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      1 /******************************************************************************
      2  *
      3  * Module Name: nswalk - Functions for walking the ACPI namespace
      4  *
      5  *****************************************************************************/
      6 
      7 /******************************************************************************
      8  *
      9  * 1. Copyright Notice
     10  *
     11  * Some or all of this work - Copyright (c) 1999 - 2025, Intel Corp.
     12  * All rights reserved.
     13  *
     14  * 2. License
     15  *
     16  * 2.1. This is your license from Intel Corp. under its intellectual property
     17  * rights. You may have additional license terms from the party that provided
     18  * you this software, covering your right to use that party's intellectual
     19  * property rights.
     20  *
     21  * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
     22  * copy of the source code appearing in this file ("Covered Code") an
     23  * irrevocable, perpetual, worldwide license under Intel's copyrights in the
     24  * base code distributed originally by Intel ("Original Intel Code") to copy,
     25  * make derivatives, distribute, use and display any portion of the Covered
     26  * Code in any form, with the right to sublicense such rights; and
     27  *
     28  * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
     29  * license (with the right to sublicense), under only those claims of Intel
     30  * patents that are infringed by the Original Intel Code, to make, use, sell,
     31  * offer to sell, and import the Covered Code and derivative works thereof
     32  * solely to the minimum extent necessary to exercise the above copyright
     33  * license, and in no event shall the patent license extend to any additions
     34  * to or modifications of the Original Intel Code. No other license or right
     35  * is granted directly or by implication, estoppel or otherwise;
     36  *
     37  * The above copyright and patent license is granted only if the following
     38  * conditions are met:
     39  *
     40  * 3. Conditions
     41  *
     42  * 3.1. Redistribution of Source with Rights to Further Distribute Source.
     43  * Redistribution of source code of any substantial portion of the Covered
     44  * Code or modification with rights to further distribute source must include
     45  * the above Copyright Notice, the above License, this list of Conditions,
     46  * and the following Disclaimer and Export Compliance provision. In addition,
     47  * Licensee must cause all Covered Code to which Licensee contributes to
     48  * contain a file documenting the changes Licensee made to create that Covered
     49  * Code and the date of any change. Licensee must include in that file the
     50  * documentation of any changes made by any predecessor Licensee. Licensee
     51  * must include a prominent statement that the modification is derived,
     52  * directly or indirectly, from Original Intel Code.
     53  *
     54  * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
     55  * Redistribution of source code of any substantial portion of the Covered
     56  * Code or modification without rights to further distribute source must
     57  * include the following Disclaimer and Export Compliance provision in the
     58  * documentation and/or other materials provided with distribution. In
     59  * addition, Licensee may not authorize further sublicense of source of any
     60  * portion of the Covered Code, and must include terms to the effect that the
     61  * license from Licensee to its licensee is limited to the intellectual
     62  * property embodied in the software Licensee provides to its licensee, and
     63  * not to intellectual property embodied in modifications its licensee may
     64  * make.
     65  *
     66  * 3.3. Redistribution of Executable. Redistribution in executable form of any
     67  * substantial portion of the Covered Code or modification must reproduce the
     68  * above Copyright Notice, and the following Disclaimer and Export Compliance
     69  * provision in the documentation and/or other materials provided with the
     70  * distribution.
     71  *
     72  * 3.4. Intel retains all right, title, and interest in and to the Original
     73  * Intel Code.
     74  *
     75  * 3.5. Neither the name Intel nor any other trademark owned or controlled by
     76  * Intel shall be used in advertising or otherwise to promote the sale, use or
     77  * other dealings in products derived from or relating to the Covered Code
     78  * without prior written authorization from Intel.
     79  *
     80  * 4. Disclaimer and Export Compliance
     81  *
     82  * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
     83  * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
     84  * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE,
     85  * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY
     86  * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY
     87  * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
     88  * PARTICULAR PURPOSE.
     89  *
     90  * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
     91  * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
     92  * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
     93  * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
     94  * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
     95  * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS
     96  * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
     97  * LIMITED REMEDY.
     98  *
     99  * 4.3. Licensee shall not export, either directly or indirectly, any of this
    100  * software or system incorporating such software without first obtaining any
    101  * required license or other approval from the U. S. Department of Commerce or
    102  * any other agency or department of the United States Government. In the
    103  * event Licensee exports any such software from the United States or
    104  * re-exports any such software from a foreign destination, Licensee shall
    105  * ensure that the distribution and export/re-export of the software is in
    106  * compliance with all laws, regulations, orders, or other restrictions of the
    107  * U.S. Export Administration Regulations. Licensee agrees that neither it nor
    108  * any of its subsidiaries will export/re-export any technical data, process,
    109  * software, or service, directly or indirectly, to any country for which the
    110  * United States government or any agency thereof requires an export license,
    111  * other governmental approval, or letter of assurance, without first obtaining
    112  * such license, approval or letter.
