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sys: initial ProcessBuffer implementation
This commit is contained in:
Bill Zissimopoulos
280
src/sys/psbuffer.c
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280
src/sys/psbuffer.c
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/**
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* @file sys/psbuffer.c
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*
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* @copyright 2015-2017 Bill Zissimopoulos
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*/
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/*
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* This file is part of WinFsp.
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*
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* You can redistribute it and/or modify it under the terms of the GNU
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* General Public License version 3 as published by the Free Software
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* Foundation.
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*
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* Licensees holding a valid commercial license may use this file in
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* accordance with the commercial license agreement provided with the
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* software.
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*/
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#include <sys/driver.h>
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#define SafeGetCurrentProcessId() (PsGetProcessId(PsGetCurrentProcess()))
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#define FspProcessBufferCountMax (2 >= FspProcessorCount ? 2 : (8 <= FspProcessorCount ? 8 : FspProcessorCount))
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#define ProcessBufferBucketCount 61 /* are you going to have that many file systems? */
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typedef struct _FSP_PROCESS_BUFFER_ITEM
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{
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struct _FSP_PROCESS_BUFFER_ITEM *DictNext;
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struct _FSP_PROCESS_BUFFER_LIST_ENTRY *BufferList;
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ULONG BufferCount;
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HANDLE ProcessId;
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} FSP_PROCESS_BUFFER_ITEM;
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typedef struct _FSP_PROCESS_BUFFER_LIST_ENTRY
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{
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struct _FSP_PROCESS_BUFFER_LIST_ENTRY *Next;
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PVOID Buffer;
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} FSP_PROCESS_BUFFER_LIST_ENTRY;
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static KSPIN_LOCK ProcessBufferLock;
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static FSP_PROCESS_BUFFER_ITEM *ProcessBufferBuckets[ProcessBufferBucketCount];
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static VOID FspProcessBufferNotifyRoutine(HANDLE ParentId, HANDLE ProcessId, BOOLEAN Create);
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static inline FSP_PROCESS_BUFFER_ITEM *FspProcessBufferLookupItemAtDpcLevel(HANDLE ProcessId)
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{
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FSP_PROCESS_BUFFER_ITEM *Item = 0;
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ULONG HashIndex = FspHashMixPointer(ProcessId) % ProcessBufferBucketCount;
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for (FSP_PROCESS_BUFFER_ITEM *ItemX = ProcessBufferBuckets[HashIndex]; ItemX; ItemX = ItemX->DictNext)
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if (ItemX->ProcessId == ProcessId)
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{
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Item = ItemX;
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break;
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}
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return Item;
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}
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static inline VOID FspProcessBufferAddItemAtDpcLevel(FSP_PROCESS_BUFFER_ITEM *Item)
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{
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ULONG HashIndex = FspHashMixPointer(Item->ProcessId) % ProcessBufferBucketCount;
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#if DBG
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for (FSP_PROCESS_BUFFER_ITEM *ItemX = ProcessBufferBuckets[HashIndex]; ItemX; ItemX = ItemX->DictNext)
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ASSERT(ItemX->ProcessId != Item->ProcessId);
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#endif
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Item->DictNext = ProcessBufferBuckets[HashIndex];
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ProcessBufferBuckets[HashIndex] = Item;
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}
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static inline FSP_PROCESS_BUFFER_ITEM *FspProcessBufferRemoveItemAtDpcLevel(HANDLE ProcessId)
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{
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FSP_PROCESS_BUFFER_ITEM *Item = 0;
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ULONG HashIndex = FspHashMixPointer(ProcessId) % ProcessBufferBucketCount;
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for (FSP_PROCESS_BUFFER_ITEM **P = &ProcessBufferBuckets[HashIndex]; *P; P = &(*P)->DictNext)
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if ((*P)->ProcessId == ProcessId)
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{
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Item = *P;
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*P = (*P)->DictNext;
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break;
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}
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return Item;
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}
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static inline VOID FspProcessBufferReuseEntry(HANDLE ProcessId,
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FSP_PROCESS_BUFFER_LIST_ENTRY *BufferEntry)
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{
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KIRQL Irql;
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FSP_PROCESS_BUFFER_ITEM *Item;
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KeAcquireSpinLock(&ProcessBufferLock, &Irql);
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Item = FspProcessBufferLookupItemAtDpcLevel(ProcessId);
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if (0 != Item)
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{
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BufferEntry->Next = Item->BufferList;
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Item->BufferList = BufferEntry;
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}
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KeReleaseSpinLock(&ProcessBufferLock, Irql);
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if (0 == Item)
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{
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if (0 != BufferEntry->Buffer)
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{
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SIZE_T BufferSize = 0;
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ZwFreeVirtualMemory(ZwCurrentProcess(), BufferEntry->Buffer, &BufferSize, MEM_RELEASE);
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}
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FspFree(BufferEntry);
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}
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}
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NTSTATUS FspProcessBufferInitialize(VOID)
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{
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KeInitializeSpinLock(&ProcessBufferLock);
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return PsSetCreateProcessNotifyRoutine(FspProcessBufferNotifyRoutine, FALSE);
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}
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VOID FspProcessBufferFinalize(VOID)
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{
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PsSetCreateProcessNotifyRoutine(FspProcessBufferNotifyRoutine, TRUE);
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}
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static VOID FspProcessBufferNotifyRoutine(HANDLE ParentId, HANDLE ProcessId, BOOLEAN Create)
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{
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if (!Create)
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FspProcessBufferCollect(ProcessId);
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}
