xref: /linux/drivers/acpi/acpica/nsnames.c (revision b7019ac550eb3916f34d79db583e9b7ea2524afa)
1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
2 /*******************************************************************************
3  *
4  * Module Name: nsnames - Name manipulation and search
5  *
6  ******************************************************************************/
7 
8 #include <acpi/acpi.h>
9 #include "accommon.h"
10 #include "amlcode.h"
11 #include "acnamesp.h"
12 
13 #define _COMPONENT          ACPI_NAMESPACE
14 ACPI_MODULE_NAME("nsnames")
15 
16 /* Local Prototypes */
17 static void acpi_ns_normalize_pathname(char *original_path);
18 
19 /*******************************************************************************
20  *
21  * FUNCTION:    acpi_ns_get_external_pathname
22  *
23  * PARAMETERS:  node            - Namespace node whose pathname is needed
24  *
25  * RETURN:      Pointer to storage containing the fully qualified name of
26  *              the node, In external format (name segments separated by path
27  *              separators.)
28  *
29  * DESCRIPTION: Used to obtain the full pathname to a namespace node, usually
30  *              for error and debug statements.
31  *
32  ******************************************************************************/
33 
34 char *acpi_ns_get_external_pathname(struct acpi_namespace_node *node)
35 {
36 	char *name_buffer;
37 
38 	ACPI_FUNCTION_TRACE_PTR(ns_get_external_pathname, node);
39 
40 	name_buffer = acpi_ns_get_normalized_pathname(node, FALSE);
41 	return_PTR(name_buffer);
42 }
43 
44 /*******************************************************************************
45  *
46  * FUNCTION:    acpi_ns_get_pathname_length
47  *
48  * PARAMETERS:  node        - Namespace node
49  *
50  * RETURN:      Length of path, including prefix
51  *
52  * DESCRIPTION: Get the length of the pathname string for this node
53  *
54  ******************************************************************************/
55 
56 acpi_size acpi_ns_get_pathname_length(struct acpi_namespace_node *node)
57 {
58 	acpi_size size;
59 
60 	/* Validate the Node */
61 
62 	if (ACPI_GET_DESCRIPTOR_TYPE(node) != ACPI_DESC_TYPE_NAMED) {
63 		ACPI_ERROR((AE_INFO,
64 			    "Invalid/cached reference target node: %p, descriptor type %d",
65 			    node, ACPI_GET_DESCRIPTOR_TYPE(node)));
66 		return (0);
67 	}
68 
69 	size = acpi_ns_build_normalized_path(node, NULL, 0, FALSE);
70 	return (size);
71 }
72 
73 /*******************************************************************************
74  *
75  * FUNCTION:    acpi_ns_handle_to_name
76  *
77  * PARAMETERS:  target_handle           - Handle of named object whose name is
78  *                                        to be found
79  *              buffer                  - Where the name is returned
80  *
81  * RETURN:      Status, Buffer is filled with name if status is AE_OK
82  *
83  * DESCRIPTION: Build and return a full namespace name
84  *
85  ******************************************************************************/
86 
87 acpi_status
88 acpi_ns_handle_to_name(acpi_handle target_handle, struct acpi_buffer *buffer)
89 {
90 	acpi_status status;
91 	struct acpi_namespace_node *node;
92 	const char *node_name;
93 
94 	ACPI_FUNCTION_TRACE_PTR(ns_handle_to_name, target_handle);
95 
96 	node = acpi_ns_validate_handle(target_handle);
97 	if (!node) {
98 		return_ACPI_STATUS(AE_BAD_PARAMETER);
99 	}
100 
101 	/* Validate/Allocate/Clear caller buffer */
102 
103 	status = acpi_ut_initialize_buffer(buffer, ACPI_PATH_SEGMENT_LENGTH);
104 	if (ACPI_FAILURE(status)) {
105 		return_ACPI_STATUS(status);
106 	}
107 
108 	/* Just copy the ACPI name from the Node and zero terminate it */
109 
110 	node_name = acpi_ut_get_node_name(node);
111 	ACPI_COPY_NAMESEG(buffer->pointer, node_name);
112 	((char *)buffer->pointer)[ACPI_NAMESEG_SIZE] = 0;
113 
114 	ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "%4.4s\n", (char *)buffer->pointer));
115 	return_ACPI_STATUS(AE_OK);
