drivers/acpi/executer/exnames.c

   1
   2 /******************************************************************************
   3  *
   4  * Module Name: exnames - interpreter/scanner name load/execute
   5  *
   6  *****************************************************************************/
   7
   8 /*
   9  * Copyright (C) 2000 - 2006, R. Byron Moore
  10  * All rights reserved.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions, and the following disclaimer,
  17  *    without modification.
  18  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  19  *    substantially similar to the "NO WARRANTY" disclaimer below
  20  *    ("Disclaimer") and any redistribution must be conditioned upon
  21  *    including a substantially similar Disclaimer requirement for further
  22  *    binary redistribution.
  23  * 3. Neither the names of the above-listed copyright holders nor the names
  24  *    of any contributors may be used to endorse or promote products derived
  25  *    from this software without specific prior written permission.
  26  *
  27  * Alternatively, this software may be distributed under the terms of the
  28  * GNU General Public License ("GPL") version 2 as published by the Free
  29  * Software Foundation.
  30  *
  31  * NO WARRANTY
  32  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  33  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  34  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  35  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  36  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  37  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  38  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  39  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  40  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  41  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  42  * POSSIBILITY OF SUCH DAMAGES.
  43  */
  44
  45 #include <acpi/acpi.h>
  46 #include <acpi/acinterp.h>
  47 #include <acpi/amlcode.h>
  48
  49 #define _COMPONENT          ACPI_EXECUTER
  50 ACPI_MODULE_NAME("exnames")
  51
  52 /* Local prototypes */
  53 static char *acpi_ex_allocate_name_string(u32 prefix_count, u32 num_name_segs);
  54
  55 static acpi_status
  56 acpi_ex_name_segment(u8 ** in_aml_address, char *name_string);
  57
  58 /*******************************************************************************
  59  *
  60  * FUNCTION:    acpi_ex_allocate_name_string
  61  *
  62  * PARAMETERS:  prefix_count        - Count of parent levels. Special cases:
  63  *                                    (-1)==root,  0==none
  64  *              num_name_segs       - count of 4-character name segments
  65  *
  66  * RETURN:      A pointer to the allocated string segment.  This segment must
  67  *              be deleted by the caller.
  68  *
  69  * DESCRIPTION: Allocate a buffer for a name string. Ensure allocated name
  70  *              string is long enough, and set up prefix if any.
  71  *
  72  ******************************************************************************/
  73
  74 static char *acpi_ex_allocate_name_string(u32 prefix_count, u32 num_name_segs)
  75 {
  76         char *temp_ptr;
  77         char *name_string;
  78         u32 size_needed;
  79
  80         ACPI_FUNCTION_TRACE("ex_allocate_name_string");
  81
  82         /*
  83          * Allow room for all \ and ^ prefixes, all segments and a multi_name_prefix.
  84          * Also, one byte for the null terminator.
  85          * This may actually be somewhat longer than needed.
  86          */
  87         if (prefix_count == ACPI_UINT32_MAX) {
  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_MEM_ALLOCATE(size_needed);
 101         if (!name_string) {
 102                 ACPI_ERROR((AE_INFO,
 103                             "Could not allocate size %d", 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                 /* Set up multi prefixes   */
 123
 124                 *temp_ptr++ = AML_MULTI_NAME_PREFIX_OP;
 125                 *temp_ptr++ = (char)num_name_segs;
 126         } else if (2 == num_name_segs) {
 127                 /* Set up dual prefixes */
 128
 129                 *temp_ptr++ = AML_DUAL_NAME_PREFIX;
 130         }
 131
 132         /*
 133          * Terminate string following prefixes. acpi_ex_name_segment() will
 134          * append the segment(s)
 135          */
 136         *temp_ptr = 0;
 137
 138         return_PTR(name_string);
 139 }
 140
 141 /*******************************************************************************
 142  *
 143  * FUNCTION:    acpi_ex_name_segment
 144  *
 145  * PARAMETERS:  in_aml_address  - Pointer to the name in the AML code
 146  *              name_string     - Where to return the name. The name is appended
 147  *                                to any existing string to form a namepath
 148  *
 149  * RETURN:      Status
 150  *
 151  * DESCRIPTION: Extract an ACPI name (4 bytes) from the AML byte stream
