nsutils.c revision 281075
1219019Sgabor/******************************************************************************
2219019Sgabor *
3219019Sgabor * Module Name: nsutils - Utilities for accessing ACPI namespace, accessing
4219019Sgabor *                        parents and siblings and Scope manipulation
5219019Sgabor *
6219019Sgabor *****************************************************************************/
7219019Sgabor
8219019Sgabor/*
9219019Sgabor * Copyright (C) 2000 - 2015, Intel Corp.
10219019Sgabor * All rights reserved.
11219019Sgabor *
12219019Sgabor * Redistribution and use in source and binary forms, with or without
13219019Sgabor * modification, are permitted provided that the following conditions
14219019Sgabor * are met:
15219019Sgabor * 1. Redistributions of source code must retain the above copyright
16219019Sgabor *    notice, this list of conditions, and the following disclaimer,
17219019Sgabor *    without modification.
18219019Sgabor * 2. Redistributions in binary form must reproduce at minimum a disclaimer
19219019Sgabor *    substantially similar to the "NO WARRANTY" disclaimer below
20219019Sgabor *    ("Disclaimer") and any redistribution must be conditioned upon
21219019Sgabor *    including a substantially similar Disclaimer requirement for further
22260497Sdim *    binary redistribution.
23260497Sdim * 3. Neither the names of the above-listed copyright holders nor the names
24219019Sgabor *    of any contributors may be used to endorse or promote products derived
25219019Sgabor *    from this software without specific prior written permission.
26 *
27 * Alternatively, this software may be distributed under the terms of the
28 * GNU General Public License ("GPL") version 2 as published by the Free
29 * Software Foundation.
30 *
31 * NO WARRANTY
32 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
33 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
34 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
35 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
36 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
37 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
38 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
39 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
40 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
41 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
42 * POSSIBILITY OF SUCH DAMAGES.
43 */
44
45#include <contrib/dev/acpica/include/acpi.h>
46#include <contrib/dev/acpica/include/accommon.h>
47#include <contrib/dev/acpica/include/acnamesp.h>
48#include <contrib/dev/acpica/include/amlcode.h>
49
50#define _COMPONENT          ACPI_NAMESPACE
51        ACPI_MODULE_NAME    ("nsutils")
52
53/* Local prototypes */
54
55#ifdef ACPI_OBSOLETE_FUNCTIONS
56ACPI_NAME
57AcpiNsFindParentName (
58    ACPI_NAMESPACE_NODE     *NodeToSearch);
59#endif
60
61
62/*******************************************************************************
63 *
64 * FUNCTION:    AcpiNsPrintNodePathname
65 *
66 * PARAMETERS:  Node            - Object
67 *              Message         - Prefix message
68 *
69 * DESCRIPTION: Print an object's full namespace pathname
70 *              Manages allocation/freeing of a pathname buffer
71 *
72 ******************************************************************************/
73
74void
75AcpiNsPrintNodePathname (
76    ACPI_NAMESPACE_NODE     *Node,
77    const char              *Message)
78{
79    ACPI_BUFFER             Buffer;
80    ACPI_STATUS             Status;
81
82
83    if (!Node)
84    {
85        AcpiOsPrintf ("[NULL NAME]");
86        return;
87    }
88
89    /* Convert handle to full pathname and print it (with supplied message) */
90
91    Buffer.Length = ACPI_ALLOCATE_LOCAL_BUFFER;
92
93    Status = AcpiNsHandleToPathname (Node, &Buffer);
94    if (ACPI_SUCCESS (Status))
95    {
96        if (Message)
97        {
98            AcpiOsPrintf ("%s ", Message);
99        }
100
101        AcpiOsPrintf ("[%s] (Node %p)", (char *) Buffer.Pointer, Node);
102        ACPI_FREE (Buffer.Pointer);
103    }
104}
105
106
107/*******************************************************************************
108 *
109 * FUNCTION:    AcpiNsGetType
110 *
111 * PARAMETERS:  Node        - Parent Node to be examined
112 *
113 * RETURN:      Type field from Node whose handle is passed
114 *
115 * DESCRIPTION: Return the type of a Namespace node
116 *
117 ******************************************************************************/
118
119ACPI_OBJECT_TYPE
120AcpiNsGetType (
121    ACPI_NAMESPACE_NODE     *Node)
122{
123    ACPI_FUNCTION_TRACE (NsGetType);
124
125
126    if (!Node)
127    {
128        ACPI_WARNING ((AE_INFO, "Null Node parameter"));
129        return_UINT8 (ACPI_TYPE_ANY);
130    }
131
132    return_UINT8 (Node->Type);
133}
134
135
136/*******************************************************************************
137 *
138 * FUNCTION:    AcpiNsLocal
139 *
140 * PARAMETERS:  Type        - A namespace object type
141 *
142 * RETURN:      LOCAL if names must be found locally in objects of the
143 *              passed type, 0 if enclosing scopes should be searched
144 *
145 * DESCRIPTION: Returns scope rule for the given object type.
