1 /******************************************************************************
2 *
3 * Module Name: nswalk - Functions for walking the ACPI namespace
4 *
5 *****************************************************************************/
6
7 /*
8 * Copyright (C) 2000 - 2016, 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
49 ACPI_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 ******************************************************************************/
acpi_ns_get_next_node(struct acpi_namespace_node * parent_node,struct acpi_namespace_node * child_node)68 struct 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
acpi_ns_get_next_node_typed(acpi_object_type type,struct acpi_namespace_node * parent_node,struct acpi_namespace_node * child_node)106 struct 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
183 acpi_status
acpi_ns_walk_namespace(acpi_object_type type,acpi_handle start_node,u32 max_depth,u32 flags,acpi_walk_callback descending_callback,acpi_walk_callback ascending_callback,void * context,void ** return_value)184 acpi_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