reactos/ntoskrnl/ps/cid.c

   1 /* $Id$
   2  *
   3  * COPYRIGHT:       See COPYING in the top level directory
   4  * PROJECT:         ReactOS kernel
   5  * FILE:            ntoskrnl/ps/cid.c
   6  * PURPOSE:         Client ID (CID) management
   7  *
   8  * PROGRAMMERS:     Thomas Weidenmueller <w3seek@reactos.com>
   9  */
  10
  11 /* INCLUDES ******************************************************************/
  12
  13 #include <ntoskrnl.h>
  14 #define NDEBUG
  15 #include <internal/debug.h>
  16
  17 /* GLOBALS ******************************************************************/
  18
  19 /*
  20  * FIXME - use a global handle table instead!
  21  */
  22
  23 KSPIN_LOCK CidLock;
  24 LIST_ENTRY CidHead;
  25 KEVENT CidReleaseEvent;
  26 LONG CidCounter = 0;
  27 LARGE_INTEGER ShortDelay, LongDelay;
  28
  29 #define TAG_CIDOBJECT TAG('C', 'I', 'D', 'O')
  30
  31 /* FUNCTIONS *****************************************************************/
  32
  33 VOID INIT_FUNCTION
  34 PsInitClientIDManagment(VOID)
  35 {
  36    InitializeListHead(&CidHead);
  37    KeInitializeSpinLock(&CidLock);
  38    KeInitializeEvent(&CidReleaseEvent, SynchronizationEvent, FALSE);
  39    ShortDelay.QuadPart = -100LL;
  40    LongDelay.QuadPart = -100000LL;
  41 }
  42
  43 VOID
  44 PspReferenceCidObject(PCID_OBJECT Object)
  45 {
  46   InterlockedIncrement(&Object->ref);
  47 }
  48
  49 VOID
  50 PspDereferenceCidObject(PCID_OBJECT Object)
  51 {
  52   if(InterlockedDecrement(&Object->ref) == 0)
  53   {
  54     ExFreePool(Object);
  55   }
  56 }
  57
  58 NTSTATUS
  59 PsCreateCidHandle(PVOID Object, POBJECT_TYPE ObjectType, PHANDLE Handle)
  60 {
  61   KIRQL oldIrql;
  62   PCID_OBJECT cido = ExAllocatePoolWithTag(NonPagedPool,
  63                                            sizeof(CID_OBJECT),
  64                                            TAG_CIDOBJECT);
  65   if(cido != NULL)
  66   {
  67     cido->ref = 1;
  68     ExInitializeFastMutex(&cido->Lock);
  69     cido->Obj.Object = Object;
  70
  71     KeAcquireSpinLock(&CidLock, &oldIrql);
  72     cido->Handle = (HANDLE)((ULONG_PTR)(++CidCounter) << 2);
  73     InsertTailList(&CidHead, &cido->Entry);
  74     KeReleaseSpinLock(&CidLock, oldIrql);
  75
  76     *Handle = cido->Handle;
  77     return STATUS_SUCCESS;
  78   }
  79
  80   return STATUS_INSUFFICIENT_RESOURCES;
  81 }
  82
  83 NTSTATUS
  84 PsDeleteCidHandle(HANDLE CidHandle, POBJECT_TYPE ObjectType)
  85 {
  86   PCID_OBJECT cido, Found = NULL;
  87   PLIST_ENTRY Current;
  88   KIRQL oldIrql;
  89
  90   if(CidHandle == NULL)
  91   {
  92     return STATUS_INVALID_PARAMETER;
  93   }
  94
  95   KeAcquireSpinLock(&CidLock, &oldIrql);
  96   Current = CidHead.Flink;
  97   while(Current != &CidHead)
  98   {
  99     cido = CONTAINING_RECORD(Current, CID_OBJECT, Entry);
 100     if(cido->Handle == CidHandle)
 101     {
 102       RemoveEntryList(&cido->Entry);
 103       cido->Handle = NULL;
 104       Found = cido;
 105       break;
 106     }
 107     Current = Current->Flink;
 108   }
 109   KeReleaseSpinLock(&CidLock, oldIrql);
 110
 111   if(Found != NULL)
 112   {
 113     PspDereferenceCidObject(Found);
 114     return STATUS_SUCCESS;
 115   }
 116
 117   return STATUS_UNSUCCESSFUL;
 118 }
 119
 120 PCID_OBJECT
 121 PsLockCidHandle(HANDLE CidHandle, POBJECT_TYPE ObjectType)
 122 {
 123   PCID_OBJECT cido, Found = NULL;
 124   PLIST_ENTRY Current;
 125   KIRQL oldIrql;
 126
 127   if(CidHandle == NULL)
 128   {
 129     return NULL;
 130   }
 131
 132   KeAcquireSpinLock(&CidLock, &oldIrql);
 133   Current = CidHead.Flink;
 134   while(Current != &CidHead)
 135   {
 136     cido = CONTAINING_RECORD(Current, CID_OBJECT, Entry);
 137     if(cido->Handle == CidHandle)
 138     {
 139       Found = cido;
 140       PspReferenceCidObject(Found);
 141       break;
 142     }
 143     Current = Current->Flink;
 144   }
 145   KeReleaseSpinLock(&CidLock, oldIrql);
 146
 147   if(Found != NULL)
 148   {
 149     ExAcquireFastMutex(&Found->Lock);
 150   }
 151
 152   return Found;
 153 }
 154
 155 VOID
 156 PsUnlockCidObject(PCID_OBJECT CidObject)
 157 {
 158   ExReleaseFastMutex(&CidObject->Lock);
 159   PspDereferenceCidObject(CidObject);
 160 }
 161
 162 /* EOF */