146 *
147 ******************************************************************************/
148
149UINT32
150AcpiNsLocal (
151    ACPI_OBJECT_TYPE        Type)
152{
153    ACPI_FUNCTION_TRACE (NsLocal);
154
155
156    if (!AcpiUtValidObjectType (Type))
157    {
158        /* Type code out of range  */
159
160        ACPI_WARNING ((AE_INFO, "Invalid Object Type 0x%X", Type));
161        return_UINT32 (ACPI_NS_NORMAL);
162    }
163
164    return_UINT32 (AcpiGbl_NsProperties[Type] & ACPI_NS_LOCAL);
165}
166
167
168/*******************************************************************************
169 *
170 * FUNCTION:    AcpiNsGetInternalNameLength
171 *
172 * PARAMETERS:  Info            - Info struct initialized with the
173 *                                external name pointer.
174 *
175 * RETURN:      None
176 *
177 * DESCRIPTION: Calculate the length of the internal (AML) namestring
178 *              corresponding to the external (ASL) namestring.
179 *
180 ******************************************************************************/
181
182void
183AcpiNsGetInternalNameLength (
184    ACPI_NAMESTRING_INFO    *Info)
185{
186    const char              *NextExternalChar;
187    UINT32                  i;
188
189
190    ACPI_FUNCTION_ENTRY ();
191
192
193    NextExternalChar = Info->ExternalName;
194    Info->NumCarats = 0;
195    Info->NumSegments = 0;
196    Info->FullyQualified = FALSE;
197
198    /*
199     * For the internal name, the required length is 4 bytes per segment, plus
200     * 1 each for RootPrefix, MultiNamePrefixOp, segment count, trailing null
201     * (which is not really needed, but no there's harm in putting it there)
202     *
203     * strlen() + 1 covers the first NameSeg, which has no path separator
204     */
205    if (ACPI_IS_ROOT_PREFIX (*NextExternalChar))
206    {
207        Info->FullyQualified = TRUE;
208        NextExternalChar++;
209
210        /* Skip redundant RootPrefix, like \\_SB.PCI0.SBRG.EC0 */
211
212        while (ACPI_IS_ROOT_PREFIX (*NextExternalChar))
213        {
214            NextExternalChar++;
215        }
216    }
217    else
218    {
219        /* Handle Carat prefixes */
220
221        while (ACPI_IS_PARENT_PREFIX (*NextExternalChar))
222        {
223            Info->NumCarats++;
224            NextExternalChar++;
225        }
226    }
227
228    /*
229     * Determine the number of ACPI name "segments" by counting the number of
230     * path separators within the string. Start with one segment since the
231     * segment count is [(# separators) + 1], and zero separators is ok.
232     */
233    if (*NextExternalChar)
234    {
235        Info->NumSegments = 1;
236        for (i = 0; NextExternalChar[i]; i++)
237        {
238            if (ACPI_IS_PATH_SEPARATOR (NextExternalChar[i]))
239            {
240                Info->NumSegments++;
241            }
242        }
243    }
244
245    Info->Length = (ACPI_NAME_SIZE * Info->NumSegments) +
246                    4 + Info->NumCarats;
247
248    Info->NextExternalChar = NextExternalChar;
249}
250
251
252/*******************************************************************************
253 *
254 * FUNCTION:    AcpiNsBuildInternalName
255 *
256 * PARAMETERS:  Info            - Info struct fully initialized
257 *
258 * RETURN:      Status
259 *
260 * DESCRIPTION: Construct the internal (AML) namestring
261 *              corresponding to the external (ASL) namestring.
