/*******************************************************************************
   *
   * Module Name: nsaccess - Top-level functions for accessing ACPI namespace
   *
   ******************************************************************************/
  
  /*
   * 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 <acpi/acpi.h>
  #include "accommon.h"
  #include "amlcode.h"
  #include "acnamesp.h"
  #include "acdispat.h"
  
  #define _COMPONENT          ACPI_NAMESPACE
  ACPI_MODULE_NAME("nsaccess")
  
  /*******************************************************************************
   *
   * FUNCTION:    acpi_ns_root_initialize
   *
   * PARAMETERS:  None
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Allocate and initialize the default root named objects
   *
   * MUTEX:       Locks namespace for entire execution
   *
   ******************************************************************************/
  acpi_status acpi_ns_root_initialize(void)
  {
  	acpi_status status;
  	const struct acpi_predefined_names *init_val = NULL;
  	struct acpi_namespace_node *new_node;
  	union acpi_operand_object *obj_desc;
  	acpi_string val = NULL;
  
  	ACPI_FUNCTION_TRACE(ns_root_initialize);
  
  	status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
  	if (ACPI_FAILURE(status)) {
  		return_ACPI_STATUS(status);
  	}
  
  	/*
  	 * The global root ptr is initially NULL, so a non-NULL value indicates
  	 * that acpi_ns_root_initialize() has already been called; just return.
  	 */
  	if (acpi_gbl_root_node) {
  		status = AE_OK;
  		goto unlock_and_exit;
  	}
  
  	/*
  	 * Tell the rest of the subsystem that the root is initialized
  	 * (This is OK because the namespace is locked)
  	 */
  	acpi_gbl_root_node = &acpi_gbl_root_node_struct;
  
  	/* Enter the pre-defined names in the name table */
  
  	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  			  "Entering predefined entries into namespace
  "));
  
  	for (init_val = acpi_gbl_pre_defined_names; init_val->name; init_val++) {
  
  		/* _OSI is optional for now, will be permanent later */
  
  		if (!strcmp(init_val->name, "_OSI")
  		    && !acpi_gbl_create_osi_method) {
  			continue;
  		}
  
  		status = acpi_ns_lookup(NULL, init_val->name, init_val->type,
  					ACPI_IMODE_LOAD_PASS2,
  					ACPI_NS_NO_UPSEARCH, NULL, &new_node);
  		if (ACPI_FAILURE(status)) {
  			ACPI_EXCEPTION((AE_INFO, status,
  					"Could not create predefined name %s",
  					init_val->name));
  			continue;
  		}
  
  		/*
  		 * Name entered successfully. If entry in pre_defined_names[] specifies
  		 * an initial value, create the initial value.
  		 */
  		if (init_val->val) {
  			status = acpi_os_predefined_override(init_val, &val);
  			if (ACPI_FAILURE(status)) {
  				ACPI_ERROR((AE_INFO,
  					    "Could not override predefined %s",
  					    init_val->name));
  			}
  
  			if (!val) {
  				val = init_val->val;
  			}
  
  			/*
  			 * Entry requests an initial value, allocate a
  			 * descriptor for it.
  			 */
  			obj_desc =
  			    acpi_ut_create_internal_object(init_val->type);
  			if (!obj_desc) {
  				status = AE_NO_MEMORY;
  				goto unlock_and_exit;
  			}
  
  			/*
  			 * Convert value string from table entry to
  			 * internal representation. Only types actually
  			 * used for initial values are implemented here.
  			 */
  			switch (init_val->type) {
  			case ACPI_TYPE_METHOD:
  
  				obj_desc->method.param_count =
  				    (u8) ACPI_TO_INTEGER(val);
  				obj_desc->common.flags |= AOPOBJ_DATA_VALID;
  
  #if defined (ACPI_ASL_COMPILER)
  
  				/* Save the parameter count for the iASL compiler */
  
  				new_node->value = obj_desc->method.param_count;
  #else
  				/* Mark this as a very SPECIAL method */
  
  				obj_desc->method.info_flags =
  				    ACPI_METHOD_INTERNAL_ONLY;
  				obj_desc->method.dispatch.implementation =
  				    acpi_ut_osi_implementation;
  #endif
  				break;
  
  			case ACPI_TYPE_INTEGER:
  
  				obj_desc->integer.value = ACPI_TO_INTEGER(val);
  				break;
  
  			case ACPI_TYPE_STRING:
  
