xref: /linux/drivers/acpi/acpica/nsnames.c (revision e5c86679d5e864947a52fb31e45a425dea3e7fa9)
1 /*******************************************************************************
2  *
3  * Module Name: nsnames - Name manipulation and search
4  *
5  ******************************************************************************/
6 
7 /*
8  * Copyright (C) 2000 - 2017, 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 "amlcode.h"
47 #include "acnamesp.h"
48 
49 #define _COMPONENT          ACPI_NAMESPACE
50 ACPI_MODULE_NAME("nsnames")
51 
52 /*******************************************************************************
53  *
54  * FUNCTION:    acpi_ns_get_external_pathname
55  *
56  * PARAMETERS:  node            - Namespace node whose pathname is needed
57  *
58  * RETURN:      Pointer to storage containing the fully qualified name of
59  *              the node, In external format (name segments separated by path
60  *              separators.)
61  *
62  * DESCRIPTION: Used to obtain the full pathname to a namespace node, usually
63  *              for error and debug statements.
64  *
65  ******************************************************************************/
66 char *acpi_ns_get_external_pathname(struct acpi_namespace_node *node)
67 {
68 	char *name_buffer;
69 
70 	ACPI_FUNCTION_TRACE_PTR(ns_get_external_pathname, node);
71 
72 	name_buffer = acpi_ns_get_normalized_pathname(node, FALSE);
73 	return_PTR(name_buffer);
74 }
75 
76 /*******************************************************************************
77  *
78  * FUNCTION:    acpi_ns_get_pathname_length
79  *
80  * PARAMETERS:  node        - Namespace node
81  *
82  * RETURN:      Length of path, including prefix
83  *
84  * DESCRIPTION: Get the length of the pathname string for this node
85  *
86  ******************************************************************************/
87 
88 acpi_size acpi_ns_get_pathname_length(struct acpi_namespace_node *node)
89 {
90 	acpi_size size;
91 
92 	ACPI_FUNCTION_ENTRY();
93 
94 	size = acpi_ns_build_normalized_path(node, NULL, 0, FALSE);
95 	return (size);
96 }
97 
98 /*******************************************************************************
99  *
100  * FUNCTION:    acpi_ns_handle_to_name
101  *
102  * PARAMETERS:  target_handle           - Handle of named object whose name is
103  *                                        to be found
104  *              buffer                  - Where the name is returned
105  *
106  * RETURN:      Status, Buffer is filled with name if status is AE_OK
107  *
108  * DESCRIPTION: Build and return a full namespace name
109  *
110  ******************************************************************************/
111 
112 acpi_status
113 acpi_ns_handle_to_name(acpi_handle target_handle, struct acpi_buffer *buffer)
114 {
115 	acpi_status status;
116 	struct acpi_namespace_node *node;
117 	const char *node_name;
118 
119 	ACPI_FUNCTION_TRACE_PTR(ns_handle_to_name, target_handle);
120 
121 	node = acpi_ns_validate_handle(target_handle);
122 	if (!node) {
123 		return_ACPI_STATUS(AE_BAD_PARAMETER);
124 	}
125 
126 	/* Validate/Allocate/Clear caller buffer */
127 
128 	status = acpi_ut_initialize_buffer(buffer, ACPI_PATH_SEGMENT_LENGTH);
129 	if (ACPI_FAILURE(status)) {
130 		return_ACPI_STATUS(status);
131 	}
132 
133 	/* Just copy the ACPI name from the Node and zero terminate it */
134 
135 	node_name = acpi_ut_get_node_name(node);
136 	ACPI_MOVE_NAME(buffer->pointer, node_name);
137 	((char *)buffer->pointer)[ACPI_NAME_SIZE] = 0;
138 
139 	ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "%4.4s\n", (char *)buffer->pointer));
140 	return_ACPI_STATUS(AE_OK);
141 }
142 
143 /*******************************************************************************
144  *
145  * FUNCTION:    acpi_ns_handle_to_pathname
146  *
147  * PARAMETERS:  target_handle           - Handle of named object whose name is
148  *                                        to be found
149  *              buffer                  - Where the pathname is returned
150  *              no_trailing             - Remove trailing '_' for each name
151  *                                        segment
152  *
153  * RETURN:      Status, Buffer is filled with pathname if status is AE_OK
154  *
155  * DESCRIPTION: Build and return a full namespace pathname
156  *
157  ******************************************************************************/
158 
159 acpi_status
160 acpi_ns_handle_to_pathname(acpi_handle target_handle,
161 			   struct acpi_buffer *buffer, u8 no_trailing)
162 {
163 	acpi_status status;
164 	struct acpi_namespace_node *node;
165 	acpi_size required_size;
166 
167 	ACPI_FUNCTION_TRACE_PTR(ns_handle_to_pathname, target_handle);
168 
169 	node = acpi_ns_validate_handle(target_handle);
170 	if (!node) {
171 		return_ACPI_STATUS(AE_BAD_PARAMETER);
172 	}
173 
174 	/* Determine size required for the caller buffer */
175 
176 	required_size =
177 	    acpi_ns_build_normalized_path(node, NULL, 0, no_trailing);
178 	if (!required_size) {
179 		return_ACPI_STATUS(AE_BAD_PARAMETER);
180 	}
181 
182 	/* Validate/Allocate/Clear caller buffer */
183 
184 	status = acpi_ut_initialize_buffer(buffer, required_size);
185 	if (ACPI_FAILURE(status)) {
186 		return_ACPI_STATUS(status);
187 	}
188 
189 	/* Build the path in the caller buffer */
190 
191 	(void)acpi_ns_build_normalized_path(node, buffer->pointer,
192 					    required_size, no_trailing);
193 	if (ACPI_FAILURE(status)) {
194 		return_ACPI_STATUS(status);
195 	}
196 
197 	ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "%s [%X]\n",
198 			  (char *)buffer->pointer, (u32) required_size));
199 	return_ACPI_STATUS(AE_OK);
200 }
201 
202 /*******************************************************************************
203  *
204  * FUNCTION:    acpi_ns_build_normalized_path
205  *
206  * PARAMETERS:  node        - Namespace node
207  *              full_path   - Where the path name is returned
208  *              path_size   - Size of returned path name buffer
209  *              no_trailing - Remove trailing '_' from each name segment
210  *
211  * RETURN:      Return 1 if the AML path is empty, otherwise returning (length
212  *              of pathname + 1) which means the 'FullPath' contains a trailing
213  *              null.
