1// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
2/******************************************************************************
3 *
4 * Module Name: exnames - interpreter/scanner name load/execute
5 *
6 * Copyright (C) 2000 - 2025, Intel Corp.
7 *
8 *****************************************************************************/
9
10#include <acpi/acpi.h>
11#include "accommon.h"
12#include "acinterp.h"
13#include "amlcode.h"
14
15#define _COMPONENT ACPI_EXECUTER
16ACPI_MODULE_NAME("exnames")
17
18/* Local prototypes */
19static char *acpi_ex_allocate_name_string(u32 prefix_count, u32 num_name_segs);
20
21static acpi_status acpi_ex_name_segment(u8 **in_aml_address, char *name_string);
22
23/*******************************************************************************
24 *
25 * FUNCTION: acpi_ex_allocate_name_string
26 *
27 * PARAMETERS: prefix_count - Count of parent levels. Special cases:
28 * (-1)==root, 0==none
29 * num_name_segs - count of 4-character name segments
30 *
31 * RETURN: A pointer to the allocated string segment. This segment must
32 * be deleted by the caller.
33 *
34 * DESCRIPTION: Allocate a buffer for a name string. Ensure allocated name
35 * string is long enough, and set up prefix if any.
36 *
37 ******************************************************************************/
38
39static char *acpi_ex_allocate_name_string(u32 prefix_count, u32 num_name_segs)
40{
41 char *temp_ptr;
42 char *name_string;
43 u32 size_needed;
44
45 ACPI_FUNCTION_TRACE(ex_allocate_name_string);
46
47 /*
48 * Allow room for all \ and ^ prefixes, all segments and a multi_name_prefix.
49 * Also, one byte for the null terminator.
50 * This may actually be somewhat longer than needed.
51 */
52 if (prefix_count == ACPI_UINT32_MAX) {
53
54 /* Special case for root */
55
56 size_needed = 1 + (ACPI_NAMESEG_SIZE * num_name_segs) + 2 + 1;
57 } else {
58 size_needed =
59 prefix_count + (ACPI_NAMESEG_SIZE * num_name_segs) + 2 + 1;
60 }
61
62 /*
63 * Allocate a buffer for the name.
64 * This buffer must be deleted by the caller!
65 */
66 name_string = ACPI_ALLOCATE(size_needed);
67 if (!name_string) {
68 ACPI_ERROR((AE_INFO,
69 "Could not allocate size %u", size_needed));
70 return_PTR(NULL);
71 }
72
73 temp_ptr = name_string;
74
75 /* Set up Root or Parent prefixes if needed */
76
77 if (prefix_count == ACPI_UINT32_MAX) {
78 *temp_ptr++ = AML_ROOT_PREFIX;
79 } else {
80 while (prefix_count--) {
81 *temp_ptr++ = AML_PARENT_PREFIX;
82 }
83 }
84
85 /* Set up Dual or Multi prefixes if needed */
86
87 if (num_name_segs > 2) {
88
89 /* Set up multi prefixes */
90
91 *temp_ptr++ = AML_MULTI_NAME_PREFIX;
92 *temp_ptr++ = (char)num_name_segs;
93 } else if (2 == num_name_segs) {
94
95 /* Set up dual prefixes */
96
97 *temp_ptr++ = AML_DUAL_NAME_PREFIX;
98 }
99
100 /*
101 * Terminate string following prefixes. acpi_ex_name_segment() will
102 * append the segment(s)
103 */
104 *temp_ptr = 0;
105
106 return_PTR(name_string);
107}
108
109/*******************************************************************************
110 *
111 * FUNCTION: acpi_ex_name_segment
112 *
113 * PARAMETERS: in_aml_address - Pointer to the name in the AML code
114 * name_string - Where to return the name. The name is appended
115 * to any existing string to form a namepath
116 *
117 * RETURN: Status
118 *
119 * DESCRIPTION: Extract an ACPI name (4 bytes) from the AML byte stream
120 *