116 }
117 
118 /*******************************************************************************
119  *
120  * FUNCTION:    acpi_ns_handle_to_pathname
121  *
122  * PARAMETERS:  target_handle           - Handle of named object whose name is
123  *                                        to be found
124  *              buffer                  - Where the pathname is returned
125  *              no_trailing             - Remove trailing '_' for each name
126  *                                        segment
127  *
128  * RETURN:      Status, Buffer is filled with pathname if status is AE_OK
129  *
130  * DESCRIPTION: Build and return a full namespace pathname
131  *
132  ******************************************************************************/
133 
134 acpi_status
135 acpi_ns_handle_to_pathname(acpi_handle target_handle,
136 			   struct acpi_buffer *buffer, u8 no_trailing)
137 {
138 	acpi_status status;
139 	struct acpi_namespace_node *node;
140 	acpi_size required_size;
141 
142 	ACPI_FUNCTION_TRACE_PTR(ns_handle_to_pathname, target_handle);
143 
144 	node = acpi_ns_validate_handle(target_handle);
145 	if (!node) {
146 		return_ACPI_STATUS(AE_BAD_PARAMETER);
147 	}
148 
149 	/* Determine size required for the caller buffer */
150 
151 	required_size =
152 	    acpi_ns_build_normalized_path(node, NULL, 0, no_trailing);
153 	if (!required_size) {
154 		return_ACPI_STATUS(AE_BAD_PARAMETER);
155 	}
156 
157 	/* Validate/Allocate/Clear caller buffer */
158 
159 	status = acpi_ut_initialize_buffer(buffer, required_size);
160 	if (ACPI_FAILURE(status)) {
161 		return_ACPI_STATUS(status);
162 	}
163 
164 	/* Build the path in the caller buffer */
165 
166 	(void)acpi_ns_build_normalized_path(node, buffer->pointer,
167 					    required_size, no_trailing);
168 
169 	ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "%s [%X]\n",
170 			  (char *)buffer->pointer, (u32) required_size));
171 	return_ACPI_STATUS(AE_OK);
172 }
173 
174 /*******************************************************************************
175  *
176  * FUNCTION:    acpi_ns_build_normalized_path
177  *
178  * PARAMETERS:  node        - Namespace node
179  *              full_path   - Where the path name is returned
180  *              path_size   - Size of returned path name buffer
181  *              no_trailing - Remove trailing '_' from each name segment
182  *
183  * RETURN:      Return 1 if the AML path is empty, otherwise returning (length
184  *              of pathname + 1) which means the 'FullPath' contains a trailing
185  *              null.
186  *
187  * DESCRIPTION: Build and return a full namespace pathname.
188  *              Note that if the size of 'FullPath' isn't large enough to
189  *              contain the namespace node's path name, the actual required
190  *              buffer length is returned, and it should be greater than
191  *              'PathSize'. So callers are able to check the returning value
192  *              to determine the buffer size of 'FullPath'.
193  *
194  ******************************************************************************/
195 
196 u32
197 acpi_ns_build_normalized_path(struct acpi_namespace_node *node,
198 			      char *full_path, u32 path_size, u8 no_trailing)
199 {
200 	u32 length = 0, i;
201 	char name[ACPI_NAMESEG_SIZE];
202 	u8 do_no_trailing;
203 	char c, *left, *right;
204 	struct acpi_namespace_node *next_node;
205 
206 	ACPI_FUNCTION_TRACE_PTR(ns_build_normalized_path, node);
207 
208 #define ACPI_PATH_PUT8(path, size, byte, length)    \
209 	do {                                            \
210 		if ((length) < (size))                      \
211 		{                                           \
212 			(path)[(length)] = (byte);              \
213 		}                                           \
214 		(length)++;                                 \
215 	} while (0)
216 
217 	/*
218 	 * Make sure the path_size is correct, so that we don't need to
219 	 * validate both full_path and path_size.
