Sweden-Number/dlls/ntdll/handletable.c

306 lines
9.4 KiB
C

/*
* Handle Tables
*
* Copyright (C) 2004 Robert Shearman
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
*/
#include <stdarg.h>
#include "ntstatus.h"
#define WIN32_NO_STATUS
#include "windef.h"
#include "winternl.h"
#include "wine/debug.h"
#include "ntdll_misc.h"
WINE_DEFAULT_DEBUG_CHANNEL(ntdll);
/**************************************************************************
* RtlInitializeHandleTable (NTDLL.@)
*
* Initializes a handle table.
*
* PARAMS
* MaxHandleCount [I] The maximum number of handles the handle table will support.
* HandleSize [I] The size of each handle.
* HandleTable [I/O] The handle table.
*
* RETURNS
* Nothing.
*
* SEE
* RtlDestroyHandleTable().
*/
void WINAPI RtlInitializeHandleTable(ULONG MaxHandleCount, ULONG HandleSize, RTL_HANDLE_TABLE * HandleTable)
{
TRACE("(%u, %u, %p)\n", MaxHandleCount, HandleSize, HandleTable);
memset(HandleTable, 0, sizeof(*HandleTable));
HandleTable->MaxHandleCount = MaxHandleCount;
HandleTable->HandleSize = HandleSize;
}
/**************************************************************************
* RtlDestroyHandleTable (NTDLL.@)
*
* Destroys a handle table and frees associated resources.
*
* PARAMS
* HandleTable [I] The handle table.
*
* RETURNS
* Any status code returned by NtFreeVirtualMemory().
*
* NOTES
* The native version of this API doesn't free the virtual memory that has
* been previously reserved, only the committed memory. There is no harm
* in also freeing the reserved memory because it won't have been handed out
* to any callers. I believe it is "more polite" to free everything.
*
* SEE
* RtlInitializeHandleTable().
*/
NTSTATUS WINAPI RtlDestroyHandleTable(RTL_HANDLE_TABLE * HandleTable)
{
SIZE_T Size = 0;
TRACE("(%p)\n", HandleTable);
/* native version only releases committed memory, but we also release reserved */
return NtFreeVirtualMemory(
NtCurrentProcess(),
&HandleTable->FirstHandle,
&Size,
MEM_RELEASE);
}
/**************************************************************************
* RtlpAllocateSomeHandles (internal)
*
* Reserves memory for the handles if not previously done and commits memory
* for a batch of handles if none are free and adds them to the free list.
*
* PARAMS
* HandleTable [I/O] The handle table.
*
* RETURNS
* NTSTATUS code.
*/
static NTSTATUS RtlpAllocateSomeHandles(RTL_HANDLE_TABLE * HandleTable)
{
NTSTATUS status;
if (!HandleTable->FirstHandle)
{
PVOID FirstHandleAddr = NULL;
SIZE_T MaxSize = HandleTable->MaxHandleCount * HandleTable->HandleSize;
/* reserve memory for the handles, but don't commit it yet because we
* probably won't use most of it and it will use up physical memory */
status = NtAllocateVirtualMemory(
NtCurrentProcess(),
&FirstHandleAddr,
0,
&MaxSize,
MEM_RESERVE,
PAGE_READWRITE);
if (status != STATUS_SUCCESS)
return status;
HandleTable->FirstHandle = FirstHandleAddr;
HandleTable->ReservedMemory = HandleTable->FirstHandle;
HandleTable->MaxHandle = (char *)HandleTable->FirstHandle + MaxSize;
}
if (!HandleTable->NextFree)
{
SIZE_T Offset, CommitSize = 4096; /* one page */
RTL_HANDLE * FreeHandle = NULL;
PVOID NextAvailAddr = HandleTable->ReservedMemory;
if (HandleTable->ReservedMemory >= HandleTable->MaxHandle)
return STATUS_NO_MEMORY; /* the handle table is completely full */
status = NtAllocateVirtualMemory(
NtCurrentProcess(),
&NextAvailAddr,
0,
&CommitSize,
MEM_COMMIT,
PAGE_READWRITE);
if (status != STATUS_SUCCESS)
return status;
for (Offset = 0; Offset < CommitSize; Offset += HandleTable->HandleSize)
{
/* make sure we don't go over handle limit, even if we can
* because of rounding of the table size up to the next page
* boundary */
if ((char *)HandleTable->ReservedMemory + Offset >= (char *)HandleTable->MaxHandle)
break;
FreeHandle = (RTL_HANDLE *)((char *)HandleTable->ReservedMemory + Offset);
FreeHandle->Next = (RTL_HANDLE *)((char *)HandleTable->ReservedMemory +
Offset + HandleTable->HandleSize);
}
/* shouldn't happen because we already test for this above, but
* handle it just in case */
if (!FreeHandle)
return STATUS_NO_MEMORY;
/* set the last handle's Next pointer to NULL so that when we run
* out of free handles we trigger another commit of memory and
* initialize the free pointers */
FreeHandle->Next = NULL;
HandleTable->NextFree = HandleTable->ReservedMemory;
HandleTable->ReservedMemory = (char *)HandleTable->ReservedMemory + CommitSize;
}
return STATUS_SUCCESS;
}
/**************************************************************************
* RtlAllocateHandle (NTDLL.@)
*
* Allocates a handle from the handle table.