  				/* Build an object around the static string */
  
  				obj_desc->string.length = (u32)strlen(val);
  				obj_desc->string.pointer = val;
  				obj_desc->common.flags |= AOPOBJ_STATIC_POINTER;
  				break;
  
  			case ACPI_TYPE_MUTEX:
  
  				obj_desc->mutex.node = new_node;
  				obj_desc->mutex.sync_level =
  				    (u8) (ACPI_TO_INTEGER(val) - 1);
  
  				/* Create a mutex */
  
  				status =
  				    acpi_os_create_mutex(&obj_desc->mutex.
  							 os_mutex);
  				if (ACPI_FAILURE(status)) {
  					acpi_ut_remove_reference(obj_desc);
  					goto unlock_and_exit;
  				}
  
  				/* Special case for ACPI Global Lock */
  
  				if (strcmp(init_val->name, "_GL_") == 0) {
  					acpi_gbl_global_lock_mutex = obj_desc;
  
  					/* Create additional counting semaphore for global lock */
  
  					status =
  					    acpi_os_create_semaphore(1, 0,
  								     &acpi_gbl_global_lock_semaphore);
  					if (ACPI_FAILURE(status)) {
  						acpi_ut_remove_reference
  						    (obj_desc);
  						goto unlock_and_exit;
  					}
  				}
  				break;
  
  			default:
  
  				ACPI_ERROR((AE_INFO,
  					    "Unsupported initial type value 0x%X",
  					    init_val->type));
  				acpi_ut_remove_reference(obj_desc);
  				obj_desc = NULL;
  				continue;
  			}
  
  			/* Store pointer to value descriptor in the Node */
  
  			status = acpi_ns_attach_object(new_node, obj_desc,
  						       obj_desc->common.type);
  
  			/* Remove local reference to the object */
  
  			acpi_ut_remove_reference(obj_desc);
  		}
  	}
  
  unlock_and_exit:
  	(void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
  
  	/* Save a handle to "_GPE", it is always present */
  
  	if (ACPI_SUCCESS(status)) {
  		status = acpi_ns_get_node(NULL, "\\_GPE", ACPI_NS_NO_UPSEARCH,
  					  &acpi_gbl_fadt_gpe_device);
  	}
  
  	return_ACPI_STATUS(status);
  }
  
  /*******************************************************************************
   *
   * FUNCTION:    acpi_ns_lookup
   *
   * PARAMETERS:  scope_info      - Current scope info block
   *              pathname        - Search pathname, in internal format
   *                                (as represented in the AML stream)
   *              type            - Type associated with name
   *              interpreter_mode - IMODE_LOAD_PASS2 => add name if not found
   *              flags           - Flags describing the search restrictions
   *              walk_state      - Current state of the walk
   *              return_node     - Where the Node is placed (if found
   *                                or created successfully)
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Find or enter the passed name in the name space.
   *              Log an error if name not found in Exec mode.
   *
   * MUTEX:       Assumes namespace is locked.
   *
   ******************************************************************************/
  
  acpi_status
  acpi_ns_lookup(union acpi_generic_state *scope_info,
  	       char *pathname,
  	       acpi_object_type type,
  	       acpi_interpreter_mode interpreter_mode,
  	       u32 flags,
  	       struct acpi_walk_state *walk_state,
  	       struct acpi_namespace_node **return_node)
  {
  	acpi_status status;
  	char *path = pathname;
  	struct acpi_namespace_node *prefix_node;
  	struct acpi_namespace_node *current_node = NULL;
  	struct acpi_namespace_node *this_node = NULL;
  	u32 num_segments;
  	u32 num_carats;
  	acpi_name simple_name;
  	acpi_object_type type_to_check_for;
  	acpi_object_type this_search_type;
  	u32 search_parent_flag = ACPI_NS_SEARCH_PARENT;
  	u32 local_flags;
  