220 	 */
221 	if (!full_path) {
222 		path_size = 0;
223 	}
224 
225 	if (!node) {
226 		goto build_trailing_null;
227 	}
228 
229 	next_node = node;
230 	while (next_node && next_node != acpi_gbl_root_node) {
231 		if (next_node != node) {
232 			ACPI_PATH_PUT8(full_path, path_size,
233 				       AML_DUAL_NAME_PREFIX, length);
234 		}
235 
236 		ACPI_MOVE_32_TO_32(name, &next_node->name);
237 		do_no_trailing = no_trailing;
238 		for (i = 0; i < 4; i++) {
239 			c = name[4 - i - 1];
240 			if (do_no_trailing && c != '_') {
241 				do_no_trailing = FALSE;
242 			}
243 			if (!do_no_trailing) {
244 				ACPI_PATH_PUT8(full_path, path_size, c, length);
245 			}
246 		}
247 
248 		next_node = next_node->parent;
249 	}
250 
251 	ACPI_PATH_PUT8(full_path, path_size, AML_ROOT_PREFIX, length);
252 
253 	/* Reverse the path string */
254 
255 	if (length <= path_size) {
256 		left = full_path;
257 		right = full_path + length - 1;
258 
259 		while (left < right) {
260 			c = *left;
261 			*left++ = *right;
262 			*right-- = c;
263 		}
264 	}
265 
266 	/* Append the trailing null */
267 
268 build_trailing_null:
269 	ACPI_PATH_PUT8(full_path, path_size, '\0', length);
270 
271 #undef ACPI_PATH_PUT8
272 
273 	return_UINT32(length);
274 }
275 
276 /*******************************************************************************
277  *
278  * FUNCTION:    acpi_ns_get_normalized_pathname
279  *
280  * PARAMETERS:  node            - Namespace node whose pathname is needed
281  *              no_trailing     - Remove trailing '_' from each name segment
282  *
283  * RETURN:      Pointer to storage containing the fully qualified name of
284  *              the node, In external format (name segments separated by path
285  *              separators.)
286  *
287  * DESCRIPTION: Used to obtain the full pathname to a namespace node, usually
288  *              for error and debug statements. All trailing '_' will be
289  *              removed from the full pathname if 'NoTrailing' is specified..
290  *
291  ******************************************************************************/
292 
293 char *acpi_ns_get_normalized_pathname(struct acpi_namespace_node *node,
294 				      u8 no_trailing)
295 {
296 	char *name_buffer;
297 	acpi_size size;
298 
299 	ACPI_FUNCTION_TRACE_PTR(ns_get_normalized_pathname, node);
300 
301 	/* Calculate required buffer size based on depth below root */
302 
303 	size = acpi_ns_build_normalized_path(node, NULL, 0, no_trailing);
304 	if (!size) {
305 		return_PTR(NULL);
306 	}
307 
308 	/* Allocate a buffer to be returned to caller */
309 
310 	name_buffer = ACPI_ALLOCATE_ZEROED(size);
311 	if (!name_buffer) {
312 		ACPI_ERROR((AE_INFO, "Could not allocate %u bytes", (u32)size));
313 		return_PTR(NULL);
314 	}
315 
316 	/* Build the path in the allocated buffer */
317 
318 	(void)acpi_ns_build_normalized_path(node, name_buffer, size,
319 					    no_trailing);
320 
321 	ACPI_DEBUG_PRINT_RAW((ACPI_DB_NAMES, "%s: Path \"%s\"\n",
322 			      ACPI_GET_FUNCTION_NAME, name_buffer));
323 
324 	return_PTR(name_buffer);
325 }
326 
327 /*******************************************************************************
328  *
329  * FUNCTION:    acpi_ns_build_prefixed_pathname
330  *
331  * PARAMETERS:  prefix_scope        - Scope/Path that prefixes the internal path
332  *              internal_path       - Name or path of the namespace node
333  *
334  * RETURN:      None
335  *
336  * DESCRIPTION: Construct a fully qualified pathname from a concatenation of:
337  *              1) Path associated with the prefix_scope namespace node
