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/clientid.c
   6  * PURPOSE:           Client ID (CID) management
   7  * PROGRAMMER:        Thomas Weidenmueller <w3seek@reactos.com>
   8  * REVISION HISTORY:
   9  *              9/20/2004: Created
  10  */
  11
  12 /* INCLUDES ******************************************************************/
  13
  14 #include <ntoskrnl.h>
  15 #define NDEBUG
  16 #include <internal/debug.h>
  17
  18 /* GLOBALS ******************************************************************/
  19
  20 /*
  21  * FIXME - use a global handle table instead!
  22  */
  23
  24 KSPIN_LOCK CidLock;
  25 LIST_ENTRY CidHead;
  26 KEVENT CidReleaseEvent;
  27 LONG CidCounter = 0;
  28 LARGE_INTEGER ShortDelay, LongDelay;
  29
  30 #define TAG_CIDOBJECT TAG('C', 'I', 'D', 'O')
  31
  32 /* FUNCTIONS *****************************************************************/
  33
  34 VOID INIT_FUNCTION
  35 PsInitClientIDManagment(VOID)
  36 {
  37    InitializeListHead(&CidHead);
  38    KeInitializeSpinLock(&CidLock);
  39    KeInitializeEvent(&CidReleaseEvent, SynchronizationEvent, FALSE);
  40    ShortDelay.QuadPart = -100LL;
  41    LongDelay.QuadPart = -100000LL;
  42 }
  43
  44 VOID
  45 PspReferenceCidObject(PCID_OBJECT Object)
  46 {
  47   InterlockedIncrement(&Object->ref);
  48 }
  49
  50 VOID
  51 PspDereferenceCidObject(PCID_OBJECT Object)
  52 {
  53   if(InterlockedDecrement(&Object->ref) == 0)
  54   {
  55     ExFreePool(Object);
  56   }
  57 }
  58
  59 NTSTATUS
  60 PsCreateCidHandle(PVOID Object, POBJECT_TYPE ObjectType, PHANDLE Handle)
  61 {
  62   KIRQL oldIrql;
  63   PCID_OBJECT cido = ExAllocatePoolWithTag(NonPagedPool,
  64                                            sizeof(CID_OBJECT),
  65                                            TAG_CIDOBJECT);
  66   if(cido != NULL)
  67   {
  68     cido->ref = 1;
  69     ExInitializeFastMutex(&cido->Lock);
  70     cido->Obj.Object = Object;
  71
  72     KeAcquireSpinLock(&CidLock, &oldIrql);
  73     cido->Handle = (HANDLE)(++CidCounter);
  74     InsertTailList(&CidHead, &cido->Entry);
  75     KeReleaseSpinLock(&CidLock, oldIrql);
  76
  77     *Handle = cido->Handle;
  78     return STATUS_SUCCESS;
  79   }
  80
  81   return STATUS_INSUFFICIENT_RESOURCES;
  82 }
  83
  84 NTSTATUS
  85 PsDeleteCidHandle(HANDLE CidHandle, POBJECT_TYPE ObjectType)
  86 {
  87   PCID_OBJECT cido, Found = NULL;
  88   PLIST_ENTRY Current;
  89   KIRQL oldIrql;
  90
  91   if(CidHandle == NULL)
  92   {
  93     return STATUS_INVALID_PARAMETER;
  94   }
  95
  96   KeAcquireSpinLock(&CidLock, &oldIrql);
  97   Current = CidHead.Flink;
  98   while(Current != &CidHead)
  99   {
 100     cido = CONTAINING_RECORD(Current, CID_OBJECT, Entry);
 101     if(cido->Handle == CidHandle)
 102     {
 103       RemoveEntryList(&cido->Entry);
 104       cido->Handle = NULL;
 105       Found = cido;
 106       break;
 107     }
 108     Current = Current->Flink;
 109   }
 110   KeReleaseSpinLock(&CidLock, oldIrql);
 111
 112   if(Found != NULL)
 113   {
 114     PspDereferenceCidObject(Found);
 115     return STATUS_SUCCESS;
 116   }
 117
 118   return STATUS_UNSUCCESSFUL;
 119 }
 120
 121 PCID_OBJECT
 122 PsLockCidHandle(HANDLE CidHandle, POBJECT_TYPE ObjectType)
 123 {
 124   PCID_OBJECT cido, Found = NULL;
 125   PLIST_ENTRY Current;
 126   KIRQL oldIrql;
 127
 128   if(CidHandle == NULL)
 129   {
 130     return NULL;
 131   }
 132
 133   KeAcquireSpinLock(&CidLock, &oldIrql);
 134   Current = CidHead.Flink;
 135   while(Current != &CidHead)
 136   {
 137     cido = CONTAINING_RECORD(Current, CID_OBJECT, Entry);
 138     if(cido->Handle == CidHandle)
 139     {
 140       Found = cido;
 141       PspReferenceCidObject(Found);
 142       break;
 143     }
 144     Current = Current->Flink;
 145   }
 146   KeReleaseSpinLock(&CidLock, oldIrql);
 147
 148   if(Found != NULL)
 149   {
 150     ExAcquireFastMutex(&Found->Lock);
 151   }
 152
 153   return Found;
 154 }
 155
 156 VOID
 157 PsUnlockCidObject(PCID_OBJECT CidObject)
 158 {
 159   ExReleaseFastMutex(&CidObject->Lock);
 160   PspDereferenceCidObject(CidObject);
 161 }
 162
 163 /* EOF */