reactos/drivers/fs/vfat/fcb.c

   1 /* $Id: fcb.c,v 1.1 2001/05/02 03:18:03 rex Exp $
   2  *
   3  *
   4  * FILE:             fcb.c
   5  * PURPOSE:          Routines to manipulate FCBs.
   6  * COPYRIGHT:        See COPYING in the top level directory
   7  * PROJECT:          ReactOS kernel
   8  * PROGRAMMER:       Jason Filby (jasonfilby@yahoo.com)
   9  *                   Rex Jolliff (rex@lvcablemodem.com)
  10  */
  11
  12 /*  -------------------------------------------------------  INCLUDES  */
  13
  14 #include <ddk/ntddk.h>
  15 #include <wchar.h>
  16 #include <limits.h>
  17
  18 #define NDEBUG
  19 #include <debug.h>
  20
  21 #include "vfat.h"
  22
  23 /*  --------------------------------------------------------  DEFINES  */
  24
  25 #define TAG(A, B, C, D) (ULONG)(((A)<<0) + ((B)<<8) + ((C)<<16) + ((D)<<24))
  26 #define TAG_FCB TAG('V', 'F', 'C', 'B')
  27
  28 /*  --------------------------------------------------------  PUBLICS  */
  29
  30 PVFATFCB  vfatNewFCB (PWCHAR pFileName)
  31 {
  32   PVFATFCB  rcFCB;
  33
  34   rcFCB = ExAllocatePoolWithTag (NonPagedPool, sizeof (VFATFCB), TAG_FCB);
  35   memset (rcFCB, 0, sizeof (VFATFCB));
  36   if (pFileName)
  37   {
  38     wcscpy (rcFCB->PathName, pFileName);
  39     if (wcsrchr (rcFCB->PathName, '\\') != 0)
  40     {
  41       rcFCB->ObjectName = wcsrchr (rcFCB->PathName, '\\');
  42     }
  43     else
  44     {
  45       rcFCB->ObjectName = rcFCB->PathName;
  46     }
  47   }
  48
  49   return  rcFCB;
  50 }
  51
  52 void  vfatGrabFCB (PDEVICE_EXTENSION  pVCB,  PVFATFCB  pFCB)
  53 {
  54   KIRQL  oldIrql;
  55
  56   KeAcquireSpinLock (&pVCB->FcbListLock, &oldIrql);
  57   pFCB->RefCount++;
  58   KeReleaseSpinLock (&pVCB->FcbListLock, oldIrql);
  59 }
  60
  61 void  vfatReleaseFCB (PDEVICE_EXTENSION  pVCB,  PVFATFCB  pFCB)
  62 {
  63   KIRQL  oldIrql;
  64
  65   KeAcquireSpinLock (&pVCB->FcbListLock, &oldIrql);
  66   pFCB->RefCount--;
  67   if (pFCB->RefCount <= 0)
  68   {
  69     RemoveEntryList (&pFCB->FcbListEntry);
  70     ExFreePool (pFCB);
  71   }
  72   KeReleaseSpinLock (&pVCB->FcbListLock, oldIrql);
  73 }
  74
  75 void  vfatAddFCBToTable (PDEVICE_EXTENSION  pVCB,  PVFATFCB  pFCB)
  76 {
  77   KIRQL  oldIrql;
  78
  79   KeAcquireSpinLock (&pVCB->FcbListLock, &oldIrql);
  80   pFCB->pDevExt = pVCB;
  81   InsertTailList (&pVCB->FcbListHead, &pFCB->FcbListEntry);
  82   KeReleaseSpinLock (&pVCB->FcbListLock, oldIrql);
  83 }
  84
  85 PVFATFCB  vfatGrabFCBFromTable (PDEVICE_EXTENSION  pDeviceExt, PWSTR  pFileName)
  86 {
  87   KIRQL  oldIrql;
  88   PVFATFCB  rcFCB;
  89   PLIST_ENTRY  current_entry;
  90
  91   KeAcquireSpinLock (&pDeviceExt->FcbListLock, &oldIrql);
  92   current_entry = pDeviceExt->FcbListHead.Flink;
  93   while (current_entry != &pDeviceExt->FcbListHead)
  94   {
  95     rcFCB = CONTAINING_RECORD (current_entry, VFATFCB, FcbListEntry);
  96
  97     DPRINT ("Scanning %x(%S)\n", rcFCB, rcFCB->PathName);
  98
  99     if (wstrcmpi (pFileName, rcFCB->PathName))
 100     {
 101       rcFCB->RefCount++;
 102       KeReleaseSpinLock (&pDeviceExt->FcbListLock, oldIrql);
 103       return  rcFCB;
 104     }
 105     current_entry = current_entry->Flink;
 106   }
 107   KeReleaseSpinLock (&pDeviceExt->FcbListLock, oldIrql);
 108
 109   return  NULL;
 110 }