/*******************************************************************************
   *
   * Module Name: nssearch - Namespace search
   *
   ******************************************************************************/
  
  /*
   * Copyright (C) 2000 - 2013, 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 <acpi/acpi.h>
  #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)
  ",
  					  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
  ",
  					  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
  ",
  			  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
  ",
  				  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)
  ",
  				  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]
  ",
  			  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) && (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]
  ",
  				  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);
  }