262 *
263 ******************************************************************************/
264
265ACPI_STATUS
266AcpiNsBuildInternalName (
267    ACPI_NAMESTRING_INFO    *Info)
268{
269    UINT32                  NumSegments = Info->NumSegments;
270    char                    *InternalName = Info->InternalName;
271    const char              *ExternalName = Info->NextExternalChar;
272    char                    *Result = NULL;
273    UINT32                  i;
274
275
276    ACPI_FUNCTION_TRACE (NsBuildInternalName);
277
278
279    /* Setup the correct prefixes, counts, and pointers */
280
281    if (Info->FullyQualified)
282    {
283        InternalName[0] = AML_ROOT_PREFIX;
284
285        if (NumSegments <= 1)
286        {
287            Result = &InternalName[1];
288        }
289        else if (NumSegments == 2)
290        {
291            InternalName[1] = AML_DUAL_NAME_PREFIX;
292            Result = &InternalName[2];
293        }
294        else
295        {
296            InternalName[1] = AML_MULTI_NAME_PREFIX_OP;
297            InternalName[2] = (char) NumSegments;
298            Result = &InternalName[3];
299        }
300    }
301    else
302    {
303        /*
304         * Not fully qualified.
305         * Handle Carats first, then append the name segments
306         */
307        i = 0;
308        if (Info->NumCarats)
309        {
310            for (i = 0; i < Info->NumCarats; i++)
311            {
312                InternalName[i] = AML_PARENT_PREFIX;
313            }
314        }
315
316        if (NumSegments <= 1)
317        {
318            Result = &InternalName[i];
319        }
320        else if (NumSegments == 2)
321        {
322            InternalName[i] = AML_DUAL_NAME_PREFIX;
323            Result = &InternalName[(ACPI_SIZE) i+1];
324        }
325        else
326        {
327            InternalName[i] = AML_MULTI_NAME_PREFIX_OP;
328            InternalName[(ACPI_SIZE) i+1] = (char) NumSegments;
329            Result = &InternalName[(ACPI_SIZE) i+2];
330        }
331    }
332
333    /* Build the name (minus path separators) */
334
335    for (; NumSegments; NumSegments--)
336    {
337        for (i = 0; i < ACPI_NAME_SIZE; i++)
338        {
339            if (ACPI_IS_PATH_SEPARATOR (*ExternalName) ||
340               (*ExternalName == 0))
341            {
342                /* Pad the segment with underscore(s) if segment is short */
343
344                Result[i] = '_';
345            }
346            else
347            {
348                /* Convert the character to uppercase and save it */
349
350                Result[i] = (char) ACPI_TOUPPER ((int) *ExternalName);
351                ExternalName++;
352            }
353        }
354
355        /* Now we must have a path separator, or the pathname is bad */
356
357        if (!ACPI_IS_PATH_SEPARATOR (*ExternalName) &&
358            (*ExternalName != 0))
359        {
360            return_ACPI_STATUS (AE_BAD_PATHNAME);
361        }
362
363        /* Move on the next segment */
364
365        ExternalName++;
366        Result += ACPI_NAME_SIZE;
367    }
368
369    /* Terminate the string */
370
371    *Result = 0;
372
373    if (Info->FullyQualified)
374    {
375        ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "Returning [%p] (abs) \"\\%s\"\n",
376            InternalName, InternalName));
377    }
378    else
379    {
380        ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "Returning [%p] (rel) \"%s\"\n",
381            InternalName, InternalName));
382    }
383
384    return_ACPI_STATUS (AE_OK);
385}
386
387
388/*******************************************************************************
389 *
390 * FUNCTION:    AcpiNsInternalizeName
391 *
392 * PARAMETERS:  *ExternalName           - External representation of name
393 *              **Converted Name        - Where to return the resulting
394 *                                        internal represention of the name
395 *
396 * RETURN:      Status
397 *
398 * DESCRIPTION: Convert an external representation (e.g. "\_PR_.CPU0")
399 *              to internal form (e.g. 5c 2f 02 5f 50 52 5f 43 50 55 30)
400 *
401 *******************************************************************************/
402
403ACPI_STATUS
404AcpiNsInternalizeName (
405    const char              *ExternalName,
406    char                    **ConvertedName)
407{
408    char                    *InternalName;
409    ACPI_NAMESTRING_INFO    Info;