    113  *
    114  *****************************************************************************
    115  *
    116  * Alternatively, you may choose to be licensed under the terms of the
    117  * following license:
    118  *
    119  * Redistribution and use in source and binary forms, with or without
    120  * modification, are permitted provided that the following conditions
    121  * are met:
    122  * 1. Redistributions of source code must retain the above copyright
    123  *    notice, this list of conditions, and the following disclaimer,
    124  *    without modification.
    125  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
    126  *    substantially similar to the "NO WARRANTY" disclaimer below
    127  *    ("Disclaimer") and any redistribution must be conditioned upon
    128  *    including a substantially similar Disclaimer requirement for further
    129  *    binary redistribution.
    130  * 3. Neither the names of the above-listed copyright holders nor the names
    131  *    of any contributors may be used to endorse or promote products derived
    132  *    from this software without specific prior written permission.
    133  *
    134  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    135  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    136  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    137  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    138  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    139  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    140  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    141  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    142  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    143  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    144  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    145  *
    146  * Alternatively, you may choose to be licensed under the terms of the
    147  * GNU General Public License ("GPL") version 2 as published by the Free
    148  * Software Foundation.
    149  *
    150  *****************************************************************************/
    151 
    152 #include "acpi.h"
    153 #include "accommon.h"
    154 #include "acnamesp.h"
    155 
    156 
    157 #define _COMPONENT          ACPI_NAMESPACE
    158         ACPI_MODULE_NAME    ("nswalk")
    159 
    160 
    161 /*******************************************************************************
    162  *
    163  * FUNCTION:    AcpiNsGetNextNode
    164  *
    165  * PARAMETERS:  ParentNode          - Parent node whose children we are
    166  *                                    getting
    167  *              ChildNode           - Previous child that was found.
    168  *                                    The NEXT child will be returned
    169  *
    170  * RETURN:      ACPI_NAMESPACE_NODE - Pointer to the NEXT child or NULL if
    171  *                                    none is found.
    172  *
    173  * DESCRIPTION: Return the next peer node within the namespace. If Handle
    174  *              is valid, Scope is ignored. Otherwise, the first node
    175  *              within Scope is returned.
    176  *
    177  ******************************************************************************/
    178 
    179 ACPI_NAMESPACE_NODE *
    180 AcpiNsGetNextNode (
    181     ACPI_NAMESPACE_NODE     *ParentNode,
    182     ACPI_NAMESPACE_NODE     *ChildNode)
    183 {
    184     ACPI_FUNCTION_ENTRY ();
    185 
    186 
    187     if (!ChildNode)
    188     {
    189         /* It's really the parent's _scope_ that we want */
    190 
    191         return (ParentNode->Child);
    192     }
    193 
    194     /* Otherwise just return the next peer */
    195 
    196     return (ChildNode->Peer);
    197 }
    198 
    199 
    200 /*******************************************************************************
    201  *
    202  * FUNCTION:    AcpiNsGetNextNodeTyped
    203  *
    204  * PARAMETERS:  Type                - Type of node to be searched for
    205  *              ParentNode          - Parent node whose children we are
    206  *                                    getting
    207  *              ChildNode           - Previous child that was found.
    208  *                                    The NEXT child will be returned
    209  *
    210  * RETURN:      ACPI_NAMESPACE_NODE - Pointer to the NEXT child or NULL if
    211  *                                    none is found.
    212  *
    213  * DESCRIPTION: Return the next peer node within the namespace. If Handle
    214  *              is valid, Scope is ignored. Otherwise, the first node
    215  *              within Scope is returned.
