1/******************************************************************************
2 *
3 * Module Name: exnames - interpreter/scanner name load/execute
4 *
5 *****************************************************************************/
6
7/*
8 * Copyright (C) 2000 - 2015, 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 "acinterp.h"
47#include "amlcode.h"
48
49#define _COMPONENT          ACPI_EXECUTER
50ACPI_MODULE_NAME("exnames")
51
52/* Local prototypes */
53static char *acpi_ex_allocate_name_string(u32 prefix_count, u32 num_name_segs);
54
55static acpi_status acpi_ex_name_segment(u8 **in_aml_address, char *name_string);
56
57/*******************************************************************************
58 *
59 * FUNCTION:    acpi_ex_allocate_name_string
60 *
61 * PARAMETERS:  prefix_count        - Count of parent levels. Special cases:
62 *                                    (-1)==root,  0==none
63 *              num_name_segs       - count of 4-character name segments
64 *
65 * RETURN:      A pointer to the allocated string segment. This segment must
66 *              be deleted by the caller.
67 *
68 * DESCRIPTION: Allocate a buffer for a name string. Ensure allocated name
69 *              string is long enough, and set up prefix if any.
70 *
71 ******************************************************************************/
72
73static char *acpi_ex_allocate_name_string(u32 prefix_count, u32 num_name_segs)
74{
75	char *temp_ptr;
76	char *name_string;
77	u32 size_needed;
78
79	ACPI_FUNCTION_TRACE(ex_allocate_name_string);
80
81	/*
82	 * Allow room for all \ and ^ prefixes, all segments and a multi_name_prefix.
83	 * Also, one byte for the null terminator.
84	 * This may actually be somewhat longer than needed.
85	 */
86	if (prefix_count == ACPI_UINT32_MAX) {
87
88		/* Special case for root */
89
90		size_needed = 1 + (ACPI_NAME_SIZE * num_name_segs) + 2 + 1;
91	} else {
92		size_needed =
93		    prefix_count + (ACPI_NAME_SIZE * num_name_segs) + 2 + 1;
94	}
95
96	/*
97	 * Allocate a buffer for the name.
98	 * This buffer must be deleted by the caller!
99	 */
100	name_string = ACPI_ALLOCATE(size_needed);
101	if (!name_string) {
102		ACPI_ERROR((AE_INFO,
103			    "Could not allocate size %u", size_needed));
104		return_PTR(NULL);
105	}
106
107	temp_ptr = name_string;
108
109	/* Set up Root or Parent prefixes if needed */
110
111	if (prefix_count == ACPI_UINT32_MAX) {
112		*temp_ptr++ = AML_ROOT_PREFIX;
113	} else {
114		while (prefix_count--) {
115			*temp_ptr++ = AML_PARENT_PREFIX;
116		}
117	}
118
119	/* Set up Dual or Multi prefixes if needed */
120
121	if (num_name_segs > 2) {
122
123		/* Set up multi prefixes   */
124
125		*temp_ptr++ = AML_MULTI_NAME_PREFIX_OP;
126		*temp_ptr++ = (char)num_name_segs;
127	} else if (2 == num_name_segs) {
128
129		/* Set up dual prefixes */
130
131		*temp_ptr++ = AML_DUAL_NAME_PREFIX;
132	}
133
134	/*
135	 * Terminate string following prefixes. acpi_ex_name_segment() will
136	 * append the segment(s)
137	 */
138	*temp_ptr = 0;
139
140	return_PTR(name_string);
141}
142
143/*******************************************************************************
144 *
145 * FUNCTION:    acpi_ex_name_segment
146 *
147 * PARAMETERS:  in_aml_address  - Pointer to the name in the AML code
148 *              name_string     - Where to return the name. The name is appended
149 *                                to any existing string to form a namepath
150 *
151 * RETURN:      Status
152 *
153 * DESCRIPTION: Extract an ACPI name (4 bytes) from the AML byte stream
154 *
155 ******************************************************************************/
156