410    ACPI_STATUS             Status;
411
412
413    ACPI_FUNCTION_TRACE (NsInternalizeName);
414
415
416    if ((!ExternalName)      ||
417        (*ExternalName == 0) ||
418        (!ConvertedName))
419    {
420        return_ACPI_STATUS (AE_BAD_PARAMETER);
421    }
422
423    /* Get the length of the new internal name */
424
425    Info.ExternalName = ExternalName;
426    AcpiNsGetInternalNameLength (&Info);
427
428    /* We need a segment to store the internal  name */
429
430    InternalName = ACPI_ALLOCATE_ZEROED (Info.Length);
431    if (!InternalName)
432    {
433        return_ACPI_STATUS (AE_NO_MEMORY);
434    }
435
436    /* Build the name */
437
438    Info.InternalName = InternalName;
439    Status = AcpiNsBuildInternalName (&Info);
440    if (ACPI_FAILURE (Status))
441    {
442        ACPI_FREE (InternalName);
443        return_ACPI_STATUS (Status);
444    }
445
446    *ConvertedName = InternalName;
447    return_ACPI_STATUS (AE_OK);
448}
449
450
451/*******************************************************************************
452 *
453 * FUNCTION:    AcpiNsExternalizeName
454 *
455 * PARAMETERS:  InternalNameLength  - Lenth of the internal name below
456 *              InternalName        - Internal representation of name
457 *              ConvertedNameLength - Where the length is returned
458 *              ConvertedName       - Where the resulting external name
459 *                                    is returned
460 *
461 * RETURN:      Status
462 *
463 * DESCRIPTION: Convert internal name (e.g. 5c 2f 02 5f 50 52 5f 43 50 55 30)
464 *              to its external (printable) form (e.g. "\_PR_.CPU0")
465 *
466 ******************************************************************************/
467
468ACPI_STATUS
469AcpiNsExternalizeName (
470    UINT32                  InternalNameLength,
471    const char              *InternalName,
472    UINT32                  *ConvertedNameLength,
473    char                    **ConvertedName)
474{
475    UINT32                  NamesIndex = 0;
476    UINT32                  NumSegments = 0;
477    UINT32                  RequiredLength;
478    UINT32                  PrefixLength = 0;
479    UINT32                  i = 0;
480    UINT32                  j = 0;
481
482
483    ACPI_FUNCTION_TRACE (NsExternalizeName);
484
485
486    if (!InternalNameLength     ||
487        !InternalName           ||
488        !ConvertedName)
489    {
490        return_ACPI_STATUS (AE_BAD_PARAMETER);
491    }
492
493    /* Check for a prefix (one '\' | one or more '^') */
494
495    switch (InternalName[0])
496    {
497    case AML_ROOT_PREFIX:
498
499        PrefixLength = 1;
500        break;
501
502    case AML_PARENT_PREFIX:
503
504        for (i = 0; i < InternalNameLength; i++)
505        {
506            if (ACPI_IS_PARENT_PREFIX (InternalName[i]))
507            {
508                PrefixLength = i + 1;
509            }
510            else
511            {
512                break;
513            }
514        }
515
516        if (i == InternalNameLength)
517        {
518            PrefixLength = i;
519        }
520
521        break;
522
523    default:
524
525        break;
526    }
527
528    /*
529     * Check for object names. Note that there could be 0-255 of these
530     * 4-byte elements.
531     */
532    if (PrefixLength < InternalNameLength)
533    {
534        switch (InternalName[PrefixLength])
535        {
536        case AML_MULTI_NAME_PREFIX_OP:
537
538            /* <count> 4-byte names */
539
540            NamesIndex = PrefixLength + 2;
541            NumSegments = (UINT8)
542                InternalName[(ACPI_SIZE) PrefixLength + 1];
543            break;
544
545        case AML_DUAL_NAME_PREFIX:
546
547            /* Two 4-byte names */
548
549            NamesIndex = PrefixLength + 1;
550            NumSegments = 2;
551            break;
552
553        case 0:
554
555            /* NullName */
556
557            NamesIndex = 0;
558            NumSegments = 0;
559            break;
560
561        default:
562
563            /* one 4-byte name */
564
565            NamesIndex = PrefixLength;
566            NumSegments = 1;
567            break;
568        }
569    }
570
571    /*
572     * Calculate the length of ConvertedName, which equals the length
573     * of the prefix, length of all object names, length of any required
574     * punctuation ('.') between object names, plus the NULL terminator.
