1/******************************************************************************
2 *
3 * Module Name: nswalk - Functions for walking the ACPI namespace
4 *
5 *****************************************************************************/
6
7/*
8 * Copyright (C) 2000 - 2015, Intel Corp.
9 * All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions, and the following disclaimer,
16 *    without modification.
17 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
18 *    substantially similar to the "NO WARRANTY" disclaimer below
19 *    ("Disclaimer") and any redistribution must be conditioned upon
20 *    including a substantially similar Disclaimer requirement for further
21 *    binary redistribution.
22 * 3. Neither the names of the above-listed copyright holders nor the names
23 *    of any contributors may be used to endorse or promote products derived
24 *    from this software without specific prior written permission.
25 *
26 * Alternatively, this software may be distributed under the terms of the
27 * GNU General Public License ("GPL") version 2 as published by the Free
28 * Software Foundation.
29 *
30 * NO WARRANTY
31 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
32 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
33 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
34 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
35 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
36 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
37 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
40 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
41 * POSSIBILITY OF SUCH DAMAGES.
42 */
43
44#include <acpi/acpi.h>
45#include "accommon.h"
46#include "acnamesp.h"
47
48#define _COMPONENT          ACPI_NAMESPACE
49ACPI_MODULE_NAME("nswalk")
50
51/*******************************************************************************
52 *
53 * FUNCTION:    acpi_ns_get_next_node
54 *
55 * PARAMETERS:  parent_node         - Parent node whose children we are
56 *                                    getting
57 *              child_node          - Previous child that was found.
58 *                                    The NEXT child will be returned
59 *
60 * RETURN:      struct acpi_namespace_node - Pointer to the NEXT child or NULL if
61 *                                    none is found.
62 *
63 * DESCRIPTION: Return the next peer node within the namespace. If Handle
64 *              is valid, Scope is ignored. Otherwise, the first node
65 *              within Scope is returned.
66 *
67 ******************************************************************************/
68struct acpi_namespace_node *acpi_ns_get_next_node(struct acpi_namespace_node
69						  *parent_node,
70						  struct acpi_namespace_node
71						  *child_node)
72{
73	ACPI_FUNCTION_ENTRY();
74
75	if (!child_node) {
76
77		/* It's really the parent's _scope_ that we want */
78
79		return (parent_node->child);
80	}
81
82	/* Otherwise just return the next peer */
83
84	return (child_node->peer);
85}
86
87/*******************************************************************************
88 *
89 * FUNCTION:    acpi_ns_get_next_node_typed
90 *
91 * PARAMETERS:  type                - Type of node to be searched for
92 *              parent_node         - Parent node whose children we are
93 *                                    getting
94 *              child_node          - Previous child that was found.
95 *                                    The NEXT child will be returned
96 *
97 * RETURN:      struct acpi_namespace_node - Pointer to the NEXT child or NULL if
98 *                                    none is found.
99 *
100 * DESCRIPTION: Return the next peer node within the namespace. If Handle
101 *              is valid, Scope is ignored. Otherwise, the first node
102 *              within Scope is returned.
103 *
104 ******************************************************************************/
105
106struct acpi_namespace_node *acpi_ns_get_next_node_typed(acpi_object_type type,
107							struct
108							acpi_namespace_node
109							*parent_node,
110							struct
111							acpi_namespace_node
112							*child_node)
113{
114	struct acpi_namespace_node *next_node = NULL;
115
116	ACPI_FUNCTION_ENTRY();
117
118	next_node = acpi_ns_get_next_node(parent_node, child_node);
119
120
121	/* If any type is OK, we are done */
122
123	if (type == ACPI_TYPE_ANY) {
124
125		/* next_node is NULL if we are at the end-of-list */
126
127		return (next_node);
128	}
129
130	/* Must search for the node -- but within this scope only */
131
132	while (next_node) {
133
134		/* If type matches, we are done */
135
136		if (next_node->type == type) {
137			return (next_node);
138		}
139
140		/* Otherwise, move on to the next peer node */
141
142		next_node = next_node->peer;
143	}
144
145	/* Not found */
146
147	return (NULL);
148}
149
150/*******************************************************************************
151 *
152 * FUNCTION:    acpi_ns_walk_namespace
153 *
154 * PARAMETERS:  type                - acpi_object_type to search for
155 *              start_node          - Handle in namespace where search begins
156 *              max_depth           - Depth to which search is to reach
157 *              flags               - Whether to unlock the NS before invoking
158 *                                    the callback routine
159 *              descending_callback - Called during tree descent
160 *                                    when an object of "Type" is found
161 *              ascending_callback  - Called during tree ascent
162 *                                    when an object of "Type" is found
163 *              context             - Passed to user function(s) above
164 *              return_value        - from the user_function if terminated
165 *                                    early. Otherwise, returns NULL.
166 * RETURNS:     Status
167 *
168 * DESCRIPTION: Performs a modified depth-first walk of the namespace tree,
169 *              starting (and ending) at the node specified by start_handle.
170 *              The callback function is called whenever a node that matches
171 *              the type parameter is found. If the callback function returns
172 *              a non-zero value, the search is terminated immediately and
173 *              this value is returned to the caller.