 152  *
 153  ******************************************************************************/
 154
 155 static acpi_status acpi_ex_name_segment(u8 ** in_aml_address, char *name_string)
 156 {
 157         char *aml_address = (void *)*in_aml_address;
 158         acpi_status status = AE_OK;
 159         u32 index;
 160         char char_buf[5];
 161
 162         ACPI_FUNCTION_TRACE("ex_name_segment");
 163
 164         /*
 165          * If first character is a digit, then we know that we aren't looking at a
 166          * valid name segment
 167          */
 168         char_buf[0] = *aml_address;
 169
 170         if ('0' <= char_buf[0] && char_buf[0] <= '9') {
 171                 ACPI_ERROR((AE_INFO, "Invalid leading digit: %c", char_buf[0]));
 172                 return_ACPI_STATUS(AE_CTRL_PENDING);
 173         }
 174
 175         ACPI_DEBUG_PRINT((ACPI_DB_LOAD, "Bytes from stream:\n"));
 176
 177         for (index = 0;
 178              (index < ACPI_NAME_SIZE)
 179              && (acpi_ut_valid_acpi_character(*aml_address)); index++) {
 180                 char_buf[index] = *aml_address++;
 181                 ACPI_DEBUG_PRINT((ACPI_DB_LOAD, "%c\n", char_buf[index]));
 182         }
 183
 184         /* Valid name segment  */
 185
 186         if (index == 4) {
 187                 /* Found 4 valid characters */
 188
 189                 char_buf[4] = '\0';
 190
 191                 if (name_string) {
 192                         ACPI_STRCAT(name_string, char_buf);
 193                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 194                                           "Appended to - %s\n", name_string));
 195                 } else {
 196                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 197                                           "No Name string - %s\n", char_buf));
 198                 }
 199         } else if (index == 0) {
 200                 /*
 201                  * First character was not a valid name character,
 202                  * so we are looking at something other than a name.
 203                  */
 204                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 205                                   "Leading character is not alpha: %02Xh (not a name)\n",
 206                                   char_buf[0]));
 207                 status = AE_CTRL_PENDING;
 208         } else {
 209                 /*
 210                  * Segment started with one or more valid characters, but fewer than
 211                  * the required 4
 212                  */
 213                 status = AE_AML_BAD_NAME;
 214                 ACPI_ERROR((AE_INFO,
 215                             "Bad character %02x in name, at %p",
 216                             *aml_address, aml_address));
 217         }
 218
 219         *in_aml_address = ACPI_CAST_PTR(u8, aml_address);
 220         return_ACPI_STATUS(status);
 221 }
 222
 223 /*******************************************************************************
 224  *
 225  * FUNCTION:    acpi_ex_get_name_string
 226  *
 227  * PARAMETERS:  data_type           - Object type to be associated with this
 228  *                                    name
 229  *              in_aml_address      - Pointer to the namestring in the AML code
 230  *              out_name_string     - Where the namestring is returned
 231  *              out_name_length     - Length of the returned string
 232  *
 233  * RETURN:      Status, namestring and length
 234  *
 235  * DESCRIPTION: Extract a full namepath from the AML byte stream,
 236  *              including any prefixes.
 237  *
 238  ******************************************************************************/
 239
 240 acpi_status
 241 acpi_ex_get_name_string(acpi_object_type data_type,
 242                         u8 * in_aml_address,
 243                         char **out_name_string, u32 * out_name_length)
 244 {
 245         acpi_status status = AE_OK;
 246         u8 *aml_address = in_aml_address;
 247         char *name_string = NULL;
 248         u32 num_segments;
 249         u32 prefix_count = 0;
 250         u8 has_prefix = FALSE;
 251
 252         ACPI_FUNCTION_TRACE_PTR("ex_get_name_string", aml_address);
 253
 254         if (ACPI_TYPE_LOCAL_REGION_FIELD == data_type ||
 255             ACPI_TYPE_LOCAL_BANK_FIELD == data_type ||
 256             ACPI_TYPE_LOCAL_INDEX_FIELD == data_type) {
 257                 /* Disallow prefixes for types associated with field_unit names */
 258
 259                 name_string = acpi_ex_allocate_name_string(0, 1);
 260                 if (!name_string) {
 261                         status = AE_NO_MEMORY;
 262                 } else {
 263                         status =
 264                             acpi_ex_name_segment(&aml_address, name_string);
 265                 }
 266         } else {
 267                 /*
 268                  * data_type is not a field name.