157static acpi_status acpi_ex_name_segment(u8 ** in_aml_address, char *name_string)
158{
159	char *aml_address = (void *)*in_aml_address;
160	acpi_status status = AE_OK;
161	u32 index;
162	char char_buf[5];
163
164	ACPI_FUNCTION_TRACE(ex_name_segment);
165
166	/*
167	 * If first character is a digit, then we know that we aren't looking at a
168	 * valid name segment
169	 */
170	char_buf[0] = *aml_address;
171
172	if ('0' <= char_buf[0] && char_buf[0] <= '9') {
173		ACPI_ERROR((AE_INFO, "Invalid leading digit: %c", char_buf[0]));
174		return_ACPI_STATUS(AE_CTRL_PENDING);
175	}
176
177	ACPI_DEBUG_PRINT((ACPI_DB_LOAD, "Bytes from stream:\n"));
178
179	for (index = 0;
180	     (index < ACPI_NAME_SIZE)
181	     && (acpi_ut_valid_acpi_char(*aml_address, 0)); index++) {
182		char_buf[index] = *aml_address++;
183		ACPI_DEBUG_PRINT((ACPI_DB_LOAD, "%c\n", char_buf[index]));
184	}
185
186	/* Valid name segment  */
187
188	if (index == 4) {
189
190		/* Found 4 valid characters */
191
192		char_buf[4] = '\0';
193
194		if (name_string) {
195			ACPI_STRCAT(name_string, char_buf);
196			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
197					  "Appended to - %s\n", name_string));
198		} else {
199			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
200					  "No Name string - %s\n", char_buf));
201		}
202	} else if (index == 0) {
203		/*
204		 * First character was not a valid name character,
205		 * so we are looking at something other than a name.
206		 */
207		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
208				  "Leading character is not alpha: %02Xh (not a name)\n",
209				  char_buf[0]));
210		status = AE_CTRL_PENDING;
211	} else {
212		/*
213		 * Segment started with one or more valid characters, but fewer than
214		 * the required 4
215		 */
216		status = AE_AML_BAD_NAME;
217		ACPI_ERROR((AE_INFO,
218			    "Bad character 0x%02x in name, at %p",
219			    *aml_address, aml_address));
220	}
221
222	*in_aml_address = ACPI_CAST_PTR(u8, aml_address);
223	return_ACPI_STATUS(status);
224}
225
226/*******************************************************************************
227 *
228 * FUNCTION:    acpi_ex_get_name_string
229 *
230 * PARAMETERS:  data_type           - Object type to be associated with this
231 *                                    name
232 *              in_aml_address      - Pointer to the namestring in the AML code
233 *              out_name_string     - Where the namestring is returned
234 *              out_name_length     - Length of the returned string
235 *
236 * RETURN:      Status, namestring and length
237 *
238 * DESCRIPTION: Extract a full namepath from the AML byte stream,
239 *              including any prefixes.
240 *
241 ******************************************************************************/
242
243acpi_status
244acpi_ex_get_name_string(acpi_object_type data_type,
245			u8 * in_aml_address,
246			char **out_name_string, u32 * out_name_length)
247{
248	acpi_status status = AE_OK;
249	u8 *aml_address = in_aml_address;
250	char *name_string = NULL;
251	u32 num_segments;
252	u32 prefix_count = 0;
253	u8 has_prefix = FALSE;
254
255	ACPI_FUNCTION_TRACE_PTR(ex_get_name_string, aml_address);
256
257	if (ACPI_TYPE_LOCAL_REGION_FIELD == data_type ||
258	    ACPI_TYPE_LOCAL_BANK_FIELD == data_type ||
259	    ACPI_TYPE_LOCAL_INDEX_FIELD == data_type) {
260
261		/* Disallow prefixes for types associated with field_unit names */
262
263		name_string = acpi_ex_allocate_name_string(0, 1);
264		if (!name_string) {
265			status = AE_NO_MEMORY;
266		} else {
267			status =
268			    acpi_ex_name_segment(&aml_address, name_string);
269		}
270	} else {
271		/*
272		 * data_type is not a field name.