    216  *
    217  ******************************************************************************/
    218 
    219 ACPI_NAMESPACE_NODE *
    220 AcpiNsGetNextNodeTyped (
    221     ACPI_OBJECT_TYPE        Type,
    222     ACPI_NAMESPACE_NODE     *ParentNode,
    223     ACPI_NAMESPACE_NODE     *ChildNode)
    224 {
    225     ACPI_NAMESPACE_NODE     *NextNode = NULL;
    226 
    227 
    228     ACPI_FUNCTION_ENTRY ();
    229 
    230 
    231     NextNode = AcpiNsGetNextNode (ParentNode, ChildNode);
    232 
    233     /* If any type is OK, we are done */
    234 
    235     if (Type == ACPI_TYPE_ANY)
    236     {
    237         /* NextNode is NULL if we are at the end-of-list */
    238 
    239         return (NextNode);
    240     }
    241 
    242     /* Must search for the node -- but within this scope only */
    243 
    244     while (NextNode)
    245     {
    246         /* If type matches, we are done */
    247 
    248         if (NextNode->Type == Type)
    249         {
    250             return (NextNode);
    251         }
    252 
    253         /* Otherwise, move on to the next peer node */
    254 
    255         NextNode = NextNode->Peer;
    256     }
    257 
    258     /* Not found */
    259 
    260     return (NULL);
    261 }
    262 
    263 
    264 /*******************************************************************************
    265  *
    266  * FUNCTION:    AcpiNsWalkNamespace
    267  *
    268  * PARAMETERS:  Type                - ACPI_OBJECT_TYPE to search for
    269  *              StartNode           - Handle in namespace where search begins
    270  *              MaxDepth            - Depth to which search is to reach
    271  *              Flags               - Whether to unlock the NS before invoking
    272  *                                    the callback routine
    273  *              DescendingCallback  - Called during tree descent
    274  *                                    when an object of "Type" is found
    275  *              AscendingCallback   - Called during tree ascent
    276  *                                    when an object of "Type" is found
    277  *              Context             - Passed to user function(s) above
    278  *              ReturnValue         - from the UserFunction if terminated
    279  *                                    early. Otherwise, returns NULL.
    280  * RETURNS:     Status
    281  *
    282  * DESCRIPTION: Performs a modified depth-first walk of the namespace tree,
    283  *              starting (and ending) at the node specified by StartHandle.
    284  *              The callback function is called whenever a node that matches
    285  *              the type parameter is found. If the callback function returns
    286  *              a non-zero value, the search is terminated immediately and
    287  *              this value is returned to the caller.
    288  *
    289  *              The point of this procedure is to provide a generic namespace
    290  *              walk routine that can be called from multiple places to
    291  *              provide multiple services; the callback function(s) can be
    292  *              tailored to each task, whether it is a print function,
    293  *              a compare function, etc.
    294  *
    295  ******************************************************************************/
    296 
    297 ACPI_STATUS
    298 AcpiNsWalkNamespace (
    299     ACPI_OBJECT_TYPE        Type,
    300     ACPI_HANDLE             StartNode,
    301     UINT32                  MaxDepth,
    302     UINT32                  Flags,
    303     ACPI_WALK_CALLBACK      DescendingCallback,
    304     ACPI_WALK_CALLBACK      AscendingCallback,
    305     void                    *Context,
    306     void                    **ReturnValue)
    307 {
    308     ACPI_STATUS             Status;
    309     ACPI_STATUS             MutexStatus;
    310     ACPI_NAMESPACE_NODE     *ChildNode;
    311     ACPI_NAMESPACE_NODE     *ParentNode;
    312     ACPI_OBJECT_TYPE        ChildType;
    313     UINT32                  Level;
    314     BOOLEAN                 NodePreviouslyVisited = FALSE;
    315 
    316 
    317     ACPI_FUNCTION_TRACE (NsWalkNamespace);
    318 
    319 
    320     /* Special case for the namespace Root Node */
    321 
    322     if (StartNode == ACPI_ROOT_OBJECT)
    323     {
    324         StartNode = AcpiGbl_RootNode;
    325         if (!StartNode)
    326         {
    327             return_ACPI_STATUS (AE_NO_NAMESPACE);
    328         }
    329     }
    330 
    331     /* Null child means "get first node" */
    332 
    333     ParentNode = StartNode;
    334     ChildNode = AcpiNsGetNextNode (ParentNode, NULL);
    335     ChildType = ACPI_TYPE_ANY;
    336     Level = 1;
    337 
    338     /*
    339      * Traverse the tree of nodes until we bubble back up to where we
    340      * started. When Level is zero, the loop is done because we have
    341      * bubbled up to (and passed) the original parent handle (StartEntry)
    342      */
    343     while (Level > 0 && ChildNode)
    344     {
    345         Status = AE_OK;
    346 
    347         /* Found next child, get the type if we are not searching for ANY */
    348 
    349         if (Type != ACPI_TYPE_ANY)
    350         {
    351             ChildType = ChildNode->Type;
    352         }
    353 
    354         /*
    355          * Ignore all temporary namespace nodes (created during control
    356          * method execution) unless told otherwise. These temporary nodes
    357          * can cause a race condition because they can be deleted during
    358          * the execution of the user function (if the namespace is
    359          * unlocked before invocation of the user function.) Only the
    360          * debugger namespace dump will examine the temporary nodes.