  	ACPI_FUNCTION_TRACE(ns_lookup);
  
  	if (!return_node) {
  		return_ACPI_STATUS(AE_BAD_PARAMETER);
  	}
  
  	local_flags = flags &
  	    ~(ACPI_NS_ERROR_IF_FOUND | ACPI_NS_OVERRIDE_IF_FOUND |
  	      ACPI_NS_SEARCH_PARENT);
  	*return_node = ACPI_ENTRY_NOT_FOUND;
  	acpi_gbl_ns_lookup_count++;
  
  	if (!acpi_gbl_root_node) {
  		return_ACPI_STATUS(AE_NO_NAMESPACE);
  	}
  
  	/* Get the prefix scope. A null scope means use the root scope */
  
  	if ((!scope_info) || (!scope_info->scope.node)) {
  		ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
  				  "Null scope prefix, using root node (%p)
  ",
  				  acpi_gbl_root_node));
  
  		prefix_node = acpi_gbl_root_node;
  	} else {
  		prefix_node = scope_info->scope.node;
  		if (ACPI_GET_DESCRIPTOR_TYPE(prefix_node) !=
  		    ACPI_DESC_TYPE_NAMED) {
  			ACPI_ERROR((AE_INFO, "%p is not a namespace node [%s]",
  				    prefix_node,
  				    acpi_ut_get_descriptor_name(prefix_node)));
  			return_ACPI_STATUS(AE_AML_INTERNAL);
  		}
  
  		if (!(flags & ACPI_NS_PREFIX_IS_SCOPE)) {
  			/*
  			 * This node might not be a actual "scope" node (such as a
  			 * Device/Method, etc.)  It could be a Package or other object
  			 * node. Backup up the tree to find the containing scope node.
  			 */
  			while (!acpi_ns_opens_scope(prefix_node->type) &&
  			       prefix_node->type != ACPI_TYPE_ANY) {
  				prefix_node = prefix_node->parent;
  			}
  		}
  	}
  
  	/* Save type. TBD: may be no longer necessary */
  
  	type_to_check_for = type;
  
  	/*
  	 * Begin examination of the actual pathname
  	 */
  	if (!pathname) {
  
  		/* A Null name_path is allowed and refers to the root */
  
  		num_segments = 0;
  		this_node = acpi_gbl_root_node;
  		path = "";
  
  		ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
  				  "Null Pathname (Zero segments), Flags=%X
  ",
  				  flags));
  	} else {
  		/*
  		 * Name pointer is valid (and must be in internal name format)
  		 *
  		 * Check for scope prefixes:
  		 *
  		 * As represented in the AML stream, a namepath consists of an
  		 * optional scope prefix followed by a name segment part.
  		 *
  		 * If present, the scope prefix is either a Root Prefix (in
  		 * which case the name is fully qualified), or one or more
  		 * Parent Prefixes (in which case the name's scope is relative
  		 * to the current scope).
  		 */
  		if (*path == (u8) AML_ROOT_PREFIX) {
  
  			/* Pathname is fully qualified, start from the root */
  
  			this_node = acpi_gbl_root_node;
  			search_parent_flag = ACPI_NS_NO_UPSEARCH;
  
  			/* Point to name segment part */
  
  			path++;
  
  			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
  					  "Path is absolute from root [%p]
  ",
  					  this_node));
  		} else {
  			/* Pathname is relative to current scope, start there */
  
  			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
  					  "Searching relative to prefix scope [%4.4s] (%p)
  ",
  					  acpi_ut_get_node_name(prefix_node),
  					  prefix_node));
  
  			/*
  			 * Handle multiple Parent Prefixes (carat) by just getting
  			 * the parent node for each prefix instance.
  			 */
  			this_node = prefix_node;
  			num_carats = 0;
  			while (*path == (u8) AML_PARENT_PREFIX) {
  
  				/* Name is fully qualified, no search rules apply */
  
  				search_parent_flag = ACPI_NS_NO_UPSEARCH;
  
  				/*
  				 * Point past this prefix to the name segment
  				 * part or the next Parent Prefix
  				 */
  				path++;
  
