nswalk.c

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/******************************************************************************
 *
 * Module Name: nswalk - Functions for walking the ACPI namespace
 *
 *****************************************************************************/

/******************************************************************************
 *
 * 1. Copyright Notice
 *
 * Some or all of this work - Copyright (c) 1999 - 2011, Intel Corp.
 * All rights reserved.
 *
 * 2. License
 *
 * 2.1. This is your license from Intel Corp. under its intellectual property
 * rights.  You may have additional license terms from the party that provided
 * you this software, covering your right to use that party's intellectual
 * property rights.
 *
 * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
 * copy of the source code appearing in this file ("Covered Code") an
 * irrevocable, perpetual, worldwide license under Intel's copyrights in the
 * base code distributed originally by Intel ("Original Intel Code") to copy,
 * make derivatives, distribute, use and display any portion of the Covered
 * Code in any form, with the right to sublicense such rights; and
 *
 * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
 * license (with the right to sublicense), under only those claims of Intel
 * patents that are infringed by the Original Intel Code, to make, use, sell,
 * offer to sell, and import the Covered Code and derivative works thereof
 * solely to the minimum extent necessary to exercise the above copyright
 * license, and in no event shall the patent license extend to any additions
 * to or modifications of the Original Intel Code.  No other license or right
 * is granted directly or by implication, estoppel or otherwise;
 *
 * The above copyright and patent license is granted only if the following
 * conditions are met:
 *
 * 3. Conditions
 *
 * 3.1. Redistribution of Source with Rights to Further Distribute Source.
 * Redistribution of source code of any substantial portion of the Covered
 * Code or modification with rights to further distribute source must include
 * the above Copyright Notice, the above License, this list of Conditions,
 * and the following Disclaimer and Export Compliance provision.  In addition,
 * Licensee must cause all Covered Code to which Licensee contributes to
 * contain a file documenting the changes Licensee made to create that Covered
 * Code and the date of any change.  Licensee must include in that file the
 * documentation of any changes made by any predecessor Licensee.  Licensee
 * must include a prominent statement that the modification is derived,
 * directly or indirectly, from Original Intel Code.
 *
 * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
 * Redistribution of source code of any substantial portion of the Covered
 * Code or modification without rights to further distribute source must
 * include the following Disclaimer and Export Compliance provision in the
 * documentation and/or other materials provided with distribution.  In
 * addition, Licensee may not authorize further sublicense of source of any
 * portion of the Covered Code, and must include terms to the effect that the
 * license from Licensee to its licensee is limited to the intellectual
 * property embodied in the software Licensee provides to its licensee, and
 * not to intellectual property embodied in modifications its licensee may
 * make.
 *
 * 3.3. Redistribution of Executable. Redistribution in executable form of any
 * substantial portion of the Covered Code or modification must reproduce the
 * above Copyright Notice, and the following Disclaimer and Export Compliance
 * provision in the documentation and/or other materials provided with the
 * distribution.
 *
 * 3.4. Intel retains all right, title, and interest in and to the Original
 * Intel Code.
 *
 * 3.5. Neither the name Intel nor any other trademark owned or controlled by
 * Intel shall be used in advertising or otherwise to promote the sale, use or
 * other dealings in products derived from or relating to the Covered Code
 * without prior written authorization from Intel.
 *
 * 4. Disclaimer and Export Compliance
 *
 * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
 * HERE.  ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
 * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT,  ASSISTANCE,
 * INSTALLATION, TRAINING OR OTHER SERVICES.  INTEL WILL NOT PROVIDE ANY
 * UPDATES, ENHANCEMENTS OR EXTENSIONS.  INTEL SPECIFICALLY DISCLAIMS ANY
 * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
 * PARTICULAR PURPOSE.
 *
 * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
 * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
 * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
 * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
 * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
 * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.  THESE LIMITATIONS
 * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
 * LIMITED REMEDY.
 *
 * 4.3. Licensee shall not export, either directly or indirectly, any of this
 * software or system incorporating such software without first obtaining any
 * required license or other approval from the U. S. Department of Commerce or
 * any other agency or department of the United States Government.  In the
 * event Licensee exports any such software from the United States or
 * re-exports any such software from a foreign destination, Licensee shall
 * ensure that the distribution and export/re-export of the software is in
 * compliance with all laws, regulations, orders, or other restrictions of the
 * U.S. Export Administration Regulations. Licensee agrees that neither it nor
 * any of its subsidiaries will export/re-export any technical data, process,
 * software, or service, directly or indirectly, to any country for which the
 * United States government or any agency thereof requires an export license,
 * other governmental approval, or letter of assurance, without first obtaining
 * such license, approval or letter.
 *
 *****************************************************************************/


#define __NSWALK_C__

#include "acpi.h"
#include "accommon.h"
#include "acnamesp.h"