*
* PARAMS
* HandleTable [I/O] The handle table.
* HandleIndex [O] Index of the handle returned. Optional.
*
* RETURNS
* Success: Pointer to allocated handle.
* Failure: NULL.
*
* NOTES
* A valid handle must have the bit set as indicated in the code below
* otherwise subsequent RtlIsValidHandle() calls will fail.
*
* static inline void RtlpMakeHandleAllocated(RTL_HANDLE * Handle)
* {
* ULONG_PTR *AllocatedBit = (ULONG_PTR *)(&Handle->Next);
* *AllocatedBit = *AllocatedBit | 1;
* }
*
* SEE
* RtlFreeHandle().
*/
RTL_HANDLE * WINAPI RtlAllocateHandle(RTL_HANDLE_TABLE * HandleTable, ULONG * HandleIndex)
{
RTL_HANDLE * ret;
TRACE("(%p, %p)\n", HandleTable, HandleIndex);
if (!HandleTable->NextFree && RtlpAllocateSomeHandles(HandleTable) != STATUS_SUCCESS)
return NULL;
ret = (RTL_HANDLE *)HandleTable->NextFree;
HandleTable->NextFree = ret->Next;
if (HandleIndex)
*HandleIndex = (ULONG)(((PCHAR)ret - (PCHAR)HandleTable->FirstHandle) / HandleTable->HandleSize);
return ret;
}
/**************************************************************************
* RtlFreeHandle (NTDLL.@)
*
* Frees an allocated handle.
*
* PARAMS
* HandleTable [I/O] The handle table.
* Handle [I] The handle to be freed.
*
* RETURNS
* Success: TRUE.
* Failure: FALSE.
*
* SEE
* RtlAllocateHandle().
*/
BOOLEAN WINAPI RtlFreeHandle(RTL_HANDLE_TABLE * HandleTable, RTL_HANDLE * Handle)
{
TRACE("(%p, %p)\n", HandleTable, Handle);
/* NOTE: we don't validate the handle and we don't make Handle->Next even
* again to signal that it is no longer in user - that is done as a side
* effect of setting Handle->Next to the previously next free handle in
* the handle table */
memset(Handle, 0, HandleTable->HandleSize);
Handle->Next = (RTL_HANDLE *)HandleTable->NextFree;
HandleTable->NextFree = Handle;
return TRUE;
}
/**************************************************************************
* RtlIsValidHandle (NTDLL.@)
*
* Determines whether a handle is valid or not.
*
* PARAMS
* HandleTable [I] The handle table.
* Handle [I] The handle to be tested.
*
* RETURNS
* Valid: TRUE.
* Invalid: FALSE.
*/
BOOLEAN WINAPI RtlIsValidHandle(const RTL_HANDLE_TABLE * HandleTable, const RTL_HANDLE * Handle)
{
TRACE("(%p, %p)\n", HandleTable, Handle);
/* make sure handle is within used region and that it is aligned on
* a HandleTable->HandleSize boundary and that Handle->Next is odd,
* indicating that the handle is active */
if ((Handle >= (RTL_HANDLE *)HandleTable->FirstHandle) &&
(Handle < (RTL_HANDLE *)HandleTable->ReservedMemory) &&
!((ULONG_PTR)Handle & (HandleTable->HandleSize - 1)) &&
((ULONG_PTR)Handle->Next & 1))
return TRUE;
else
return FALSE;
}
/**************************************************************************
* RtlIsValidIndexHandle (NTDLL.@)
*
* Determines whether a handle index is valid or not.
*
* PARAMS
* HandleTable [I] The handle table.
* Index [I] The index of the handle to be tested.
* ValidHandle [O] The handle Index refers to.
*
* RETURNS
* Valid: TRUE.
* Invalid: FALSE.
*/
BOOLEAN WINAPI RtlIsValidIndexHandle(const RTL_HANDLE_TABLE * HandleTable, ULONG Index, RTL_HANDLE ** ValidHandle)
{
RTL_HANDLE * Handle;
TRACE("(%p, %u, %p)\n", HandleTable, Index, ValidHandle);
Handle = (RTL_HANDLE *)
((char *)HandleTable->FirstHandle + Index * HandleTable->HandleSize);
if (RtlIsValidHandle(HandleTable, Handle))
{
*ValidHandle = Handle;
return TRUE;
}
return FALSE;
}