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VOID FspProcessBufferCollect(HANDLE ProcessId)
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{
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KIRQL Irql;
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FSP_PROCESS_BUFFER_ITEM *Item = 0;
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KeAcquireSpinLock(&ProcessBufferLock, &Irql);
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Item = FspProcessBufferRemoveItemAtDpcLevel(ProcessId);
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KeReleaseSpinLock(&ProcessBufferLock, Irql);
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if (0 != Item)
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{
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DEBUGLOG("pid=%ld", (ULONG)(UINT_PTR)ProcessId);
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for (FSP_PROCESS_BUFFER_LIST_ENTRY *P = Item->BufferList, *Next; P; P = Next)
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{
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Next = P->Next;
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FspFree(P);
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}
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FspFree(Item);
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}
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}
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NTSTATUS FspProcessBufferAcquire(SIZE_T BufferSize, PVOID *PBufferCookie, PVOID *PBuffer)
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{
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if (FspProcessBufferSizeMax >= BufferSize)
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{
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HANDLE ProcessId = SafeGetCurrentProcessId();
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KIRQL Irql;
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FSP_PROCESS_BUFFER_ITEM *Item, *NewItem;
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FSP_PROCESS_BUFFER_LIST_ENTRY *BufferEntry = 0;
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BOOLEAN AllocNoReuse;
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NTSTATUS Result;
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KeAcquireSpinLock(&ProcessBufferLock, &Irql);
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Item = FspProcessBufferLookupItemAtDpcLevel(ProcessId);
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if (0 != Item)
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{
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BufferEntry = Item->BufferList;
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if (0 != BufferEntry)
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Item->BufferList = BufferEntry->Next;
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}
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AllocNoReuse = 0 == BufferEntry &&
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(0 != Item && FspProcessBufferCountMax <= Item->BufferCount);
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KeReleaseSpinLock(&ProcessBufferLock, Irql);
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if (AllocNoReuse)
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goto alloc_no_reuse;
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if (0 == BufferEntry)
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{
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*PBufferCookie = 0;
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*PBuffer = 0;
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BufferEntry = FspAllocNonPaged(sizeof *BufferEntry);
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if (0 == BufferEntry)
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return STATUS_INSUFFICIENT_RESOURCES;
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RtlZeroMemory(BufferEntry, sizeof *BufferEntry);
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NewItem = FspAllocNonPaged(sizeof *NewItem);
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if (0 == NewItem)
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{
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FspFree(BufferEntry);
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return STATUS_INSUFFICIENT_RESOURCES;
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}
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RtlZeroMemory(NewItem, sizeof *NewItem);
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KeAcquireSpinLock(&ProcessBufferLock, &Irql);
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Item = FspProcessBufferLookupItemAtDpcLevel(ProcessId);
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if (0 == Item)
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{
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Item = NewItem;
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NewItem = 0;
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Item->BufferCount = 1;
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Item->ProcessId = ProcessId;
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FspProcessBufferAddItemAtDpcLevel(Item);
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}
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else if (FspProcessBufferCountMax > Item->BufferCount)
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Item->BufferCount++;
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else
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AllocNoReuse = TRUE;
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KeReleaseSpinLock(&ProcessBufferLock, Irql);
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if (0 != NewItem)
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FspFree(NewItem);
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if (AllocNoReuse)
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{
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FspFree(BufferEntry);
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goto alloc_no_reuse;
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}
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}
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if (0 == BufferEntry->Buffer)
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{
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BufferSize = FspProcessBufferSizeMax;
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Result = ZwAllocateVirtualMemory(ZwCurrentProcess(),
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&BufferEntry->Buffer, 0, &BufferSize, MEM_COMMIT, PAGE_READWRITE);
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if (!NT_SUCCESS(Result))
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{
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/* failed to allocate actual buffer; reuse BufferEntry */
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FspProcessBufferReuseEntry(ProcessId, BufferEntry);
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return Result;
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}
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}
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*PBufferCookie = BufferEntry;
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*PBuffer = BufferEntry->Buffer;
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return STATUS_SUCCESS;
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}
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else
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{
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alloc_no_reuse:
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NTSTATUS Result;
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*PBufferCookie = 0;
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Result = ZwAllocateVirtualMemory(ZwCurrentProcess(),
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PBuffer, 0, &BufferSize, MEM_COMMIT, PAGE_READWRITE);
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return Result;
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}
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}
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VOID FspProcessBufferRelease(PVOID BufferCookie, PVOID Buffer)
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{
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if (0 != BufferCookie)
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{
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HANDLE ProcessId = SafeGetCurrentProcessId();
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FSP_PROCESS_BUFFER_LIST_ENTRY *BufferEntry = BufferCookie;
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ASSERT(Buffer == BufferEntry->Buffer);
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FspProcessBufferReuseEntry(ProcessId, BufferEntry);
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}
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else
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{
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SIZE_T BufferSize = 0;
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ZwFreeVirtualMemory(ZwCurrentProcess(), Buffer, &BufferSize, MEM_RELEASE);
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}
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}
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