214  *
215  * DESCRIPTION: Build and return a full namespace pathname.
216  *              Note that if the size of 'FullPath' isn't large enough to
217  *              contain the namespace node's path name, the actual required
218  *              buffer length is returned, and it should be greater than
219  *              'PathSize'. So callers are able to check the returning value
220  *              to determine the buffer size of 'FullPath'.
221  *
222  ******************************************************************************/
223 
224 u32
225 acpi_ns_build_normalized_path(struct acpi_namespace_node *node,
226 			      char *full_path, u32 path_size, u8 no_trailing)
227 {
228 	u32 length = 0, i;
229 	char name[ACPI_NAME_SIZE];
230 	u8 do_no_trailing;
231 	char c, *left, *right;
232 	struct acpi_namespace_node *next_node;
233 
234 	ACPI_FUNCTION_TRACE_PTR(ns_build_normalized_path, node);
235 
236 #define ACPI_PATH_PUT8(path, size, byte, length)    \
237 	do {                                            \
238 		if ((length) < (size))                      \
239 		{                                           \
240 			(path)[(length)] = (byte);              \
241 		}                                           \
242 		(length)++;                                 \
243 	} while (0)
244 
245 	/*
246 	 * Make sure the path_size is correct, so that we don't need to
247 	 * validate both full_path and path_size.
248 	 */
249 	if (!full_path) {
250 		path_size = 0;
251 	}
252 
253 	if (!node) {
254 		goto build_trailing_null;
255 	}
256 
257 	next_node = node;
258 	while (next_node && next_node != acpi_gbl_root_node) {
259 		if (next_node != node) {
260 			ACPI_PATH_PUT8(full_path, path_size,
261 				       AML_DUAL_NAME_PREFIX, length);
262 		}
263 
264 		ACPI_MOVE_32_TO_32(name, &next_node->name);
265 		do_no_trailing = no_trailing;
266 		for (i = 0; i < 4; i++) {
267 			c = name[4 - i - 1];
268 			if (do_no_trailing && c != '_') {
269 				do_no_trailing = FALSE;
270 			}
271 			if (!do_no_trailing) {
272 				ACPI_PATH_PUT8(full_path, path_size, c, length);
273 			}
274 		}
275 
276 		next_node = next_node->parent;
277 	}
278 
279 	ACPI_PATH_PUT8(full_path, path_size, AML_ROOT_PREFIX, length);
280 
281 	/* Reverse the path string */
282 
283 	if (length <= path_size) {
284 		left = full_path;
285 		right = full_path + length - 1;
286 
287 		while (left < right) {
288 			c = *left;
289 			*left++ = *right;
290 			*right-- = c;
291 		}
292 	}
293 
294 	/* Append the trailing null */
295 
296 build_trailing_null:
297 	ACPI_PATH_PUT8(full_path, path_size, '\0', length);
298 
299 #undef ACPI_PATH_PUT8
300 
301 	return_UINT32(length);
302 }
303 
304 /*******************************************************************************
305  *
306  * FUNCTION:    acpi_ns_get_normalized_pathname
307  *
308  * PARAMETERS:  node            - Namespace node whose pathname is needed
309  *              no_trailing     - Remove trailing '_' from each name segment
310  *
311  * RETURN:      Pointer to storage containing the fully qualified name of
312  *              the node, In external format (name segments separated by path
313  *              separators.)
314  *
315  * DESCRIPTION: Used to obtain the full pathname to a namespace node, usually
316  *              for error and debug statements. All trailing '_' will be
317  *              removed from the full pathname if 'NoTrailing' is specified..
318  *
319  ******************************************************************************/
320 
321 char *acpi_ns_get_normalized_pathname(struct acpi_namespace_node *node,
322 				      u8 no_trailing)
323 {
324 	char *name_buffer;
325 	acpi_size size;
326 
327 	ACPI_FUNCTION_TRACE_PTR(ns_get_normalized_pathname, node);
328 
329 	/* Calculate required buffer size based on depth below root */
330 
331 	size = acpi_ns_build_normalized_path(node, NULL, 0, no_trailing);
332 	if (!size) {
333 		return_PTR(NULL);
334 	}
335 
336 	/* Allocate a buffer to be returned to caller */
337 
338 	name_buffer = ACPI_ALLOCATE_ZEROED(size);
339 	if (!name_buffer) {
340 		ACPI_ERROR((AE_INFO, "Could not allocate %u bytes", (u32)size));
341 		return_PTR(NULL);
342 	}
343 
344 	/* Build the path in the allocated buffer */
345 
346 	(void)acpi_ns_build_normalized_path(node, name_buffer, size,
347 					    no_trailing);
348 
349 	return_PTR(name_buffer);
350 }
351