NTSTATUS NTAPI NtFindAtom	(	IN PWSTR	AtomName,
		IN ULONG	AtomNameLength,
		OUT PRTL_ATOM Atom
	)
Definition at line 239 of file atom.c.
Referenced by InternalFindAtom().
{
    PRTL_ATOM_TABLE AtomTable = ExpGetGlobalAtomTable();
    NTSTATUS Status;
    KPROCESSOR_MODE PreviousMode = ExGetPreviousMode();
    LPWSTR CapturedName = NULL;
    ULONG CapturedSize;
    RTL_ATOM SafeAtom;
    PAGED_CODE();

    /* Check for the table */
    if (AtomTable == NULL) return STATUS_ACCESS_DENIED;

    /* Check for valid name */
    if (AtomNameLength > (RTL_MAXIMUM_ATOM_LENGTH * sizeof(WCHAR)))
    {
        /* Fail */
        DPRINT1("Atom name too long\n");
        return STATUS_INVALID_PARAMETER;
    }
    
    /* Re-use the given name if kernel mode or no atom name */
    CapturedName = AtomName;

    /* Check if we're called from user-mode*/
    if (PreviousMode != KernelMode)
    {
        /* Enter SEH */
        _SEH2_TRY
        {
            /* Check if we have a name */
            if (AtomName)
            {
                /* Probe the atom */
                ProbeForRead(AtomName, AtomNameLength, sizeof(WCHAR));

                /* Allocate an aligned buffer + the null char */
                CapturedSize = ((AtomNameLength + sizeof(WCHAR)) &~
                                (sizeof(WCHAR) -1));
                CapturedName = ExAllocatePoolWithTag(PagedPool,
                                                     CapturedSize,
                                                     TAG_ATOM);
                if (!CapturedName)
                {
                    /* Fail the call */
                    Status = STATUS_INSUFFICIENT_RESOURCES;
                }
                else
                {
                    /* Copy the name and null-terminate it */
                    RtlCopyMemory(CapturedName, AtomName, AtomNameLength);
                    CapturedName[AtomNameLength / sizeof(WCHAR)] = UNICODE_NULL;
                }

                /* Probe the atom too */
                if (Atom) ProbeForWriteUshort(Atom);
            }
        }
        _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
        {
            /* Return the exception code */
            _SEH2_YIELD(return _SEH2_GetExceptionCode());
        }
        _SEH2_END;
    }

    /* Call the runtime function */
    Status = RtlLookupAtomInAtomTable(AtomTable, CapturedName, &SafeAtom);
    if (NT_SUCCESS(Status) && (Atom))
    {
        /* Success and caller wants the atom back.. .enter SEH */
        _SEH2_TRY
        {
            /* Return the atom */
            *Atom = SafeAtom;
        }
        _SEH2_EXCEPT(ExSystemExceptionFilter())
        {
            Status = _SEH2_GetExceptionCode();
        }
        _SEH2_END;
    }

    /* If we captured anything, free it */
    if ((CapturedName) && (CapturedName != AtomName))
        ExFreePoolWithTag(CapturedName, TAG_ATOM);

    /* Return to caller */
    return Status;
}
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