ReactOS Development > Doxygen
Definition at line 456 of file obdir.c. Referenced by QueryDosDeviceW(), ScmCheckDriver(), ScmGetDriverStatus(), SmpTranslateSystemPartitionInformation(), and xHalpGetRDiskCount(). {
POBJECT_DIRECTORY Directory;
KPROCESSOR_MODE PreviousMode = ExGetPreviousMode();
ULONG SkipEntries = 0;
NTSTATUS Status;
PVOID LocalBuffer;
POBJECT_DIRECTORY_INFORMATION DirectoryInfo;
ULONG Length, TotalLength;
ULONG Count, CurrentEntry;
ULONG Hash;
POBJECT_DIRECTORY_ENTRY Entry;
POBJECT_HEADER ObjectHeader;
POBJECT_HEADER_NAME_INFO ObjectNameInfo;
UNICODE_STRING Name;
PWSTR p;
OBP_LOOKUP_CONTEXT LookupContext;
PAGED_CODE();
/* Initialize lookup */
ObpInitializeLookupContext(&LookupContext);
/* Check if we need to do any probing */
if (PreviousMode != KernelMode)
{
_SEH2_TRY
{
/* Probe the buffer (assuming it will hold Unicode characters) */
ProbeForWrite(Buffer, BufferLength, sizeof(WCHAR));
/* Probe the context and copy it unless scan-restart was requested */
ProbeForWriteUlong(Context);
if (!RestartScan) SkipEntries = *Context;
/* Probe the return length if the caller specified one */
if (ReturnLength) ProbeForWriteUlong(ReturnLength);
}
_SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
{
/* Return the exception code */
_SEH2_YIELD(return _SEH2_GetExceptionCode());
}
_SEH2_END;
}
else if (!RestartScan)
{
/* This is kernel mode, save the context without probing, if needed */
SkipEntries = *Context;
}
/* Allocate a buffer */
LocalBuffer = ExAllocatePoolWithTag(PagedPool,
sizeof(OBJECT_DIRECTORY_INFORMATION) +
BufferLength,
OB_NAME_TAG);
if (!LocalBuffer) return STATUS_INSUFFICIENT_RESOURCES;
RtlZeroMemory(LocalBuffer, BufferLength);
/* Get a reference to directory */
Status = ObReferenceObjectByHandle(DirectoryHandle,
DIRECTORY_QUERY,
ObDirectoryType,
PreviousMode,
(PVOID*)&Directory,
NULL);
if (!NT_SUCCESS(Status))
{
/* Free the buffer and fail */
ExFreePoolWithTag(LocalBuffer, OB_NAME_TAG);
return Status;
}
/* Lock directory in shared mode */
ObpAcquireDirectoryLockShared(Directory, &LookupContext);
/* Start at position 0 */
DirectoryInfo = (POBJECT_DIRECTORY_INFORMATION)LocalBuffer;
TotalLength = sizeof(OBJECT_DIRECTORY_INFORMATION);
/* Start with 0 entries */
Count = 0;
CurrentEntry = 0;
/* Set default status and start looping */
Status = STATUS_NO_MORE_ENTRIES;
for (Hash = 0; Hash < 37; Hash++)
{
/* Get this entry and loop all of them */
Entry = Directory->HashBuckets[Hash];
while (Entry)
{
/* Check if we should process this entry */
if (SkipEntries == CurrentEntry++)
{
/* Get the header data */
ObjectHeader = OBJECT_TO_OBJECT_HEADER(Entry->Object);
ObjectNameInfo = OBJECT_HEADER_TO_NAME_INFO(ObjectHeader);
/* Get the object name */
if (ObjectNameInfo)
{
/* Use the one we have */
Name = ObjectNameInfo->Name;
}
else
{
/* Otherwise, use an empty one */
RtlInitEmptyUnicodeString(&Name, NULL, 0);
}
/* Calculate the length for this entry */
Length = sizeof(OBJECT_DIRECTORY_INFORMATION) +
Name.Length + sizeof(UNICODE_NULL) +
ObjectHeader->Type->Name.Length + sizeof(UNICODE_NULL);