#define _COMPONENT          ACPI_NAMESPACE
        ACPI_MODULE_NAME    ("nswalk")


/*******************************************************************************
 *
 * FUNCTION:    AcpiNsGetNextNode
 *
 * PARAMETERS:  ParentNode          - Parent node whose children we are
 *                                    getting
 *              ChildNode           - Previous child that was found.
 *                                    The NEXT child will be returned
 *
 * RETURN:      ACPI_NAMESPACE_NODE - Pointer to the NEXT child or NULL if
 *                                    none is found.
 *
 * DESCRIPTION: Return the next peer node within the namespace.  If Handle
 *              is valid, Scope is ignored.  Otherwise, the first node
 *              within Scope is returned.
 *
 ******************************************************************************/

ACPI_NAMESPACE_NODE *
AcpiNsGetNextNode (
    ACPI_NAMESPACE_NODE     *ParentNode,
    ACPI_NAMESPACE_NODE     *ChildNode)
{
    ACPI_FUNCTION_ENTRY ();


    if (!ChildNode)
    {
        /* It's really the parent's _scope_ that we want */

        return (ParentNode->Child);
    }

    /* Otherwise just return the next peer */

    return (ChildNode->Peer);
}


/*******************************************************************************
 *
 * FUNCTION:    AcpiNsGetNextNodeTyped
 *
 * PARAMETERS:  Type                - Type of node to be searched for
 *              ParentNode          - Parent node whose children we are
 *                                    getting
 *              ChildNode           - Previous child that was found.
 *                                    The NEXT child will be returned
 *
 * RETURN:      ACPI_NAMESPACE_NODE - Pointer to the NEXT child or NULL if
 *                                    none is found.
 *
 * DESCRIPTION: Return the next peer node within the namespace.  If Handle
 *              is valid, Scope is ignored.  Otherwise, the first node
 *              within Scope is returned.
 *
 ******************************************************************************/

ACPI_NAMESPACE_NODE *
AcpiNsGetNextNodeTyped (
    ACPI_OBJECT_TYPE        Type,
    ACPI_NAMESPACE_NODE     *ParentNode,
    ACPI_NAMESPACE_NODE     *ChildNode)
{
    ACPI_NAMESPACE_NODE     *NextNode = NULL;


    ACPI_FUNCTION_ENTRY ();


    NextNode = AcpiNsGetNextNode (ParentNode, ChildNode);

    /* If any type is OK, we are done */

    if (Type == ACPI_TYPE_ANY)
    {
        /* NextNode is NULL if we are at the end-of-list */

        return (NextNode);
    }

    /* Must search for the node -- but within this scope only */

    while (NextNode)
    {
        /* If type matches, we are done */

        if (NextNode->Type == Type)
        {
            return (NextNode);
        }

        /* Otherwise, move on to the next peer node */

        NextNode = NextNode->Peer;
    }

    /* Not found */

    return (NULL);
}


/*******************************************************************************
 *
 * FUNCTION:    AcpiNsWalkNamespace
 *
 * PARAMETERS:  Type                - ACPI_OBJECT_TYPE to search for
 *              StartNode           - Handle in namespace where search begins
 *              MaxDepth            - Depth to which search is to reach
 *              Flags               - Whether to unlock the NS before invoking
 *                                    the callback routine
 *              PreOrderVisit       - Called during tree pre-order visit
 *                                    when an object of "Type" is found
 *              PostOrderVisit      - Called during tree post-order visit
 *                                    when an object of "Type" is found
 *              Context             - Passed to user function(s) above
 *              ReturnValue         - from the UserFunction if terminated
 *                                    early. Otherwise, returns NULL.
 * RETURNS:     Status
 *
 * DESCRIPTION: Performs a modified depth-first walk of the namespace tree,
 *              starting (and ending) at the node specified by StartHandle.
 *              The callback function is called whenever a node that matches
 *              the type parameter is found. If the callback function returns
 *              a non-zero value, the search is terminated immediately and
 *              this value is returned to the caller.
 *
 *              The point of this procedure is to provide a generic namespace
 *              walk routine that can be called from multiple places to
 *              provide multiple services; the callback function(s) can be
 *              tailored to each task, whether it is a print function,
 *              a compare function, etc.
 *
 ******************************************************************************/

ACPI_STATUS
AcpiNsWalkNamespace (
    ACPI_OBJECT_TYPE        Type,
    ACPI_HANDLE             StartNode,
    UINT32                  MaxDepth,
    UINT32                  Flags,
    ACPI_WALK_CALLBACK      PreOrderVisit,
    ACPI_WALK_CALLBACK      PostOrderVisit,
    void                    *Context,
    void                    **ReturnValue)
{
    ACPI_STATUS             Status;
    ACPI_STATUS             MutexStatus;
    ACPI_NAMESPACE_NODE     *ChildNode;
    ACPI_NAMESPACE_NODE     *ParentNode;
    ACPI_OBJECT_TYPE        ChildType;
    UINT32                  Level;
    BOOLEAN                 NodePreviouslyVisited = FALSE;


