor
TRUE, // Discretionary ACL
0, // The null ACL (all access)
FALSE ) ) // Not a default disc. ACL
{ THROW( CException() ); }
psd = &sd._sdMaxAccess; }
Init( pwszName, cb, psd, fWrite );}
//+---------------------------------------------------------------------------
//
// Member: CNamedSharedMem::Init, public
//
// Synopsis: Create/Open named shared memory
//
// Arguments: [pwszName] -- Name of shared memory region
// [cb] -- Size of shared memory region
// [psd] -- Security
// [fWrite] -- TRUE if write-access is required
//
// History: 06-Oct-1999 KyleP Heavily modified
//
//----------------------------------------------------------------------------
void CNamedSharedMem::Init( WCHAR const * pwszName, ULONG cb, SECURITY_DESCRIPTOR * psd, BOOL fWrite ){ Win4Assert( 0 == _hMap ); Win4Assert( 0 == _pb );
//Win4Assert( 0 == psd ); // Handy assert to enable to analyze security problems.
SECURITY_ATTRIBUTES sa = { sizeof(SECURITY_ATTRIBUTES), psd, FALSE };
//
// Set up flags
//
DWORD dwCFMMode; DWORD dwMVoFMode;
if ( fWrite ) { dwCFMMode = PAGE_READWRITE; dwMVoFMode = FILE_MAP_WRITE; } else { dwCFMMode = PAGE_READWRITE; // make it so that others can map for write
dwMVoFMode = FILE_MAP_READ; }
_hMap = CreateFileMapping( INVALID_HANDLE_VALUE, // Map to page file
&sa, // Security attributes
dwCFMMode, // Page-level protection
0, // Size high
cb, // size low
pwszName ); // Name
#if 0
if ( 0 != psd ) { BYTE ab[1000]; DWORD dwl;
BOOL fOk = GetKernelObjectSecurity( _hMap, // handle to object
FILE_MAP_WRITEDACL_SECURITY_INFORMATION, // request
(SECURITY_DESCRIPTOR *)&ab[0], // SD
sizeof(ab), // size of SD
&dwl ); // required size of buffer
Win4Assert( fOk ); Win4Assert( !fOk );
ciDebugOut(( DEB_ERROR, "pb = 0x%x\n", &ab[0] ));
Win4Assert( !fOk );
//HANDLE hTemp = OpenFileMapping( PAGE_READONLY, // Access
// FALSE, // Inherit
// pwszName ); // Name
HANDLE hTemp = CreateFileMapping( INVALID_HANDLE_VALUE, // Map to page file
&sa, // Security attributes
PAGE_READONLY, // Page-level protection
0, // Size high
cb, // size low
pwszName ); // Name
Win4Assert( 0 != hTemp );
BYTE * pbTemp = (BYTE *) MapViewOfFile( hTemp, // Handle to map
FILE_MAP_READ, // Access
0, // Offset (high)
0, // Offset (low)
0 ); // Map all
Win4Assert( 0 != pbTemp );
UnmapViewOfFile( pbTemp ); CloseHandle( hTemp ); }
#endif
if ( 0 != _hMap ) _pb = (BYTE *) MapViewOfFile( _hMap, // Handle to map
dwMVoFMode, // Access
0, // Offset (high)
0, // Offset (low)
0 ); // Map all
}
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