linux/drivers/acpi/acpica/nsnames.c

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

/*
 * Copyright (C) 2000 - 2016, 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 "amlcode.h"
#include "acnamesp.h"

#define _COMPONENT          ACPI_NAMESPACE
ACPI_MODULE_NAME("nsnames")

/*******************************************************************************
 *
 * 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 to obtain the full pathname to a namespace node, usually
 *              for error and debug statements.
 *
 ******************************************************************************/
char *acpi_ns_get_external_pathname(struct acpi_namespace_node *node)
{
	char *name_buffer;

	ACPI_FUNCTION_TRACE_PTR(ns_get_external_pathname, node);

	name_buffer = acpi_ns_get_normalized_pathname(node, FALSE);
	return_PTR(name_buffer);
}

/*******************************************************************************
 *
 * 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;

	ACPI_FUNCTION_ENTRY();

	size = acpi_ns_build_normalized_path(node, NULL, 0, FALSE);
	return (size);
}

/*******************************************************************************
 *
 * 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
 *              no_trailing             - Remove trailing '_' for each name
 *                                        segment
 *
 * 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, u8 no_trailing)
{
	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_validate_handle(target_handle);
	if (!node) {
		return_ACPI_STATUS(AE_BAD_PARAMETER);
	}

	/* Determine size required for the caller buffer */

	required_size =
	    acpi_ns_build_normalized_path(node, NULL, 0, no_trailing);
	if (!required_size) {
		return_ACPI_STATUS(AE_BAD_PARAMETER);
	}

	/* 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 */

	(void)acpi_ns_build_normalized_path(node, buffer->pointer,
					    required_size, no_trailing);
	if (ACPI_FAILURE(status)) {
		return_ACPI_STATUS(status);
	}

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

/*******************************************************************************
 *
 * FUNCTION:    acpi_ns_build_normalized_path
 *
 * PARAMETERS:  node        - Namespace node
 *              full_path   - Where the path name is returned
 *              path_size   - Size of returned path name buffer
 *              no_trailing - Remove trailing '_' from each name segment
 *
 * RETURN:      Return 1 if the AML path is empty, otherwise returning (length
 *              of pathname + 1) which means the 'FullPath' contains a trailing
 *              null.
 *
 * DESCRIPTION: Build and return a full namespace pathname.
 *              Note that if the size of 'FullPath' isn't large enough to
 *              contain the namespace node's path name, the actual required
 *              buffer length is returned, and it should be greater than
 *              'PathSize'. So callers are able to check the returning value
 *              to determine the buffer size of 'FullPath'.
 *
 ******************************************************************************/

u32
acpi_ns_build_normalized_path(struct acpi_namespace_node *node,
			      char *full_path, u32 path_size, u8 no_trailing)
{
	u32 length = 0, i;
	char name[ACPI_NAME_SIZE];
	u8 do_no_trailing;
	char c, *left, *right;
	struct acpi_namespace_node *next_node;

	ACPI_FUNCTION_TRACE_PTR(ns_build_normalized_path, node);

#define ACPI_PATH_PUT8(path, size, byte, length)    \
	do {                                            \
		if ((length) < (size))                      \
		{                                           \
			(path)[(length)] = (byte);              \
		}                                           \
		(length)++;                                 \
	} while (0)

	/*
	 * Make sure the path_size is correct, so that we don't need to
	 * validate both full_path and path_size.
	 */
	if (!full_path) {
		path_size = 0;
	}

	if (!node) {
		goto build_trailing_null;
	}

	next_node = node;
	while (next_node && next_node != acpi_gbl_root_node) {
		if (next_node != node) {
			ACPI_PATH_PUT8(full_path, path_size,
				       AML_DUAL_NAME_PREFIX, length);
		}

		ACPI_MOVE_32_TO_32(name, &next_node->name);
		do_no_trailing = no_trailing;
		for (i = 0; i < 4; i++) {
			c = name[4 - i - 1];
			if (do_no_trailing && c != '_') {
				do_no_trailing = FALSE;
			}
			if (!do_no_trailing) {
				ACPI_PATH_PUT8(full_path, path_size, c, length);
			}
		}

		next_node = next_node->parent;
	}

	ACPI_PATH_PUT8(full_path, path_size, AML_ROOT_PREFIX, length);

	/* Reverse the path string */

	if (length <= path_size) {
		left = full_path;
		right = full_path + length - 1;

		while (left < right) {
			c = *left;
			*left++ = *right;
			*right-- = c;
		}
	}

	/* Append the trailing null */

build_trailing_null:
	ACPI_PATH_PUT8(full_path, path_size, '\0', length);

#undef ACPI_PATH_PUT8

	return_UINT32(length);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ns_get_normalized_pathname
 *
 * PARAMETERS:  node            - Namespace node whose pathname is needed
 *              no_trailing     - Remove trailing '_' from each name segment
 *
 * RETURN:      Pointer to storage containing the fully qualified name of
 *              the node, In external format (name segments separated by path
 *              separators.)
 *
 * DESCRIPTION: Used to obtain the full pathname to a namespace node, usually
 *              for error and debug statements. All trailing '_' will be
 *              removed from the full pathname if 'NoTrailing' is specified..
 *
 ******************************************************************************/

char *acpi_ns_get_normalized_pathname(struct acpi_namespace_node *node,
				      u8 no_trailing)
{
	char *name_buffer;
	acpi_size size;

	ACPI_FUNCTION_TRACE_PTR(ns_get_normalized_pathname, node);

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

	size = acpi_ns_build_normalized_path(node, NULL, 0, no_trailing);
	if (!size) {
		return_PTR(NULL);
	}

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

	name_buffer = ACPI_ALLOCATE_ZEROED(size);
	if (!name_buffer) {
		ACPI_ERROR((AE_INFO, "Could not allocate %u bytes", (u32)size));
		return_PTR(NULL);
	}

	/* Build the path in the allocated buffer */

	(void)acpi_ns_build_normalized_path(node, name_buffer, size,
					    no_trailing);

	return_PTR(name_buffer);
}