121 ******************************************************************************/
122
123static acpi_status acpi_ex_name_segment(u8 ** in_aml_address, char *name_string)
124{
125 char *aml_address = (void *)*in_aml_address;
126 acpi_status status = AE_OK;
127 u32 index;
128 char char_buf[5];
129
130 ACPI_FUNCTION_TRACE(ex_name_segment);
131
132 /*
133 * If first character is a digit, then we know that we aren't looking
134 * at a valid name segment
135 */
136 char_buf[0] = *aml_address;
137
138 if ('0' <= char_buf[0] && char_buf[0] <= '9') {
139 ACPI_ERROR((AE_INFO, "Invalid leading digit: %c", char_buf[0]));
140 return_ACPI_STATUS(AE_CTRL_PENDING);
141 }
142
143 for (index = 0;
144 (index < ACPI_NAMESEG_SIZE)
145 && (acpi_ut_valid_name_char(character: *aml_address, position: 0)); index++) {
146 char_buf[index] = *aml_address++;
147 }
148
149 /* Valid name segment */
150
151 if (index == 4) {
152
153 /* Found 4 valid characters */
154
155 char_buf[4] = '\0';
156
157 if (name_string) {
158 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
159 "Appending NameSeg %s\n", char_buf));
160 strcat(name_string, char_buf);
161 } else {
162 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
163 "No Name string - %s\n", char_buf));
164 }
165 } else if (index == 0) {
166 /*
167 * First character was not a valid name character,
168 * so we are looking at something other than a name.
169 */
170 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
171 "Leading character is not alpha: %02Xh (not a name)\n",
172 char_buf[0]));
173 status = AE_CTRL_PENDING;
174 } else {
175 /*
176 * Segment started with one or more valid characters, but fewer than
177 * the required 4
178 */
179 status = AE_AML_BAD_NAME;
180 ACPI_ERROR((AE_INFO,
181 "Bad character 0x%02x in name, at %p",
182 *aml_address, aml_address));
183 }
184
185 *in_aml_address = ACPI_CAST_PTR(u8, aml_address);
186 return_ACPI_STATUS(status);
187}
188
189/*******************************************************************************
190 *
191 * FUNCTION: acpi_ex_get_name_string
192 *
193 * PARAMETERS: data_type - Object type to be associated with this
194 * name
195 * in_aml_address - Pointer to the namestring in the AML code
196 * out_name_string - Where the namestring is returned
197 * out_name_length - Length of the returned string
198 *
199 * RETURN: Status, namestring and length
200 *
201 * DESCRIPTION: Extract a full namepath from the AML byte stream,
202 * including any prefixes.
203 *
204 ******************************************************************************/
205
206acpi_status
207acpi_ex_get_name_string(acpi_object_type data_type,
208 u8 * in_aml_address,
209 char **out_name_string, u32 * out_name_length)
210{
211 acpi_status status = AE_OK;
212 u8 *aml_address = in_aml_address;
213 char *name_string = NULL;
214 u32 num_segments;
215 u32 prefix_count = 0;
216 u8 has_prefix = FALSE;
217
218 ACPI_FUNCTION_TRACE_PTR(ex_get_name_string, aml_address);
219
220 if (ACPI_TYPE_LOCAL_REGION_FIELD == data_type ||
221 ACPI_TYPE_LOCAL_BANK_FIELD == data_type ||
222 ACPI_TYPE_LOCAL_INDEX_FIELD == data_type) {
223
224 /* Disallow prefixes for types associated with field_unit names */
225
226 name_string = acpi_ex_allocate_name_string(prefix_count: 0, num_name_segs: 1);
227 if (!name_string) {
228 status = AE_NO_MEMORY;
229 } else {
230 status =
231 acpi_ex_name_segment(in_aml_address: &aml_address, name_string);
232 }
233 } else {
234 /*
235 * data_type is not a field name.