174 *
175 *              The point of this procedure is to provide a generic namespace
176 *              walk routine that can be called from multiple places to
177 *              provide multiple services; the callback function(s) can be
178 *              tailored to each task, whether it is a print function,
179 *              a compare function, etc.
180 *
181 ******************************************************************************/
182
183acpi_status
184acpi_ns_walk_namespace(acpi_object_type type,
185		       acpi_handle start_node,
186		       u32 max_depth,
187		       u32 flags,
188		       acpi_walk_callback descending_callback,
189		       acpi_walk_callback ascending_callback,
190		       void *context, void **return_value)
191{
192	acpi_status status;
193	acpi_status mutex_status;
194	struct acpi_namespace_node *child_node;
195	struct acpi_namespace_node *parent_node;
196	acpi_object_type child_type;
197	u32 level;
198	u8 node_previously_visited = FALSE;
199
200	ACPI_FUNCTION_TRACE(ns_walk_namespace);
201
202	/* Special case for the namespace Root Node */
203
204	if (start_node == ACPI_ROOT_OBJECT) {
205		start_node = acpi_gbl_root_node;
206	}
207
208	/* Null child means "get first node" */
209
210	parent_node = start_node;
211	child_node = acpi_ns_get_next_node(parent_node, NULL);
212	child_type = ACPI_TYPE_ANY;
213	level = 1;
214
215	/*
216	 * Traverse the tree of nodes until we bubble back up to where we
217	 * started. When Level is zero, the loop is done because we have
218	 * bubbled up to (and passed) the original parent handle (start_entry)
219	 */
220	while (level > 0 && child_node) {
221		status = AE_OK;
222
223		/* Found next child, get the type if we are not searching for ANY */
224
225		if (type != ACPI_TYPE_ANY) {
226			child_type = child_node->type;
227		}
228
229		/*
230		 * Ignore all temporary namespace nodes (created during control
231		 * method execution) unless told otherwise. These temporary nodes
232		 * can cause a race condition because they can be deleted during
233		 * the execution of the user function (if the namespace is
234		 * unlocked before invocation of the user function.) Only the
235		 * debugger namespace dump will examine the temporary nodes.
236		 */
237		if ((child_node->flags & ANOBJ_TEMPORARY) &&
238		    !(flags & ACPI_NS_WALK_TEMP_NODES)) {
239			status = AE_CTRL_DEPTH;
240		}
241
242		/* Type must match requested type */
243
244		else if (child_type == type) {
245			/*
246			 * Found a matching node, invoke the user callback function.
247			 * Unlock the namespace if flag is set.
248			 */
249			if (flags & ACPI_NS_WALK_UNLOCK) {
250				mutex_status =
251				    acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
252				if (ACPI_FAILURE(mutex_status)) {
253					return_ACPI_STATUS(mutex_status);
254				}
255			}
256
257			/*
258			 * Invoke the user function, either descending, ascending,
259			 * or both.
260			 */
261			if (!node_previously_visited) {
262				if (descending_callback) {
263					status =
264					    descending_callback(child_node,
265								level, context,
266								return_value);
267				}
268			} else {
269				if (ascending_callback) {
270					status =
271					    ascending_callback(child_node,
272							       level, context,
273							       return_value);
274				}
275			}
276
277			if (flags & ACPI_NS_WALK_UNLOCK) {
278				mutex_status =
279				    acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
280				if (ACPI_FAILURE(mutex_status)) {
281					return_ACPI_STATUS(mutex_status);
282				}
283			}
284
285			switch (status) {
286			case AE_OK:
287			case AE_CTRL_DEPTH:
288
289				/* Just keep going */
290				break;
291
292			case AE_CTRL_TERMINATE:
293
294				/* Exit now, with OK status */
295
296				return_ACPI_STATUS(AE_OK);
297
298			default:
299
300				/* All others are valid exceptions */
301
302				return_ACPI_STATUS(status);
303			}
304		}
305
306		/*
307		 * Depth first search: Attempt to go down another level in the
308		 * namespace if we are allowed to. Don't go any further if we have
309		 * reached the caller specified maximum depth or if the user
310		 * function has specified that the maximum depth has been reached.
311		 */
312		if (!node_previously_visited &&
313		    (level < max_depth) && (status != AE_CTRL_DEPTH)) {
314			if (child_node->child) {
315
316				/* There is at least one child of this node, visit it */
317
318				level++;
319				parent_node = child_node;
320				child_node =
321				    acpi_ns_get_next_node(parent_node, NULL);
322				continue;
323			}
324		}
325
326		/* No more children, re-visit this node */
327
328		if (!node_previously_visited) {
329			node_previously_visited = TRUE;
330			continue;
331		}
332
333		/* No more children, visit peers */
334
335		child_node = acpi_ns_get_next_node(parent_node, child_node);
336		if (child_node) {
337			node_previously_visited = FALSE;
338		}
339
340		/* No peers, re-visit parent */
341
342		else {
343			/*
344			 * No more children of this node (acpi_ns_get_next_node failed), go
345			 * back upwards in the namespace tree to the node's parent.
346			 */
347			level--;
348			child_node = parent_node;
349			parent_node = parent_node->parent;
350
351			node_previously_visited = TRUE;
352		}
353	}
354
355	/* Complete walk, not terminated by user function */
356
357	return_ACPI_STATUS(AE_OK);
358}
359