linux/drivers/acpi/namespace/nsnames.c

/*******************************************************************************
 *
 * Module Name: nsnames - Name manipulation and search
 *
 ******************************************************************************/

/*
 * Copyright (C) 2000 - 2005, R. Byron Moore
 * 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 <acpi/amlcode.h>
#include <acpi/acnamesp.h>


#define _COMPONENT          ACPI_NAMESPACE
	 ACPI_MODULE_NAME    ("nsnames")

/* Local prototypes */

static void
acpi_ns_build_external_path (
	struct acpi_namespace_node      *node,
	acpi_size                       size,
	char                            *name_buffer);


/*******************************************************************************
 *
 * FUNCTION:    acpi_ns_build_external_path
 *
 * PARAMETERS:  Node            - NS node whose pathname is needed
 *              Size            - Size of the pathname
 *              *name_buffer    - Where to return the pathname
 *
 * RETURN:      Places the pathname into the name_buffer, in external format
 *              (name segments separated by path separators)
 *
 * DESCRIPTION: Generate a full pathaname
 *
 ******************************************************************************/

static void
acpi_ns_build_external_path (
	struct acpi_namespace_node      *node,
	acpi_size                       size,
	char                            *name_buffer)
{
	acpi_size                       index;
	struct acpi_namespace_node      *parent_node;


	ACPI_FUNCTION_NAME ("ns_build_external_path");


	/* Special case for root */

	index = size - 1;
	if (index < ACPI_NAME_SIZE) {
		name_buffer[0] = AML_ROOT_PREFIX;
		name_buffer[1] = 0;
		return;
	}

	/* Store terminator byte, then build name backwards */

	parent_node = node;
	name_buffer[index] = 0;

	while ((index > ACPI_NAME_SIZE) && (parent_node != acpi_gbl_root_node)) {
		index -= ACPI_NAME_SIZE;

		/* Put the name into the buffer */

		ACPI_MOVE_32_TO_32 ((name_buffer + index), &parent_node->name);
		parent_node = acpi_ns_get_parent_node (parent_node);

		/* Prefix name with the path separator */

		index--;
		name_buffer[index] = ACPI_PATH_SEPARATOR;
	}

	/* Overwrite final separator with the root prefix character */

	name_buffer[index] = AML_ROOT_PREFIX;

	if (index != 0) {
		ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
			"Could not construct pathname; index=%X, size=%X, Path=%s\n",
			(u32) index, (u32) size, &name_buffer[size]));
	}

	return;
}


#ifdef ACPI_DEBUG_OUTPUT
/*******************************************************************************
 *
 * FUNCTION:    acpi_ns_get_external_pathname
 *
 * PARAMETERS:  Node            - Namespace node whose pathname is needed
 *
 * RETURN:      Pointer to storage containing the fully qualified name of
 *              the node, In external format (name segments separated by path
 *              separators.)
 *
 * DESCRIPTION: Used for debug printing in acpi_ns_search_table().
 *
 ******************************************************************************/

char *
acpi_ns_get_external_pathname (
	struct acpi_namespace_node      *node)
{
	char                            *name_buffer;
	acpi_size                       size;


	ACPI_FUNCTION_TRACE_PTR ("ns_get_external_pathname", node);


	/* Calculate required buffer size based on depth below root */

	size = acpi_ns_get_pathname_length (node);

	/* Allocate a buffer to be returned to caller */

	name_buffer = ACPI_MEM_CALLOCATE (size);
	if (!name_buffer) {
		ACPI_REPORT_ERROR (("ns_get_table_pathname: allocation failure\n"));
		return_PTR (NULL);
	}

	/* Build the path in the allocated buffer */

	acpi_ns_build_external_path (node, size, name_buffer);
	return_PTR (name_buffer);
}
#endif


/*******************************************************************************
 *
 * FUNCTION:    acpi_ns_get_pathname_length
 *
 * PARAMETERS:  Node        - Namespace node
 *
 * RETURN:      Length of path, including prefix
 *
 * DESCRIPTION: Get the length of the pathname string for this node
 *
 ******************************************************************************/

acpi_size
acpi_ns_get_pathname_length (
	struct acpi_namespace_node      *node)
{
	acpi_size                       size;
	struct acpi_namespace_node      *next_node;


	ACPI_FUNCTION_ENTRY ();


	/*
	 * Compute length of pathname as 5 * number of name segments.
	 * Go back up the parent tree to the root
	 */
	size = 0;
	next_node = node;

	while (next_node && (next_node != acpi_gbl_root_node)) {
		size += ACPI_PATH_SEGMENT_LENGTH;
		next_node = acpi_ns_get_parent_node (next_node);
	}

	if (!size) {
		size = 1;       /* Root node case */
	}

	return (size + 1);  /* +1 for null string terminator */
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ns_handle_to_pathname
 *
 * PARAMETERS:  target_handle           - Handle of named object whose name is
 *                                        to be found
 *              Buffer                  - Where the pathname is returned
 *
 * RETURN:      Status, Buffer is filled with pathname if status is AE_OK
 *
 * DESCRIPTION: Build and return a full namespace pathname
 *
 ******************************************************************************/

acpi_status
acpi_ns_handle_to_pathname (
	acpi_handle                     target_handle,
	struct acpi_buffer              *buffer)
{
	acpi_status                     status;
	struct acpi_namespace_node      *node;
	acpi_size                       required_size;


	ACPI_FUNCTION_TRACE_PTR ("ns_handle_to_pathname", target_handle);


	node = acpi_ns_map_handle_to_node (target_handle);
	if (!node) {
		return_ACPI_STATUS (AE_BAD_PARAMETER);
	}

	/* Determine size required for the caller buffer */

	required_size = acpi_ns_get_pathname_length (node);

	/* Validate/Allocate/Clear caller buffer */

	status = acpi_ut_initialize_buffer (buffer, required_size);
	if (ACPI_FAILURE (status)) {
		return_ACPI_STATUS (status);
	}

	/* Build the path in the caller buffer */

	acpi_ns_build_external_path (node, required_size, buffer->pointer);

	ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "%s [%X] \n",
		(char *) buffer->pointer, (u32) required_size));
	return_ACPI_STATUS (AE_OK);
}