 269                  * Examine first character of name for root or parent prefix operators
 270                  */
 271                 switch (*aml_address) {
 272                 case AML_ROOT_PREFIX:
 273
 274                         ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
 275                                           "root_prefix(\\) at %p\n",
 276                                           aml_address));
 277
 278                         /*
 279                          * Remember that we have a root_prefix --
 280                          * see comment in acpi_ex_allocate_name_string()
 281                          */
 282                         aml_address++;
 283                         prefix_count = ACPI_UINT32_MAX;
 284                         has_prefix = TRUE;
 285                         break;
 286
 287                 case AML_PARENT_PREFIX:
 288
 289                         /* Increment past possibly multiple parent prefixes */
 290
 291                         do {
 292                                 ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
 293                                                   "parent_prefix (^) at %p\n",
 294                                                   aml_address));
 295
 296                                 aml_address++;
 297                                 prefix_count++;
 298
 299                         } while (*aml_address == AML_PARENT_PREFIX);
 300
 301                         has_prefix = TRUE;
 302                         break;
 303
 304                 default:
 305
 306                         /* Not a prefix character */
 307
 308                         break;
 309                 }
 310
 311                 /* Examine first character of name for name segment prefix operator */
 312
 313                 switch (*aml_address) {
 314                 case AML_DUAL_NAME_PREFIX:
 315
 316                         ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
 317                                           "dual_name_prefix at %p\n",
 318                                           aml_address));
 319
 320                         aml_address++;
 321                         name_string =
 322                             acpi_ex_allocate_name_string(prefix_count, 2);
 323                         if (!name_string) {
 324                                 status = AE_NO_MEMORY;
 325                                 break;
 326                         }
 327
 328                         /* Indicate that we processed a prefix */
 329
 330                         has_prefix = TRUE;
 331
 332                         status =
 333                             acpi_ex_name_segment(&aml_address, name_string);
 334                         if (ACPI_SUCCESS(status)) {
 335                                 status =
 336                                     acpi_ex_name_segment(&aml_address,
 337                                                          name_string);
 338                         }
 339                         break;
 340
 341                 case AML_MULTI_NAME_PREFIX_OP:
 342
 343                         ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
 344                                           "multi_name_prefix at %p\n",
 345                                           aml_address));
 346
 347                         /* Fetch count of segments remaining in name path */
 348
 349                         aml_address++;
 350                         num_segments = *aml_address;
 351
 352                         name_string =
 353                             acpi_ex_allocate_name_string(prefix_count,
 354                                                          num_segments);
 355                         if (!name_string) {
 356                                 status = AE_NO_MEMORY;
 357                                 break;
 358                         }
 359
 360                         /* Indicate that we processed a prefix */
 361
 362                         aml_address++;
 363                         has_prefix = TRUE;
 364
 365                         while (num_segments &&
 366                                (status =
 367                                 acpi_ex_name_segment(&aml_address,
 368                                                      name_string)) == AE_OK) {
 369                                 num_segments--;
 370                         }
 371
 372                         break;
 373
 374                 case 0:
 375
 376                         /* null_name valid as of 8-12-98 ASL/AML Grammar Update */
 377
 378                         if (prefix_count == ACPI_UINT32_MAX) {
 379                                 ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
 380                                                   "name_seg is \"\\\" followed by NULL\n"));
 381                         }
 382
 383                         /* Consume the NULL byte */
 384
 385                         aml_address++;
 386                         name_string =
 387                             acpi_ex_allocate_name_string(prefix_count, 0);
 388                         if (!name_string) {
 389                                 status = AE_NO_MEMORY;
 390                                 break;
 391                         }
 392
 393                         break;
 394
 395                 default:
 396
 397                         /* Name segment string */
 398
 399                         name_string =
 400                             acpi_ex_allocate_name_string(prefix_count, 1);
 401                         if (!name_string) {
 402                                 status = AE_NO_MEMORY;
 403                                 break;
 404                         }
 405
 406                         status =
 407                             acpi_ex_name_segment(&aml_address, name_string);
 408                         break;
 409                 }
 410         }
 411
 412         if (AE_CTRL_PENDING == status && has_prefix) {
 413                 /* Ran out of segments after processing a prefix */
 414
 415                 ACPI_ERROR((AE_INFO, "Malformed Name at %p", name_string));
 416                 status = AE_AML_BAD_NAME;
 417         }
 418
 419         if (ACPI_FAILURE(status)) {
 420                 if (name_string) {
 421                         ACPI_MEM_FREE(name_string);
 422                 }
 423                 return_ACPI_STATUS(status);
 424         }
 425
 426         *out_name_string = name_string;
 427         *out_name_length = (u32) (aml_address - in_aml_address);
 428
 429         return_ACPI_STATUS(status);
 430 }