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/*******************************************************************************

 *

 * Module Name: nssearch - Namespace search

 *

 ******************************************************************************/

/*

 * Copyright (C) 2000 - 2015, Intel Corp.

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions, and the following disclaimer,

 *    without modification.

 * 2. Redistributions in binary form must reproduce at minimum a disclaimer

 *    substantially similar to the "NO WARRANTY" disclaimer below

 *    ("Disclaimer") and any redistribution must be conditioned upon

 *    including a substantially similar Disclaimer requirement for further

 *    binary redistribution.

 * 3. Neither the names of the above-listed copyright holders nor the names

 *    of any contributors may be used to endorse or promote products derived

 *    from this software without specific prior written permission.

 *

 * Alternatively, this software may be distributed under the terms of the

 * GNU General Public License ("GPL") version 2 as published by the Free

 * Software Foundation.

 *

 * NO WARRANTY

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR

 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,

 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING

 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

 * POSSIBILITY OF SUCH DAMAGES.

 */

#include 

#include "accommon.h"

#include "acnamesp.h"

#ifdef ACPI_ASL_COMPILER

#include "amlcode.h"

#endif

#define _COMPONENT          ACPI_NAMESPACE

ACPI_MODULE_NAME("nssearch")

/* Local prototypes */

static acpi_status

acpi_ns_search_parent_tree(u32 target_name,

			   struct acpi_namespace_node *node,

			   acpi_object_type type,

			   struct acpi_namespace_node **return_node);

/*******************************************************************************

 *

 * FUNCTION:    acpi_ns_search_one_scope

 *

 * PARAMETERS:  target_name     - Ascii ACPI name to search for

 *              parent_node     - Starting node where search will begin

 *              type            - Object type to match

 *              return_node     - Where the matched Named obj is returned

 *

 * RETURN:      Status

 *

 * DESCRIPTION: Search a single level of the namespace. Performs a

 *              simple search of the specified level, and does not add

 *              entries or search parents.

 *

 *

 *      Named object lists are built (and subsequently dumped) in the

 *      order in which the names are encountered during the namespace load;

 *

 *      All namespace searching is linear in this implementation, but

 *      could be easily modified to support any improved search

 *      algorithm. However, the linear search was chosen for simplicity

 *      and because the trees are small and the other interpreter

 *      execution overhead is relatively high.

 *

 *      Note: CPU execution analysis has shown that the AML interpreter spends

 *      a very small percentage of its time searching the namespace. Therefore,

 *      the linear search seems to be sufficient, as there would seem to be

 *      little value in improving the search.

 *

 ******************************************************************************/

acpi_status

acpi_ns_search_one_scope(u32 target_name,

			 struct acpi_namespace_node *parent_node,

			 acpi_object_type type,

			 struct acpi_namespace_node **return_node)

{

	struct acpi_namespace_node *node;

	ACPI_FUNCTION_TRACE(ns_search_one_scope);

#ifdef ACPI_DEBUG_OUTPUT

	if (ACPI_LV_NAMES & acpi_dbg_level) {

		char *scope_name;

		scope_name = acpi_ns_get_external_pathname(parent_node);

		if (scope_name) {

			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,

					  "Searching %s (%p) For [%4.4s] (%s)\n",

					  scope_name, parent_node,

					  ACPI_CAST_PTR(char, &target_name),

					  acpi_ut_get_type_name(type)));

			ACPI_FREE(scope_name);

		}

	}

#endif

	/*

	 * Search for name at this namespace level, which is to say that we

	 * must search for the name among the children of this object

	 */

	node = parent_node->child;

	while (node) {

		/* Check for match against the name */

		if (node->name.integer == target_name) {

			/* Resolve a control method alias if any */

			if (acpi_ns_get_type(node) ==

			    ACPI_TYPE_LOCAL_METHOD_ALIAS) {

				node =

				    ACPI_CAST_PTR(struct acpi_namespace_node,

						  node->object);

			}

			/* Found matching entry */

			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,

					  "Name [%4.4s] (%s) %p found in scope [%4.4s] %p\n",

					  ACPI_CAST_PTR(char, &target_name),

					  acpi_ut_get_type_name(node->type),

					  node,

					  acpi_ut_get_node_name(parent_node),

					  parent_node));

			*return_node = node;

			return_ACPI_STATUS(AE_OK);

		}

		/* Didn't match name, move on to the next peer object */

		node = node->peer;

	}

	/* Searched entire namespace level, not found */

	ACPI_DEBUG_PRINT((ACPI_DB_NAMES,

			  "Name [%4.4s] (%s) not found in search in scope [%4.4s] "