  				/* Backup to the parent node */
  
  				num_carats++;
  				this_node = this_node->parent;
  				if (!this_node) {
  
  					/* Current scope has no parent scope */
  
  					ACPI_ERROR((AE_INFO,
  						    "%s: Path has too many parent prefixes (^) "
  						    "- reached beyond root node",
  						    pathname));
  					return_ACPI_STATUS(AE_NOT_FOUND);
  				}
  			}
  
  			if (search_parent_flag == ACPI_NS_NO_UPSEARCH) {
  				ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
  						  "Search scope is [%4.4s], path has %u carat(s)
  ",
  						  acpi_ut_get_node_name
  						  (this_node), num_carats));
  			}
  		}
  
  		/*
  		 * Determine the number of ACPI name segments in this pathname.
  		 *
  		 * The segment part consists of either:
  		 *  - A Null name segment (0)
  		 *  - A dual_name_prefix followed by two 4-byte name segments
  		 *  - A multi_name_prefix followed by a byte indicating the
  		 *      number of segments and the segments themselves.
  		 *  - A single 4-byte name segment
  		 *
  		 * Examine the name prefix opcode, if any, to determine the number of
  		 * segments.
  		 */
  		switch (*path) {
  		case 0:
  			/*
  			 * Null name after a root or parent prefixes. We already
  			 * have the correct target node and there are no name segments.
  			 */
  			num_segments = 0;
  			type = this_node->type;
  
  			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
  					  "Prefix-only Pathname (Zero name segments), Flags=%X
  ",
  					  flags));
  			break;
  
  		case AML_DUAL_NAME_PREFIX:
  
  			/* More than one name_seg, search rules do not apply */
  
  			search_parent_flag = ACPI_NS_NO_UPSEARCH;
  
  			/* Two segments, point to first name segment */
  
  			num_segments = 2;
  			path++;
  
  			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
  					  "Dual Pathname (2 segments, Flags=%X)
  ",
  					  flags));
  			break;
  
  		case AML_MULTI_NAME_PREFIX_OP:
  
  			/* More than one name_seg, search rules do not apply */
  
  			search_parent_flag = ACPI_NS_NO_UPSEARCH;
  
  			/* Extract segment count, point to first name segment */
  
  			path++;
  			num_segments = (u32) (u8) * path;
  			path++;
  
  			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
  					  "Multi Pathname (%u Segments, Flags=%X)
  ",
  					  num_segments, flags));
  			break;
  
  		default:
  			/*
  			 * Not a Null name, no Dual or Multi prefix, hence there is
  			 * only one name segment and Pathname is already pointing to it.
  			 */
  			num_segments = 1;
  
  			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
  					  "Simple Pathname (1 segment, Flags=%X)
  ",
  					  flags));
  			break;
  		}
  
  		ACPI_DEBUG_EXEC(acpi_ns_print_pathname(num_segments, path));
  	}
  
  	/*
  	 * Search namespace for each segment of the name. Loop through and
  	 * verify (or add to the namespace) each name segment.
  	 *
  	 * The object type is significant only at the last name
  	 * segment. (We don't care about the types along the path, only
  	 * the type of the final target object.)
  	 */
  	this_search_type = ACPI_TYPE_ANY;
  	current_node = this_node;
  	while (num_segments && current_node) {
  		num_segments--;
  		if (!num_segments) {
  
  			/* This is the last segment, enable typechecking */
  
  			this_search_type = type;
  
  			/*
  			 * Only allow automatic parent search (search rules) if the caller
  			 * requested it AND we have a single, non-fully-qualified name_seg
  			 */
  			if ((search_parent_flag != ACPI_NS_NO_UPSEARCH) &&
  			    (flags & ACPI_NS_SEARCH_PARENT)) {
  				local_flags |= ACPI_NS_SEARCH_PARENT;
  			}
  
  			/* Set error flag according to caller */
  
  			if (flags & ACPI_NS_ERROR_IF_FOUND) {
  				local_flags |= ACPI_NS_ERROR_IF_FOUND;
  			}
  
  			/* Set override flag according to caller */
  
  			if (flags & ACPI_NS_OVERRIDE_IF_FOUND) {
  				local_flags |= ACPI_NS_OVERRIDE_IF_FOUND;
  			}
  		}
  
