xref: /openbmc/linux/drivers/acpi/acpica/nsnames.c (revision 7aacf86b)
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 
194 	ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "%s [%X]\n",
195 			  (char *)buffer->pointer, (u32) required_size));
196 	return_ACPI_STATUS(AE_OK);
197 }
198 
199 /*******************************************************************************
200  *
201  * FUNCTION:    acpi_ns_build_normalized_path
202  *
203  * PARAMETERS:  node        - Namespace node
204  *              full_path   - Where the path name is returned
205  *              path_size   - Size of returned path name buffer
206  *              no_trailing - Remove trailing '_' from each name segment
207  *
208  * RETURN:      Return 1 if the AML path is empty, otherwise returning (length
209  *              of pathname + 1) which means the 'FullPath' contains a trailing
210  *              null.
211  *
212  * DESCRIPTION: Build and return a full namespace pathname.
213  *              Note that if the size of 'FullPath' isn't large enough to
214  *              contain the namespace node's path name, the actual required
215  *              buffer length is returned, and it should be greater than
216  *              'PathSize'. So callers are able to check the returning value
217  *              to determine the buffer size of 'FullPath'.
218  *
219  ******************************************************************************/
220 
221 u32
222 acpi_ns_build_normalized_path(struct acpi_namespace_node *node,
223 			      char *full_path, u32 path_size, u8 no_trailing)
224 {
225 	u32 length = 0, i;
226 	char name[ACPI_NAME_SIZE];
227 	u8 do_no_trailing;
228 	char c, *left, *right;
229 	struct acpi_namespace_node *next_node;
230 
231 	ACPI_FUNCTION_TRACE_PTR(ns_build_normalized_path, node);
232 
233 #define ACPI_PATH_PUT8(path, size, byte, length)    \
234 	do {                                            \
235 		if ((length) < (size))                      \
236 		{                                           \
237 			(path)[(length)] = (byte);              \
238 		}                                           \
239 		(length)++;                                 \
240 	} while (0)
241 
242 	/*
243 	 * Make sure the path_size is correct, so that we don't need to
244 	 * validate both full_path and path_size.
245 	 */
246 	if (!full_path) {
247 		path_size = 0;
248 	}
249 
250 	if (!node) {
251 		goto build_trailing_null;
252 	}
253 
254 	next_node = node;
255 	while (next_node && next_node != acpi_gbl_root_node) {
256 		if (next_node != node) {
257 			ACPI_PATH_PUT8(full_path, path_size,
258 				       AML_DUAL_NAME_PREFIX, length);
259 		}
260 
261 		ACPI_MOVE_32_TO_32(name, &next_node->name);
262 		do_no_trailing = no_trailing;
263 		for (i = 0; i < 4; i++) {
264 			c = name[4 - i - 1];
265 			if (do_no_trailing && c != '_') {
266 				do_no_trailing = FALSE;
267 			}
268 			if (!do_no_trailing) {
269 				ACPI_PATH_PUT8(full_path, path_size, c, length);
270 			}
271 		}
272 
273 		next_node = next_node->parent;
274 	}
275 
276 	ACPI_PATH_PUT8(full_path, path_size, AML_ROOT_PREFIX, length);
277 
278 	/* Reverse the path string */
279 
280 	if (length <= path_size) {
281 		left = full_path;
282 		right = full_path + length - 1;
283 
284 		while (left < right) {
285 			c = *left;
286 			*left++ = *right;
287 			*right-- = c;
288 		}
289 	}
290 
291 	/* Append the trailing null */
292 
293 build_trailing_null:
294 	ACPI_PATH_PUT8(full_path, path_size, '\0', length);
295 
296 #undef ACPI_PATH_PUT8
297 
298 	return_UINT32(length);
299 }
300 
301 /*******************************************************************************
302  *
303  * FUNCTION:    acpi_ns_get_normalized_pathname
304  *
305  * PARAMETERS:  node            - Namespace node whose pathname is needed
306  *              no_trailing     - Remove trailing '_' from each name segment
307  *
308  * RETURN:      Pointer to storage containing the fully qualified name of
309  *              the node, In external format (name segments separated by path
310  *              separators.)
311  *
312  * DESCRIPTION: Used to obtain the full pathname to a namespace node, usually
313  *              for error and debug statements. All trailing '_' will be
314  *              removed from the full pathname if 'NoTrailing' is specified..
315  *
316  ******************************************************************************/
317 
318 char *acpi_ns_get_normalized_pathname(struct acpi_namespace_node *node,
319 				      u8 no_trailing)
320 {
321 	char *name_buffer;
322 	acpi_size size;
323 
324 	ACPI_FUNCTION_TRACE_PTR(ns_get_normalized_pathname, node);
325 
326 	/* Calculate required buffer size based on depth below root */
327 
328 	size = acpi_ns_build_normalized_path(node, NULL, 0, no_trailing);
329 	if (!size) {
330 		return_PTR(NULL);
331 	}
332 
333 	/* Allocate a buffer to be returned to caller */
334 
335 	name_buffer = ACPI_ALLOCATE_ZEROED(size);
336 	if (!name_buffer) {
337 		ACPI_ERROR((AE_INFO, "Could not allocate %u bytes", (u32)size));
338 		return_PTR(NULL);
339 	}
340 
341 	/* Build the path in the allocated buffer */
342 
343 	(void)acpi_ns_build_normalized_path(node, name_buffer, size,
344 					    no_trailing);
345 
346 	return_PTR(name_buffer);
347 }
348