    361          */
    362         if ((ChildNode->Flags & ANOBJ_TEMPORARY) &&
    363             !(Flags & ACPI_NS_WALK_TEMP_NODES))
    364         {
    365             Status = AE_CTRL_DEPTH;
    366         }
    367 
    368         /* Type must match requested type */
    369 
    370         else if (ChildType == Type)
    371         {
    372             /*
    373              * Found a matching node, invoke the user callback function.
    374              * Unlock the namespace if flag is set.
    375              */
    376             if (Flags & ACPI_NS_WALK_UNLOCK)
    377             {
    378                 MutexStatus = AcpiUtReleaseMutex (ACPI_MTX_NAMESPACE);
    379                 if (ACPI_FAILURE (MutexStatus))
    380                 {
    381                     return_ACPI_STATUS (MutexStatus);
    382                 }
    383             }
    384 
    385             /*
    386              * Invoke the user function, either descending, ascending,
    387              * or both.
    388              */
    389             if (!NodePreviouslyVisited)
    390             {
    391                 if (DescendingCallback)
    392                 {
    393                     Status = DescendingCallback (ChildNode, Level,
    394                         Context, ReturnValue);
    395                 }
    396             }
    397             else
    398             {
    399                 if (AscendingCallback)
    400                 {
    401                     Status = AscendingCallback (ChildNode, Level,
    402                         Context, ReturnValue);
    403                 }
    404             }
    405 
    406             if (Flags & ACPI_NS_WALK_UNLOCK)
    407             {
    408                 MutexStatus = AcpiUtAcquireMutex (ACPI_MTX_NAMESPACE);
    409                 if (ACPI_FAILURE (MutexStatus))
    410                 {
    411                     return_ACPI_STATUS (MutexStatus);
    412                 }
    413             }
    414 
    415             switch (Status)
    416             {
    417             case AE_OK:
    418             case AE_CTRL_DEPTH:
    419 
    420                 /* Just keep going */
    421                 break;
    422 
    423             case AE_CTRL_TERMINATE:
    424 
    425                 /* Exit now, with OK status */
    426 
    427                 return_ACPI_STATUS (AE_OK);
    428 
    429             default:
    430 
    431                 /* All others are valid exceptions */
    432 
    433                 return_ACPI_STATUS (Status);
    434             }
    435         }
    436 
    437         /*
    438          * Depth first search: Attempt to go down another level in the
    439          * namespace if we are allowed to. Don't go any further if we have
    440          * reached the caller specified maximum depth or if the user
    441          * function has specified that the maximum depth has been reached.
    442          */
    443         if (!NodePreviouslyVisited &&
    444             (Level < MaxDepth) &&
    445             (Status != AE_CTRL_DEPTH))
    446         {
    447             if (ChildNode->Child)
    448             {
    449                 /* There is at least one child of this node, visit it */
    450 
    451                 Level++;
    452                 ParentNode = ChildNode;
    453                 ChildNode = AcpiNsGetNextNode (ParentNode, NULL);
    454                 continue;
    455             }
    456         }
    457 
    458         /* No more children, re-visit this node */
    459 
    460         if (!NodePreviouslyVisited)
    461         {
    462             NodePreviouslyVisited = TRUE;
    463             continue;
    464         }
    465 
    466         /* No more children, visit peers */
    467 
    468         ChildNode = AcpiNsGetNextNode (ParentNode, ChildNode);
    469         if (ChildNode)
    470         {
    471             NodePreviouslyVisited = FALSE;
    472         }
    473 
    474         /* No peers, re-visit parent */
    475 
    476         else
    477         {
    478             /*
    479              * No more children of this node (AcpiNsGetNextNode failed), go
    480              * back upwards in the namespace tree to the node's parent.
    481              */
    482             Level--;
    483             ChildNode = ParentNode;
    484             ParentNode = ParentNode->Parent;
    485 
    486             NodePreviouslyVisited = TRUE;
    487         }
    488     }
    489 
    490     /* Complete walk, not terminated by user function */
    491 
    492     return_ACPI_STATUS (AE_OK);
    493 }
    494