273		 * Examine first character of name for root or parent prefix operators
274		 */
275		switch (*aml_address) {
276		case AML_ROOT_PREFIX:
277
278			ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
279					  "RootPrefix(\\) at %p\n",
280					  aml_address));
281
282			/*
283			 * Remember that we have a root_prefix --
284			 * see comment in acpi_ex_allocate_name_string()
285			 */
286			aml_address++;
287			prefix_count = ACPI_UINT32_MAX;
288			has_prefix = TRUE;
289			break;
290
291		case AML_PARENT_PREFIX:
292
293			/* Increment past possibly multiple parent prefixes */
294
295			do {
296				ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
297						  "ParentPrefix (^) at %p\n",
298						  aml_address));
299
300				aml_address++;
301				prefix_count++;
302
303			} while (*aml_address == AML_PARENT_PREFIX);
304
305			has_prefix = TRUE;
306			break;
307
308		default:
309
310			/* Not a prefix character */
311
312			break;
313		}
314
315		/* Examine first character of name for name segment prefix operator */
316
317		switch (*aml_address) {
318		case AML_DUAL_NAME_PREFIX:
319
320			ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
321					  "DualNamePrefix at %p\n",
322					  aml_address));
323
324			aml_address++;
325			name_string =
326			    acpi_ex_allocate_name_string(prefix_count, 2);
327			if (!name_string) {
328				status = AE_NO_MEMORY;
329				break;
330			}
331
332			/* Indicate that we processed a prefix */
333
334			has_prefix = TRUE;
335
336			status =
337			    acpi_ex_name_segment(&aml_address, name_string);
338			if (ACPI_SUCCESS(status)) {
339				status =
340				    acpi_ex_name_segment(&aml_address,
341							 name_string);
342			}
343			break;
344
345		case AML_MULTI_NAME_PREFIX_OP:
346
347			ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
348					  "MultiNamePrefix at %p\n",
349					  aml_address));
350
351			/* Fetch count of segments remaining in name path */
352
353			aml_address++;
354			num_segments = *aml_address;
355
356			name_string =
357			    acpi_ex_allocate_name_string(prefix_count,
358							 num_segments);
359			if (!name_string) {
360				status = AE_NO_MEMORY;
361				break;
362			}
363
364			/* Indicate that we processed a prefix */
365
366			aml_address++;
367			has_prefix = TRUE;
368
369			while (num_segments &&
370			       (status =
371				acpi_ex_name_segment(&aml_address,
372						     name_string)) == AE_OK) {
373				num_segments--;
374			}
375
376			break;
377
378		case 0:
379
380			/* null_name valid as of 8-12-98 ASL/AML Grammar Update */
381
382			if (prefix_count == ACPI_UINT32_MAX) {
383				ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
384						  "NameSeg is \"\\\" followed by NULL\n"));
385			}
386
387			/* Consume the NULL byte */
388
389			aml_address++;
390			name_string =
391			    acpi_ex_allocate_name_string(prefix_count, 0);
392			if (!name_string) {
393				status = AE_NO_MEMORY;
394				break;
395			}
396
397			break;
398
399		default:
400
401			/* Name segment string */
402
403			name_string =
404			    acpi_ex_allocate_name_string(prefix_count, 1);
405			if (!name_string) {
406				status = AE_NO_MEMORY;
407				break;
408			}
409
410			status =
411			    acpi_ex_name_segment(&aml_address, name_string);
412			break;
413		}
414	}
415
416	if (AE_CTRL_PENDING == status && has_prefix) {
417
418		/* Ran out of segments after processing a prefix */
419
420		ACPI_ERROR((AE_INFO, "Malformed Name at %p", name_string));
421		status = AE_AML_BAD_NAME;
422	}
423
424	if (ACPI_FAILURE(status)) {
425		if (name_string) {
426			ACPI_FREE(name_string);
427		}
428		return_ACPI_STATUS(status);
429	}
430
431	*out_name_string = name_string;
432	*out_name_length = (u32) (aml_address - in_aml_address);
433
434	return_ACPI_STATUS(status);
435}
436