			  "%p first child %p\n",

			  ACPI_CAST_PTR(char, &target_name),

			  acpi_ut_get_type_name(type),

			  acpi_ut_get_node_name(parent_node), parent_node,

			  parent_node->child));

	return_ACPI_STATUS(AE_NOT_FOUND);

}

/*******************************************************************************

 *

 * FUNCTION:    acpi_ns_search_parent_tree

 *

 * PARAMETERS:  target_name     - Ascii ACPI name to search for

 *              node            - Starting node where search will begin

 *              type            - Object type to match

 *              return_node     - Where the matched Node is returned

 *

 * RETURN:      Status

 *

 * DESCRIPTION: Called when a name has not been found in the current namespace

 *              level. Before adding it or giving up, ACPI scope rules require

 *              searching enclosing scopes in cases identified by acpi_ns_local().

 *

 *              "A name is located by finding the matching name in the current

 *              name space, and then in the parent name space. If the parent

 *              name space does not contain the name, the search continues

 *              recursively until either the name is found or the name space

 *              does not have a parent (the root of the name space). This

 *              indicates that the name is not found" (From ACPI Specification,

 *              section 5.3)

 *

 ******************************************************************************/

static acpi_status

acpi_ns_search_parent_tree(u32 target_name,

			   struct acpi_namespace_node *node,

			   acpi_object_type type,

			   struct acpi_namespace_node **return_node)

{

	acpi_status status;

	struct acpi_namespace_node *parent_node;

	ACPI_FUNCTION_TRACE(ns_search_parent_tree);

	parent_node = node->parent;

	/*

	 * If there is no parent (i.e., we are at the root) or type is "local",

	 * we won't be searching the parent tree.

	 */

	if (!parent_node) {

		ACPI_DEBUG_PRINT((ACPI_DB_NAMES, "[%4.4s] has no parent\n",

				  ACPI_CAST_PTR(char, &target_name)));

		return_ACPI_STATUS(AE_NOT_FOUND);

	}

	if (acpi_ns_local(type)) {

		ACPI_DEBUG_PRINT((ACPI_DB_NAMES,

				  "[%4.4s] type [%s] must be local to this scope (no parent search)\n",

				  ACPI_CAST_PTR(char, &target_name),

				  acpi_ut_get_type_name(type)));

		return_ACPI_STATUS(AE_NOT_FOUND);

	}

	/* Search the parent tree */

	ACPI_DEBUG_PRINT((ACPI_DB_NAMES,

			  "Searching parent [%4.4s] for [%4.4s]\n",

			  acpi_ut_get_node_name(parent_node),

			  ACPI_CAST_PTR(char, &target_name)));

	/* Search parents until target is found or we have backed up to the root */

	while (parent_node) {

		/*

		 * Search parent scope. Use TYPE_ANY because we don't care about the

		 * object type at this point, we only care about the existence of

		 * the actual name we are searching for. Typechecking comes later.

		 */

		status =

		    acpi_ns_search_one_scope(target_name, parent_node,

					     ACPI_TYPE_ANY, return_node);

		if (ACPI_SUCCESS(status)) {

			return_ACPI_STATUS(status);

		}

		/* Not found here, go up another level (until we reach the root) */

		parent_node = parent_node->parent;

	}

	/* Not found in parent tree */

	return_ACPI_STATUS(AE_NOT_FOUND);

}

/*******************************************************************************

 *

 * FUNCTION:    acpi_ns_search_and_enter

 *

 * PARAMETERS:  target_name         - Ascii ACPI name to search for (4 chars)

 *              walk_state          - Current state of the walk

 *              node                - Starting node where search will begin

 *              interpreter_mode    - Add names only in ACPI_MODE_LOAD_PASS_x.

 *                                    Otherwise,search only.

 *              type                - Object type to match

 *              flags               - Flags describing the search restrictions

 *              return_node         - Where the Node is returned

 *

 * RETURN:      Status

 *

 * DESCRIPTION: Search for a name segment in a single namespace level,

 *              optionally adding it if it is not found. If the passed

 *              Type is not Any and the type previously stored in the

 *              entry was Any (i.e. unknown), update the stored type.

 *

 *              In ACPI_IMODE_EXECUTE, search only.

 *              In other modes, search and add if not found.