    ACPI_FUNCTION_TRACE (NsWalkNamespace);


    /* Special case for the namespace Root Node */

    if (StartNode == ACPI_ROOT_OBJECT)
    {
        StartNode = AcpiGbl_RootNode;
    }

    /* Null child means "get first node" */

    ParentNode  = StartNode;
    ChildNode   = AcpiNsGetNextNode (ParentNode, NULL);
    ChildType   = ACPI_TYPE_ANY;
    Level       = 1;

    /*
     * Traverse the tree of nodes until we bubble back up to where we
     * started. When Level is zero, the loop is done because we have
     * bubbled up to (and passed) the original parent handle (StartEntry)
     */
    while (Level > 0 && ChildNode)
    {
        Status = AE_OK;

        /* Found next child, get the type if we are not searching for ANY */

        if (Type != ACPI_TYPE_ANY)
        {
            ChildType = ChildNode->Type;
        }

        /*
         * Ignore all temporary namespace nodes (created during control
         * method execution) unless told otherwise. These temporary nodes
         * can cause a race condition because they can be deleted during
         * the execution of the user function (if the namespace is
         * unlocked before invocation of the user function.) Only the
         * debugger namespace dump will examine the temporary nodes.
         */
        if ((ChildNode->Flags & ANOBJ_TEMPORARY) &&
            !(Flags & ACPI_NS_WALK_TEMP_NODES))
        {
            Status = AE_CTRL_DEPTH;
        }

        /* Type must match requested type */

        else if (ChildType == Type)
        {
            /*
             * Found a matching node, invoke the user callback function.
             * Unlock the namespace if flag is set.
             */
            if (Flags & ACPI_NS_WALK_UNLOCK)
            {
                MutexStatus = AcpiUtReleaseMutex (ACPI_MTX_NAMESPACE);
                if (ACPI_FAILURE (MutexStatus))
                {
                    return_ACPI_STATUS (MutexStatus);
                }
            }

            /*
             * Invoke the user function, either pre-order or post-order
             * or both.
             */
            if (!NodePreviouslyVisited)
            {
                if (PreOrderVisit)
                {
                    Status = PreOrderVisit (ChildNode, Level,
                                Context, ReturnValue);
                }
            }
            else
            {
                if (PostOrderVisit)
                {
                    Status = PostOrderVisit (ChildNode, Level,
                                Context, ReturnValue);
                }
            }

            if (Flags & ACPI_NS_WALK_UNLOCK)
            {
                MutexStatus = AcpiUtAcquireMutex (ACPI_MTX_NAMESPACE);
                if (ACPI_FAILURE (MutexStatus))
                {
                    return_ACPI_STATUS (MutexStatus);
                }
            }

            switch (Status)
            {
            case AE_OK:
            case AE_CTRL_DEPTH:

                /* Just keep going */
                break;

            case AE_CTRL_TERMINATE:

                /* Exit now, with OK status */

                return_ACPI_STATUS (AE_OK);

            default:

                /* All others are valid exceptions */

                return_ACPI_STATUS (Status);
            }
        }

        /*
         * Depth first search: Attempt to go down another level in the
         * namespace if we are allowed to.  Don't go any further if we have
         * reached the caller specified maximum depth or if the user
         * function has specified that the maximum depth has been reached.
         */
        if (!NodePreviouslyVisited &&
            (Level < MaxDepth) &&
            (Status != AE_CTRL_DEPTH))
        {
            if (ChildNode->Child)
            {
                /* There is at least one child of this node, visit it */

                Level++;
                ParentNode = ChildNode;
                ChildNode = AcpiNsGetNextNode (ParentNode, NULL);
                continue;
            }
        }

        /* No more children, re-visit this node */

        if (!NodePreviouslyVisited)
        {
            NodePreviouslyVisited = TRUE;
            continue;
        }

        /* No more children, visit peers */

        ChildNode = AcpiNsGetNextNode (ParentNode, ChildNode);
        if (ChildNode)
        {
            NodePreviouslyVisited = FALSE;
        }

        /* No peers, re-visit parent */

        else
        {
            /*
             * No more children of this node (AcpiNsGetNextNode failed), go
             * back upwards in the namespace tree to the node's parent.
             */
            Level--;
            ChildNode = ParentNode;
            ParentNode = ParentNode->Parent;

            NodePreviouslyVisited = TRUE;
        }
    }

    /* Complete walk, not terminated by user function */

    return_ACPI_STATUS (AE_OK);
}