236 * Examine first character of name for root or parent prefix operators
237 */
238 switch (*aml_address) {
239 case AML_ROOT_PREFIX:
240
241 ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
242 "RootPrefix(\\) at %p\n",
243 aml_address));
244
245 /*
246 * Remember that we have a root_prefix --
247 * see comment in acpi_ex_allocate_name_string()
248 */
249 aml_address++;
250 prefix_count = ACPI_UINT32_MAX;
251 has_prefix = TRUE;
252 break;
253
254 case AML_PARENT_PREFIX:
255
256 /* Increment past possibly multiple parent prefixes */
257
258 do {
259 ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
260 "ParentPrefix (^) at %p\n",
261 aml_address));
262
263 aml_address++;
264 prefix_count++;
265
266 } while (*aml_address == AML_PARENT_PREFIX);
267
268 has_prefix = TRUE;
269 break;
270
271 default:
272
273 /* Not a prefix character */
274
275 break;
276 }
277
278 /* Examine first character of name for name segment prefix operator */
279
280 switch (*aml_address) {
281 case AML_DUAL_NAME_PREFIX:
282
283 ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
284 "DualNamePrefix at %p\n",
285 aml_address));
286
287 aml_address++;
288 name_string =
289 acpi_ex_allocate_name_string(prefix_count, num_name_segs: 2);
290 if (!name_string) {
291 status = AE_NO_MEMORY;
292 break;
293 }
294
295 /* Indicate that we processed a prefix */
296
297 has_prefix = TRUE;
298
299 status =
300 acpi_ex_name_segment(in_aml_address: &aml_address, name_string);
301 if (ACPI_SUCCESS(status)) {
302 status =
303 acpi_ex_name_segment(in_aml_address: &aml_address,
304 name_string);
305 }
306 break;
307
308 case AML_MULTI_NAME_PREFIX:
309
310 ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
311 "MultiNamePrefix at %p\n",
312 aml_address));
313
314 /* Fetch count of segments remaining in name path */
315
316 aml_address++;
317 num_segments = *aml_address;
318
319 name_string =
320 acpi_ex_allocate_name_string(prefix_count,
321 num_name_segs: num_segments);
322 if (!name_string) {
323 status = AE_NO_MEMORY;
324 break;
325 }
326
327 /* Indicate that we processed a prefix */
328
329 aml_address++;
330 has_prefix = TRUE;
331
332 while (num_segments &&
333 (status =
334 acpi_ex_name_segment(in_aml_address: &aml_address,
335 name_string)) == AE_OK) {
336 num_segments--;
337 }
338
339 break;
340
341 case 0:
342
343 /* null_name valid as of 8-12-98 ASL/AML Grammar Update */
344
345 if (prefix_count == ACPI_UINT32_MAX) {
346 ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
347 "NameSeg is \"\\\" followed by NULL\n"));
348 }
349
350 /* Consume the NULL byte */
351
352 aml_address++;
353 name_string =
354 acpi_ex_allocate_name_string(prefix_count, num_name_segs: 0);
355 if (!name_string) {
356 status = AE_NO_MEMORY;
357 break;
358 }
359
360 break;
361
362 default:
363
364 /* Name segment string */
365
366 name_string =
367 acpi_ex_allocate_name_string(prefix_count, num_name_segs: 1);
368 if (!name_string) {
369 status = AE_NO_MEMORY;
370 break;
371 }
372
373 status =
374 acpi_ex_name_segment(in_aml_address: &aml_address, name_string);
375 break;
376 }
377 }
378
379 if (AE_CTRL_PENDING == status && has_prefix) {
380
381 /* Ran out of segments after processing a prefix */
382
383 ACPI_ERROR((AE_INFO, "Malformed Name at %p", name_string));
384 status = AE_AML_BAD_NAME;
385 }
386
387 if (ACPI_FAILURE(status)) {
388 if (name_string) {
389 ACPI_FREE(name_string);
390 }
391 return_ACPI_STATUS(status);
392 }
393
394 *out_name_string = name_string;
395 *out_name_length = (u32) (aml_address - in_aml_address);
396
397 return_ACPI_STATUS(status);
398}
399