reactos/drivers/filters/fltmgr/Object.c

   1 /*
   2 * PROJECT:         Filesystem Filter Manager
   3 * LICENSE:         GPL - See COPYING in the top level directory
   4 * FILE:            drivers/filters/fltmgr/Object.c
   5 * PURPOSE:         Miscellaneous library functions
   6 * PROGRAMMERS:     Ged Murphy (gedmurphy@reactos.org)
   7 */
   8
   9 // NOTE: Split this file into filter object and device object functions
  10 // when the code base grows sufficiently
  11
  12 /* INCLUDES ******************************************************************/
  13
  14 #include "fltmgr.h"
  15 #include "fltmgrint.h"
  16
  17 #define NDEBUG
  18 #include <debug.h>
  19
  20
  21 /* DATA *********************************************************************/
  22
  23
  24
  25 /* EXPORTED FUNCTIONS ******************************************************/
  26
  27
  28 NTSTATUS
  29 FLTAPI
  30 FltObjectReference(_Inout_ PVOID Object)
  31 {
  32     if (!FltpExAcquireRundownProtection(&((PFLT_OBJECT)Object)->RundownRef))
  33     {
  34         return STATUS_FLT_DELETING_OBJECT;
  35     }
  36
  37     return STATUS_SUCCESS;
  38 }
  39
  40 VOID
  41 FLTAPI
  42 FltObjectDereference(_Inout_ PVOID Object)
  43 {
  44     FltpExReleaseRundownProtection(&((PFLT_OBJECT)Object)->RundownRef);
  45 }
  46
  47
  48
  49 /* INTERNAL FUNCTIONS ******************************************************/
  50
  51 VOID
  52 FltpExInitializeRundownProtection(_Out_ PEX_RUNDOWN_REF RundownRef)
  53 {
  54     ExInitializeRundownProtection(RundownRef);
  55 }
  56
  57 BOOLEAN
  58 FltpExAcquireRundownProtection(_Inout_ PEX_RUNDOWN_REF RundownRef)
  59 {
  60     return ExAcquireRundownProtection(RundownRef);
  61 }
  62
  63 BOOLEAN
  64 FltpExReleaseRundownProtection(_Inout_ PEX_RUNDOWN_REF RundownRef)
  65 {
  66     ExReleaseRundownProtection(RundownRef);
  67     return TRUE;
  68 }
  69
  70 BOOLEAN
  71 FltpExRundownCompleted(_Inout_ PEX_RUNDOWN_REF RundownRef)
  72 {
  73     return _InterlockedExchange((PLONG)RundownRef, 1);
  74 }
  75
  76 NTSTATUS
  77 NTAPI
  78 FltpObjectRundownWait(_Inout_ PEX_RUNDOWN_REF RundownRef)
  79 {
  80     //return FltpExWaitForRundownProtectionRelease(RundownRef);
  81     return 0;
  82 }
  83
  84 NTSTATUS
  85 FltpGetBaseDeviceObjectName(_In_ PDEVICE_OBJECT DeviceObject,
  86                             _Inout_ PUNICODE_STRING ObjectName)
  87 {
  88     PDEVICE_OBJECT BaseDeviceObject;
  89     NTSTATUS Status;
  90
  91     /*
  92     * Get the lowest device object on the stack, which may be the
  93     * object we were passed, and lookup the name for that object
  94     */
  95     BaseDeviceObject = IoGetDeviceAttachmentBaseRef(DeviceObject);
  96     Status = FltpGetObjectName(BaseDeviceObject, ObjectName);
  97     ObDereferenceObject(BaseDeviceObject);
  98
  99     return Status;
 100 }
 101
 102 NTSTATUS
 103 FltpGetObjectName(_In_ PVOID Object,
 104                   _Inout_ PUNICODE_STRING ObjectName)
 105 {
 106     POBJECT_NAME_INFORMATION ObjectNameInfo = NULL;
 107     OBJECT_NAME_INFORMATION LocalNameInfo;
 108     ULONG ReturnLength;
 109     NTSTATUS Status;
 110
 111     if (ObjectName == NULL)
 112         return STATUS_INVALID_PARAMETER;
 113
 114     /* Get the size of the buffer required to hold the nameinfo */
 115     Status = ObQueryNameString(Object,
 116                                &LocalNameInfo,
 117                                sizeof(LocalNameInfo),
 118                                &ReturnLength);
 119     if (Status == STATUS_INFO_LENGTH_MISMATCH)
 120     {
 121         ObjectNameInfo = ExAllocatePoolWithTag(PagedPool,
 122                                                ReturnLength,
 123                                                FM_TAG_UNICODE_STRING);
 124         if (ObjectNameInfo == NULL) return STATUS_INSUFFICIENT_RESOURCES;
 125
 126         /* Get the actual name info now we have the buffer to hold it */
 127         Status = ObQueryNameString(Object,
 128                                    ObjectNameInfo,
 129                                    ReturnLength,
 130                                    &ReturnLength);
 131     }
 132
 133
 134     if (NT_SUCCESS(Status))
 135     {
 136         /* Make sure the buffer we were passed is large enough to hold the string */
 137         if (ObjectName->MaximumLength < ObjectNameInfo->Name.Length)
 138         {
 139             /* It wasn't, let's enlarge the buffer */
 140             Status = FltpReallocateUnicodeString(ObjectName,
 141                                                  ObjectNameInfo->Name.Length,
 142                                                  FALSE);
 143
 144         }
 145
 146         if (NT_SUCCESS(Status))
 147         {
 148             /* Copy the object name into the callers buffer */
 149             RtlCopyUnicodeString(ObjectName, &ObjectNameInfo->Name);
 150         }
 151     }
 152
 153     if (ObjectNameInfo)
 154     {
 155         ExFreePoolWithTag(ObjectNameInfo, FM_TAG_UNICODE_STRING);
 156     }
 157
 158     return Status;
 159 }