338  *              2) External path representation of the Internal path
339  *
340  ******************************************************************************/
341 
342 char *acpi_ns_build_prefixed_pathname(union acpi_generic_state *prefix_scope,
343 				      const char *internal_path)
344 {
345 	acpi_status status;
346 	char *full_path = NULL;
347 	char *external_path = NULL;
348 	char *prefix_path = NULL;
349 	u32 prefix_path_length = 0;
350 
351 	/* If there is a prefix, get the pathname to it */
352 
353 	if (prefix_scope && prefix_scope->scope.node) {
354 		prefix_path =
355 		    acpi_ns_get_normalized_pathname(prefix_scope->scope.node,
356 						    TRUE);
357 		if (prefix_path) {
358 			prefix_path_length = strlen(prefix_path);
359 		}
360 	}
361 
362 	status = acpi_ns_externalize_name(ACPI_UINT32_MAX, internal_path,
363 					  NULL, &external_path);
364 	if (ACPI_FAILURE(status)) {
365 		goto cleanup;
366 	}
367 
368 	/* Merge the prefix path and the path. 2 is for one dot and trailing null */
369 
370 	full_path =
371 	    ACPI_ALLOCATE_ZEROED(prefix_path_length + strlen(external_path) +
372 				 2);
373 	if (!full_path) {
374 		goto cleanup;
375 	}
376 
377 	/* Don't merge if the External path is already fully qualified */
378 
379 	if (prefix_path && (*external_path != '\\') && (*external_path != '^')) {
380 		strcat(full_path, prefix_path);
381 		if (prefix_path[1]) {
382 			strcat(full_path, ".");
383 		}
384 	}
385 
386 	acpi_ns_normalize_pathname(external_path);
387 	strcat(full_path, external_path);
388 
389 cleanup:
390 	if (prefix_path) {
391 		ACPI_FREE(prefix_path);
392 	}
393 	if (external_path) {
394 		ACPI_FREE(external_path);
395 	}
396 
397 	return (full_path);
398 }
399 
400 /*******************************************************************************
401  *
402  * FUNCTION:    acpi_ns_normalize_pathname
403  *
404  * PARAMETERS:  original_path       - Path to be normalized, in External format
405  *
406  * RETURN:      The original path is processed in-place
407  *
408  * DESCRIPTION: Remove trailing underscores from each element of a path.
409  *
410  *              For example:  \A___.B___.C___ becomes \A.B.C
411  *
412  ******************************************************************************/
413 
414 static void acpi_ns_normalize_pathname(char *original_path)
415 {
416 	char *input_path = original_path;
417 	char *new_path_buffer;
418 	char *new_path;
419 	u32 i;
420 
421 	/* Allocate a temp buffer in which to construct the new path */
422 
423 	new_path_buffer = ACPI_ALLOCATE_ZEROED(strlen(input_path) + 1);
424 	new_path = new_path_buffer;
425 	if (!new_path_buffer) {
426 		return;
427 	}
428 
429 	/* Special characters may appear at the beginning of the path */
430 
431 	if (*input_path == '\\') {
432 		*new_path = *input_path;
433 		new_path++;
434 		input_path++;
435 	}
436 
437 	while (*input_path == '^') {
438 		*new_path = *input_path;
439 		new_path++;
440 		input_path++;
441 	}
442 
443 	/* Remainder of the path */
444 
445 	while (*input_path) {
446 
447 		/* Do one nameseg at a time */
448 
449 		for (i = 0; (i < ACPI_NAMESEG_SIZE) && *input_path; i++) {
450 			if ((i == 0) || (*input_path != '_')) {	/* First char is allowed to be underscore */
451 				*new_path = *input_path;
452 				new_path++;
453 			}
454 
455 			input_path++;
456 		}
457 
458 		/* Dot means that there are more namesegs to come */
459 
460 		if (*input_path == '.') {
461 			*new_path = *input_path;
462 			new_path++;
463 			input_path++;
464 		}
465 	}
466 
467 	*new_path = 0;
468 	strcpy(original_path, new_path_buffer);
469 	ACPI_FREE(new_path_buffer);
470 }
471