575     */
576    RequiredLength = PrefixLength + (4 * NumSegments) +
577                        ((NumSegments > 0) ? (NumSegments - 1) : 0) + 1;
578
579    /*
580     * Check to see if we're still in bounds. If not, there's a problem
581     * with InternalName (invalid format).
582     */
583    if (RequiredLength > InternalNameLength)
584    {
585        ACPI_ERROR ((AE_INFO, "Invalid internal name"));
586        return_ACPI_STATUS (AE_BAD_PATHNAME);
587    }
588
589    /* Build the ConvertedName */
590
591    *ConvertedName = ACPI_ALLOCATE_ZEROED (RequiredLength);
592    if (!(*ConvertedName))
593    {
594        return_ACPI_STATUS (AE_NO_MEMORY);
595    }
596
597    j = 0;
598
599    for (i = 0; i < PrefixLength; i++)
600    {
601        (*ConvertedName)[j++] = InternalName[i];
602    }
603
604    if (NumSegments > 0)
605    {
606        for (i = 0; i < NumSegments; i++)
607        {
608            if (i > 0)
609            {
610                (*ConvertedName)[j++] = '.';
611            }
612
613            /* Copy and validate the 4-char name segment */
614
615            ACPI_MOVE_NAME (&(*ConvertedName)[j], &InternalName[NamesIndex]);
616            AcpiUtRepairName (&(*ConvertedName)[j]);
617
618            j += ACPI_NAME_SIZE;
619            NamesIndex += ACPI_NAME_SIZE;
620        }
621    }
622
623    if (ConvertedNameLength)
624    {
625        *ConvertedNameLength = (UINT32) RequiredLength;
626    }
627
628    return_ACPI_STATUS (AE_OK);
629}
630
631
632/*******************************************************************************
633 *
634 * FUNCTION:    AcpiNsValidateHandle
635 *
636 * PARAMETERS:  Handle          - Handle to be validated and typecast to a
637 *                                namespace node.
638 *
639 * RETURN:      A pointer to a namespace node
640 *
641 * DESCRIPTION: Convert a namespace handle to a namespace node. Handles special
642 *              cases for the root node.
643 *
644 * NOTE: Real integer handles would allow for more verification
645 *       and keep all pointers within this subsystem - however this introduces
646 *       more overhead and has not been necessary to this point. Drivers
647 *       holding handles are typically notified before a node becomes invalid
648 *       due to a table unload.
649 *
650 ******************************************************************************/
651
652ACPI_NAMESPACE_NODE *
653AcpiNsValidateHandle (
654    ACPI_HANDLE             Handle)
655{
656
657    ACPI_FUNCTION_ENTRY ();
658
659
660    /* Parameter validation */
661
662    if ((!Handle) || (Handle == ACPI_ROOT_OBJECT))
663    {
664        return (AcpiGbl_RootNode);
665    }
666
667    /* We can at least attempt to verify the handle */
668
669    if (ACPI_GET_DESCRIPTOR_TYPE (Handle) != ACPI_DESC_TYPE_NAMED)
670    {
671        return (NULL);
672    }
673
674    return (ACPI_CAST_PTR (ACPI_NAMESPACE_NODE, Handle));
675}
676
677
678/*******************************************************************************
679 *
680 * FUNCTION:    AcpiNsTerminate
681 *
682 * PARAMETERS:  none
683 *
684 * RETURN:      none
685 *
686 * DESCRIPTION: free memory allocated for namespace and ACPI table storage.