  		/* Extract one ACPI name from the front of the pathname */
  
  		ACPI_MOVE_32_TO_32(&simple_name, path);
  
  		/* Try to find the single (4 character) ACPI name */
  
  		status =
  		    acpi_ns_search_and_enter(simple_name, walk_state,
  					     current_node, interpreter_mode,
  					     this_search_type, local_flags,
  					     &this_node);
  		if (ACPI_FAILURE(status)) {
  			if (status == AE_NOT_FOUND) {
  
  				/* Name not found in ACPI namespace */
  
  				ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
  						  "Name [%4.4s] not found in scope [%4.4s] %p
  ",
  						  (char *)&simple_name,
  						  (char *)&current_node->name,
  						  current_node));
  			}
  
  			*return_node = this_node;
  			return_ACPI_STATUS(status);
  		}
  
  		/* More segments to follow? */
  
  		if (num_segments > 0) {
  			/*
  			 * If we have an alias to an object that opens a scope (such as a
  			 * device or processor), we need to dereference the alias here so
  			 * that we can access any children of the original node (via the
  			 * remaining segments).
  			 */
  			if (this_node->type == ACPI_TYPE_LOCAL_ALIAS) {
  				if (!this_node->object) {
  					return_ACPI_STATUS(AE_NOT_EXIST);
  				}
  
  				if (acpi_ns_opens_scope
  				    (((struct acpi_namespace_node *)
  				      this_node->object)->type)) {
  					this_node =
  					    (struct acpi_namespace_node *)
  					    this_node->object;
  				}
  			}
  		}
  
  		/* Special handling for the last segment (num_segments == 0) */
  
  		else {
  			/*
  			 * Sanity typecheck of the target object:
  			 *
  			 * If 1) This is the last segment (num_segments == 0)
  			 *    2) And we are looking for a specific type
  			 *       (Not checking for TYPE_ANY)
  			 *    3) Which is not an alias
  			 *    4) Which is not a local type (TYPE_SCOPE)
  			 *    5) And the type of target object is known (not TYPE_ANY)
  			 *    6) And target object does not match what we are looking for
  			 *
  			 * Then we have a type mismatch. Just warn and ignore it.
  			 */
  			if ((type_to_check_for != ACPI_TYPE_ANY) &&
  			    (type_to_check_for != ACPI_TYPE_LOCAL_ALIAS) &&
  			    (type_to_check_for != ACPI_TYPE_LOCAL_METHOD_ALIAS)
  			    && (type_to_check_for != ACPI_TYPE_LOCAL_SCOPE)
  			    && (this_node->type != ACPI_TYPE_ANY)
  			    && (this_node->type != type_to_check_for)) {
  
  				/* Complain about a type mismatch */
  
  				ACPI_WARNING((AE_INFO,
  					      "NsLookup: Type mismatch on %4.4s (%s), searching for (%s)",
  					      ACPI_CAST_PTR(char, &simple_name),
  					      acpi_ut_get_type_name(this_node->
  								    type),
  					      acpi_ut_get_type_name
  					      (type_to_check_for)));
  			}
  
  			/*
  			 * If this is the last name segment and we are not looking for a
  			 * specific type, but the type of found object is known, use that
  			 * type to (later) see if it opens a scope.
  			 */
  			if (type == ACPI_TYPE_ANY) {
  				type = this_node->type;
  			}
  		}
  
  		/* Point to next name segment and make this node current */
  
  		path += ACPI_NAME_SIZE;
  		current_node = this_node;
  	}
  
  	/* Always check if we need to open a new scope */
  
  	if (!(flags & ACPI_NS_DONT_OPEN_SCOPE) && (walk_state)) {
  		/*
  		 * If entry is a type which opens a scope, push the new scope on the
  		 * scope stack.
  		 */
  		if (acpi_ns_opens_scope(type)) {
  			status =
  			    acpi_ds_scope_stack_push(this_node, type,
  						     walk_state);
  			if (ACPI_FAILURE(status)) {
  				return_ACPI_STATUS(status);
  			}
  		}
  	}
  
  	*return_node = this_node;
  	return_ACPI_STATUS(AE_OK);
  }