 *

 ******************************************************************************/

acpi_status

acpi_ns_search_and_enter(u32 target_name,

			 struct acpi_walk_state *walk_state,

			 struct acpi_namespace_node *node,

			 acpi_interpreter_mode interpreter_mode,

			 acpi_object_type type,

			 u32 flags, struct acpi_namespace_node **return_node)

{

	acpi_status status;

	struct acpi_namespace_node *new_node;

	ACPI_FUNCTION_TRACE(ns_search_and_enter);

	/* Parameter validation */

	if (!node || !target_name || !return_node) {

		ACPI_ERROR((AE_INFO,

			    "Null parameter: Node %p Name 0x%X ReturnNode %p",

			    node, target_name, return_node));

		return_ACPI_STATUS(AE_BAD_PARAMETER);

	}

	/*

	 * Name must consist of valid ACPI characters. We will repair the name if

	 * necessary because we don't want to abort because of this, but we want

	 * all namespace names to be printable. A warning message is appropriate.

	 *

	 * This issue came up because there are in fact machines that exhibit

	 * this problem, and we want to be able to enable ACPI support for them,

	 * even though there are a few bad names.

	 */

	acpi_ut_repair_name(ACPI_CAST_PTR(char, &target_name));

	/* Try to find the name in the namespace level specified by the caller */

	*return_node = ACPI_ENTRY_NOT_FOUND;

	status = acpi_ns_search_one_scope(target_name, node, type, return_node);

	if (status != AE_NOT_FOUND) {

		/*

		 * If we found it AND the request specifies that a find is an error,

		 * return the error

		 */

		if (status == AE_OK) {

			/* The node was found in the namespace */

			/*

			 * If the namespace override feature is enabled for this node,

			 * delete any existing attached sub-object and make the node

			 * look like a new node that is owned by the override table.

			 */

			if (flags & ACPI_NS_OVERRIDE_IF_FOUND) {

				ACPI_DEBUG_PRINT((ACPI_DB_NAMES,

						  "Namespace override: %4.4s pass %u type %X Owner %X\n",

						  ACPI_CAST_PTR(char,

								&target_name),

						  interpreter_mode,

						  (*return_node)->type,

						  walk_state->owner_id));

				acpi_ns_delete_children(*return_node);

				if (acpi_gbl_runtime_namespace_override) {

					acpi_ut_remove_reference((*return_node)->object);

					(*return_node)->object = NULL;

					(*return_node)->owner_id =

					    walk_state->owner_id;

				} else {

					acpi_ns_remove_node(*return_node);

					*return_node = ACPI_ENTRY_NOT_FOUND;

				}

			}

			/* Return an error if we don't expect to find the object */

			else if (flags & ACPI_NS_ERROR_IF_FOUND) {

				status = AE_ALREADY_EXISTS;

			}

		}

#ifdef ACPI_ASL_COMPILER

		if (*return_node && (*return_node)->type == ACPI_TYPE_ANY) {

			(*return_node)->flags |= ANOBJ_IS_EXTERNAL;

		}

#endif

		/* Either found it or there was an error: finished either way */

		return_ACPI_STATUS(status);

	}

	/*

	 * The name was not found. If we are NOT performing the first pass

	 * (name entry) of loading the namespace, search the parent tree (all the

	 * way to the root if necessary.) We don't want to perform the parent

	 * search when the namespace is actually being loaded. We want to perform

	 * the search when namespace references are being resolved (load pass 2)

	 * and during the execution phase.

	 */

	if ((interpreter_mode != ACPI_IMODE_LOAD_PASS1) &&

	    (flags & ACPI_NS_SEARCH_PARENT)) {

		/*

		 * Not found at this level - search parent tree according to the

		 * ACPI specification

		 */

		status =

		    acpi_ns_search_parent_tree(target_name, node, type,

					       return_node);

		if (ACPI_SUCCESS(status)) {

			return_ACPI_STATUS(status);

		}

	}

	/* In execute mode, just search, never add names. Exit now */

	if (interpreter_mode == ACPI_IMODE_EXECUTE) {

		ACPI_DEBUG_PRINT((ACPI_DB_NAMES,

				  "%4.4s Not found in %p [Not adding]\n",

				  ACPI_CAST_PTR(char, &target_name), node));

		return_ACPI_STATUS(AE_NOT_FOUND);

	}

	/* Create the new named object */

	new_node = acpi_ns_create_node(target_name);

	if (!new_node) {

		return_ACPI_STATUS(AE_NO_MEMORY);

	}

#ifdef ACPI_ASL_COMPILER

	/* Node is an object defined by an External() statement */

	if (flags & ACPI_NS_EXTERNAL ||

	    (walk_state && walk_state->opcode == AML_SCOPE_OP)) {

		new_node->flags |= ANOBJ_IS_EXTERNAL;

	}

#endif

	if (flags & ACPI_NS_TEMPORARY) {

		new_node->flags |= ANOBJ_TEMPORARY;

	}

	/* Install the new object into the parent's list of children */

	acpi_ns_install_node(walk_state, node, new_node, type);

	*return_node = new_node;

	return_ACPI_STATUS(AE_OK);

}