/* Make sure this entry won't overflow */
if ((TotalLength + Length) > BufferLength)
{
/* Check if the caller wanted only an entry */
if (ReturnSingleEntry)
{
/* Then we'll fail and ask for more buffer */
TotalLength += Length;
Status = STATUS_BUFFER_TOO_SMALL;
}
else
{
/* Otherwise, we'll say we're done for now */
Status = STATUS_MORE_ENTRIES;
}
/* Decrease the entry since we didn't process */
CurrentEntry--;
goto Quickie;
}
/* Now fill in the buffer */
DirectoryInfo->Name.Length = Name.Length;
DirectoryInfo->Name.MaximumLength = Name.Length +
sizeof(UNICODE_NULL);
DirectoryInfo->Name.Buffer = Name.Buffer;
DirectoryInfo->TypeName.Length = ObjectHeader->
Type->Name.Length;
DirectoryInfo->TypeName.MaximumLength = ObjectHeader->
Type->Name.Length +
sizeof(UNICODE_NULL);
DirectoryInfo->TypeName.Buffer = ObjectHeader->
Type->Name.Buffer;
/* Set success */
Status = STATUS_SUCCESS;
/* Increase statistics */
TotalLength += Length;
DirectoryInfo++;
Count++;
/* If the caller only wanted an entry, bail out */
if (ReturnSingleEntry) goto Quickie;
/* Increase the key by one */
SkipEntries++;
}
/* Move to the next directory */
Entry = Entry->ChainLink;
}
}
Quickie:
/* Make sure we got success */
if (NT_SUCCESS(Status))
{
/* Clear the current pointer and set it */
RtlZeroMemory(DirectoryInfo, sizeof(OBJECT_DIRECTORY_INFORMATION));
DirectoryInfo++;
/* Set the buffer here now and loop entries */
p = (PWSTR)DirectoryInfo;
DirectoryInfo = LocalBuffer;
while (Count--)
{
/* Copy the name buffer */
RtlCopyMemory(p,
DirectoryInfo->Name.Buffer,
DirectoryInfo->Name.Length);
/* Now fixup the pointers */
DirectoryInfo->Name.Buffer = (PVOID)((ULONG_PTR)Buffer +
((ULONG_PTR)p -
(ULONG_PTR)LocalBuffer));
/* Advance in buffer and NULL-terminate */
p = (PVOID)((ULONG_PTR)p + DirectoryInfo->Name.Length);
*p++ = UNICODE_NULL;
/* Now copy the type name buffer */
RtlCopyMemory(p,
DirectoryInfo->TypeName.Buffer,
DirectoryInfo->TypeName.Length);
/* Now fixup the pointers */
DirectoryInfo->TypeName.Buffer = (PVOID)((ULONG_PTR)Buffer +
((ULONG_PTR)p -
(ULONG_PTR)LocalBuffer));
/* Advance in buffer and NULL-terminate */
p = (PVOID)((ULONG_PTR)p + DirectoryInfo->TypeName.Length);
*p++ = UNICODE_NULL;
/* Move to the next entry */
DirectoryInfo++;
}
/* Set the key */
*Context = CurrentEntry;
}
_SEH2_TRY
{
/* Copy the buffer */
RtlCopyMemory(Buffer,
LocalBuffer,
(TotalLength <= BufferLength) ?
TotalLength : BufferLength);
/* Check if the caller requested the return length and return it*/
if (ReturnLength) *ReturnLength = TotalLength;
}
_SEH2_EXCEPT(ExSystemExceptionFilter())
{
/* Get the exception code */
Status = _SEH2_GetExceptionCode();
}
_SEH2_END;
/* Unlock the directory */
ObpReleaseDirectoryLock(Directory, &LookupContext);
/* Dereference the directory and free our buffer */
ObDereferenceObject(Directory);
ExFreePoolWithTag(LocalBuffer, OB_NAME_TAG);
/* Return status to caller */
return Status;
}
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Generated on Sat May 26 2012 06:07:42 for ReactOS by
1.7.6.1
