nssearch.c

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/*******************************************************************************
 *
 * Module Name: nssearch - Namespace search
 *              $Revision: 62 $
 *
 ******************************************************************************/

/*
 *  Copyright (C) 2000 R. Byron Moore
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */


#include "acpi.h"
#include "amlcode.h"
#include "acinterp.h"
#include "acnamesp.h"


#define _COMPONENT          NAMESPACE
	 MODULE_NAME         ("nssearch")


/*******************************************************************************
 *
 * FUNCTION:    Acpi_ns_search_node
 *
 * PARAMETERS:  *Target_name        - Ascii ACPI name to search for
 *              *Node           - Starting table where search will begin
 *              Type                - Object type to match
 *              **Return_node   - Where the matched Named obj is returned
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Search a single namespace table.  Performs a simple search,
 *              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.
 *
 ******************************************************************************/

ACPI_STATUS
acpi_ns_search_node (
	u32                     target_name,
	ACPI_NAMESPACE_NODE     *node,
	OBJECT_TYPE_INTERNAL    type,
	ACPI_NAMESPACE_NODE     **return_node)
{
	ACPI_NAMESPACE_NODE     *next_node;




	/*
	 * Search for name in this table, which is to say that we must search
	 * for the name among the children of this object
	 */

	next_node = node->child;
	while (next_node) {
		/* Check for match against the name */

		if (next_node->name == target_name) {
			/*
			 * Found matching entry.  Capture type if
			 * appropriate before returning the entry.
			 */

			/*
			 * The Def_field_defn and Bank_field_defn cases
			 * are actually looking up the Region in which
			 * the field will be defined
			 */

			if ((INTERNAL_TYPE_DEF_FIELD_DEFN == type) ||
				(INTERNAL_TYPE_BANK_FIELD_DEFN == type))
			{
				type = ACPI_TYPE_REGION;
			}

			/*
			 * Scope, Def_any, and Index_field_defn are bogus
			 * "types" which do not actually have anything
			 * to do with the type of the name being looked
			 * up.  For any other value of Type, if the type
			 * stored in the entry is Any (i.e. unknown),
			 * save the actual type.
			 */

			if (type != INTERNAL_TYPE_SCOPE &&
				type != INTERNAL_TYPE_DEF_ANY &&
				type != INTERNAL_TYPE_INDEX_FIELD_DEFN &&
				next_node->type == ACPI_TYPE_ANY)
			{
				next_node->type = (u8) type;
			}

			*return_node = next_node;
			return (AE_OK);
		}


		/*
		 * The last entry in the list points back to the parent,
		 * so a flag is used to indicate the end-of-list
		 */
		if (next_node->flags & ANOBJ_END_OF_PEER_LIST) {
			/* Searched entire list, we are done */

			break;
		}

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

		next_node = next_node->peer;
	}


	/* Searched entire table, not found */


	return (AE_NOT_FOUND);
}


/*******************************************************************************
 *
 * FUNCTION:    Acpi_ns_search_parent_tree
 *
 * PARAMETERS:  *Target_name        - Ascii ACPI name to search for
 *              *Node           - Starting table where search will begin
 *              Type                - Object type to match
 *              **Return_node   - Where the matched Named Obj is returned
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Called when a name has not been found in the current namespace
 *              table.  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,
	ACPI_NAMESPACE_NODE     *node,
	OBJECT_TYPE_INTERNAL    type,
	ACPI_NAMESPACE_NODE     **return_node)
{
	ACPI_STATUS             status;
	ACPI_NAMESPACE_NODE     *parent_node;


	parent_node = acpi_ns_get_parent_object (node);

	/*
	 * If there is no parent (at the root) or type is "local", we won't be
	 * searching the parent tree.
	 */
	if ((acpi_ns_local (type))  ||
		(!parent_node))
	{


		return (AE_NOT_FOUND);
	}


	/* Search the parent tree */

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

	while (parent_node) {
		/* Search parent scope */
		/* TBD: [Investigate] Why ACPI_TYPE_ANY? */

		status = acpi_ns_search_node (target_name, parent_node,
				   ACPI_TYPE_ANY, return_node);

		if (ACPI_SUCCESS (status)) {
			return (status);
		}

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

		parent_node = acpi_ns_get_parent_object (parent_node);
	}


	/* Not found in parent tree */

	return (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 table where search will begin
 *              Interpreter_mode    - Add names only in 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 name table,
 *              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 IMODE_EXECUTE, search only.
 *              In other modes, search and add if not found.
 *
 ******************************************************************************/

ACPI_STATUS
acpi_ns_search_and_enter (
	u32                     target_name,
	ACPI_WALK_STATE         *walk_state,
	ACPI_NAMESPACE_NODE     *node,
	OPERATING_MODE          interpreter_mode,
	OBJECT_TYPE_INTERNAL    type,
	u32                     flags,
	ACPI_NAMESPACE_NODE     **return_node)
{
	ACPI_STATUS             status;
	ACPI_NAMESPACE_NODE     *new_node;


	/* Parameter validation */

	if (!node || !target_name || !return_node) {
		REPORT_ERROR (("Ns_search_and_enter: bad (null) parameter\n"));
		return (AE_BAD_PARAMETER);
	}


	/* Name must consist of printable characters */

	if (!acpi_cm_valid_acpi_name (target_name)) {
		REPORT_ERROR (("Ns_search_and_enter: Bad character in ACPI Name\n"));
		return (AE_BAD_CHARACTER);
	}


	/* Try to find the name in the table specified by the caller */

	*return_node = ENTRY_NOT_FOUND;
	status = acpi_ns_search_node (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 & NS_ERROR_IF_FOUND))
		{
			status = AE_EXIST;
		}

		/*
		 * Either found it or there was an error
		 * -- finished either way
		 */
		return (status);
	}


	/*
	 * Not found in the table.  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 != IMODE_LOAD_PASS1) &&
		(flags & NS_SEARCH_PARENT))
	{
		/*
		 * Not found in table - search parent tree according
		 * to ACPI specification
		 */

		status = acpi_ns_search_parent_tree (target_name, node,
				 type, return_node);
		if (ACPI_SUCCESS (status)) {
			return (status);
		}
	}


	/*
	 * In execute mode, just search, never add names.  Exit now.
	 */
	if (interpreter_mode == IMODE_EXECUTE) {
		return (AE_NOT_FOUND);
	}


	/* Create the new named object */

	new_node = acpi_ns_create_node (target_name);
	if (!new_node) {
		return (AE_NO_MEMORY);
	}

	/* 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 (AE_OK);
}