687 *
688 ******************************************************************************/
689
690void
691AcpiNsTerminate (
692    void)
693{
694    ACPI_STATUS             Status;
695
696
697    ACPI_FUNCTION_TRACE (NsTerminate);
698
699
700    /*
701     * Free the entire namespace -- all nodes and all objects
702     * attached to the nodes
703     */
704    AcpiNsDeleteNamespaceSubtree (AcpiGbl_RootNode);
705
706    /* Delete any objects attached to the root node */
707
708    Status = AcpiUtAcquireMutex (ACPI_MTX_NAMESPACE);
709    if (ACPI_FAILURE (Status))
710    {
711        return_VOID;
712    }
713
714    AcpiNsDeleteNode (AcpiGbl_RootNode);
715    (void) AcpiUtReleaseMutex (ACPI_MTX_NAMESPACE);
716
717    ACPI_DEBUG_PRINT ((ACPI_DB_INFO, "Namespace freed\n"));
718    return_VOID;
719}
720
721
722/*******************************************************************************
723 *
724 * FUNCTION:    AcpiNsOpensScope
725 *
726 * PARAMETERS:  Type        - A valid namespace type
727 *
728 * RETURN:      NEWSCOPE if the passed type "opens a name scope" according
729 *              to the ACPI specification, else 0
730 *
731 ******************************************************************************/
732
733UINT32
734AcpiNsOpensScope (
735    ACPI_OBJECT_TYPE        Type)
736{
737    ACPI_FUNCTION_ENTRY ();
738
739
740    if (Type > ACPI_TYPE_LOCAL_MAX)
741    {
742        /* type code out of range  */
743
744        ACPI_WARNING ((AE_INFO, "Invalid Object Type 0x%X", Type));
745        return (ACPI_NS_NORMAL);
746    }
747
748    return (((UINT32) AcpiGbl_NsProperties[Type]) & ACPI_NS_NEWSCOPE);
749}
750
751
752/*******************************************************************************
753 *
754 * FUNCTION:    AcpiNsGetNode
755 *
756 * PARAMETERS:  *Pathname   - Name to be found, in external (ASL) format. The
757 *                            \ (backslash) and ^ (carat) prefixes, and the
758 *                            . (period) to separate segments are supported.
759 *              PrefixNode   - Root of subtree to be searched, or NS_ALL for the
760 *                            root of the name space. If Name is fully
761 *                            qualified (first INT8 is '\'), the passed value
762 *                            of Scope will not be accessed.
763 *              Flags       - Used to indicate whether to perform upsearch or
764 *                            not.
765 *              ReturnNode  - Where the Node is returned
766 *
767 * DESCRIPTION: Look up a name relative to a given scope and return the
768 *              corresponding Node. NOTE: Scope can be null.
769 *
770 * MUTEX:       Locks namespace
771 *
772 ******************************************************************************/
773
774ACPI_STATUS
775AcpiNsGetNode (
776    ACPI_NAMESPACE_NODE     *PrefixNode,
777    const char              *Pathname,
778    UINT32                  Flags,
779    ACPI_NAMESPACE_NODE     **ReturnNode)
780{
781    ACPI_GENERIC_STATE      ScopeInfo;
782    ACPI_STATUS             Status;
783    char                    *InternalPath;
784
785
786    ACPI_FUNCTION_TRACE_PTR (NsGetNode, ACPI_CAST_PTR (char, Pathname));
787
788
789    /* Simplest case is a null pathname */
790
791    if (!Pathname)
792    {
793        *ReturnNode = PrefixNode;
794        if (!PrefixNode)
795        {
796            *ReturnNode = AcpiGbl_RootNode;
797        }
798        return_ACPI_STATUS (AE_OK);
799    }
800
801    /* Quick check for a reference to the root */
802
803    if (ACPI_IS_ROOT_PREFIX (Pathname[0]) && (!Pathname[1]))
804    {
805        *ReturnNode = AcpiGbl_RootNode;
806        return_ACPI_STATUS (AE_OK);
807    }
808
809    /* Convert path to internal representation */
810
811    Status = AcpiNsInternalizeName (Pathname, &InternalPath);
812    if (ACPI_FAILURE (Status))
813    {
814        return_ACPI_STATUS (Status);
815    }
816
817    /* Must lock namespace during lookup */
818
819    Status = AcpiUtAcquireMutex (ACPI_MTX_NAMESPACE);
820    if (ACPI_FAILURE (Status))
821    {
822        goto Cleanup;
823    }
824
825    /* Setup lookup scope (search starting point) */
826
827    ScopeInfo.Scope.Node = PrefixNode;
828
829    /* Lookup the name in the namespace */
830
831    Status = AcpiNsLookup (&ScopeInfo, InternalPath, ACPI_TYPE_ANY,
832                ACPI_IMODE_EXECUTE, (Flags | ACPI_NS_DONT_OPEN_SCOPE),
833                NULL, ReturnNode);
834    if (ACPI_FAILURE (Status))
835    {
836        ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "%s, %s\n",
837                Pathname, AcpiFormatException (Status)));
838    }
839
840    (void) AcpiUtReleaseMutex (ACPI_MTX_NAMESPACE);
841
842Cleanup:
843    ACPI_FREE (InternalPath);
844    return_ACPI_STATUS (Status);
845}
846